KVM: arm64: Add support for hypercall services selection
Subsystems (5)
v6 cover KVM: arm64: Add support for hypercall services selection
Hello,
Continuing the discussion from [1], the series tries to add support for the userspace to elect the hypercall services that it wishes to expose to the guest, rather than the guest discovering them unconditionally. The idea employed by the series was taken from
[1] as suggested by Marc Z.
In a broad sense, the concept is similar to the current implementation of PSCI interface- create a 'firmware psuedo-register' to handle the firmware revisions. The series extends this idea to all the other hypercalls such as TRNG (True Random Number Generator), PV_TIME (Paravirtualized Time), and PTP (Precision Time protocol).
For better categorization and future scaling, these firmware registers are categorized based on the service call owners. Also, unlike the existing firmware psuedo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers holds an upper-limit of the features supported by each one of them. It's expected that the userspace discover the features provided by each register via GET_ONE_REG, and writeback the desired values using SET_ONE_REG. KVM allows this modification only until the VM has started.
Some of the standard function-ids, such as ARM_SMCCC_VERSION_FUNC_ID, need not be associated with a feature bit. For such ids, the series introduced an allowed-list (in kvm_hvc_call_default_allowed()), that holds all such ids. As a result, the functions that are not elected by userspace, or if they are not a part of this allowed-list, will be denied for when the guests invoke them.
Older VMMs can simply ignore this interface and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
The patches are based off of mainline kernel 5.18-rc3, with the selftest patches from [2] applied.
Patch-1 factors out the non-PSCI related interface from psci.c to hypercalls.c, as the series would extend the list in the upcoming patches.
Patch-2 sets up the framework for the bitmap firmware psuedo-registers. It includes read/write support for the registers, and a helper to check if a particular hypercall service is supported for the guest. It also adds the register KVM_REG_ARM_STD_HYP_BMAP to support ARM's standard secure services.
Patch-3 introduces the firmware register, KVM_REG_ARM_STD_HYP_BMAP, which holds the standard hypervisor services (such as PV_TIME).
Patch-4 introduces the firmware register, KVM_REG_ARM_VENDOR_HYP_BMAP, which holds the vendor specific hypercall services.
Patch-5,6 Add the necessary documentation for the newly added firmware registers.
Patch-7 imports the SMCCC definitions from linux/arm-smccc.h into tools/ for further use in selftests.
Patch-8 adds the selftest to test the guest (using 'hvc') and userspace interfaces (SET/GET_ONE_REG).
Patch-9 adds these firmware registers into the get-reg-list selftest.
[1]: https://lore.kernel.org/kvmarm/[email protected]/T/
[2]: https://lore.kernel.org/all/[email protected]/
Regards,
Raghavendra
v5 -> v6:
Addressed the comments by Marc and Gavin:
- Bitmaps are represented using 'unsigned long' inctead of 'u64' (Marc).
- Replaced the array holding the allowed-list, hvc_func_default_allowed_list[], which looked up the func_id using a loop, with a switch-case statement (Marc).
- kvm_arm_set_fw_reg_bmap() now always returns -EBUSY for any 'write' of the bitmap value after the VM has started running. Documentation is adjusted accordingly (Marc).
- kvm_psci_func_id_is_valid() is moved from an inline function to kvm/psci.c (Marc).
- Merged ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID into bit-0 of the vendor hypervisor firmware register (Gavin).
- Macro optimizations and replace arg0 with arg1 (to comply with KVM convention) in hypercalls.c selftest (Gavin).
- Dropped the patch v5 10/10 (Add KVM_REG_ARM_FW_REG(3) to get-reg-list) as it was already uploaded by Andrew.
- Fixed typos
v4 -> v5:
Addressed comments by Oliver (thank you!):
- Rebased the series to accommodate ARM_SMCCC_ARCH_WORKAROUND_3 and PSCI 1.1 changes, and capturing VM's first run.
- Removed the patches related to register scoping (v4 02/13 and 03/13). I plan to re-introduce them in its own series.
- Dropped the patch that captures VM's first run.
- Moved the bitmap feature firmware registers to its own CORPOC space (0x0016).
- Move the KVM_REG_ARM_*_BIT_MAX definitions from uapi header to internal header (arm_hypercalls.h).
- Renamed the hypercall descriptor to 'struct kvm_smccc_features', and kvm_hvc_call_supported() to kvm_hvc_call_allowed().
- Introduced an allowed-list to hold the function-ids that aren't represented by feature-bits.
- Introduced kvm_psci_func_id_is_valid() to check if a given function-id is a valid PSCI id, which is used in kvm_hvc_call_allowed().
- Introduced KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT as bit-0 of KVM_REG_ARM_VENDOR_HYP_BMAP register and KVM_REG_ARM_VENDOR_HYP_BIT_PTP is moved to bit-1.
- Updated the arm-smccc.h import to include the definition of ARM_SMCCC_ARCH_WORKAROUND_3.
- Introduced the KVM_REG_ARM_FW_FEAT_BMAP COPROC definition to get-reg-list selftest.
- Created a new patch to include KVM_REG_ARM_FW_REG(3) in get-reg-list.
v3 -> v4
Addressed comments and took suggestions by Reiji, Oliver, Marc, Sean and Jim:
- Renamed and moved the VM has run once check to arm64.
- Introduced the capability to dynamically modify the register encodings to include the scope information.
- Replaced mutex_lock with READ_ONCE and WRITE_ONCE when the bitmaps are accessed.
- The hypercalls selftest re-runs with KVM_CAP_ARM_REG_SCOPE enabled.
v2 -> v3
Addressed comments by Marc and Andrew:
- Dropped kvm_vcpu_has_run_once() implementation.
- Redifined kvm_vm_has_run_once() as kvm_vm_has_started() in the core KVM code that introduces a new field, 'vm_started', to track this.
- KVM_CAP_ARM_HVC_FW_REG_BMAP returns the number of psuedo-firmware bitmap registers upon a 'read'. Support for 'write' removed.
- Removed redundant spinlock, 'fw_reg_bmap_enabled' fields from the hypercall descriptor structure.
- A separate sub-struct to hold the bitmap info is removed. The bitmap info is directly stored in the hypercall descriptor structure (struct kvm_hvc_desc).
v1 -> v2
Addressed comments by Oliver (thanks!):
- Introduced kvm_vcpu_has_run_once() and kvm_vm_has_run_once() in the core kvm code, rather than relying on ARM specific vcpu->arch.has_run_once.
- Writing to KVM_REG_ARM_PSCI_VERSION is done in hypercalls.c itself, rather than separating out to psci.c.
- Introduced KVM_CAP_ARM_HVC_FW_REG_BMAP to enable the extension.
- Tracks the register accesses from VMM to decide whether to sanitize a register or not, as opposed to sanitizing upon the first 'write' in v1.
- kvm_hvc_call_supported() is implemented using a direct switch-case statement, instead of looping over all the registers to pick the register for the function-id.
- Replaced the register bit definitions with #defines, instead of enums.
- Removed the patch v1-06/08 that imports the firmware register definitions as it's not needed.
- Separated out the documentations in its own patch, and the renaming of hypercalls.rst to psci.rst into another patch.
- Add the new firmware registers to get-reg-list KVM selftest.
v1: https://lore.kernel.org/kvmarm/[email protected]/
v2: https://lore.kernel.org/kvmarm/[email protected]/
v3: https://lore.kernel.org/linux-arm-kernel/[email protected]/
v4: https://lore.kernel.org/lkml/[email protected]/
v5: https://lore.kernel.org/lkml/[email protected]/
Raghavendra Rao Ananta (9):
KVM: arm64: Factor out firmware register handling from psci.c
KVM: arm64: Setup a framework for hypercall bitmap firmware registers
KVM: arm64: Add standard hypervisor firmware register
KVM: arm64: Add vendor hypervisor firmware register
Docs: KVM: Rename psci.rst to hypercalls.rst
Docs: KVM: Add doc for the bitmap firmware registers
tools: Import ARM SMCCC definitions
selftests: KVM: aarch64: Introduce hypercall ABI test
selftests: KVM: aarch64: Add the bitmap firmware registers to
get-reg-list
Documentation/virt/kvm/api.rst | 16 + Documentation/virt/kvm/arm/hypercalls.rst | 135 +++++++ Documentation/virt/kvm/arm/psci.rst | 77 ---- arch/arm64/include/asm/kvm_host.h | 16 + arch/arm64/include/uapi/asm/kvm.h | 16 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 10 +- arch/arm64/kvm/hypercalls.c | 313 +++++++++++++++- arch/arm64/kvm/psci.c | 186 +--------- include/kvm/arm_hypercalls.h | 17 + include/kvm/arm_psci.h | 9 +- tools/include/linux/arm-smccc.h | 193 ++++++++++ tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/get-reg-list.c | 8 + .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++ 16 files changed, 1065 insertions(+), 269 deletions(-) create mode 100644 Documentation/virt/kvm/arm/hypercalls.rst delete mode 100644 Documentation/virt/kvm/arm/psci.rst create mode 100644 tools/include/linux/arm-smccc.h create mode 100644 tools/testing/selftests/kvm/aarch64/hypercalls.c
Signature · 1 line
2.36.0.rc2.479.g8af0fa9b8e-goog
PATCH v6 1/9 KVM: arm64: Factor out firmware register handling from psci.c
Common hypercall firmware register handing is currently employed by psci.c. Since the upcoming patches add more of these registers, it's better to move the generic handling to hypercall.c for a cleaner presentation.
While we are at it, collect all the firmware registers under fw_reg_ids[] to help implement kvm_arm_get_fw_num_regs() and kvm_arm_copy_fw_reg_indices() in a generic way. Also, define KVM_REG_FEATURE_LEVEL_MASK using a GENMASK instead.
No functional change intended.
--- arch/arm64/kvm/guest.c | 2 +- arch/arm64/kvm/hypercalls.c | 185 +++++++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 183 ---------------------------------- include/kvm/arm_hypercalls.h | 7 ++ include/kvm/arm_psci.h | 7 -- 5 files changed, 193 insertions(+), 191 deletions(-)
arch/arm64/kvm/guest.c +1 -1
@@ -18,7 +18,7 @@#include <linux/string.h> #include <linux/vmalloc.h> #include <linux/fs.h> -#include <kvm/arm_psci.h> +#include <kvm/arm_hypercalls.h> #include <asm/cputype.h> #include <linux/uaccess.h> #include <asm/fpsimd.h>
arch/arm64/kvm/hypercalls.c +185 -0
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arch/arm64/kvm/psci.c +0 -183
186 lines not on this page · raw message
include/kvm/arm_hypercalls.h +7 -0
@@ -40,4 +40,11 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu, vcpu_set_reg(vcpu, 3, a3); } +struct kvm_one_reg ; + +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu); +int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices); +int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg); +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg); +#endif
include/kvm/arm_psci.h +0 -7
@@ -39,11 +39,4 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)int kvm_psci_call (struct kvm_vcpu *vcpu); -struct kvm_one_reg ; - -int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu); -int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices); -int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg); -int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg); -#endif /* __KVM_ARM_PSCI_H__ */
Signature · 1 line
2.36.0.rc2.479.g8af0fa9b8e-goog
PATCH v6 2/9 KVM: arm64: Setup a framework for hypercall bitmap firmware registers
In reply to Raghavendra Rao AnantaKVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.
These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via GET_ONE_REG, and write back the desired values using SET_ONE_REG. KVM allows this modification only until the VM has started.
Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed in kvm_hvc_call_default_allowed, will be returned as SMCCC_RET_NOT_SUPPORTED to the guest.
Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kvm_host.h +12 -0
@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { }; +/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +struct kvm_arch {struct kvm_s2_mmu mmu;
@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {
arch/arm64/include/uapi/asm/kvm.h +9 -0
@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
arch/arm64/kvm/arm.c +1 -0
@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:
arch/arm64/kvm/guest.c +6 -2
@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }
@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }
arch/arm64/kvm/hypercalls.c +94 -0
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arch/arm64/kvm/psci.c +13 -0
@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } } + +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true; + +return false; +}
include/kvm/arm_hypercalls.h +6 -0
@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)
@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);
include/kvm/arm_psci.h +1 -1
@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu) return KVM_ARM_PSCI_0_1; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */
Signature · 6 lines
2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Hi Raghu,
Quoted 266 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)arch/arm64/include/asm/kvm_host.h +12
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { }; +/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +69
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); } +static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} + +static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ;
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 340
Quoted 10 lines
arch/arm64/kvm/hypercalls.c +10
-0+break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features) +return -EINVAL ; + +mutex_lock (&kvm->lock);
Why don't you check if the register value will be modified before getting the lock ? (then there is nothing to do)
It would help reduce unnecessary serialization for live migration (even without the vm-scoped register capability).
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 346
Quoted 6 lines
arch/arm64/kvm/hypercalls.c +6
-0+ +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + }
I just would like to make sure that you are sure that existing userspace you know will not run KVM_RUN for any vCPUs until KVM_SET_ONE_REG is complete for all vCPUs (even for migration), correct ?
Quoted 27 lines
arch/arm64/kvm/hypercalls.c +9
-0+ +WRITE_ONCE (*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +0
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } }
arch/arm64/kvm/psci.c int kvm_psci_call(struct kvm_vcpu *vcpu) · line 448
Quoted 10 lines
arch/arm64/kvm/psci.c +10
-0+ +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true;
For PSCI 0.1, the function checks if the funct_id is valid for the vCPU (according to the vCPU's PSCI version).
For other version of PSCI, the function doesn't care the vCPU's PSCI version (although supported functions depend on the PSCI version and not all of them are defined yet, the code returns true as long as the function id is within the reserved PSCI function id range).
So, the behavior appears to be inconsistent.
Shouldn't it return the validity of the function id according to the vCPU's psci version for non-PSCI 0.1 case as well ? (Otherwise, shouldn't it return true if the function id is valid for any of the PSCI versions ?)
Thanks,
Reiji
Quoted 41 lines
arch/arm64/kvm/psci.c +3
-0+ +return false; +}include/kvm/arm_hypercalls.h +6
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +1
-2@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu) return KVM_ARM_PSCI_0_1; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */ --
Quoted 2 lines
2.36.0.rc2.479.g8af0fa9b8e-goog
_______________________________________________
kvmarm mailing list
[email protected]
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Hi Reiji,
Quoted 278 lines · Reiji Watanabe
Hi Raghu,
Quoted 273 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)arch/arm64/include/asm/kvm_host.h +12
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { }; +/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +76
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); } +static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} + +static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features)
Quoted 9 lines
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 340
Quoted 3 lines
arch/arm64/kvm/hypercalls.c +3
-0+return -EINVAL ; + +mutex_lock (&kvm->lock);Why don't you check if the register value will be modified before getting the lock ? (then there is nothing to do)
It would help reduce unnecessary serialization for live migration (even without the vm-scoped register capability).
That was the case until v5. Since v6, we return -EBUSY unconditionally regardless of the incoming value. See Marc's comments in [1].
Quoted 9 lines
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 346
Quoted 8 lines
arch/arm64/kvm/hypercalls.c +6
-0+ +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + }
Quoted 5 lines
I just would like to make sure that you are sure that existing userspace you know will not run
KVM_RUNfor any vCPUs untilKVM_SET_ONE_REGis complete for all vCPUs (even for migration), correct ?
Since v6, that is something that we are leaving with the userspace to synchronize. See [1].
Quoted 43 lines
Quoted 28 lines
arch/arm64/kvm/hypercalls.c +9
-0+ +WRITE_ONCE (*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +0
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } }arch/arm64/kvm/psci.c int kvm_psci_call(struct kvm_vcpu *vcpu) · line 448
Quoted 10 lines
arch/arm64/kvm/psci.c +10
-0+ +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true;For PSCI 0.1, the function checks if the
funct_idis valid for the vCPU (according to the vCPU's PSCI version).
For other version of PSCI, the function doesn't care the vCPU's PSCI version (although supported functions depend on the PSCI
Quoted 9 lines
version and not all of them are defined yet, the code returns true as long as the function id is within the reserved PSCI function id range).
So, the behavior appears to be inconsistent.
Shouldn't it return the validity of the function id according to the vCPU's psci version for non-PSCI 0.1 case as well ? (Otherwise, shouldn't it return true if the function id is valid for any of the PSCI versions ?)
Well, PSCI 1.0 is somewhat of an odd implementation. It doesn't comply with the SMCCC, hence needed some special handling. Only two func_ids are currently supported by KVM, and we just check for each. The second 'if' statement is for all the PSCI versions >= 0.2. Thankfully, the specification defines a range of acceptable PSCI func_ids.
If it's confusing, I can add a comment above the second 'if' that it's for all PSCI versions >= 0.2.
Quoted 3 lines
Thanks,
Reiji
Thank you.
Raghavendra
[1]: https://lore.kernel.org/lkml/[email protected]/
Quoted 37 lines
Quoted 37 lines
arch/arm64/kvm/psci.c +3
-0+ +return false; +}include/kvm/arm_hypercalls.h +6
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +0
-0@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)return KVM_ARM_PSCI_0_1 ; }
Quoted 8 lines
Quoted 8 lines
include/kvm/arm_psci.h +1
-2-int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */ --2.36.0.rc2.479.g8af0fa9b8e-goog
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Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Hi Raghu,
Quoted 291 lines · Raghavendra Rao Ananta
Hi Reiji,
Quoted 278 lines · Reiji Watanabe
Hi Raghu,
Quoted 273 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)arch/arm64/include/asm/kvm_host.h +12
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { }; +/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +76
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); } +static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} + +static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features)Quoted 9 lines
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 340
Quoted 3 lines
arch/arm64/kvm/hypercalls.c +3
-0+return -EINVAL ; + +mutex_lock (&kvm->lock);Why don't you check if the register value will be modified before getting the lock ? (then there is nothing to do)
It would help reduce unnecessary serialization for live migration (even without the vm-scoped register capability).
Quoted 5 lines
That was the case until v5. Since v6, we return
-EBUSYunconditionally regardless of the incoming value. See Marc's comments in [1].That was the case until v5. Since v6, we return
-EBUSYunconditionally regardless of the incoming value. See Marc's comments in [1].
Even with that, the function could do below to avoid
the unnecessary serialization.
(I would expect mostly the function returns before getting the lock)
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags))
return -EBUSY;
if (val == *fw_reg_bmap)
return 0;
mutex_lock(&kvm->lock);
<...>Quoted 9 lines
Quoted 9 lines
Quoted 8 lines
arch/arm64/kvm/hypercalls.c +6
-0+ +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + }
Quoted 7 lines
Quoted 5 lines
I just would like to make sure that you are sure that existing userspace you know will not run
KVM_RUNfor any vCPUs untilKVM_SET_ONE_REGis complete for all vCPUs (even for migration), correct ?Since v6, that is something that we are leaving with the userspace to synchronize. See [1].
Understood.
Quoted 51 lines
Quoted 42 lines
Quoted 27 lines
arch/arm64/kvm/hypercalls.c +9
-0+o + WRITE_ONCE(*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +0
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } }arch/arm64/kvm/psci.c int kvm_psci_call(struct kvm_vcpu *vcpu) · line 448
Quoted 10 lines
arch/arm64/kvm/psci.c +10
-0+ +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true;For PSCI 0.1, the function checks if the
funct_idis valid for the vCPU (according to the vCPU's PSCI version).
For other version of PSCI, the function doesn't care the vCPU's PSCI version (although supported functions depend on the PSCIQuoted 9 lines
version and not all of them are defined yet, the code returns true as long as the function id is within the reserved PSCI function id range).
So, the behavior appears to be inconsistent.
Shouldn't it return the validity of the function id according to the vCPU's psci version for non-PSCI 0.1 case as well ? (Otherwise, shouldn't it return true if the function id is valid for any of the PSCI versions ?)
Quoted 4 lines
Well, PSCI 1.0 is somewhat of an odd implementation. It doesn't comply
with the SMCCC, hence needed some special handling. Only twofunc_ids> are currently supported by KVM, and we just check for each. The second 'if' statement is for all the PSCI versions >= 0.2. Thankfully, the
specification defines a range of acceptable PSCIfunc_ids.
I understand PSCI 0.1 is different from PSCI 0.2 or newer versions. But, my question is: What would you consider "valid" psci function id ? It seems that the function checks whether or not the func_id is valid on the vCPU for PSCI 0.1, and checks whether or not the func_id is a PSCI function id for vCPU with PSCI 0.2 or newer.
I understand either one works for your purpose, but I would think the behavior should be consistent.
Thanks,
Reiji
Quoted 47 lines
If it's confusing, I can add a comment above the second 'if' that it's for all PSCI versions >= 0.2.
Quoted 3 lines
Thanks,
ReijiThank you.
Raghavendra[1]: https://lore.kernel.org/lkml/[email protected]/
Quoted 37 lines
Quoted 37 lines
arch/arm64/kvm/psci.c +3
-0+ +return false; +}include/kvm/arm_hypercalls.h +6
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +0
-0@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)return KVM_ARM_PSCI_0_1 ; }
Quoted 8 lines
Quoted 8 lines
Quoted 8 lines
include/kvm/arm_psci.h +1
-2-int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */ --2.36.0.rc2.479.g8af0fa9b8e-goog
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Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Quoted 306 lines · Reiji Watanabe
Hi Raghu,
Quoted 291 lines · Raghavendra Rao Ananta
Hi Reiji,
Quoted 278 lines · Reiji Watanabe
Hi Raghu,
Quoted 273 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)arch/arm64/include/asm/kvm_host.h +12
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { }; +/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +76
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); } +static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} + +static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features)Quoted 9 lines
arch/arm64/kvm/hypercalls.c int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) · line 340
Quoted 3 lines
arch/arm64/kvm/hypercalls.c +3
-0+return -EINVAL ; + +mutex_lock (&kvm->lock);Why don't you check if the register value will be modified before getting the lock ? (then there is nothing to do)
It would help reduce unnecessary serialization for live migration (even without the vm-scoped register capability).Quoted 5 lines
That was the case until v5. Since v6, we return
-EBUSYunconditionally regardless of the incoming value. See Marc's comments in [1].That was the case until v5. Since v6, we return
-EBUSYunconditionally regardless of the incoming value. See Marc's comments in [1].Even with that, the function could do below to avoid
the unnecessary serialization.
(I would expect mostly the function returns before getting the lock)
Quoted 10 lines
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags))
return -EBUSY;
if (val == *fw_reg_bmap)
return 0;
mutex_lock(&kvm->lock);
<...>Great idea! I can try this out. Thanks for the suggestion.
Quoted 76 lines
Quoted 9 lines
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Quoted 8 lines
arch/arm64/kvm/hypercalls.c +6
-0+ +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + }Quoted 7 lines
Quoted 5 lines
I just would like to make sure that you are sure that existing userspace you know will not run
KVM_RUNfor any vCPUs untilKVM_SET_ONE_REGis complete for all vCPUs (even for migration), correct ?Since v6, that is something that we are leaving with the userspace to synchronize. See [1].
Understood.
Quoted 51 lines
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arch/arm64/kvm/hypercalls.c +9
-0+o + WRITE_ONCE(*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +0
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } }arch/arm64/kvm/psci.c int kvm_psci_call(struct kvm_vcpu *vcpu) · line 448
Quoted 10 lines
arch/arm64/kvm/psci.c +10
-0+ +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true;For PSCI 0.1, the function checks if the
funct_idis valid for the vCPU (according to the vCPU's PSCI version).
For other version of PSCI, the function doesn't care the vCPU's PSCI version (although supported functions depend on the PSCIQuoted 9 lines
version and not all of them are defined yet, the code returns true as long as the function id is within the reserved PSCI function id range).
So, the behavior appears to be inconsistent.
Shouldn't it return the validity of the function id according to the vCPU's psci version for non-PSCI 0.1 case as well ? (Otherwise, shouldn't it return true if the function id is valid for any of the PSCI versions ?)Quoted 4 lines
Well, PSCI 1.0 is somewhat of an odd implementation. It doesn't comply
with the SMCCC, hence needed some special handling. Only twofunc_ids> are currently supported by KVM, and we just check for each. The second 'if' statement is for all the PSCI versions >= 0.2. Thankfully, the
specification defines a range of acceptable PSCIfunc_ids.
Quoted 9 lines
I understand PSCI 0.1 is different from PSCI 0.2 or newer versions. But, my question is: What would you consider "valid" psci function id ? It seems that the function checks whether or not the
func_idis valid on the vCPU for PSCI 0.1, and checks whether or not thefunc_idis a PSCI function id for vCPU with PSCI 0.2 or newer.I understand either one works for your purpose, but I would think the behavior should be consistent.
I guess checking for the version caused the confusion here, but that was done since there isn't a standard way to check the 0.1's range of func_ids. Alternatively, instead of version, since the base of the 0.1's range is different as well, I can just check for that to avoid the confusion (no functional change though).
Thank you.
Raghavendra
Quoted 59 lines
Thanks,
ReijiQuoted 55 lines
If it's confusing, I can add a comment above the second 'if' that it's for all PSCI versions >= 0.2.
Quoted 3 lines
Thanks,
ReijiThank you.
Raghavendra[1]: https://lore.kernel.org/lkml/[email protected]/
Quoted 45 lines
Quoted 45 lines
arch/arm64/kvm/psci.c +3
-0+ +return false; +}include/kvm/arm_hypercalls.h +6
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +1
-2@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu) return KVM_ARM_PSCI_0_1; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */ --2.36.0.rc2.479.g8af0fa9b8e-goog
Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
In reply to Raghavendra Rao AnantaHi Raghavendra,
Quoted 45 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>
Quoted 11 lines
--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)
Some nits as below, please consider to improve if you need another respin.
Quoted 7 lines
arch/arm64/include/asm/kvm_host.h +0
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { };
arch/arm64/include/asm/kvm_host.h struct kvm_s2_mmu { · line 112
Quoted 10 lines
arch/arm64/include/asm/kvm_host.h +9
-0+/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +
s/Descriptor/Descriptor of
Quoted 76 lines
arch/arm64/include/asm/kvm_host.h +3
-0struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +0
-0
arch/arm64/kvm/hypercalls.c static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) · line 65
Quoted 8 lines
arch/arm64/kvm/hypercalls.c +5
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); } +static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} +
Might be worhty to be 'inline'. This function would be called frequently.
Quoted 169 lines
arch/arm64/kvm/hypercalls.c +89
-0+static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features) +return -EINVAL ; + +mutex_lock (&kvm->lock); + +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + } + +WRITE_ONCE (*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +13
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } } + +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true; + +return false; +}include/kvm/arm_hypercalls.h +0
-0
include/kvm/arm_hypercalls.h line 13
Quoted 8 lines
include/kvm/arm_hypercalls.h +5
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +
s/bits of/bit of
Quoted 17 lines
include/kvm/arm_hypercalls.h +1
-0int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +0
-0
include/kvm/arm_psci.h static inline int kvm_psci_version(struct kvm_vcpu *vcpu) · line 42
Quoted 8 lines
include/kvm/arm_psci.h +1
-1@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu) return KVM_ARM_PSCI_0_1; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);#endif /* __KVM_ARM_PSCI_H__ */
Thanks,
Gavin
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Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Hi Gavin,
Quoted 74 lines · Gavin Shan
Hi Raghavendra,
Quoted 45 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>Quoted 11 lines
--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)Some nits as below, please consider to improve if you need another respin.
Reviewed-by Gavin Shan <[email protected]>Quoted 8 lines
arch/arm64/include/asm/kvm_host.h +0
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { };
Quoted 12 lines
arch/arm64/include/asm/kvm_host.h struct kvm_s2_mmu { · line 112
Quoted 9 lines
arch/arm64/include/asm/kvm_host.h +9
-0+/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +s/Descriptor/Descriptor of
Nice catch!
Quoted 79 lines
Quoted 79 lines
arch/arm64/include/asm/kvm_host.h +3
-0struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +0
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); }
Quoted 9 lines
arch/arm64/kvm/hypercalls.c static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) · line 65
Quoted 5 lines
arch/arm64/kvm/hypercalls.c +5
-0+static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} +Might be worhty to be 'inline'. This function would be called frequently.
I was hoping the compiler would optimize it for us as needed.
Quoted 172 lines
Quoted 172 lines
arch/arm64/kvm/hypercalls.c +89
-0+static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features) +return -EINVAL ; + +mutex_lock (&kvm->lock); + +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + } + +WRITE_ONCE (*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +13
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } } + +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true; + +return false; +}include/kvm/arm_hypercalls.h +0
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h>
Quoted 8 lines
include/kvm/arm_hypercalls.h line 13
Quoted 5 lines
include/kvm/arm_hypercalls.h +5
-0+/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +s/bits of/bit of
Great catch again!
Quoted 23 lines
Quoted 23 lines
include/kvm/arm_hypercalls.h +1
-0int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +1
-1@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)return KVM_ARM_PSCI_0_1 ; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);
Quoted 6 lines
include/kvm/arm_psci.h static inline int kvm_psci_version(struct kvm_vcpu *vcpu) · line 42
Quoted 2 lines
include/kvm/arm_psci.h +0
-0#endif /* __KVM_ARM_PSCI_H__ */ Thanks,
Gavin
Thanks for the review, Gavin.
- Raghavendra
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Re: [PATCH v6 2/9] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
Hi Raghavendra,
Quoted 174 lines · Raghavendra Rao Ananta
Quoted 71 lines · Gavin Shan
Quoted 45 lines · Raghavendra Rao Ananta
KVM regularly introduces new hypercall services to the guests without any consent from the userspace. This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic.
As a result, there's a need for the userspace to elect the services that it wishes the guest to discover. It can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware pseudo-registers, such as
KVM_REG_ARM_PSCI_VERSION, but by creating a new COPROC register space for all the hypercall services available.These firmware registers are categorized based on the service call owners, but unlike the existing firmware pseudo-registers, they hold the features supported in the form of a bitmap.
During the VM initialization, the registers are set to upper-limit of the features supported by the corresponding registers. It's expected that the VMMs discover the features provided by each register via
GET_ONE_REG, and write back the desired values usingSET_ONE_REG. KVM allows this modification only until the VM has started.Some of the standard features are not mapped to any bits of the registers. But since they can recreate the original problem of making it available without userspace's consent, they need to be explicitly added to the case-list in
kvm_hvc_call_default_allowed(). Any function-id that's not enabled via the bitmap, or not listed inkvm_hvc_call_default_allowed, will be returned asSMCCC_RET_NOT_SUPPORTEDto the guest.Older userspace code can simply ignore the feature and the hypercall services will be exposed unconditionally to the guests, thus ensuring backward compatibility.
In this patch, the framework adds the register only for ARM's standard secure services (owner value 4). Currently, this includes support only for ARM True Random Number Generator (TRNG) service, with bit-0 of the register representing mandatory features of v1.0. Other services are momentarily added in the upcoming patches.
Signed-off-by Raghavendra Rao Ananta <[email protected]>Quoted 11 lines
--- arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/uapi/asm/kvm.h | 9 +++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/guest.c | 8 ++- arch/arm64/kvm/hypercalls.c | 94 +++++++++++++++++++++++++++++++ arch/arm64/kvm/psci.c | 13 +++++ include/kvm/arm_hypercalls.h | 6 ++ include/kvm/arm_psci.h | 2 +- 8 files changed, 142 insertions(+), 3 deletions(-)Some nits as below, please consider to improve if you need another respin.
Reviewed-by Gavin Shan <[email protected]>Quoted 8 lines
arch/arm64/include/asm/kvm_host.h +0
-0@@ -101,6 +101,15 @@ struct kvm_s2_mmu {struct kvm_arch_memory_slot { };Quoted 12 lines
arch/arm64/include/asm/kvm_host.h struct kvm_s2_mmu { · line 112
Quoted 9 lines
arch/arm64/include/asm/kvm_host.h +9
-0+/** +* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests +* +* @std_bmap: Bitmap of standard secure service calls +*/ +struct kvm_smccc_features { +unsigned long std_bmap; +}; +s/Descriptor/Descriptor of
Nice catch!
Quoted 79 lines
Quoted 79 lines
arch/arm64/include/asm/kvm_host.h +3
-0struct kvm_arch {struct kvm_s2_mmu mmu;@@ -150,6 +159,9 @@ struct kvm_arch {u8 pfr0_csv2;u8 pfr0_csv3; + +/* Hypercall features firmware registers' descriptor */ +struct kvm_smccc_features smccc_feat; };struct kvm_vcpu_fault_info {arch/arm64/include/uapi/asm/kvm.h +9
-0@@ -332,6 +332,15 @@ struct kvm_arm_copy_mte_tags {#define KVM_ARM64_SVE_VLS_WORDS \ ((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1) +/* Bitmap feature firmware registers */ +#define KVM_REG_ARM_FW_FEAT_BMAP (0x0016 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_FW_FEAT_BMAP_REG (r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ + KVM_REG_ARM_FW_FEAT_BMAP | \ + ((r) & 0xffff)) + +#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0) +#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/arm.c +1
-0@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.max_vcpus =kvm_arm_default_max_vcpus ();set_default_spectre (kvm); +kvm_arm_init_hypercalls (kvm);return ret; out_free_stage2_pgd:arch/arm64/kvm/guest.c +6
-2@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return get_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_get_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_get_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return get_sve_reg (vcpu, reg); }@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)switch (reg->id &KVM_REG_ARM_COPROC_MASK ) {case KVM_REG_ARM_CORE :return set_core_reg (vcpu, reg); -case KVM_REG_ARM_FW :return kvm_arm_set_fw_reg (vcpu, reg); +case KVM_REG_ARM_FW : +case KVM_REG_ARM_FW_FEAT_BMAP : +return kvm_arm_set_fw_reg (vcpu, reg);case KVM_REG_ARM64_SVE :return set_sve_reg (vcpu, reg); }arch/arm64/kvm/hypercalls.c +0
-0@@ -58,6 +58,48 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) val[3 ] =lower_32_bits (cycles); }Quoted 9 lines
arch/arm64/kvm/hypercalls.c static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) · line 65
Quoted 5 lines
arch/arm64/kvm/hypercalls.c +5
-0+static bool kvm_arm_fw_reg_feat_enabled (unsigned long *reg_bmap,unsigned long feat_bit) +{ +return test_bit (feat_bit, reg_bmap); +} +Might be worhty to be 'inline'. This function would be called frequently.
Quoted 2 lines
I was hoping the compiler would optimize it for us as needed.
Yeah, GCC is smart enough. It could be compiled to inline function even it's not specified explicitly. I guess __always_inline can be used here. However, it seems __always_inline isn't used broadly in kvm/arm64 scope. Anyway, it's not a big deal in this specific case :)
Quoted 205 lines
Quoted 172 lines
Quoted 172 lines
arch/arm64/kvm/hypercalls.c +89
-0+static bool kvm_hvc_call_default_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +switch (func_id) { +/* +* List of function-ids that are not gated with the bitmapped feature +* firmware registers, and are to be allowed for servicing the call by default. +*/ +case ARM_SMCCC_VERSION_FUNC_ID : +case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return true; +default : +return kvm_psci_func_id_is_valid (vcpu, func_id); + } +} + +static bool kvm_hvc_call_allowed (struct kvm_vcpu *vcpu,u32 func_id) +{ +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; + +switch (func_id) { +case ARM_SMCCC_TRNG_VERSION : +case ARM_SMCCC_TRNG_FEATURES : +case ARM_SMCCC_TRNG_GET_UUID : +case ARM_SMCCC_TRNG_RND32 : +case ARM_SMCCC_TRNG_RND64 : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap, +KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +default : +return kvm_hvc_call_default_allowed (vcpu, func_id); + } +} +int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) {u32 func_id =smccc_get_function (vcpu);@@ -65,6 +107,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)u32 feature;gpa_t gpa; +if (!kvm_hvc_call_allowed (vcpu, func_id)) + goto out; +switch (func_id) {case ARM_SMCCC_VERSION_FUNC_ID : val[0 ] =ARM_SMCCC_VERSION_1_1 ;@@ -155,6 +200,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)return kvm_psci_call (vcpu); } +out:smccc_set_retval (vcpu, val[0 ], val[1 ], val[2 ], val[3 ]);return 1 ; }@@ -164,8 +210,16 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 , + KVM_REG_ARM_STD_BMAP, }; +void kvm_arm_init_hypercalls (struct kvm *kvm) +{ +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; + + smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; +} +int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu) {return ARRAY_SIZE (kvm_arm_fw_reg_ids);@@ -237,6 +291,7 @@ static int get_kernel_wa_level(u64 regid)int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;void __user *uaddr = (void __user *)(long )reg->addr;u64 val;@@ -249,6 +304,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 : val =get_kernel_wa_level (reg->id) &KVM_REG_FEATURE_LEVEL_MASK ;break ; +case KVM_REG_ARM_STD_BMAP : + val =READ_ONCE (smccc_feat->std_bmap); +break ;default :return -ENOENT ; }@@ -259,6 +317,40 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ; } +static int kvm_arm_set_fw_reg_bmap (struct kvm_vcpu *vcpu,u64 reg_id,u64 val) +{ +int ret =0 ; +struct kvm *kvm = vcpu->kvm; +struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; +unsigned long *fw_reg_bmap, fw_reg_features; + +switch (reg_id) { +case KVM_REG_ARM_STD_BMAP : + fw_reg_bmap = &smccc_feat->std_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ; +break ; +default : +return -ENOENT ; + } + +/* Check for unsupported bit */ +if (val & ~fw_reg_features) +return -EINVAL ; + +mutex_lock (&kvm->lock); + +/* Return -EBUSY if the VM (any vCPU) has already started running. */ +if (test_bit (KVM_ARCH_FLAG_HAS_RAN_ONCE , &kvm->arch.flags)) { + ret = -EBUSY ; + goto out; + } + +WRITE_ONCE (*fw_reg_bmap, val); +out: +mutex_unlock (&kvm->lock); +return ret; +} +int kvm_arm_set_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg) {void __user *uaddr = (void __user *)(long )reg->addr;@@ -337,6 +429,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return -EINVAL ;return 0 ; +case KVM_REG_ARM_STD_BMAP : +return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ; }arch/arm64/kvm/psci.c +13
-0@@ -436,3 +436,16 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)return -EINVAL ; } } + +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id) +{ +/* PSCI 0.1 doesn't comply with the standard SMCCC */ +if (kvm_psci_version (vcpu) ==KVM_ARM_PSCI_0_1 ) +return (func_id ==KVM_PSCI_FN_CPU_OFF || func_id ==KVM_PSCI_FN_CPU_ON ); + +if (ARM_SMCCC_OWNER_NUM (func_id) ==ARM_SMCCC_OWNER_STANDARD && +ARM_SMCCC_FUNC_NUM (func_id) >=0 &&ARM_SMCCC_FUNC_NUM (func_id) <=0x1f ) +return true; + +return false; +}include/kvm/arm_hypercalls.h +0
-0@@ -6,6 +6,11 @@#include <asm/kvm_emulate.h> Quoted 8 lines
include/kvm/arm_hypercalls.h line 13
Quoted 5 lines
include/kvm/arm_hypercalls.h +5
-0+/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 + +#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +s/bits of/bit of
Great catch again!
Quoted 23 lines
Quoted 23 lines
include/kvm/arm_hypercalls.h +1
-0int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);static inline u32 smccc_get_function (struct kvm_vcpu *vcpu)@@ -42,6 +47,7 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,struct kvm_one_reg ; +void kvm_arm_init_hypercalls (struct kvm *kvm);int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu);int kvm_arm_copy_fw_reg_indices (struct kvm_vcpu *vcpu,u64 __user *uindices);int kvm_arm_get_fw_reg (struct kvm_vcpu *vcpu,const struct kvm_one_reg *reg);include/kvm/arm_psci.h +1
-1@@ -36,7 +36,7 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)return KVM_ARM_PSCI_0_1 ; } -int kvm_psci_call (struct kvm_vcpu *vcpu); +bool kvm_psci_func_id_is_valid (struct kvm_vcpu *vcpu,u32 func_id);
Quoted 9 lines
Quoted 6 lines
include/kvm/arm_psci.h static inline int kvm_psci_version(struct kvm_vcpu *vcpu) · line 42
Quoted 2 lines
include/kvm/arm_psci.h +0
-0#endif /* __KVM_ARM_PSCI_H__ */ Thanks,
GavinThanks for the review, Gavin.
No worries :)
Thanks,
Gavin
PATCH v6 3/9 KVM: arm64: Add standard hypervisor firmware register
In reply to Raghavendra Rao AnantaIntroduce the firmware register to hold the standard hypervisor service calls (owner value 5) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support only for Paravirtualized time, represented by bit-0.
--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 3 +++ arch/arm64/kvm/hypercalls.c | 21 ++++++++++++++++++--- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 25 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kvm_host.h +2 -0
@@ -105,9 +105,11 @@ struct kvm_arch_memory_slot {* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests * * @std_bmap: Bitmap of standard secure service calls +* @std_hyp_bmap: Bitmap of standard hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap; +unsigned long std_hyp_bmap; };struct kvm_arch {
arch/arm64/include/uapi/asm/kvm.h +3 -0
@@ -341,6 +341,9 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0)#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1) +#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
arch/arm64/kvm/hypercalls.c +18 -3
@@ -72,8 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_HV_PV_TIME_FEATURES : -case ARM_SMCCC_HV_PV_TIME_ST :case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID :case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID :case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :
@@ -95,6 +93,10 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_TRNG_RND64 :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap,KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap, +KVM_REG_ARM_STD_HYP_BIT_PV_TIME );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }
@@ -102,6 +104,7 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;u32 func_id =smccc_get_function (vcpu);u64 val[4 ] = {SMCCC_RET_NOT_SUPPORTED };u32 feature;
@@ -165,7 +168,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) }break ;case ARM_SMCCC_HV_PV_TIME_FEATURES : - val[0 ] =SMCCC_RET_SUCCESS ; +if (kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap, +KVM_REG_ARM_STD_HYP_BIT_PV_TIME )) + val[0 ] =SMCCC_RET_SUCCESS ;break ; }break ;
@@ -211,6 +216,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP , + KVM_REG_ARM_STD_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)
@@ -218,6 +224,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; + smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)
@@ -307,6 +314,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_BMAP : val =READ_ONCE (smccc_feat->std_bmap);break ; +case KVM_REG_ARM_STD_HYP_BMAP : + val =READ_ONCE (smccc_feat->std_hyp_bmap); +break ;default :return -ENOENT ; }
@@ -329,6 +339,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ;break ; +case KVM_REG_ARM_STD_HYP_BMAP : + fw_reg_bmap = &smccc_feat->std_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ; +break ;default :return -ENOENT ; }
@@ -430,6 +444,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP : +case KVM_REG_ARM_STD_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;
include/kvm/arm_hypercalls.h +2 -0
@@ -8,8 +8,10 @@/* Last valid bits of the bitmapped firmware registers */ #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);
Signature · 6 lines
2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 3/9] KVM: arm64: Add standard hypervisor firmware register
Quoted 6 lines · Raghavendra Rao Ananta
Introduce the firmware register to hold the standard hypervisor service calls (owner value 5) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support only for Paravirtualized time, represented by bit-0.
Quoted 8 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 3 +++ arch/arm64/kvm/hypercalls.c | 21 ++++++++++++++++++--- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 25 insertions(+), 3 deletions(-)
Quoted 134 lines
arch/arm64/include/asm/kvm_host.h +2
-0@@ -105,9 +105,11 @@ struct kvm_arch_memory_slot {* struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests * * @std_bmap: Bitmap of standard secure service calls +* @std_hyp_bmap: Bitmap of standard hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap; +unsigned long std_hyp_bmap; };struct kvm_arch {arch/arm64/include/uapi/asm/kvm.h +3
-0@@ -341,6 +341,9 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0)#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0 +#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1) +#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/hypercalls.c +18
-3@@ -72,8 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_HV_PV_TIME_FEATURES : -case ARM_SMCCC_HV_PV_TIME_ST :case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID :case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID :case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :@@ -95,6 +93,10 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_TRNG_RND64 :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_bmap,KVM_REG_ARM_STD_BIT_TRNG_V1_0 ); +case ARM_SMCCC_HV_PV_TIME_FEATURES : +case ARM_SMCCC_HV_PV_TIME_ST : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap, +KVM_REG_ARM_STD_HYP_BIT_PV_TIME );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }@@ -102,6 +104,7 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu) { +struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;u32 func_id =smccc_get_function (vcpu);u64 val[4 ] = {SMCCC_RET_NOT_SUPPORTED };u32 feature;@@ -165,7 +168,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) }break ;case ARM_SMCCC_HV_PV_TIME_FEATURES : - val[0 ] =SMCCC_RET_SUCCESS ; +if (kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap, +KVM_REG_ARM_STD_HYP_BIT_PV_TIME )) + val[0 ] =SMCCC_RET_SUCCESS ;break ; }break ;@@ -211,6 +216,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 ,KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP , + KVM_REG_ARM_STD_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)@@ -218,6 +224,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat; smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; + smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)@@ -307,6 +314,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_BMAP : val =READ_ONCE (smccc_feat->std_bmap);break ; +case KVM_REG_ARM_STD_HYP_BMAP : + val =READ_ONCE (smccc_feat->std_hyp_bmap); +break ;default :return -ENOENT ; }@@ -329,6 +339,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_FEATURES ;break ; +case KVM_REG_ARM_STD_HYP_BMAP : + fw_reg_bmap = &smccc_feat->std_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ; +break ;default :return -ENOENT ; }@@ -430,6 +444,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP : +case KVM_REG_ARM_STD_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;include/kvm/arm_hypercalls.h +2
-0@@ -8,8 +8,10 @@/* Last valid bits of the bitmapped firmware registers */ #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);
PATCH v6 4/9 KVM: arm64: Add vendor hypervisor firmware register
In reply to Raghavendra Rao AnantaIntroduce the firmware register to hold the vendor specific hypervisor service calls (owner value 6) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support for KVM-vendor features along with reading the UID, represented by bit-0, and Precision Time Protocol (PTP), represented by bit-1.
--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 4 ++++ arch/arm64/kvm/hypercalls.c | 23 ++++++++++++++++++----- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 26 insertions(+), 5 deletions(-)
arch/arm64/include/asm/kvm_host.h +2 -0
@@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {* * @std_bmap: Bitmap of standard secure service calls * @std_hyp_bmap: Bitmap of standard hypervisor service calls +* @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap;unsigned long std_hyp_bmap; +unsigned long vendor_hyp_bmap; };struct kvm_arch {
arch/arm64/include/uapi/asm/kvm.h +4 -0
@@ -344,6 +344,10 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2) +#define KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT 0 +#define KVM_REG_ARM_VENDOR_HYP_BIT_PTP 1 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
arch/arm64/kvm/hypercalls.c +18 -5
@@ -72,9 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :return true;default :return kvm_psci_func_id_is_valid (vcpu, func_id);
@@ -97,6 +94,13 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_HV_PV_TIME_ST :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap,KVM_REG_ARM_STD_HYP_BIT_PV_TIME ); +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT ); +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_PTP );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }
@@ -189,8 +193,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) val[3 ] =ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 ;break ;case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : - val[0 ] =BIT (ARM_SMCCC_KVM_FUNC_FEATURES ); - val[0 ] |=BIT (ARM_SMCCC_KVM_FUNC_PTP ); + val[0 ] = smccc_feat->vendor_hyp_bmap;break ;case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :kvm_ptp_get_time (vcpu, val);
@@ -217,6 +220,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP ,KVM_REG_ARM_STD_HYP_BMAP , + KVM_REG_ARM_VENDOR_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)
@@ -225,6 +229,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm) smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; + smccc_feat->vendor_hyp_bmap =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)
@@ -317,6 +322,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_HYP_BMAP : val =READ_ONCE (smccc_feat->std_hyp_bmap);break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + val =READ_ONCE (smccc_feat->vendor_hyp_bmap); +break ;default :return -ENOENT ; }
@@ -343,6 +351,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_hyp_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ;break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; +break ;default :return -ENOENT ; }
@@ -445,6 +457,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP :case KVM_REG_ARM_STD_HYP_BMAP : +case KVM_REG_ARM_VENDOR_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;
include/kvm/arm_hypercalls.h +2 -0
@@ -9,9 +9,11 @@/* Last valid bits of the bitmapped firmware registers */ #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);
Signature · 6 lines
2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 4/9] KVM: arm64: Add vendor hypervisor firmware register
Hi Raghu,
Quoted 137 lines · Raghavendra Rao Ananta
Introduce the firmware register to hold the vendor specific hypervisor service calls (owner value 6) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support for KVM-vendor features along with reading the UID, represented by bit-0, and Precision Time Protocol (PTP), represented by bit-1.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 4 ++++ arch/arm64/kvm/hypercalls.c | 23 ++++++++++++++++++----- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 26 insertions(+), 5 deletions(-)arch/arm64/include/asm/kvm_host.h +2
-0@@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {* * @std_bmap: Bitmap of standard secure service calls * @std_hyp_bmap: Bitmap of standard hypervisor service calls +* @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap;unsigned long std_hyp_bmap; +unsigned long vendor_hyp_bmap; };struct kvm_arch {arch/arm64/include/uapi/asm/kvm.h +4
-0@@ -344,6 +344,10 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2) +#define KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT 0 +#define KVM_REG_ARM_VENDOR_HYP_BIT_PTP 1 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/hypercalls.c +18
-5@@ -72,9 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :return true;default :return kvm_psci_func_id_is_valid (vcpu, func_id);@@ -97,6 +94,13 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_HV_PV_TIME_ST :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap,KVM_REG_ARM_STD_HYP_BIT_PV_TIME ); +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT ); +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_PTP );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }@@ -189,8 +193,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) val[3 ] =ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 ;break ;case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : - val[0 ] =BIT (ARM_SMCCC_KVM_FUNC_FEATURES ); - val[0 ] |=BIT (ARM_SMCCC_KVM_FUNC_PTP ); + val[0 ] = smccc_feat->vendor_hyp_bmap;break ;case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :kvm_ptp_get_time (vcpu, val);@@ -217,6 +220,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP ,KVM_REG_ARM_STD_HYP_BMAP , + KVM_REG_ARM_VENDOR_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)@@ -225,6 +229,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm) smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; + smccc_feat->vendor_hyp_bmap =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)@@ -317,6 +322,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_HYP_BMAP : val =READ_ONCE (smccc_feat->std_hyp_bmap);break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + val =READ_ONCE (smccc_feat->vendor_hyp_bmap); +break ;default :return -ENOENT ; }@@ -343,6 +351,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_hyp_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ;break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; +break ;default :return -ENOENT ; }@@ -445,6 +457,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP :case KVM_REG_ARM_STD_HYP_BMAP : +case KVM_REG_ARM_VENDOR_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;include/kvm/arm_hypercalls.h +0
-0
include/kvm/arm_hypercalls.h line 12
Quoted 4 lines
include/kvm/arm_hypercalls.h +1
-0@@ -9,9 +9,11 @@/* Last valid bits of the bitmapped firmware registers */ #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1
Nit: IMHO perhaps it might be more convenient to define the MAX macro in arch/arm64/include/uapi/asm/kvm.h like below for maintenance ? (The same comments are applied to other KVM_REG_ARM_*_BMAP_BIT_MAX)
#define KVM_REG_ARM_VENDOR_HYP_BIT_MAX KVM_REG_ARM_VENDOR_HYP_BIT_PTP
Thanks,
Reiji
Quoted 10 lines
include/kvm/arm_hypercalls.h +1
-1#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu); --2.36.0.rc2.479.g8af0fa9b8e-goog
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Re: [PATCH v6 4/9] KVM: arm64: Add vendor hypervisor firmware register
Hi Reiji,
Quoted 151 lines · Reiji Watanabe
Hi Raghu,
Quoted 137 lines · Raghavendra Rao Ananta
Introduce the firmware register to hold the vendor specific hypervisor service calls (owner value 6) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support for KVM-vendor features along with reading the UID, represented by bit-0, and Precision Time Protocol (PTP), represented by bit-1.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 4 ++++ arch/arm64/kvm/hypercalls.c | 23 ++++++++++++++++++----- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 26 insertions(+), 5 deletions(-)arch/arm64/include/asm/kvm_host.h +2
-0@@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {* * @std_bmap: Bitmap of standard secure service calls * @std_hyp_bmap: Bitmap of standard hypervisor service calls +* @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap;unsigned long std_hyp_bmap; +unsigned long vendor_hyp_bmap; };struct kvm_arch {arch/arm64/include/uapi/asm/kvm.h +4
-0@@ -344,6 +344,10 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2) +#define KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT 0 +#define KVM_REG_ARM_VENDOR_HYP_BIT_PTP 1 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/hypercalls.c +18
-5@@ -72,9 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :return true;default :return kvm_psci_func_id_is_valid (vcpu, func_id);@@ -97,6 +94,13 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_HV_PV_TIME_ST :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap,KVM_REG_ARM_STD_HYP_BIT_PV_TIME ); +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT ); +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_PTP );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }@@ -189,8 +193,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) val[3 ] =ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 ;break ;case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : - val[0 ] =BIT (ARM_SMCCC_KVM_FUNC_FEATURES ); - val[0 ] |=BIT (ARM_SMCCC_KVM_FUNC_PTP ); + val[0 ] = smccc_feat->vendor_hyp_bmap;break ;case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :kvm_ptp_get_time (vcpu, val);@@ -217,6 +220,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP ,KVM_REG_ARM_STD_HYP_BMAP , + KVM_REG_ARM_VENDOR_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)@@ -225,6 +229,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm) smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; + smccc_feat->vendor_hyp_bmap =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)@@ -317,6 +322,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_HYP_BMAP : val =READ_ONCE (smccc_feat->std_hyp_bmap);break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + val =READ_ONCE (smccc_feat->vendor_hyp_bmap); +break ;default :return -ENOENT ; }@@ -343,6 +351,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_hyp_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ;break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; +break ;default :return -ENOENT ; }@@ -445,6 +457,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP :case KVM_REG_ARM_STD_HYP_BMAP : +case KVM_REG_ARM_VENDOR_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;include/kvm/arm_hypercalls.h +0
-0include/kvm/arm_hypercalls.h line 12
Quoted 4 lines
include/kvm/arm_hypercalls.h +1
-0@@ -9,9 +9,11 @@/* Last valid bits of the bitmapped firmware registers */ #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1Nit: IMHO perhaps it might be more convenient to define the MAX macro in
arch/arm64/include/uapi/asm/kvm.hlike below for maintenance ? (The same comments are applied to other KVM_REG_ARM_*_BMAP_BIT_MAX)
Quoted 2 lines
#define
KVM_REG_ARM_VENDOR_HYP_BIT_MAXKVM_REG_ARM_VENDOR_HYP_BIT_PTP
We have been going back and forth on this :)
It made sense for me to keep it in uapi as well, but I took Oliver's suggestion of keeping it outside of uapi since this is something that could be constantly changing [1].
Thank you.
Raghavendra
[1]: https://lore.kernel.org/lkml/CAJHc60wz5WsZWTn66i41+G4-dsjCFuFkthXU_Vf6QeXHkgzrZg@mail.gmail.com/
Quoted 14 lines
Thanks,
ReijiQuoted 10 lines
include/kvm/arm_hypercalls.h +1
-1#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu); --2.36.0.rc2.479.g8af0fa9b8e-goog
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Re: [PATCH v6 4/9] KVM: arm64: Add vendor hypervisor firmware register
On Mon, Apr 25, 2022 at 9:52 AM Raghavendra Rao Ananta <[email protected]> wrote:
[...]
Quoted 6 lines
Quoted 6 lines
Quoted 1 line
+#define
KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX1Nit: IMHO perhaps it might be more convenient to define the MAX macro in
arch/arm64/include/uapi/asm/kvm.hlike below for maintenance ? (The same comments are applied to other KVM_REG_ARM_*_BMAP_BIT_MAX)
Quoted 6 lines
Quoted 2 lines
#define
KVM_REG_ARM_VENDOR_HYP_BIT_MAXKVM_REG_ARM_VENDOR_HYP_BIT_PTPWe have been going back and forth on this :)
It made sense for me to keep it in uapi as well, but I took Oliver's suggestion of keeping it outside of uapi since this is something that could be constantly changing [1].
The maximum set of features in a given bitmap register is a property of the running system, not the headers chosen at compile time. There is an illusion of ABI breakage when adding new bits to the registers if we've declared the max bit in UAPI. We also define KVM_VCPU_MAX_FEATURES outside of UAPI, even though it is related to the KVM_ARM_VCPU_INIT ioctl.
--
Thanks,
Oliver
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Re: [PATCH v6 4/9] KVM: arm64: Add vendor hypervisor firmware register
In reply to Raghavendra Rao AnantaQuoted 8 lines · Raghavendra Rao Ananta
Introduce the firmware register to hold the vendor specific hypervisor service calls (owner value 6) as a bitmap. The bitmap represents the features that'll be enabled for the guest, as configured by the user-space. Currently, this includes support for KVM-vendor features along with reading the UID, represented by bit-0, and Precision Time Protocol (PTP), represented by bit-1.
Quoted 8 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 4 ++++ arch/arm64/kvm/hypercalls.c | 23 ++++++++++++++++++----- include/kvm/arm_hypercalls.h | 2 ++ 4 files changed, 26 insertions(+), 5 deletions(-)
Quoted 122 lines
arch/arm64/include/asm/kvm_host.h +2
-0@@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {* * @std_bmap: Bitmap of standard secure service calls * @std_hyp_bmap: Bitmap of standard hypervisor service calls +* @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls */ struct kvm_smccc_features {unsigned long std_bmap;unsigned long std_hyp_bmap; +unsigned long vendor_hyp_bmap; };struct kvm_arch {arch/arm64/include/uapi/asm/kvm.h +4
-0@@ -344,6 +344,10 @@ struct kvm_arm_copy_mte_tags {#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2) +#define KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT 0 +#define KVM_REG_ARM_VENDOR_HYP_BIT_PTP 1 +/* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1arch/arm64/kvm/hypercalls.c +18
-5@@ -72,9 +72,6 @@ static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)*/ case ARM_SMCCC_VERSION_FUNC_ID :case ARM_SMCCC_ARCH_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : -case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :return true;default :return kvm_psci_func_id_is_valid (vcpu, func_id);@@ -97,6 +94,13 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)case ARM_SMCCC_HV_PV_TIME_ST :return kvm_arm_fw_reg_feat_enabled (&smccc_feat->std_hyp_bmap,KVM_REG_ARM_STD_HYP_BIT_PV_TIME ); +case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : +case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT ); +case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID : +return kvm_arm_fw_reg_feat_enabled (&smccc_feat->vendor_hyp_bmap, +KVM_REG_ARM_VENDOR_HYP_BIT_PTP );default :return kvm_hvc_call_default_allowed (vcpu, func_id); }@@ -189,8 +193,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) val[3 ] =ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 ;break ;case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID : - val[0 ] =BIT (ARM_SMCCC_KVM_FUNC_FEATURES ); - val[0 ] |=BIT (ARM_SMCCC_KVM_FUNC_PTP ); + val[0 ] = smccc_feat->vendor_hyp_bmap;break ;case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID :kvm_ptp_get_time (vcpu, val);@@ -217,6 +220,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 ,KVM_REG_ARM_STD_BMAP ,KVM_REG_ARM_STD_HYP_BMAP , + KVM_REG_ARM_VENDOR_HYP_BMAP, };void kvm_arm_init_hypercalls (struct kvm *kvm)@@ -225,6 +229,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm) smccc_feat->std_bmap =KVM_ARM_SMCCC_STD_FEATURES ; smccc_feat->std_hyp_bmap =KVM_ARM_SMCCC_STD_HYP_FEATURES ; + smccc_feat->vendor_hyp_bmap =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; }int kvm_arm_get_fw_num_regs (struct kvm_vcpu *vcpu)@@ -317,6 +322,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)case KVM_REG_ARM_STD_HYP_BMAP : val =READ_ONCE (smccc_feat->std_hyp_bmap);break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + val =READ_ONCE (smccc_feat->vendor_hyp_bmap); +break ;default :return -ENOENT ; }@@ -343,6 +351,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) fw_reg_bmap = &smccc_feat->std_hyp_bmap; fw_reg_features =KVM_ARM_SMCCC_STD_HYP_FEATURES ;break ; +case KVM_REG_ARM_VENDOR_HYP_BMAP : + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap; + fw_reg_features =KVM_ARM_SMCCC_VENDOR_HYP_FEATURES ; +break ;default :return -ENOENT ; }@@ -445,6 +457,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)return 0 ;case KVM_REG_ARM_STD_BMAP :case KVM_REG_ARM_STD_HYP_BMAP : +case KVM_REG_ARM_VENDOR_HYP_BMAP :return kvm_arm_set_fw_reg_bmap (vcpu, reg->id, val);default :return -ENOENT ;include/kvm/arm_hypercalls.h +0
-0@@ -9,9 +9,11 @@/* Last valid bits of the bitmapped firmware registers */
include/kvm/arm_hypercalls.h line 19
Quoted 10 lines
include/kvm/arm_hypercalls.h +2
-0#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0) +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX, 0)int kvm_hvc_call_handler (struct kvm_vcpu *vcpu);
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PATCH v6 5/9 Docs: KVM: Rename psci.rst to hypercalls.rst
In reply to Raghavendra Rao AnantaSince the doc also covers general hypercalls' details, rather than just PSCI, and the fact that the bitmap firmware registers' details will be added to this doc, rename the file to a more appropriate name- hypercalls.rst.
---
Documentation/virt/kvm/arm/{psci.rst => hypercalls.rst} | 0
1 file changed, 0 insertions(+), 0 deletions(-)
rename Documentation/virt/kvm/arm/{psci.rst => hypercalls.rst} (100%)Documentation/virt/kvm/arm/hypercalls.rst renamed from Documentation/virt/kvm/arm/psci.rst +0 -0
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2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 5/9] Docs: KVM: Rename psci.rst to hypercalls.rst
Quoted 5 lines · Raghavendra Rao Ananta
Since the doc also covers general hypercalls' details, rather than just PSCI, and the fact that the bitmap firmware registers' details will be added to this doc, rename the file to a more appropriate name-
hypercalls.rst.
Quoted 7 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>Reviewed-by Oliver Upton <[email protected]>--- Documentation/virt/kvm/arm/{psci.rst => hypercalls.rst} | 0 1 file changed, 0 insertions(+), 0 deletions(-)rename
Documentation/virt/kvm/arm/{psci.rst=>hypercalls.rst} (100%)
Documentation/virt/kvm/arm/hypercalls.rst
Quoted 5 lines
Documentation/virt/kvm/arm/hypercalls.rst renamed from Documentation/virt/kvm/arm/psci.rst +0
-0
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PATCH v6 6/9 Docs: KVM: Add doc for the bitmap firmware registers
In reply to Raghavendra Rao AnantaAdd the documentation for the bitmap firmware registers in hypercalls.rst and api.rst. This includes the details for KVM_REG_ARM_STD_BMAP, KVM_REG_ARM_STD_HYP_BMAP, and KVM_REG_ARM_VENDOR_HYP_BMAP registers.
Since the document is growing to carry other hypercall related information, make necessary adjustments to present the document in a generic sense, rather than being PSCI focused.
--- Documentation/virt/kvm/api.rst | 16 ++++ Documentation/virt/kvm/arm/hypercalls.rst | 94 ++++++++++++++++++----- 2 files changed, 92 insertions(+), 18 deletions(-)
Documentation/virt/kvm/api.rst +16 -0
@@ -2542,6 +2542,22 @@ arm64 firmware pseudo-registers have the following bit pattern:: 0x6030 0000 0014 <regno:16> +arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: + + 0x6030 0000 0016 <regno:16> + +The bitmap feature firmware registers exposes the hypercall services that are +available for userspace to configure. The set bits corresponds to the services +that are available for the guests to access. By default, KVM sets all the +supported bits during VM initialization. The userspace can discover the +available services via KVM_GET_ONE_REG, and write back the bitmap corresponding +to the features that it wishes guests to see via KVM_SET_ONE_REG. + +Note: These registers are immutable once any of the vCPUs of the VM has run at +least once. A KVM_SET_ONE_REG in such a scenario will return a -EBUSY to userspace. + +(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) + arm64 SVE registers have the following bit patterns:: 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]
Documentation/virt/kvm/arm/hypercalls.rst +76 -18
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Re: [PATCH v6 6/9] Docs: KVM: Add doc for the bitmap firmware registers
Hi Raghu,
Quoted 138 lines · Raghavendra Rao Ananta
Add the documentation for the bitmap firmware registers in
hypercalls.rstandapi.rst. This includes the details forKVM_REG_ARM_STD_BMAP,KVM_REG_ARM_STD_HYP_BMAP, andKVM_REG_ARM_VENDOR_HYP_BMAPregisters.Since the document is growing to carry other hypercall related information, make necessary adjustments to present the document in a generic sense, rather than being PSCI focused.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- Documentation/virt/kvm/api.rst | 16 ++++ Documentation/virt/kvm/arm/hypercalls.rst | 94 ++++++++++++++++++----- 2 files changed, 92 insertions(+), 18 deletions(-)Documentation/virt/kvm/api.rst +16
-0@@ -2542,6 +2542,22 @@ arm64 firmware pseudo-registers have the following bit pattern:: 0x6030 0000 0014 <regno:16> +arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: + + 0x6030 0000 0016 <regno:16> + +The bitmap feature firmware registers exposes the hypercall services that are +available for userspace to configure. The set bits corresponds to the services +that are available for the guests to access. By default, KVM sets all the +supported bits during VM initialization. The userspace can discover the +available services via KVM_GET_ONE_REG, and write back the bitmap corresponding +to the features that it wishes guests to see via KVM_SET_ONE_REG. + +Note: These registers are immutable once any of the vCPUs of the VM has run at +least once. A KVM_SET_ONE_REG in such a scenario will return a -EBUSY to userspace. + +(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) + arm64 SVE registers have the following bit patterns:: 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]Documentation/virt/kvm/arm/hypercalls.rst +53
-18@@ -1,32 +1,32 @@ .. SPDX-License-Identifier: GPL-2.0 -========================================= -Power State Coordination Interface (PSCI) -========================================= +======================= +ARM Hypercall Interface +======================= -KVM implements the PSCI (Power State Coordination Interface) -specification in order to provide services such as CPU on/off, reset -and power-off to the guest. +KVM handles the hypercall services as requested by the guests. New hypercall +services are regularly made available by the ARM specification or by KVM (as +vendor services) if they make sense from a virtualization point of view. -The PSCI specification is regularly updated to provide new features, -and KVM implements these updates if they make sense from a virtualization -point of view. - -This means that a guest booted on two different versions of KVM can -observe two different "firmware" revisions. This could cause issues if -a given guest is tied to a particular PSCI revision (unlikely), or if -a migration causes a different PSCI version to be exposed out of the -blue to an unsuspecting guest. +This means that a guest booted on two different versions of KVM can observe +two different "firmware" revisions. This could cause issues if a given guest +is tied to a particular version of a hypercall service, or if a migration +causes a different version to be exposed out of the blue to an unsuspecting +guest. In order to remedy this situation, KVM exposes a set of "firmware pseudo-registers" that can be manipulated using the GET/SET_ONE_REG interface. These registers can be saved/restored by userspace, and set -to a convenient value if required. +to a convenient value as required. -The following register is defined: +The following registers are defined: * KVM_REG_ARM_PSCI_VERSION: + KVM implements the PSCI (Power State Coordination Interface) + specification in order to provide services such as CPU on/off, reset + and power-off to the guest. + - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set (and thus has already been initialized) - Returns the current PSCI version on GET_ONE_REG (defaulting to the@@ -74,4 +74,62 @@ The following register is defined: KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED: The workaround is always active on this vCPU or it is not needed. -.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf + +Bitmap Feature Firmware Registers +--------------------------------- + +Contrary to the above registers, the following registers exposes the hypercall +services in the form of a feature-bitmap to the userspace. This bitmap is +translated to the services that are available to the guest. There is a register +defined per service call owner and can be accessed via GET/SET_ONE_REG interface. + +By default, these registers are set with the upper limit of the features that +are supported. This way userspace can discover all the electable hypercall services +via GET_ONE_REG. The user-space can write-back the desired bitmap back via +SET_ONE_REG. The features for the registers that are untouched, probably because +userspace isn't aware of them, will be exposed as is to the guest. + +Note that KVM would't allow the userspace to configure the registers anymore once +any of the vCPUs has run at least once. Instead, it will return a -EBUSY. + +The psuedo-firmware bitmap register are as follows: + +* KVM_REG_ARM_STD_BMAP: + Controls the bitmap of the ARM Standard Secure Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_BIT_TRNG_V1_0: + The bit represents the services offered under v1.0 of ARM True Random + Number Generator (TRNG) specification, ARM DEN0098. + +* KVM_REG_ARM_STD_HYP_BMAP: + Controls the bitmap of the ARM Standard Hypervisor Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_HYP_BIT_PV_TIME: + The bit represents the Paravirtualized Time service as represented by
Documentation/virt/kvm/arm/hypercalls.rst The following register is defined: · line 122
Quoted 10 lines
Documentation/virt/kvm/arm/hypercalls.rst +10
-0+ ARM DEN0057A. + +* KVM_REG_ARM_VENDOR_HYP_BMAP: + Controls the bitmap of the Vendor specific Hypervisor Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT + The bit represents the ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID + function-id
Looking at the code,
the bit also represents ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID.
Thanks,
Reiji
Quoted 15 lines
Documentation/virt/kvm/arm/hypercalls.rst +13
-1+ + Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP: + The bit represents the Precision Time Protocol KVM service. + +Errors: + + ======= ============================================================= + -ENOENT Unknown register accessed. + -EBUSY Attempt a 'write' to the register after the VM has started. + -EINVAL Invalid bitmap written to the register. + ======= ============================================================= + +.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf --
Quoted 2 lines
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Re: [PATCH v6 6/9] Docs: KVM: Add doc for the bitmap firmware registers
Quoted 148 lines · Reiji Watanabe
Hi Raghu,
Quoted 143 lines · Raghavendra Rao Ananta
Add the documentation for the bitmap firmware registers in
hypercalls.rstandapi.rst. This includes the details forKVM_REG_ARM_STD_BMAP,KVM_REG_ARM_STD_HYP_BMAP, andKVM_REG_ARM_VENDOR_HYP_BMAPregisters.Since the document is growing to carry other hypercall related information, make necessary adjustments to present the document in a generic sense, rather than being PSCI focused.
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- Documentation/virt/kvm/api.rst | 16 ++++ Documentation/virt/kvm/arm/hypercalls.rst | 94 ++++++++++++++++++----- 2 files changed, 92 insertions(+), 18 deletions(-)Documentation/virt/kvm/api.rst +16
-0@@ -2542,6 +2542,22 @@ arm64 firmware pseudo-registers have the following bit pattern:: 0x6030 0000 0014 <regno:16> +arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: + + 0x6030 0000 0016 <regno:16> + +The bitmap feature firmware registers exposes the hypercall services that are +available for userspace to configure. The set bits corresponds to the services +that are available for the guests to access. By default, KVM sets all the +supported bits during VM initialization. The userspace can discover the +available services via KVM_GET_ONE_REG, and write back the bitmap corresponding +to the features that it wishes guests to see via KVM_SET_ONE_REG. + +Note: These registers are immutable once any of the vCPUs of the VM has run at +least once. A KVM_SET_ONE_REG in such a scenario will return a -EBUSY to userspace. + +(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) + arm64 SVE registers have the following bit patterns:: 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]Documentation/virt/kvm/arm/hypercalls.rst +58
-18@@ -1,32 +1,32 @@ .. SPDX-License-Identifier: GPL-2.0 -========================================= -Power State Coordination Interface (PSCI) -========================================= +======================= +ARM Hypercall Interface +======================= -KVM implements the PSCI (Power State Coordination Interface) -specification in order to provide services such as CPU on/off, reset -and power-off to the guest. +KVM handles the hypercall services as requested by the guests. New hypercall +services are regularly made available by the ARM specification or by KVM (as +vendor services) if they make sense from a virtualization point of view. -The PSCI specification is regularly updated to provide new features, -and KVM implements these updates if they make sense from a virtualization -point of view. - -This means that a guest booted on two different versions of KVM can -observe two different "firmware" revisions. This could cause issues if -a given guest is tied to a particular PSCI revision (unlikely), or if -a migration causes a different PSCI version to be exposed out of the -blue to an unsuspecting guest. +This means that a guest booted on two different versions of KVM can observe +two different "firmware" revisions. This could cause issues if a given guest +is tied to a particular version of a hypercall service, or if a migration +causes a different version to be exposed out of the blue to an unsuspecting +guest. In order to remedy this situation, KVM exposes a set of "firmware pseudo-registers" that can be manipulated using the GET/SET_ONE_REG interface. These registers can be saved/restored by userspace, and set -to a convenient value if required. +to a convenient value as required. -The following register is defined: +The following registers are defined: * KVM_REG_ARM_PSCI_VERSION: + KVM implements the PSCI (Power State Coordination Interface) + specification in order to provide services such as CPU on/off, reset + and power-off to the guest. + - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set (and thus has already been initialized) - Returns the current PSCI version on GET_ONE_REG (defaulting to the@@ -74,4 +74,62 @@ The following register is defined: KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED: The workaround is always active on this vCPU or it is not needed. -.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf + +Bitmap Feature Firmware Registers +--------------------------------- + +Contrary to the above registers, the following registers exposes the hypercall +services in the form of a feature-bitmap to the userspace. This bitmap is +translated to the services that are available to the guest. There is a register +defined per service call owner and can be accessed via GET/SET_ONE_REG interface. + +By default, these registers are set with the upper limit of the features that +are supported. This way userspace can discover all the electable hypercall services +via GET_ONE_REG. The user-space can write-back the desired bitmap back via +SET_ONE_REG. The features for the registers that are untouched, probably because +userspace isn't aware of them, will be exposed as is to the guest. + +Note that KVM would't allow the userspace to configure the registers anymore once +any of the vCPUs has run at least once. Instead, it will return a -EBUSY. + +The psuedo-firmware bitmap register are as follows: + +* KVM_REG_ARM_STD_BMAP: + Controls the bitmap of the ARM Standard Secure Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_BIT_TRNG_V1_0: + The bit represents the services offered under v1.0 of ARM True Random + Number Generator (TRNG) specification, ARM DEN0098. + +* KVM_REG_ARM_STD_HYP_BMAP: + Controls the bitmap of the ARM Standard Hypervisor Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_HYP_BIT_PV_TIME: + The bit represents the Paravirtualized Time service as represented by + ARM DEN0057A. + +* KVM_REG_ARM_VENDOR_HYP_BMAP: + Controls the bitmap of the Vendor specific Hypervisor Service Calls. +
Quoted 9 lines
Documentation/virt/kvm/arm/hypercalls.rst The following register is defined: · line 122
Quoted 5 lines
Documentation/virt/kvm/arm/hypercalls.rst +5
-0+ The following bits are accepted: + + Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT + The bit represents the ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID + function-idLooking at the code,
the bit also representsARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID.
You are right, I missed it here in the doc. I'll fix this.
Regards,
Raghavendra
Quoted 13 lines
Thanks,
ReijiQuoted 9 lines
Documentation/virt/kvm/arm/hypercalls.rst +9
-0+ + Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP: + The bit represents the Precision Time Protocol KVM service. + +Errors: + + ======= ============================================================= + -ENOENT Unknown register accessed. + -EBUSY Attempt a 'write' to the register after the VM has started.
Quoted 8 lines
Quoted 8 lines
Documentation/virt/kvm/arm/hypercalls.rst +4
-1+ -EINVAL Invalid bitmap written to the register. + ======= ============================================================= + +.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf --2.36.0.rc2.479.g8af0fa9b8e-goog
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Re: [PATCH v6 6/9] Docs: KVM: Add doc for the bitmap firmware registers
In reply to Raghavendra Rao AnantaQuoted 9 lines · Raghavendra Rao Ananta
Add the documentation for the bitmap firmware registers in
hypercalls.rstandapi.rst. This includes the details forKVM_REG_ARM_STD_BMAP,KVM_REG_ARM_STD_HYP_BMAP, andKVM_REG_ARM_VENDOR_HYP_BMAPregisters.Since the document is growing to carry other hypercall related information, make necessary adjustments to present the document in a generic sense, rather than being PSCI focused.
Quoted 6 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- Documentation/virt/kvm/api.rst | 16 ++++ Documentation/virt/kvm/arm/hypercalls.rst | 94 ++++++++++++++++++----- 2 files changed, 92 insertions(+), 18 deletions(-)
With Reiji's comment fixed:
Quoted 137 lines
Documentation/virt/kvm/api.rst +16
-0@@ -2542,6 +2542,22 @@ arm64 firmware pseudo-registers have the following bit pattern:: 0x6030 0000 0014 <regno:16> +arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: + + 0x6030 0000 0016 <regno:16> + +The bitmap feature firmware registers exposes the hypercall services that are +available for userspace to configure. The set bits corresponds to the services +that are available for the guests to access. By default, KVM sets all the +supported bits during VM initialization. The userspace can discover the +available services via KVM_GET_ONE_REG, and write back the bitmap corresponding +to the features that it wishes guests to see via KVM_SET_ONE_REG. + +Note: These registers are immutable once any of the vCPUs of the VM has run at +least once. A KVM_SET_ONE_REG in such a scenario will return a -EBUSY to userspace. + +(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) + arm64 SVE registers have the following bit patterns:: 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]Documentation/virt/kvm/arm/hypercalls.rst +67
-18@@ -1,32 +1,32 @@ .. SPDX-License-Identifier: GPL-2.0 -========================================= -Power State Coordination Interface (PSCI) -========================================= +======================= +ARM Hypercall Interface +======================= -KVM implements the PSCI (Power State Coordination Interface) -specification in order to provide services such as CPU on/off, reset -and power-off to the guest. +KVM handles the hypercall services as requested by the guests. New hypercall +services are regularly made available by the ARM specification or by KVM (as +vendor services) if they make sense from a virtualization point of view. -The PSCI specification is regularly updated to provide new features, -and KVM implements these updates if they make sense from a virtualization -point of view. - -This means that a guest booted on two different versions of KVM can -observe two different "firmware" revisions. This could cause issues if -a given guest is tied to a particular PSCI revision (unlikely), or if -a migration causes a different PSCI version to be exposed out of the -blue to an unsuspecting guest. +This means that a guest booted on two different versions of KVM can observe +two different "firmware" revisions. This could cause issues if a given guest +is tied to a particular version of a hypercall service, or if a migration +causes a different version to be exposed out of the blue to an unsuspecting +guest. In order to remedy this situation, KVM exposes a set of "firmware pseudo-registers" that can be manipulated using the GET/SET_ONE_REG interface. These registers can be saved/restored by userspace, and set -to a convenient value if required. +to a convenient value as required. -The following register is defined: +The following registers are defined: * KVM_REG_ARM_PSCI_VERSION: + KVM implements the PSCI (Power State Coordination Interface) + specification in order to provide services such as CPU on/off, reset + and power-off to the guest. + - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set (and thus has already been initialized) - Returns the current PSCI version on GET_ONE_REG (defaulting to the@@ -74,4 +74,62 @@ The following register is defined: KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED: The workaround is always active on this vCPU or it is not needed. -.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf + +Bitmap Feature Firmware Registers +--------------------------------- + +Contrary to the above registers, the following registers exposes the hypercall +services in the form of a feature-bitmap to the userspace. This bitmap is +translated to the services that are available to the guest. There is a register +defined per service call owner and can be accessed via GET/SET_ONE_REG interface. + +By default, these registers are set with the upper limit of the features that +are supported. This way userspace can discover all the electable hypercall services +via GET_ONE_REG. The user-space can write-back the desired bitmap back via +SET_ONE_REG. The features for the registers that are untouched, probably because +userspace isn't aware of them, will be exposed as is to the guest. + +Note that KVM would't allow the userspace to configure the registers anymore once +any of the vCPUs has run at least once. Instead, it will return a -EBUSY. + +The psuedo-firmware bitmap register are as follows: + +* KVM_REG_ARM_STD_BMAP: + Controls the bitmap of the ARM Standard Secure Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_BIT_TRNG_V1_0: + The bit represents the services offered under v1.0 of ARM True Random + Number Generator (TRNG) specification, ARM DEN0098. + +* KVM_REG_ARM_STD_HYP_BMAP: + Controls the bitmap of the ARM Standard Hypervisor Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_STD_HYP_BIT_PV_TIME: + The bit represents the Paravirtualized Time service as represented by + ARM DEN0057A. + +* KVM_REG_ARM_VENDOR_HYP_BMAP: + Controls the bitmap of the Vendor specific Hypervisor Service Calls. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT + The bit represents the ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID + function-id + + Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP: + The bit represents the Precision Time Protocol KVM service. +
Documentation/virt/kvm/arm/hypercalls.rst The following register is defined: · line 135
Quoted 10 lines
Documentation/virt/kvm/arm/hypercalls.rst +9
-0+Errors: + + ======= ============================================================= + -ENOENT Unknown register accessed. + -EBUSY Attempt a 'write' to the register after the VM has started. + -EINVAL Invalid bitmap written to the register. + ======= ============================================================= + +.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf
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PATCH v6 7/9 tools: Import ARM SMCCC definitions
In reply to Raghavendra Rao AnantaImport the standard SMCCC definitions from include/linux/arm-smccc.h.
--- tools/include/linux/arm-smccc.h | 193 ++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 tools/include/linux/arm-smccc.h
tools/include/linux/arm-smccc.h new file +193 -0
@@ -0,0 +1,193 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* +* Copyright (c) 2015, Linaro Limited +*/ +#ifndef __LINUX_ARM_SMCCC_H +#define __LINUX_ARM_SMCCC_H + +#include <linux/const.h> + +/* +* This file provides common defines for ARM SMC Calling Convention as +* specified in +* https://developer.arm.com/docs/den0028/latest +* +* This code is up-to-date with version DEN 0028 C +*/ + +#define ARM_SMCCC_STD_CALL _AC(0,U) +#define ARM_SMCCC_FAST_CALL _AC(1,U) +#define ARM_SMCCC_TYPE_SHIFT 31 + +#define ARM_SMCCC_SMC_32 0 +#define ARM_SMCCC_SMC_64 1 +#define ARM_SMCCC_CALL_CONV_SHIFT 30 + +#define ARM_SMCCC_OWNER_MASK 0x3F +#define ARM_SMCCC_OWNER_SHIFT 24 + +#define ARM_SMCCC_FUNC_MASK 0xFFFF + +#define ARM_SMCCC_IS_FAST_CALL (smc_val) \ + ((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT)) +#define ARM_SMCCC_IS_64 (smc_val) \ + ((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT)) +#define ARM_SMCCC_FUNC_NUM (smc_val) ((smc_val) & ARM_SMCCC_FUNC_MASK) +#define ARM_SMCCC_OWNER_NUM (smc_val) \ + (((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK) + +#define ARM_SMCCC_CALL_VAL (type, calling_convention, owner, func_num) \ + (((type) << ARM_SMCCC_TYPE_SHIFT) | \ + ((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \ + (((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \ + ((func_num) & ARM_SMCCC_FUNC_MASK)) + +#define ARM_SMCCC_OWNER_ARCH 0 +#define ARM_SMCCC_OWNER_CPU 1 +#define ARM_SMCCC_OWNER_SIP 2 +#define ARM_SMCCC_OWNER_OEM 3 +#define ARM_SMCCC_OWNER_STANDARD 4 +#define ARM_SMCCC_OWNER_STANDARD_HYP 5 +#define ARM_SMCCC_OWNER_VENDOR_HYP 6 +#define ARM_SMCCC_OWNER_TRUSTED_APP 48 +#define ARM_SMCCC_OWNER_TRUSTED_APP_END 49 +#define ARM_SMCCC_OWNER_TRUSTED_OS 50 +#define ARM_SMCCC_OWNER_TRUSTED_OS_END 63 + +#define ARM_SMCCC_FUNC_QUERY_CALL_UID 0xff01 + +#define ARM_SMCCC_QUIRK_NONE 0 +#define ARM_SMCCC_QUIRK_QCOM_A6 1/* Save/restore register a6 */ + +#define ARM_SMCCC_VERSION_1_0 0x10000 +#define ARM_SMCCC_VERSION_1_1 0x10001 +#define ARM_SMCCC_VERSION_1_2 0x10002 +#define ARM_SMCCC_VERSION_1_3 0x10003 + +#define ARM_SMCCC_1_3_SVE_HINT 0x10000 + +#define ARM_SMCCC_VERSION_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0) + +#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 1) + +#define ARM_SMCCC_ARCH_SOC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 2) + +#define ARM_SMCCC_ARCH_WORKAROUND_1 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x8000) + +#define ARM_SMCCC_ARCH_WORKAROUND_2 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x7fff) + +#define ARM_SMCCC_ARCH_WORKAROUND_3 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x3fff) + +#define ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_FUNC_QUERY_CALL_UID) + +/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */ +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU + +/* KVM "vendor specific" services */ +#define ARM_SMCCC_KVM_FUNC_FEATURES 0 +#define ARM_SMCCC_KVM_FUNC_PTP 1 +#define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 +#define ARM_SMCCC_KVM_NUM_FUNCS 128 + +#define ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_FEATURES) + +#define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 + +/* +* ptp_kvm is a feature used for time sync between vm and host. +* ptp_kvm module in guest kernel will get service from host using +* this hypercall ID. +*/ +#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_PTP) + +/* ptp_kvm counter type ID */ +#define KVM_PTP_VIRT_COUNTER 0 +#define KVM_PTP_PHYS_COUNTER 1 + +/* Paravirtualised time calls (defined by ARM DEN0057A) */ +#define ARM_SMCCC_HV_PV_TIME_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x20) + +#define ARM_SMCCC_HV_PV_TIME_ST \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x21) + +/* TRNG entropy source calls (defined by ARM DEN0098) */ +#define ARM_SMCCC_TRNG_VERSION \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x50) + +#define ARM_SMCCC_TRNG_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x51) + +#define ARM_SMCCC_TRNG_GET_UUID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x52) + +#define ARM_SMCCC_TRNG_RND32 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x53) + +#define ARM_SMCCC_TRNG_RND64 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x53) + +/* +* Return codes defined in ARM DEN 0070A +* ARM DEN 0070A is now merged/consolidated into ARM DEN 0028 C +*/ +#define SMCCC_RET_SUCCESS 0 +#define SMCCC_RET_NOT_SUPPORTED -1 +#define SMCCC_RET_NOT_REQUIRED -2 +#define SMCCC_RET_INVALID_PARAMETER -3 + +#endif /*__LINUX_ARM_SMCCC_H*/
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2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 7/9] tools: Import ARM SMCCC definitions
Quoted 8 lines · Raghavendra Rao Ananta
Import the standard SMCCC definitions from
include/linux/arm-smccc.h.Signed-off-by Raghavendra Rao Ananta <[email protected]>--- tools/include/linux/arm-smccc.h | 193 ++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+)create mode 100644
tools/include/linux/arm-smccc.h
Quoted 190 lines
tools/include/linux/arm-smccc.h new file +183
-0@@ -0,0 +1,193 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* +* Copyright (c) 2015, Linaro Limited +*/ +#ifndef __LINUX_ARM_SMCCC_H +#define __LINUX_ARM_SMCCC_H + +#include <linux/const.h> + +/* +* This file provides common defines for ARM SMC Calling Convention as +* specified in +* https://developer.arm.com/docs/den0028/latest +* +* This code is up-to-date with version DEN 0028 C +*/ + +#define ARM_SMCCC_STD_CALL _AC(0,U) +#define ARM_SMCCC_FAST_CALL _AC(1,U) +#define ARM_SMCCC_TYPE_SHIFT 31 + +#define ARM_SMCCC_SMC_32 0 +#define ARM_SMCCC_SMC_64 1 +#define ARM_SMCCC_CALL_CONV_SHIFT 30 + +#define ARM_SMCCC_OWNER_MASK 0x3F +#define ARM_SMCCC_OWNER_SHIFT 24 + +#define ARM_SMCCC_FUNC_MASK 0xFFFF + +#define ARM_SMCCC_IS_FAST_CALL (smc_val) \ + ((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT)) +#define ARM_SMCCC_IS_64 (smc_val) \ + ((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT)) +#define ARM_SMCCC_FUNC_NUM (smc_val) ((smc_val) & ARM_SMCCC_FUNC_MASK) +#define ARM_SMCCC_OWNER_NUM (smc_val) \ + (((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK) + +#define ARM_SMCCC_CALL_VAL (type, calling_convention, owner, func_num) \ + (((type) << ARM_SMCCC_TYPE_SHIFT) | \ + ((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \ + (((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \ + ((func_num) & ARM_SMCCC_FUNC_MASK)) + +#define ARM_SMCCC_OWNER_ARCH 0 +#define ARM_SMCCC_OWNER_CPU 1 +#define ARM_SMCCC_OWNER_SIP 2 +#define ARM_SMCCC_OWNER_OEM 3 +#define ARM_SMCCC_OWNER_STANDARD 4 +#define ARM_SMCCC_OWNER_STANDARD_HYP 5 +#define ARM_SMCCC_OWNER_VENDOR_HYP 6 +#define ARM_SMCCC_OWNER_TRUSTED_APP 48 +#define ARM_SMCCC_OWNER_TRUSTED_APP_END 49 +#define ARM_SMCCC_OWNER_TRUSTED_OS 50 +#define ARM_SMCCC_OWNER_TRUSTED_OS_END 63 + +#define ARM_SMCCC_FUNC_QUERY_CALL_UID 0xff01 + +#define ARM_SMCCC_QUIRK_NONE 0 +#define ARM_SMCCC_QUIRK_QCOM_A6 1/* Save/restore register a6 */ + +#define ARM_SMCCC_VERSION_1_0 0x10000 +#define ARM_SMCCC_VERSION_1_1 0x10001 +#define ARM_SMCCC_VERSION_1_2 0x10002 +#define ARM_SMCCC_VERSION_1_3 0x10003 + +#define ARM_SMCCC_1_3_SVE_HINT 0x10000 + +#define ARM_SMCCC_VERSION_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0) + +#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 1) + +#define ARM_SMCCC_ARCH_SOC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 2) + +#define ARM_SMCCC_ARCH_WORKAROUND_1 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x8000) + +#define ARM_SMCCC_ARCH_WORKAROUND_2 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x7fff) + +#define ARM_SMCCC_ARCH_WORKAROUND_3 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x3fff) + +#define ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_FUNC_QUERY_CALL_UID) + +/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */ +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU + +/* KVM "vendor specific" services */ +#define ARM_SMCCC_KVM_FUNC_FEATURES 0 +#define ARM_SMCCC_KVM_FUNC_PTP 1 +#define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 +#define ARM_SMCCC_KVM_NUM_FUNCS 128 + +#define ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_FEATURES) + +#define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 + +/* +* ptp_kvm is a feature used for time sync between vm and host. +* ptp_kvm module in guest kernel will get service from host using +* this hypercall ID. +*/ +#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_PTP) + +/* ptp_kvm counter type ID */ +#define KVM_PTP_VIRT_COUNTER 0 +#define KVM_PTP_PHYS_COUNTER 1 + +/* Paravirtualised time calls (defined by ARM DEN0057A) */ +#define ARM_SMCCC_HV_PV_TIME_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x20) + +#define ARM_SMCCC_HV_PV_TIME_ST \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x21) + +/* TRNG entropy source calls (defined by ARM DEN0098) */ +#define ARM_SMCCC_TRNG_VERSION \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x50) + +#define ARM_SMCCC_TRNG_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x51) + +#define ARM_SMCCC_TRNG_GET_UUID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x52) + +#define ARM_SMCCC_TRNG_RND32 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x53) + +#define ARM_SMCCC_TRNG_RND64 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD, \ + 0x53) +
tools/include/linux/arm-smccc.h line 193
Quoted 10 lines
tools/include/linux/arm-smccc.h new file +10
-0+/* +* Return codes defined in ARM DEN 0070A +* ARM DEN 0070A is now merged/consolidated into ARM DEN 0028 C +*/ +#define SMCCC_RET_SUCCESS 0 +#define SMCCC_RET_NOT_SUPPORTED -1 +#define SMCCC_RET_NOT_REQUIRED -2 +#define SMCCC_RET_INVALID_PARAMETER -3 + +#endif /*__LINUX_ARM_SMCCC_H*/
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PATCH v6 8/9 selftests: KVM: aarch64: Introduce hypercall ABI test
In reply to Raghavendra Rao AnantaIntroduce a KVM selftest to check the hypercall interface for arm64 platforms. The test validates the user-space' [GET|SET]_ONE_REG interface to read/write the psuedo-firmware registers as well as its effects on the guest upon certain configurations.
--- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++ 3 files changed, 337 insertions(+) create mode 100644 tools/testing/selftests/kvm/aarch64/hypercalls.c
tools/testing/selftests/kvm/.gitignore +1 -0
@@ -2,6 +2,7 @@ /aarch64/arch_timer /aarch64/debug-exceptions /aarch64/get-reg-list +/aarch64/hypercalls /aarch64/psci_test /aarch64/vcpu_width_config /aarch64/vgic_init
tools/testing/selftests/kvm/Makefile +1 -0
@@ -105,6 +105,7 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test TEST_GEN_PROGS_aarch64 += aarch64/arch_timer TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list +TEST_GEN_PROGS_aarch64 += aarch64/hypercalls TEST_GEN_PROGS_aarch64 += aarch64/psci_test TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +335 -0
335 lines not on this page · raw message
Signature · 6 lines
2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v6 8/9] selftests: KVM: aarch64: Introduce hypercall ABI test
Hi Raghavendra,
Quoted 6 lines · Raghavendra Rao Ananta
Introduce a KVM selftest to check the hypercall interface for arm64 platforms. The test validates the user-space' [GET|SET]_ONE_REG interface to read/write the psuedo-firmware registers as well as its effects on the guest upon certain configurations.
Quoted 8 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++ 3 files changed, 337 insertions(+)create mode 100644
tools/testing/selftests/kvm/aarch64/hypercalls.c
There are comments about @false_hvc_info[] and some nits, as below. Please evaluate and improve if it makes sense to you. Otherwise, it looks good to me:
Quoted 111 lines
tools/testing/selftests/kvm/.gitignore +1
-0@@ -2,6 +2,7 @@ /aarch64/arch_timer /aarch64/debug-exceptions /aarch64/get-reg-list +/aarch64/hypercalls /aarch64/psci_test /aarch64/vcpu_width_config /aarch64/vgic_inittools/testing/selftests/kvm/Makefile +1
-0@@ -105,6 +105,7 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test TEST_GEN_PROGS_aarch64 += aarch64/arch_timer TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list +TEST_GEN_PROGS_aarch64 += aarch64/hypercalls TEST_GEN_PROGS_aarch64 += aarch64/psci_test TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config TEST_GEN_PROGS_aarch64 += aarch64/vgic_inittools/testing/selftests/kvm/aarch64/hypercalls.c new file +81
-0@@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* hypercalls: Check the ARM64's psuedo-firmware bitmap register interface. +* +* The test validates the basic hypercall functionalities that are exposed +* via the psuedo-firmware bitmap register. This includes the registers' +* read/write behavior before and after the VM has started, and if the +* hypercalls are properly masked or unmasked to the guest when disabled or +* enabled from the KVM userspace, respectively. +*/ + +#include <errno.h> +#include <linux/arm-smccc.h> +#include <asm/kvm.h> +#include <kvm_util.h> + +#include "processor.h" + +#define FW_REG_ULIMIT_VAL (max_feat_bit) (GENMASK(max_feat_bit, 0)) + +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1 + +struct kvm_fw_reg_info { +uint64_t reg;/* Register definition */ +uint64_t max_feat_bit;/* Bit that represents the upper limit of the feature-map */ +}; + +#define FW_REG_INFO (r) \ + { \ + .reg = r, \ + .max_feat_bit = r##_BIT_MAX, \ + } + +static const struct kvm_fw_reg_info fw_reg_info[] = { +FW_REG_INFO (KVM_REG_ARM_STD_BMAP ), +FW_REG_INFO (KVM_REG_ARM_STD_HYP_BMAP ), +FW_REG_INFO (KVM_REG_ARM_VENDOR_HYP_BMAP ), +}; + +enum test_stage { +TEST_STAGE_REG_IFACE , +TEST_STAGE_HVC_IFACE_FEAT_DISABLED , +TEST_STAGE_HVC_IFACE_FEAT_ENABLED , +TEST_STAGE_HVC_IFACE_FALSE_INFO , +TEST_STAGE_END , +}; + +static int stage =TEST_STAGE_REG_IFACE ; + +struct test_hvc_info { +uint32_t func_id; +uint64_t arg1; +}; + +#define TEST_HVC_INFO (f, a1) \ + { \ + .func_id = f, \ + .arg1 = a1, \ + } + +static const struct test_hvc_info hvc_info[] = { +/* KVM_REG_ARM_STD_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_VERSION ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_TRNG_RND64 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_GET_UUID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND32 ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND64 ,0 ), + +/* KVM_REG_ARM_STD_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_HV_PV_TIME_FEATURES ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_FEATURES ,ARM_SMCCC_HV_PV_TIME_ST ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_ST ,0 ), + +/* KVM_REG_ARM_VENDOR_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID , +ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ,KVM_PTP_VIRT_COUNTER ),
tools/testing/selftests/kvm/aarch64/hypercalls.c line 91
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+}; + +/* Feed false hypercall info to test the KVM behavior */ +static const struct test_hvc_info false_hvc_info[] = { +/* Feature support check against a different family of hypercalls */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_TRNG_RND64 ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_FEATURES ,ARM_SMCCC_TRNG_RND64 ), +}; +
I don't see too much benefits of @false_hvc_info[] because NOT_SUPPORTED is always returned from its test case. I think it and its test case can be removed if you agree. I'm not sure if it was suggested by somebody else.
Quoted 124 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +124
-0+static void guest_test_hvc (const struct test_hvc_info *hc_info) +{ +unsigned int i; +struct arm_smccc_res res; +unsigned int hvc_info_arr_sz; + + hvc_info_arr_sz = + hc_info == hvc_info ?ARRAY_SIZE (hvc_info) :ARRAY_SIZE (false_hvc_info); + +for (i =0 ; i < hvc_info_arr_sz; i++, hc_info++) { +memset (&res,0 ,sizeof (res)); +smccc_hvc (hc_info->func_id, hc_info->arg1,0 ,0 ,0 ,0 ,0 ,0 , &res); + +switch (stage) { +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +GUEST_ASSERT_3 (res.a0 ==SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +GUEST_ASSERT_3 (res.a0 !=SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + } +} + +static void guest_code (void ) +{ +while (stage !=TEST_STAGE_END ) { +switch (stage) { +case TEST_STAGE_REG_IFACE : +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +guest_test_hvc (hvc_info); +break ; +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +guest_test_hvc (false_hvc_info); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + +GUEST_SYNC (stage); + } + +GUEST_DONE (); +} + +static int set_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t val) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )&val, + }; + +return _vcpu_ioctl (vm,0 ,KVM_SET_ONE_REG , ®); +} + +static void get_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t *addr) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )addr, + }; + +vcpu_ioctl (vm,0 ,KVM_GET_ONE_REG , ®); +} + +struct st_time { +uint32_t rev; +uint32_t attr; +uint64_t st_time; +}; + +#define STEAL_TIME_SIZE ((sizeof(struct st_time) + 63) & ~63) +#define ST_GPA_BASE (1 << 30) + +static void steal_time_init (struct kvm_vm *vm) +{ +uint64_t st_ipa = (ulong )ST_GPA_BASE ; +unsigned int gpages; +struct kvm_device_attr dev = { + .group =KVM_ARM_VCPU_PVTIME_CTRL , + .attr =KVM_ARM_VCPU_PVTIME_IPA , + .addr = (uint64_t )&st_ipa, + }; + + gpages =vm_calc_num_guest_pages (VM_MODE_DEFAULT ,STEAL_TIME_SIZE ); +vm_userspace_mem_region_add (vm,VM_MEM_SRC_ANONYMOUS ,ST_GPA_BASE ,1 , gpages,0 ); + +vcpu_ioctl (vm,0 ,KVM_SET_DEVICE_ATTR , &dev); +} + +static void test_fw_regs_before_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* First 'read' should be an upper limit of the features supported */ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), +"Expected all the features to be set for reg: 0x%lx; expected: 0x%lx; read: 0x%lx\n" , + reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), val); + +/* Test a 'write' by disabling all the features of the register map */ + ret =set_fw_reg (vm, reg_info->reg,0 ); +TEST_ASSERT (ret ==0 , +"Failed to clear all the features of reg: 0x%lx; ret: %d\n" , + reg_info->reg, errno); + +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , reg_info->reg); + +/* +* Test enabling a feature that's not supported.
tools/testing/selftests/kvm/aarch64/hypercalls.c line 225
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Avoid this check if all the bits are occupied. +*/ +if (reg_info->max_feat_bit <63 ) { + ret =set_fw_reg (vm, reg_info->reg,BIT (reg_info->max_feat_bit +1 )); +TEST_ASSERT (ret !=0 && errno ==EINVAL , +"Unexpected behavior or return value (%d) while setting an unsupported feature for reg: 0x%lx\n" , + errno, reg_info->reg); + } + } +}
Just in case :)
ret = set_fw_reg(vm, reg_info->reg, GENMASK(63, reg_info->max_feat_bit + 1));
Quoted 20 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +20
-0+ +static void test_fw_regs_after_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* +* Before starting the VM, the test clears all the bits. +* Check if that's still the case. +*/ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , + reg_info->reg); + +/*
tools/testing/selftests/kvm/aarch64/hypercalls.c line 255
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Set all the features for this register again. KVM shouldn't +* allow this as the VM is running. +*/ + ret =set_fw_reg (vm, reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit)); +TEST_ASSERT (ret !=0 && errno ==EBUSY , +"Unexpected behavior or return value (%d) while setting a feature while VM is running for reg: 0x%lx\n" , + errno, reg_info->reg); + } +} +
I guess you want to check -EBUSY is returned. In that case, the comments here could be clearer, something like below to emphasize '-EBUSY'.
/*
* After VM runs for once, -EBUSY should be returned on attempt
* to set features. Check if the correct errno is returned. */
Quoted 71 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +70
-0+static struct kvm_vm *test_vm_create (void ) +{ +struct kvm_vm *vm; + + vm =vm_create_default (0 ,0 , guest_code); + +ucall_init (vm,NULL ); +steal_time_init (vm); + +return vm; +} + +static struct kvm_vm *test_guest_stage (struct kvm_vm *vm) +{ +struct kvm_vm *ret_vm = vm; + +pr_debug ("Stage: %d\n" , stage); + +switch (stage) { +case TEST_STAGE_REG_IFACE : +test_fw_regs_after_vm_start (vm); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +/* Start a new VM so that all the features are now enabled by default */ +kvm_vm_free (vm); + ret_vm =test_vm_create (); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +break ; +default : +TEST_FAIL ("Unknown test stage: %d\n" , stage); + } + + stage++; +sync_global_to_guest (vm, stage); + +return ret_vm; +} + +static void test_run (void ) +{ +struct kvm_vm *vm; +struct ucall uc; +bool guest_done = false; + + vm =test_vm_create (); + +test_fw_regs_before_vm_start (vm); + +while (!guest_done) { +vcpu_run (vm,0 ); + +switch (get_ucall (vm,0 , &uc)) { +case UCALL_SYNC : + vm =test_guest_stage (vm); +break ; +case UCALL_DONE : + guest_done = true; +break ; +case UCALL_ABORT : +TEST_FAIL ("%s at %s:%ld\n\tvalues: 0x%lx, 0x%lx; 0x%lx, stage: %u" , + (const char *)uc.args[0 ], __FILE__, uc.args[1 ], + uc.args[2 ], uc.args[3 ], uc.args[4 ], stage); +break ; +default : +TEST_FAIL ("Unexpected guest exit\n" ); + } + } +
tools/testing/selftests/kvm/aarch64/hypercalls.c line 335
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+kvm_vm_free (vm); +} + +int main (void ) +{ +setbuf (stdout,NULL ); + +test_run (); +return 0 ; +}
Thanks,
Gavin
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Re: [PATCH v6 8/9] selftests: KVM: aarch64: Introduce hypercall ABI test
Hi Gavin,
Quoted 143 lines · Gavin Shan
Hi Raghavendra,
Quoted 6 lines · Raghavendra Rao Ananta
Introduce a KVM selftest to check the hypercall interface for arm64 platforms. The test validates the user-space' [GET|SET]_ONE_REG interface to read/write the psuedo-firmware registers as well as its effects on the guest upon certain configurations.
Quoted 8 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++ 3 files changed, 337 insertions(+)create mode 100644
tools/testing/selftests/kvm/aarch64/hypercalls.cThere are comments about @false_hvc_info[] and some nits, as below. Please evaluate and improve if it makes sense to you. Otherwise, it looks good to me:
Reviewed-by Gavin Shan <[email protected]>Quoted 118 lines
tools/testing/selftests/kvm/.gitignore +1
-0@@ -2,6 +2,7 @@ /aarch64/arch_timer /aarch64/debug-exceptions /aarch64/get-reg-list +/aarch64/hypercalls /aarch64/psci_test /aarch64/vcpu_width_config /aarch64/vgic_inittools/testing/selftests/kvm/Makefile +1
-0@@ -105,6 +105,7 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test TEST_GEN_PROGS_aarch64 += aarch64/arch_timer TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list +TEST_GEN_PROGS_aarch64 += aarch64/hypercalls TEST_GEN_PROGS_aarch64 += aarch64/psci_test TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config TEST_GEN_PROGS_aarch64 += aarch64/vgic_inittools/testing/selftests/kvm/aarch64/hypercalls.c new file +88
-0@@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* hypercalls: Check the ARM64's psuedo-firmware bitmap register interface. +* +* The test validates the basic hypercall functionalities that are exposed +* via the psuedo-firmware bitmap register. This includes the registers' +* read/write behavior before and after the VM has started, and if the +* hypercalls are properly masked or unmasked to the guest when disabled or +* enabled from the KVM userspace, respectively. +*/ + +#include <errno.h> +#include <linux/arm-smccc.h> +#include <asm/kvm.h> +#include <kvm_util.h> + +#include "processor.h" + +#define FW_REG_ULIMIT_VAL (max_feat_bit) (GENMASK(max_feat_bit, 0)) + +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1 + +struct kvm_fw_reg_info { +uint64_t reg;/* Register definition */ +uint64_t max_feat_bit;/* Bit that represents the upper limit of the feature-map */ +}; + +#define FW_REG_INFO (r) \ + { \ + .reg = r, \ + .max_feat_bit = r##_BIT_MAX, \ + } + +static const struct kvm_fw_reg_info fw_reg_info[] = { +FW_REG_INFO (KVM_REG_ARM_STD_BMAP ), +FW_REG_INFO (KVM_REG_ARM_STD_HYP_BMAP ), +FW_REG_INFO (KVM_REG_ARM_VENDOR_HYP_BMAP ), +}; + +enum test_stage { +TEST_STAGE_REG_IFACE , +TEST_STAGE_HVC_IFACE_FEAT_DISABLED , +TEST_STAGE_HVC_IFACE_FEAT_ENABLED , +TEST_STAGE_HVC_IFACE_FALSE_INFO , +TEST_STAGE_END , +}; + +static int stage =TEST_STAGE_REG_IFACE ; + +struct test_hvc_info { +uint32_t func_id; +uint64_t arg1; +}; + +#define TEST_HVC_INFO (f, a1) \ + { \ + .func_id = f, \ + .arg1 = a1, \ + } + +static const struct test_hvc_info hvc_info[] = { +/* KVM_REG_ARM_STD_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_VERSION ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_TRNG_RND64 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_GET_UUID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND32 ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND64 ,0 ), + +/* KVM_REG_ARM_STD_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_HV_PV_TIME_FEATURES ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_FEATURES ,ARM_SMCCC_HV_PV_TIME_ST ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_ST ,0 ), + +/* KVM_REG_ARM_VENDOR_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID , +ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ,KVM_PTP_VIRT_COUNTER ), +}; + +/* Feed false hypercall info to test the KVM behavior */ +static const struct test_hvc_info false_hvc_info[] = { +/* Feature support check against a different family of hypercalls */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_TRNG_RND64 ),
Quoted 9 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c line 91
Quoted 3 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +3
-0+ TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_TRNG_RND64), +}; +I don't see too much benefits of @false_hvc_info[] because
NOT_SUPPORTEDis always returned from its test case. I think it and its test case can be removed if you agree. I'm not sure if it was suggested by somebody else.
While this is not exactly testing the bitmap firmware registers, the idea behind introducing false_hvc_info[] was to introduce some negative tests and see if KVM handles it well. Especially with *_FEATURES func_ids, we can accidentally introduce functional bugs in KVM, and these would act as our safety net. I was planning to also test with some reserved hypercall numbers, just to test if the kernel doesn't panic for some reason.
Quoted 137 lines
Quoted 124 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +124
-0+static void guest_test_hvc (const struct test_hvc_info *hc_info) +{ +unsigned int i; +struct arm_smccc_res res; +unsigned int hvc_info_arr_sz; + + hvc_info_arr_sz = + hc_info == hvc_info ?ARRAY_SIZE (hvc_info) :ARRAY_SIZE (false_hvc_info); + +for (i =0 ; i < hvc_info_arr_sz; i++, hc_info++) { +memset (&res,0 ,sizeof (res)); +smccc_hvc (hc_info->func_id, hc_info->arg1,0 ,0 ,0 ,0 ,0 ,0 , &res); + +switch (stage) { +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +GUEST_ASSERT_3 (res.a0 ==SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +GUEST_ASSERT_3 (res.a0 !=SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + } +} + +static void guest_code (void ) +{ +while (stage !=TEST_STAGE_END ) { +switch (stage) { +case TEST_STAGE_REG_IFACE : +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +guest_test_hvc (hvc_info); +break ; +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +guest_test_hvc (false_hvc_info); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + +GUEST_SYNC (stage); + } + +GUEST_DONE (); +} + +static int set_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t val) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )&val, + }; + +return _vcpu_ioctl (vm,0 ,KVM_SET_ONE_REG , ®); +} + +static void get_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t *addr) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )addr, + }; + +vcpu_ioctl (vm,0 ,KVM_GET_ONE_REG , ®); +} + +struct st_time { +uint32_t rev; +uint32_t attr; +uint64_t st_time; +}; + +#define STEAL_TIME_SIZE ((sizeof(struct st_time) + 63) & ~63) +#define ST_GPA_BASE (1 << 30) + +static void steal_time_init (struct kvm_vm *vm) +{ +uint64_t st_ipa = (ulong )ST_GPA_BASE ; +unsigned int gpages; +struct kvm_device_attr dev = { + .group =KVM_ARM_VCPU_PVTIME_CTRL , + .attr =KVM_ARM_VCPU_PVTIME_IPA , + .addr = (uint64_t )&st_ipa, + }; + + gpages =vm_calc_num_guest_pages (VM_MODE_DEFAULT ,STEAL_TIME_SIZE ); +vm_userspace_mem_region_add (vm,VM_MEM_SRC_ANONYMOUS ,ST_GPA_BASE ,1 , gpages,0 ); + +vcpu_ioctl (vm,0 ,KVM_SET_DEVICE_ATTR , &dev); +} + +static void test_fw_regs_before_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* First 'read' should be an upper limit of the features supported */ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), +"Expected all the features to be set for reg: 0x%lx; expected: 0x%lx; read: 0x%lx\n" , + reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), val); + +/* Test a 'write' by disabling all the features of the register map */ + ret =set_fw_reg (vm, reg_info->reg,0 ); +TEST_ASSERT (ret ==0 , +"Failed to clear all the features of reg: 0x%lx; ret: %d\n" , + reg_info->reg, errno); + +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , reg_info->reg); + +/* +* Test enabling a feature that's not supported. tools/testing/selftests/kvm/aarch64/hypercalls.c line 225
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Avoid this check if all the bits are occupied. +*/ +if (reg_info->max_feat_bit <63 ) { + ret =set_fw_reg (vm, reg_info->reg,BIT (reg_info->max_feat_bit +1 )); +TEST_ASSERT (ret !=0 && errno ==EINVAL , +"Unexpected behavior or return value (%d) while setting an unsupported feature for reg: 0x%lx\n" , + errno, reg_info->reg); + } + } +}Just in case :)
Quoted 2 lines
ret = set_fw_reg(vm, reg_info->reg, GENMASK(63, reg_info->max_feat_bit + 1));
It may be better to cover the entire range, but to test only the (max_feat_bit + 1) gives us the advantage of checking if there's any discrepancy between the kernel and the test, now that *_BIT_MAX are not a part of UAPI headers.
Probably also include your test along with the existing one?
Quoted 36 lines
Quoted 21 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +20
-0+ +static void test_fw_regs_after_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* +* Before starting the VM, the test clears all the bits. +* Check if that's still the case. +*/ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , + reg_info->reg); + +/* tools/testing/selftests/kvm/aarch64/hypercalls.c line 255
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Set all the features for this register again. KVM shouldn't +* allow this as the VM is running. +*/ + ret =set_fw_reg (vm, reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit)); +TEST_ASSERT (ret !=0 && errno ==EBUSY , +"Unexpected behavior or return value (%d) while setting a feature while VM is running for reg: 0x%lx\n" , + errno, reg_info->reg); + } +} +I guess you want to check
-EBUSYis returned. In that case, the comments here could be clearer, something like below to emphasize '-EBUSY'.
Quoted 5 lines
/*
* After VM runs for once,-EBUSYshould be returned on attempt
* to set features. Check if the correct errno is returned. */
Sounds good.
Quoted 76 lines
Quoted 76 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +76
-0+static struct kvm_vm *test_vm_create (void ) +{ +struct kvm_vm *vm; + + vm =vm_create_default (0 ,0 , guest_code); + +ucall_init (vm,NULL ); +steal_time_init (vm); + +return vm; +} + +static struct kvm_vm *test_guest_stage (struct kvm_vm *vm) +{ +struct kvm_vm *ret_vm = vm; + +pr_debug ("Stage: %d\n" , stage); + +switch (stage) { +case TEST_STAGE_REG_IFACE : +test_fw_regs_after_vm_start (vm); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +/* Start a new VM so that all the features are now enabled by default */ +kvm_vm_free (vm); + ret_vm =test_vm_create (); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +break ; +default : +TEST_FAIL ("Unknown test stage: %d\n" , stage); + } + + stage++; +sync_global_to_guest (vm, stage); + +return ret_vm; +} + +static void test_run (void ) +{ +struct kvm_vm *vm; +struct ucall uc; +bool guest_done = false; + + vm =test_vm_create (); + +test_fw_regs_before_vm_start (vm); + +while (!guest_done) { +vcpu_run (vm,0 ); + +switch (get_ucall (vm,0 , &uc)) { +case UCALL_SYNC : + vm =test_guest_stage (vm); +break ; +case UCALL_DONE : + guest_done = true; +break ; +case UCALL_ABORT : +TEST_FAIL ("%s at %s:%ld\n\tvalues: 0x%lx, 0x%lx; 0x%lx, stage: %u" , + (const char *)uc.args[0 ], __FILE__, uc.args[1 ], + uc.args[2 ], uc.args[3 ], uc.args[4 ], stage); +break ; +default : +TEST_FAIL ("Unexpected guest exit\n" ); + } + } + +kvm_vm_free (vm); +} + +int main (void ) +{ +setbuf (stdout,NULL );
Quoted 9 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c line 335
Quoted 5 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +4
-0+ +test_run (); +return 0 ; +}Thanks,
Gavin
Thanks for the reviews on all the patches, Gavin.
Regards,
Raghavendra
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Re: [PATCH v6 8/9] selftests: KVM: aarch64: Introduce hypercall ABI test
Hi Raghavendra,
Quoted 150 lines · Raghavendra Rao Ananta
Quoted 140 lines · Gavin Shan
Quoted 6 lines · Raghavendra Rao Ananta
Introduce a KVM selftest to check the hypercall interface for arm64 platforms. The test validates the user-space' [GET|SET]_ONE_REG interface to read/write the psuedo-firmware registers as well as its effects on the guest upon certain configurations.
Quoted 8 lines
Signed-off-by Raghavendra Rao Ananta <[email protected]>--- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++ 3 files changed, 337 insertions(+)create mode 100644
tools/testing/selftests/kvm/aarch64/hypercalls.cThere are comments about @false_hvc_info[] and some nits, as below. Please evaluate and improve if it makes sense to you. Otherwise, it looks good to me:
Reviewed-by Gavin Shan <[email protected]>Quoted 118 lines
tools/testing/selftests/kvm/.gitignore +1
-0@@ -2,6 +2,7 @@ /aarch64/arch_timer /aarch64/debug-exceptions /aarch64/get-reg-list +/aarch64/hypercalls /aarch64/psci_test /aarch64/vcpu_width_config /aarch64/vgic_inittools/testing/selftests/kvm/Makefile +1
-0@@ -105,6 +105,7 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test TEST_GEN_PROGS_aarch64 += aarch64/arch_timer TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list +TEST_GEN_PROGS_aarch64 += aarch64/hypercalls TEST_GEN_PROGS_aarch64 += aarch64/psci_test TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config TEST_GEN_PROGS_aarch64 += aarch64/vgic_inittools/testing/selftests/kvm/aarch64/hypercalls.c new file +88
-0@@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* hypercalls: Check the ARM64's psuedo-firmware bitmap register interface. +* +* The test validates the basic hypercall functionalities that are exposed +* via the psuedo-firmware bitmap register. This includes the registers' +* read/write behavior before and after the VM has started, and if the +* hypercalls are properly masked or unmasked to the guest when disabled or +* enabled from the KVM userspace, respectively. +*/ + +#include <errno.h> +#include <linux/arm-smccc.h> +#include <asm/kvm.h> +#include <kvm_util.h> + +#include "processor.h" + +#define FW_REG_ULIMIT_VAL (max_feat_bit) (GENMASK(max_feat_bit, 0)) + +/* Last valid bits of the bitmapped firmware registers */ +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0 +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1 + +struct kvm_fw_reg_info { +uint64_t reg;/* Register definition */ +uint64_t max_feat_bit;/* Bit that represents the upper limit of the feature-map */ +}; + +#define FW_REG_INFO (r) \ + { \ + .reg = r, \ + .max_feat_bit = r##_BIT_MAX, \ + } + +static const struct kvm_fw_reg_info fw_reg_info[] = { +FW_REG_INFO (KVM_REG_ARM_STD_BMAP ), +FW_REG_INFO (KVM_REG_ARM_STD_HYP_BMAP ), +FW_REG_INFO (KVM_REG_ARM_VENDOR_HYP_BMAP ), +}; + +enum test_stage { +TEST_STAGE_REG_IFACE , +TEST_STAGE_HVC_IFACE_FEAT_DISABLED , +TEST_STAGE_HVC_IFACE_FEAT_ENABLED , +TEST_STAGE_HVC_IFACE_FALSE_INFO , +TEST_STAGE_END , +}; + +static int stage =TEST_STAGE_REG_IFACE ; + +struct test_hvc_info { +uint32_t func_id; +uint64_t arg1; +}; + +#define TEST_HVC_INFO (f, a1) \ + { \ + .func_id = f, \ + .arg1 = a1, \ + } + +static const struct test_hvc_info hvc_info[] = { +/* KVM_REG_ARM_STD_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_VERSION ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_TRNG_RND64 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_GET_UUID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND32 ,0 ), +TEST_HVC_INFO (ARM_SMCCC_TRNG_RND64 ,0 ), + +/* KVM_REG_ARM_STD_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_HV_PV_TIME_FEATURES ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_FEATURES ,ARM_SMCCC_HV_PV_TIME_ST ), +TEST_HVC_INFO (ARM_SMCCC_HV_PV_TIME_ST ,0 ), + +/* KVM_REG_ARM_VENDOR_HYP_BMAP */ +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID , +ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID ,0 ), +TEST_HVC_INFO (ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ,KVM_PTP_VIRT_COUNTER ), +}; + +/* Feed false hypercall info to test the KVM behavior */ +static const struct test_hvc_info false_hvc_info[] = { +/* Feature support check against a different family of hypercalls */ +TEST_HVC_INFO (ARM_SMCCC_TRNG_FEATURES ,ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID ), +TEST_HVC_INFO (ARM_SMCCC_ARCH_FEATURES_FUNC_ID ,ARM_SMCCC_TRNG_RND64 ),Quoted 9 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c line 91
Quoted 3 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +3
-0+ TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_TRNG_RND64), +}; +I don't see too much benefits of @false_hvc_info[] because
NOT_SUPPORTEDis always returned from its test case. I think it and its test case can be removed if you agree. I'm not sure if it was suggested by somebody else.
Quoted 8 lines
While this is not exactly testing the bitmap firmware registers, the idea behind introducing false_hvc_info[] was to introduce some negative tests and see if KVM handles it well. Especially with
*_FEATURESfunc_ids, we can accidentally introduce functional bugs in KVM, and these would act as our safety net. I was planning to also test with some reserved hypercall numbers, just to test if the kernel doesn't panic for some reason.
Ok, thanks for the explanation. It makes sense to me.
Quoted 137 lines
Quoted 137 lines
Quoted 124 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +124
-0+static void guest_test_hvc (const struct test_hvc_info *hc_info) +{ +unsigned int i; +struct arm_smccc_res res; +unsigned int hvc_info_arr_sz; + + hvc_info_arr_sz = + hc_info == hvc_info ?ARRAY_SIZE (hvc_info) :ARRAY_SIZE (false_hvc_info); + +for (i =0 ; i < hvc_info_arr_sz; i++, hc_info++) { +memset (&res,0 ,sizeof (res)); +smccc_hvc (hc_info->func_id, hc_info->arg1,0 ,0 ,0 ,0 ,0 ,0 , &res); + +switch (stage) { +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +GUEST_ASSERT_3 (res.a0 ==SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +GUEST_ASSERT_3 (res.a0 !=SMCCC_RET_NOT_SUPPORTED , + res.a0, hc_info->func_id, hc_info->arg1); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + } +} + +static void guest_code (void ) +{ +while (stage !=TEST_STAGE_END ) { +switch (stage) { +case TEST_STAGE_REG_IFACE : +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +guest_test_hvc (hvc_info); +break ; +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +guest_test_hvc (false_hvc_info); +break ; +default : +GUEST_ASSERT_1 (0 , stage); + } + +GUEST_SYNC (stage); + } + +GUEST_DONE (); +} + +static int set_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t val) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )&val, + }; + +return _vcpu_ioctl (vm,0 ,KVM_SET_ONE_REG , ®); +} + +static void get_fw_reg (struct kvm_vm *vm,uint64_t id,uint64_t *addr) +{ +struct kvm_one_reg reg = { + .id = id, + .addr = (uint64_t )addr, + }; + +vcpu_ioctl (vm,0 ,KVM_GET_ONE_REG , ®); +} + +struct st_time { +uint32_t rev; +uint32_t attr; +uint64_t st_time; +}; + +#define STEAL_TIME_SIZE ((sizeof(struct st_time) + 63) & ~63) +#define ST_GPA_BASE (1 << 30) + +static void steal_time_init (struct kvm_vm *vm) +{ +uint64_t st_ipa = (ulong )ST_GPA_BASE ; +unsigned int gpages; +struct kvm_device_attr dev = { + .group =KVM_ARM_VCPU_PVTIME_CTRL , + .attr =KVM_ARM_VCPU_PVTIME_IPA , + .addr = (uint64_t )&st_ipa, + }; + + gpages =vm_calc_num_guest_pages (VM_MODE_DEFAULT ,STEAL_TIME_SIZE ); +vm_userspace_mem_region_add (vm,VM_MEM_SRC_ANONYMOUS ,ST_GPA_BASE ,1 , gpages,0 ); + +vcpu_ioctl (vm,0 ,KVM_SET_DEVICE_ATTR , &dev); +} + +static void test_fw_regs_before_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* First 'read' should be an upper limit of the features supported */ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), +"Expected all the features to be set for reg: 0x%lx; expected: 0x%lx; read: 0x%lx\n" , + reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit), val); + +/* Test a 'write' by disabling all the features of the register map */ + ret =set_fw_reg (vm, reg_info->reg,0 ); +TEST_ASSERT (ret ==0 , +"Failed to clear all the features of reg: 0x%lx; ret: %d\n" , + reg_info->reg, errno); + +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , reg_info->reg); + +/* +* Test enabling a feature that's not supported. tools/testing/selftests/kvm/aarch64/hypercalls.c line 225
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Avoid this check if all the bits are occupied. +*/ +if (reg_info->max_feat_bit <63 ) { + ret =set_fw_reg (vm, reg_info->reg,BIT (reg_info->max_feat_bit +1 )); +TEST_ASSERT (ret !=0 && errno ==EINVAL , +"Unexpected behavior or return value (%d) while setting an unsupported feature for reg: 0x%lx\n" , + errno, reg_info->reg); + } + } +}Just in case :)
Quoted 8 lines
Quoted 2 lines
ret = set_fw_reg(vm, reg_info->reg, GENMASK(63, reg_info->max_feat_bit + 1));It may be better to cover the entire range, but to test only the (
max_feat_bit+ 1) gives us the advantage of checking if there's any discrepancy between the kernel and the test, now that*_BIT_MAXare not a part of UAPI headers.Probably also include your test along with the existing one?
Thanks for your explanation again. Lets keep it as it is then.
Quoted 116 lines
Quoted 36 lines
Quoted 21 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +20
-0+ +static void test_fw_regs_after_vm_start (struct kvm_vm *vm) +{ +uint64_t val; +unsigned int i; +int ret; + +for (i =0 ; i <ARRAY_SIZE (fw_reg_info); i++) { +const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i]; + +/* +* Before starting the VM, the test clears all the bits. +* Check if that's still the case. +*/ +get_fw_reg (vm, reg_info->reg, &val); +TEST_ASSERT (val ==0 , +"Expected all the features to be cleared for reg: 0x%lx\n" , + reg_info->reg); + +/* tools/testing/selftests/kvm/aarch64/hypercalls.c line 255
Quoted 10 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +10
-0+* Set all the features for this register again. KVM shouldn't +* allow this as the VM is running. +*/ + ret =set_fw_reg (vm, reg_info->reg,FW_REG_ULIMIT_VAL (reg_info->max_feat_bit)); +TEST_ASSERT (ret !=0 && errno ==EBUSY , +"Unexpected behavior or return value (%d) while setting a feature while VM is running for reg: 0x%lx\n" , + errno, reg_info->reg); + } +} +I guess you want to check
-EBUSYis returned. In that case, the comments here could be clearer, something like below to emphasize '-EBUSY'.Quoted 5 lines
/*
* After VM runs for once,-EBUSYshould be returned on attempt
* to set features. Check if the correct errno is returned. */Sounds good.
Quoted 73 lines
Quoted 73 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c new file +73
-0+static struct kvm_vm *test_vm_create (void ) +{ +struct kvm_vm *vm; + + vm =vm_create_default (0 ,0 , guest_code); + +ucall_init (vm,NULL ); +steal_time_init (vm); + +return vm; +} + +static struct kvm_vm *test_guest_stage (struct kvm_vm *vm) +{ +struct kvm_vm *ret_vm = vm; + +pr_debug ("Stage: %d\n" , stage); + +switch (stage) { +case TEST_STAGE_REG_IFACE : +test_fw_regs_after_vm_start (vm); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_DISABLED : +/* Start a new VM so that all the features are now enabled by default */ +kvm_vm_free (vm); + ret_vm =test_vm_create (); +break ; +case TEST_STAGE_HVC_IFACE_FEAT_ENABLED : +case TEST_STAGE_HVC_IFACE_FALSE_INFO : +break ; +default : +TEST_FAIL ("Unknown test stage: %d\n" , stage); + } + + stage++; +sync_global_to_guest (vm, stage); + +return ret_vm; +} + +static void test_run (void ) +{ +struct kvm_vm *vm; +struct ucall uc; +bool guest_done = false; + + vm =test_vm_create (); + +test_fw_regs_before_vm_start (vm); + +while (!guest_done) { +vcpu_run (vm,0 ); + +switch (get_ucall (vm,0 , &uc)) { +case UCALL_SYNC : + vm =test_guest_stage (vm); +break ; +case UCALL_DONE : + guest_done = true; +break ; +case UCALL_ABORT : +TEST_FAIL ("%s at %s:%ld\n\tvalues: 0x%lx, 0x%lx; 0x%lx, stage: %u" , + (const char *)uc.args[0 ], __FILE__, uc.args[1 ], + uc.args[2 ], uc.args[3 ], uc.args[4 ], stage); +break ; +default : +TEST_FAIL ("Unexpected guest exit\n" ); + } + } + +kvm_vm_free (vm); +} +
Quoted 8 lines
Quoted 8 lines
tools/testing/selftests/kvm/aarch64/hypercalls.c line 335
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tools/testing/selftests/kvm/aarch64/hypercalls.c new file +7
-0+int main (void ) +{ +setbuf (stdout,NULL ); + +test_run (); +return 0 ; +}
[...]
Thanks,
Gavin
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PATCH v6 9/9 selftests: KVM: aarch64: Add the bitmap firmware registers to get-reg-list
In reply to Raghavendra Rao AnantaAdd the psuedo-firmware registers KVM_REG_ARM_STD_BMAP, KVM_REG_ARM_STD_HYP_BMAP, and KVM_REG_ARM_VENDOR_HYP_BMAP to the base_regs[] list.
Also, add the COPROC support for KVM_REG_ARM_FW_FEAT_BMAP.
--- tools/testing/selftests/kvm/aarch64/get-reg-list.c | 8 ++++++++ 1 file changed, 8 insertions(+)
tools/testing/selftests/kvm/aarch64/get-reg-list.c +8 -0
@@ -294,6 +294,11 @@ static void print_reg(struct vcpu_config *c, __u64 id) "%s: Unexpected bits set in FW reg id: 0x%llx", config_name(c), id);printf ("\tKVM_REG_ARM_FW_REG(%lld),\n" , id &0xffff );break ; +case KVM_REG_ARM_FW_FEAT_BMAP : +TEST_ASSERT (id ==KVM_REG_ARM_FW_FEAT_BMAP_REG (id &0xffff ), +"%s: Unexpected bits set in the bitmap feature FW reg id: 0x%llx" ,config_name (c), id); +printf ("\tKVM_REG_ARM_FW_FEAT_BMAP_REG(%lld),\n" , id &0xffff ); +break ;case KVM_REG_ARM64_SVE :if (has_cap (c,KVM_CAP_ARM_SVE ))printf ("\t%s,\n" ,sve_id_to_str (c, id));
@@ -692,6 +697,9 @@ static __u64 base_regs[] = {KVM_REG_ARM_FW_REG (1 ),/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 */ KVM_REG_ARM_FW_REG (2 ),/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 */ KVM_REG_ARM_FW_REG (3 ),/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 */ +KVM_REG_ARM_FW_FEAT_BMAP_REG (0 ),/* KVM_REG_ARM_STD_BMAP */ +KVM_REG_ARM_FW_FEAT_BMAP_REG (1 ),/* KVM_REG_ARM_STD_HYP_BMAP */ +KVM_REG_ARM_FW_FEAT_BMAP_REG (2 ),/* KVM_REG_ARM_VENDOR_HYP_BMAP */ ARM64_SYS_REG (3 ,3 ,14 ,3 ,1 ),/* CNTV_CTL_EL0 */ ARM64_SYS_REG (3 ,3 ,14 ,3 ,2 ),/* CNTV_CVAL_EL0 */ ARM64_SYS_REG(3, 3, 14, 0, 2),
Signature · 6 lines
2.36.0.rc2.479.g8af0fa9b8e-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm