add bus lock VM exit support
v3 cover add bus lock VM exit support
v2->v3 changelogs:
- use a bitmap to get/set the capability of bus lock detection. we support exit and off mode currently.
- put the handle of exiting to userspace in vmx.c, thus no need to define a shadow to track vmx->exit_reason.bus_lock_detected.
- remove the vcpu->stats.bus_locks since every bus lock exits to userspace.
---
Add the support for bus lock VM exit in KVM. It is a sub-feature of bus lock detection and the detailed info can be found in the patch 2/2.
In this patch series, the first patch applies Sean's refactor to vcpu_vmx.exit_reason available at
https://patchwork.kernel.org/patch/11500659.
It is necessary as bus lock VM exit adds a new modifier bit(bit 26) in exit_reason field in VMCS.
The second patch is the enabling work for bus lock VM exit. Add the support to set the capability to enable bus lock vm exit. The current implementation just exit to user space when handling the bus lock detected in guest.
The concrete throttling policy in user space still needs to be discussed. We can enforce ratelimit on bus lock in guest, just inject some sleep time, or maybe other ideas.
Document for Bus Lock Detection is now available at the latest "Intel Architecture Instruction Set Extensions Programming Reference" (see below). Note that the section 9.1 for Bus Lock Debug Exception requires modification due to the feedback from kernel community:
https://lore.kernel.org/lkml/[email protected]/
Chenyi Qiang (1):
KVM: VMX: Enable bus lock VM exit
Sean Christopherson (1):
KVM: VMX: Convert vcpu_vmx.exit_reason to a union
arch/x86/include/asm/kvm_host.h | 5 ++ arch/x86/include/asm/vmx.h | 1 + arch/x86/include/asm/vmxfeatures.h | 1 + arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/include/uapi/asm/vmx.h | 4 +- arch/x86/kvm/vmx/capabilities.h | 6 ++ arch/x86/kvm/vmx/nested.c | 42 ++++++++---- arch/x86/kvm/vmx/vmx.c | 106 ++++++++++++++++++++--------- arch/x86/kvm/vmx/vmx.h | 25 ++++++- arch/x86/kvm/x86.c | 27 +++++++- arch/x86/kvm/x86.h | 5 ++ include/uapi/linux/kvm.h | 7 ++ 12 files changed, 179 insertions(+), 51 deletions(-)
Signature · 1 line
2.17.1
RFC v3 1/2 KVM: VMX: Convert vcpu_vmx.exit_reason to a union
From: Sean Christopherson <[email protected]>
Convert vcpu_vmx.exit_reason from a u32 to a union (of size u32). The full VM_EXIT_REASON field is comprised of a 16-bit basic exit reason in bits 15:0, and single-bit modifiers in bits 31:16.
Historically, KVM has only had to worry about handling the "failed VM-Entry" modifier, which could only be set in very specific flows and required dedicated handling. I.e. manually stripping the FAILED_VMENTRY bit was a somewhat viable approach. But even with only a single bit to worry about, KVM has had several bugs related to comparing a basic exit reason against the full exit reason store in vcpu_vmx.
Upcoming Intel features, e.g. SGX, will add new modifier bits that can be set on more or less any VM-Exit, as opposed to the significantly more restricted FAILED_VMENTRY, i.e. correctly handling everything in one-off flows isn't scalable. Tracking exit reason in a union forces code to explicitly choose between consuming the full exit reason and the basic exit, and is a convenient way to document and access the modifiers.
No functional change intended.
Cc Xiaoyao Li <[email protected]>
Signed-off-by Sean Christopherson <[email protected]>
--- arch/x86/kvm/vmx/nested.c | 42 ++++++++++++++++--------- arch/x86/kvm/vmx/vmx.c | 64 ++++++++++++++++++++------------------- arch/x86/kvm/vmx/vmx.h | 25 ++++++++++++++- 3 files changed, 84 insertions(+), 47 deletions(-)
arch/x86/kvm/vmx/nested.c +27 -15
@@ -3304,7 +3304,11 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,struct vmcs12 *vmcs12 =get_vmcs12 (vcpu);enum vm_entry_failure_code entry_failure_code;bool evaluate_pending_interrupts; -u32 exit_reason, failed_index; +union vmx_exit_reason exit_reason = { + .basic =EXIT_REASON_INVALID_STATE , + .failed_vmentry =1 , + }; +u32 failed_index;if (kvm_check_request (KVM_REQ_TLB_FLUSH_CURRENT , vcpu))kvm_vcpu_flush_tlb_current (vcpu);
@@ -3354,7 +3358,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,if (nested_vmx_check_guest_state (vcpu, vmcs12, &entry_failure_code)) { - exit_reason =EXIT_REASON_INVALID_STATE ; + exit_reason.basic =EXIT_REASON_INVALID_STATE ; vmcs12->exit_qualification = entry_failure_code; goto vmentry_fail_vmexit; }
@@ -3365,7 +3369,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, vcpu->arch.tsc_offset += vmcs12->tsc_offset;if (prepare_vmcs02 (vcpu, vmcs12, &entry_failure_code)) { - exit_reason =EXIT_REASON_INVALID_STATE ; + exit_reason.basic =EXIT_REASON_INVALID_STATE ; vmcs12->exit_qualification = entry_failure_code; goto vmentry_fail_vmexit_guest_mode; }
@@ -3375,7 +3379,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, vmcs12->vm_entry_msr_load_addr, vmcs12->vm_entry_msr_load_count);if (failed_index) { - exit_reason =EXIT_REASON_MSR_LOAD_FAIL ; + exit_reason.basic =EXIT_REASON_MSR_LOAD_FAIL ; vmcs12->exit_qualification = failed_index; goto vmentry_fail_vmexit_guest_mode; }
@@ -3443,7 +3447,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,return NVMX_VMENTRY_VMEXIT ;load_vmcs12_host_state (vcpu, vmcs12); - vmcs12->vm_exit_reason = exit_reason |VMX_EXIT_REASONS_FAILED_VMENTRY ; + vmcs12->vm_exit_reason = exit_reason.full;if (enable_shadow_vmcs || vmx->nested.hv_evmcs) vmx->nested.need_vmcs12_to_shadow_sync = true;return NVMX_VMENTRY_VMEXIT ;
@@ -5488,7 +5492,12 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu)return kvm_skip_emulated_instruction (vcpu); fail: -nested_vmx_vmexit (vcpu, vmx->exit_reason, +/* +* This is effectively a reflected VM-Exit, as opposed to a synthesized +* nested VM-Exit. Pass the original exit reason, i.e. don't hardcode +* EXIT_REASON_VMFUNC as the exit reason. +*/ +nested_vmx_vmexit (vcpu, vmx->exit_reason.full,vmx_get_intr_info (vcpu),vmx_get_exit_qual (vcpu));return 1 ;
@@ -5556,7 +5565,8 @@ static bool nested_vmx_exit_handled_io(struct kvm_vcpu *vcpu,* MSR bitmap. This may be the case even when L0 doesn't use MSR bitmaps. */ static bool nested_vmx_exit_handled_msr (struct kvm_vcpu *vcpu, -struct vmcs12 *vmcs12,u32 exit_reason) +struct vmcs12 *vmcs12, +union vmx_exit_reason exit_reason) {u32 msr_index =kvm_rcx_read (vcpu);gpa_t bitmap;
@@ -5570,7 +5580,7 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu,* First we need to figure out which of the four to use: */ bitmap = vmcs12->msr_bitmap; -if (exit_reason ==EXIT_REASON_MSR_WRITE ) +if (exit_reason.basic ==EXIT_REASON_MSR_WRITE ) bitmap +=2048 ;if (msr_index >=0xc0000000 ) { msr_index -=0xc0000000 ;
@@ -5707,11 +5717,12 @@ static bool nested_vmx_exit_handled_mtf(struct vmcs12 *vmcs12)* Return true if L0 wants to handle an exit from L2 regardless of whether or not * L1 wants the exit. Only call this when in is_guest_mode (L2). */ -static bool nested_vmx_l0_wants_exit (struct kvm_vcpu *vcpu,u32 exit_reason) +static bool nested_vmx_l0_wants_exit (struct kvm_vcpu *vcpu, +union vmx_exit_reason exit_reason) {u32 intr_info; -switch ((u16 )exit_reason) { +switch ((u16 )exit_reason.basic) {case EXIT_REASON_EXCEPTION_NMI : intr_info =vmx_get_intr_info (vcpu);if (is_nmi (intr_info))
@@ -5767,12 +5778,13 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)* Return 1 if L1 wants to intercept an exit from L2. Only call this when in * is_guest_mode (L2). */ -static bool nested_vmx_l1_wants_exit (struct kvm_vcpu *vcpu,u32 exit_reason) +static bool nested_vmx_l1_wants_exit (struct kvm_vcpu *vcpu, +union vmx_exit_reason exit_reason) {struct vmcs12 *vmcs12 =get_vmcs12 (vcpu);u32 intr_info; -switch ((u16 )exit_reason) { +switch ((u16 )exit_reason.basic) {case EXIT_REASON_EXCEPTION_NMI : intr_info =vmx_get_intr_info (vcpu);if (is_nmi (intr_info))
@@ -5891,7 +5903,7 @@ static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)bool nested_vmx_reflect_vmexit (struct kvm_vcpu *vcpu) {struct vcpu_vmx *vmx =to_vmx (vcpu); -u32 exit_reason = vmx->exit_reason; +union vmx_exit_reason exit_reason = vmx->exit_reason;unsigned long exit_qual;u32 exit_intr_info;
@@ -5913,7 +5925,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu) exit_intr_info =vmx_get_intr_info (vcpu); exit_qual =vmx_get_exit_qual (vcpu); -trace_kvm_nested_vmexit (kvm_rip_read (vcpu), exit_reason, exit_qual, +trace_kvm_nested_vmexit (kvm_rip_read (vcpu), exit_reason.full, exit_qual, vmx->idt_vectoring_info, exit_intr_info,vmcs_read32 (VM_EXIT_INTR_ERROR_CODE ),KVM_ISA_VMX );
@@ -5942,7 +5954,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu) } reflect_vmexit: -nested_vmx_vmexit (vcpu, exit_reason, exit_intr_info, exit_qual); +nested_vmx_vmexit (vcpu, exit_reason.full, exit_intr_info, exit_qual);return true; }
arch/x86/kvm/vmx/vmx.c +33 -31
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arch/x86/kvm/vmx/vmx.h +24 -1
@@ -92,6 +92,29 @@ struct pt_desc {struct pt_ctx guest; }; +union vmx_exit_reason { +struct { +u32 basic :16 ; +u32 reserved16 :1 ; +u32 reserved17 :1 ; +u32 reserved18 :1 ; +u32 reserved19 :1 ; +u32 reserved20 :1 ; +u32 reserved21 :1 ; +u32 reserved22 :1 ; +u32 reserved23 :1 ; +u32 reserved24 :1 ; +u32 reserved25 :1 ; +u32 reserved26 :1 ; +u32 enclave_mode :1 ; +u32 smi_pending_mtf :1 ; +u32 smi_from_vmx_root :1 ; +u32 reserved30 :1 ; +u32 failed_vmentry :1 ; + }; +u32 full; +}; +/* * The nested_vmx structure is part of vcpu_vmx, and holds information we need * for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -266,7 +289,7 @@ struct vcpu_vmx {int vpid;bool emulation_required; -u32 exit_reason; +union vmx_exit_reason exit_reason;/* Posted interrupt descriptor */ struct pi_desc pi_desc;
Signature · 1 line
2.17.1
RFC v3 2/2 KVM: VMX: Enable bus lock VM exit
In reply to Chenyi QiangVirtual Machine can exploit bus locks to degrade the performance of system. Bus lock can be caused by split locked access to writeback(WB) memory or by using locks on uncacheable(UC) memory. The bus lock is typically >1000 cycles slower than an atomic operation within a cache line. It also disrupts performance on other cores (which must wait for the bus lock to be released before their memory operations can complete).
To address the threat, bus lock VM exit is introduced to notify the VMM when a bus lock was acquired, allowing it to enforce throttling or other policy based mitigations.
A VMM can enable VM exit due to bus locks by setting a new "Bus Lock Detection" VM-execution control(bit 30 of Secondary Processor-based VM execution controls). If delivery of this VM exit was preempted by a higher priority VM exit (e.g. EPT misconfiguration, EPT violation, APIC access VM exit, APIC write VM exit, exception bitmap exiting), bit 26 of exit reason in vmcs field is set to 1.
In current implementation, the KVM exposes this capability through KVM_CAP_X86_BUS_LOCK_EXIT. The user can get the supported mode bitmap (i.e. off and exit) and enable it explicitly (disabled by default). If bus locks in guest are detected by KVM, exit to user space even when current exit reason is handled by KVM internally. Set a new field KVM_RUN_BUS_LOCK in vcpu->run->flags to inform the user space that there is a bus lock in guest and it is preempted by a higher prioriy VM exit.
Document for Bus Lock VM exit is now available at the latest "Intel Architecture Instruction Set Extensions Programming Reference".
Co-developed-by Xiaoyao Li <[email protected]>
Signed-off-by Xiaoyao Li <[email protected]>
Signed-off-by Chenyi Qiang <[email protected]>
--- arch/x86/include/asm/kvm_host.h | 5 ++++ arch/x86/include/asm/vmx.h | 1 + arch/x86/include/asm/vmxfeatures.h | 1 + arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/include/uapi/asm/vmx.h | 4 ++- arch/x86/kvm/vmx/capabilities.h | 6 +++++ arch/x86/kvm/vmx/vmx.c | 42 ++++++++++++++++++++++++++++-- arch/x86/kvm/vmx/vmx.h | 2 +- arch/x86/kvm/x86.c | 27 ++++++++++++++++++- arch/x86/kvm/x86.h | 5 ++++ include/uapi/linux/kvm.h | 7 +++++ 11 files changed, 96 insertions(+), 5 deletions(-)
arch/x86/include/asm/kvm_host.h +5 -0
@@ -961,6 +961,9 @@ struct kvm_arch {bool guest_can_read_msr_platform_info;bool exception_payload_enabled; +/* Set when bus lock vm exit is enabled by user */ +bool bus_lock_exit; +struct kvm_pmu_event_filter *pmu_event_filter;struct task_struct *nx_lpage_recovery_thread; };
@@ -1347,6 +1350,8 @@ extern u8 kvm_tsc_scaling_ratio_frac_bits;extern u64 kvm_max_tsc_scaling_ratio;/* 1ull << kvm_tsc_scaling_ratio_frac_bits */ extern u64 kvm_default_tsc_scaling_ratio; +/* bus lock detection supported */ +extern bool kvm_has_bus_lock_exit;extern u64 kvm_mce_cap_supported;
arch/x86/include/asm/vmx.h +1 -0
@@ -73,6 +73,7 @@#define SECONDARY_EXEC_PT_USE_GPA VMCS_CONTROL_BIT(PT_USE_GPA)#define SECONDARY_EXEC_TSC_SCALING VMCS_CONTROL_BIT(TSC_SCALING)#define SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE VMCS_CONTROL_BIT(USR_WAIT_PAUSE) +#define SECONDARY_EXEC_BUS_LOCK_DETECTION VMCS_CONTROL_BIT(BUS_LOCK_DETECTION)#define PIN_BASED_EXT_INTR_MASK VMCS_CONTROL_BIT(INTR_EXITING)#define PIN_BASED_NMI_EXITING VMCS_CONTROL_BIT(NMI_EXITING)
arch/x86/include/asm/vmxfeatures.h +1 -0
@@ -83,5 +83,6 @@#define VMX_FEATURE_TSC_SCALING ( 2*32+ 25)/* Scale hardware TSC when read in guest */ #define VMX_FEATURE_USR_WAIT_PAUSE ( 2*32+ 26)/* Enable TPAUSE, UMONITOR, UMWAIT in guest */ #define VMX_FEATURE_ENCLV_EXITING ( 2*32+ 28)/* "" VM-Exit on ENCLV (leaf dependent) */ +#define VMX_FEATURE_BUS_LOCK_DETECTION ( 2*32+ 30)/* VM-Exit when bus lock caused */ #endif /* _ASM_X86_VMXFEATURES_H */
arch/x86/include/uapi/asm/kvm.h +1 -0
@@ -111,6 +111,7 @@ struct kvm_ioapic_state {#define KVM_NR_IRQCHIPS 3#define KVM_RUN_X86_SMM (1 << 0) +#define KVM_RUN_BUS_LOCK (1 << 1)/* for KVM_GET_REGS and KVM_SET_REGS */ struct kvm_regs {
arch/x86/include/uapi/asm/vmx.h +3 -1
@@ -88,6 +88,7 @@#define EXIT_REASON_XRSTORS 64#define EXIT_REASON_UMWAIT 67#define EXIT_REASON_TPAUSE 68 +#define EXIT_REASON_BUS_LOCK 74#define VMX_EXIT_REASONS \ { EXIT_REASON_EXCEPTION_NMI, "EXCEPTION_NMI" }, \
@@ -148,7 +149,8 @@ { EXIT_REASON_XSAVES, "XSAVES" }, \ { EXIT_REASON_XRSTORS, "XRSTORS" }, \ { EXIT_REASON_UMWAIT, "UMWAIT" }, \ - { EXIT_REASON_TPAUSE, "TPAUSE" } + { EXIT_REASON_TPAUSE, "TPAUSE" }, \ + { EXIT_REASON_BUS_LOCK, "BUS_LOCK" } #define VMX_EXIT_REASON_FLAGS \ { VMX_EXIT_REASONS_FAILED_VMENTRY, "FAILED_VMENTRY" }
arch/x86/kvm/vmx/capabilities.h +6 -0
@@ -262,6 +262,12 @@ static inline bool cpu_has_vmx_tsc_scaling(void)SECONDARY_EXEC_TSC_SCALING ; } +static inline bool cpu_has_vmx_bus_lock_detection (void ) +{ +return vmcs_config.cpu_based_2nd_exec_ctrl & +SECONDARY_EXEC_BUS_LOCK_DETECTION ; +} +static inline bool cpu_has_vmx_apicv (void ) { return cpu_has_vmx_apic_register_virt() &&
arch/x86/kvm/vmx/vmx.c +40 -2
84 lines not on this page · raw message
arch/x86/kvm/vmx/vmx.h +1 -1
@@ -105,7 +105,7 @@ union vmx_exit_reason { u32 reserved23 : 1; u32 reserved24 : 1; u32 reserved25 : 1; - u32 reserved26 : 1; + u32 bus_lock_detected : 1; u32 enclave_mode : 1; u32 smi_pending_mtf : 1; u32 smi_from_vmx_root : 1;
arch/x86/kvm/x86.c +26 -1
@@ -134,6 +134,8 @@ u64 __read_mostly kvm_max_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_max_tsc_scaling_ratio);u64 __read_mostly kvm_default_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_default_tsc_scaling_ratio); +bool __read_mostly kvm_has_bus_lock_exit; +EXPORT_SYMBOL_GPL (kvm_has_bus_lock_exit);/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */ static u32 __read_mostly tsc_tolerance_ppm =250 ;
@@ -3578,6 +3580,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_SMALLER_MAXPHYADDR : r = (int ) allow_smaller_maxphyaddr;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT : + r |=KVM_BUS_LOCK_DETECTION_OFF ; +if (kvm_has_bus_lock_exit) + r |=KVM_BUS_LOCK_DETECTION_EXIT ; +break ;default :break ; }
@@ -5030,6 +5037,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, kvm->arch.exception_payload_enabled = cap->args[0 ]; r =0 ;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT : + r = -EINVAL ; +if (cap->args[0 ] & ~KVM_BUS_LOCK_DETECTION_VALID_MODE ) +break ; + +if ((cap->args[0 ] &KVM_BUS_LOCK_DETECTION_OFF ) && + (cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT )) +break ; + +if (kvm_has_bus_lock_exit && + cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT ) + kvm->arch.bus_lock_exit = true; + r =0 ; +break ;default : r = -EINVAL ;break ;
@@ -7772,12 +7793,16 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)struct kvm_run *kvm_run = vcpu->run; kvm_run->if_flag = (kvm_get_rflags (vcpu) &X86_EFLAGS_IF ) !=0 ; - kvm_run->flags =is_smm (vcpu) ?KVM_RUN_X86_SMM :0 ; kvm_run->cr8 =kvm_get_cr8 (vcpu); kvm_run->apic_base =kvm_get_apic_base (vcpu); kvm_run->ready_for_interrupt_injection =pic_in_kernel (vcpu->kvm) ||kvm_vcpu_ready_for_interrupt_injection (vcpu); + +if (is_smm (vcpu)) + kvm_run->flags |=KVM_RUN_X86_SMM ; +else + kvm_run->flags &= ~KVM_RUN_X86_SMM ; }static void update_cr8_intercept (struct kvm_vcpu *vcpu)
arch/x86/kvm/x86.h +5 -0
@@ -335,6 +335,11 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm)return kvm->arch.cstate_in_guest; } +static inline bool kvm_bus_lock_exit_enabled (struct kvm *kvm) +{ +return kvm->arch.bus_lock_exit; +} + DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);static inline void kvm_before_interrupt (struct kvm_vcpu *vcpu)
include/uapi/linux/kvm.h +7 -0
@@ -248,6 +248,7 @@ struct kvm_hyperv_exit {#define KVM_EXIT_IOAPIC_EOI 26#define KVM_EXIT_HYPERV 27#define KVM_EXIT_ARM_NISV 28 +#define KVM_EXIT_BUS_LOCK 29/* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */
@@ -1035,6 +1036,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_LAST_CPU 184#define KVM_CAP_SMALLER_MAXPHYADDR 185#define KVM_CAP_S390_DIAG318 186 +#define KVM_CAP_X86_BUS_LOCK_EXIT 187#ifdef KVM_CAP_IRQ_ROUTING
@@ -1689,4 +1691,9 @@ struct kvm_hyperv_eventfd {#define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0)#define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) +#define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) +#define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) +#define KVM_BUS_LOCK_DETECTION_VALID_MODE (KVM_BUS_LOCK_DETECTION_OFF | \ + KVM_BUS_LOCK_DETECTION_EXIT) +#endif /* __LINUX_KVM_H */
Signature · 1 line
2.17.1
Re: [RFC v3 2/2] KVM: VMX: Enable bus lock VM exit
arch/x86/include/asm/kvm_host.h struct kvm_arch { · line 965
Quoted 10 lines · Chenyi Qiang
arch/x86/include/asm/kvm_host.h +2
-0@@ -961,6 +961,9 @@ struct kvm_arch {bool guest_can_read_msr_platform_info;bool exception_payload_enabled; +/* Set when bus lock vm exit is enabled by user */ +bool bus_lock_exit;
Maybe bus_lock_detection_enabled? Then you don't need the comment or the accessor.
arch/x86/include/asm/kvm_host.h extern u8 kvm_tsc_scaling_ratio_frac_bits; · line 1354
Quoted 10 lines
arch/x86/include/asm/kvm_host.h +3
-0+struct kvm_pmu_event_filter *pmu_event_filter;struct task_struct *nx_lpage_recovery_thread; };@@ -1347,6 +1350,8 @@ extern u8 kvm_tsc_scaling_ratio_frac_bits;extern u64 kvm_max_tsc_scaling_ratio;/* 1ull << kvm_tsc_scaling_ratio_frac_bits */ extern u64 kvm_default_tsc_scaling_ratio; +/* bus lock detection supported */ +extern bool kvm_has_bus_lock_exit;
Hrm, it'd be nice to somehow squeeze this into kvm_cpu_caps, but I can't think of a clever/clean way to do so.
Quoted 101 lines
arch/x86/include/asm/kvm_host.h +0
-0extern u64 kvm_mce_cap_supported;arch/x86/include/asm/vmx.h +1
-0@@ -73,6 +73,7 @@#define SECONDARY_EXEC_PT_USE_GPA VMCS_CONTROL_BIT(PT_USE_GPA)#define SECONDARY_EXEC_TSC_SCALING VMCS_CONTROL_BIT(TSC_SCALING)#define SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE VMCS_CONTROL_BIT(USR_WAIT_PAUSE) +#define SECONDARY_EXEC_BUS_LOCK_DETECTION VMCS_CONTROL_BIT(BUS_LOCK_DETECTION)#define PIN_BASED_EXT_INTR_MASK VMCS_CONTROL_BIT(INTR_EXITING)#define PIN_BASED_NMI_EXITING VMCS_CONTROL_BIT(NMI_EXITING)arch/x86/include/asm/vmxfeatures.h +1
-0@@ -83,5 +83,6 @@#define VMX_FEATURE_TSC_SCALING ( 2*32+ 25)/* Scale hardware TSC when read in guest */ #define VMX_FEATURE_USR_WAIT_PAUSE ( 2*32+ 26)/* Enable TPAUSE, UMONITOR, UMWAIT in guest */ #define VMX_FEATURE_ENCLV_EXITING ( 2*32+ 28)/* "" VM-Exit on ENCLV (leaf dependent) */ +#define VMX_FEATURE_BUS_LOCK_DETECTION ( 2*32+ 30)/* VM-Exit when bus lock caused */ #endif /* _ASM_X86_VMXFEATURES_H */ arch/x86/include/uapi/asm/kvm.h +1
-0@@ -111,6 +111,7 @@ struct kvm_ioapic_state {#define KVM_NR_IRQCHIPS 3#define KVM_RUN_X86_SMM (1 << 0) +#define KVM_RUN_BUS_LOCK (1 << 1)/* for KVM_GET_REGS and KVM_SET_REGS */ struct kvm_regs {arch/x86/include/uapi/asm/vmx.h +3
-1@@ -88,6 +88,7 @@#define EXIT_REASON_XRSTORS 64#define EXIT_REASON_UMWAIT 67#define EXIT_REASON_TPAUSE 68 +#define EXIT_REASON_BUS_LOCK 74#define VMX_EXIT_REASONS \ { EXIT_REASON_EXCEPTION_NMI, "EXCEPTION_NMI" }, \@@ -148,7 +149,8 @@ { EXIT_REASON_XSAVES, "XSAVES" }, \ { EXIT_REASON_XRSTORS, "XRSTORS" }, \ { EXIT_REASON_UMWAIT, "UMWAIT" }, \ - { EXIT_REASON_TPAUSE, "TPAUSE" } + { EXIT_REASON_TPAUSE, "TPAUSE" }, \ + { EXIT_REASON_BUS_LOCK, "BUS_LOCK" } #define VMX_EXIT_REASON_FLAGS \ { VMX_EXIT_REASONS_FAILED_VMENTRY, "FAILED_VMENTRY" }arch/x86/kvm/vmx/capabilities.h +6
-0@@ -262,6 +262,12 @@ static inline bool cpu_has_vmx_tsc_scaling(void)SECONDARY_EXEC_TSC_SCALING ; } +static inline bool cpu_has_vmx_bus_lock_detection (void ) +{ +return vmcs_config.cpu_based_2nd_exec_ctrl & +SECONDARY_EXEC_BUS_LOCK_DETECTION ; +} +static inline bool cpu_has_vmx_apicv (void ) { return cpu_has_vmx_apic_register_virt() &&arch/x86/kvm/vmx/vmx.c +5
-1@@ -2461,7 +2461,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE |SECONDARY_EXEC_PT_USE_GPA |SECONDARY_EXEC_PT_CONCEAL_VMX | -SECONDARY_EXEC_ENABLE_VMFUNC ; +SECONDARY_EXEC_ENABLE_VMFUNC | +SECONDARY_EXEC_BUS_LOCK_DETECTION ;if (cpu_has_sgx ()) opt2 |=SECONDARY_EXEC_ENCLS_EXITING ; if (adjust_vmx_controls(min2, opt2,@@ -4244,6 +4245,9 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx) } } +if (!kvm_bus_lock_exit_enabled (vmx->vcpu.kvm)) + exec_control &= ~SECONDARY_EXEC_BUS_LOCK_DETECTION ; + vmx->secondary_exec_control = exec_control; }
arch/x86/kvm/vmx/vmx.c static int handle_encls(struct kvm_vcpu *vcpu) · line 5696
Quoted 8 lines
arch/x86/kvm/vmx/vmx.c +5
-0@@ -5685,6 +5689,14 @@ static int handle_encls(struct kvm_vcpu *vcpu)return 1 ; } +static int handle_bus_lock (struct kvm_vcpu *vcpu) +{ +struct kvm_run *kvm_run = vcpu->run; + + kvm_run->exit_reason =KVM_EXIT_BUS_LOCK ;
No need for kvm_run, "vcpu->run->exit_reason = KVM_EXIT_BUS_LOCK" will do.
Quoted 24 lines
arch/x86/kvm/vmx/vmx.c +5
-1+return 0 ; +} +/* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs @@ -5741,6 +5753,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { [EXIT_REASON_VMFUNC] = handle_vmx_instruction, [EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer, [EXIT_REASON_ENCLS] = handle_encls, + [EXIT_REASON_BUS_LOCK] = handle_bus_lock, }; static const int kvm_vmx_max_exit_handlers =@@ -5979,7 +5992,7 @@ void dump_vmcs(void)* The guest has exited. See if we can fix it or if we need userspace * assistance. */ -static int vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) +static int __vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) {struct vcpu_vmx *vmx =to_vmx (vcpu);union vmx_exit_reason exit_reason = vmx->exit_reason;
arch/x86/kvm/vmx/vmx.c static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) · line 6149
Quoted 6 lines
arch/x86/kvm/vmx/vmx.c +3
-0@@ -6131,6 +6144,28 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)return 0 ; } +static int vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) +{ +struct vcpu_vmx *vmx =to_vmx (vcpu);
Personal preference, but I'd probably skip the local 'vmx' variable since there's only a single user, i.e. "to_vmx(vcpu)->exit_reason....".
arch/x86/kvm/vmx/vmx.c static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) · line 6156
Quoted 7 lines
arch/x86/kvm/vmx/vmx.c +7
-0+int ret =__vmx_handle_exit (vcpu, exit_fastpath); + +/* +* Even when current exit reason is handled by KVM +* internally, we still needs to exit to user space +* when bus lock detected to inform that there is a +* bus lock in guest.
Run these lines out to the edge of 80 chars, wrapping this aggressively just adds extra lines.
Quoted 16 lines
arch/x86/kvm/vmx/vmx.c +12
-0+*/ +if (vmx->exit_reason.bus_lock_detected) { +if (ret >0 ) + vcpu->run->exit_reason =KVM_EXIT_BUS_LOCK ; +else + vcpu->run->flags |=KVM_RUN_BUS_LOCK ; +return 0 ; + } + vcpu->run->flags &= ~KVM_RUN_BUS_LOCK ; +return ret; +} +/* * Software based L1D cache flush which is used when microcode providing * the cache control MSR is not loaded.
arch/x86/kvm/vmx/vmx.c static __init int hardware_setup(void) · line 8136
Quoted 5 lines
arch/x86/kvm/vmx/vmx.c +2
-0@@ -8097,6 +8132,9 @@ static __init int hardware_setup(void) kvm_tsc_scaling_ratio_frac_bits =48 ; } +if (cpu_has_vmx_bus_lock_detection ()) + kvm_has_bus_lock_exit = true;
Or simply:
kvm_has_bus_lock_exit = cpu_has_vmx_bus_lock_detection();
Quoted 31 lines
arch/x86/kvm/vmx/vmx.c +1
-0+set_bit (0 , vmx_vpid_bitmap);/* 0 is reserved for host */ if (enable_ept)arch/x86/kvm/vmx/vmx.h +1
-1@@ -105,7 +105,7 @@ union vmx_exit_reason { u32 reserved23 : 1; u32 reserved24 : 1; u32 reserved25 : 1; - u32 reserved26 : 1; + u32 bus_lock_detected : 1; u32 enclave_mode : 1; u32 smi_pending_mtf : 1; u32 smi_from_vmx_root : 1;arch/x86/kvm/x86.c +2
-0@@ -134,6 +134,8 @@ u64 __read_mostly kvm_max_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_max_tsc_scaling_ratio);u64 __read_mostly kvm_default_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_default_tsc_scaling_ratio); +bool __read_mostly kvm_has_bus_lock_exit; +EXPORT_SYMBOL_GPL (kvm_has_bus_lock_exit);/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */ static u32 __read_mostly tsc_tolerance_ppm =250 ;
arch/x86/kvm/x86.c int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) · line 3583
Quoted 4 lines
arch/x86/kvm/x86.c +1
-0@@ -3578,6 +3580,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_SMALLER_MAXPHYADDR : r = (int ) allow_smaller_maxphyaddr;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT :
Hmm, it might make more sense to do:
if (kvm_has_bus_lock_exit) r = KVM_BUS_LOCK_DETECTION_OFF | KVM_BUS_LOCK_DETECTION_EXIT; else r = 0;
On the other hand I can see it being useful for userspace to know that KVM itself supports bus lock detection, but hardware does not.
Quoted 51 lines
arch/x86/kvm/x86.c +23
-1+ r |=KVM_BUS_LOCK_DETECTION_OFF ; +if (kvm_has_bus_lock_exit) + r |=KVM_BUS_LOCK_DETECTION_EXIT ; +break ;default :break ; }@@ -5030,6 +5037,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, kvm->arch.exception_payload_enabled = cap->args[0 ]; r =0 ;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT : + r = -EINVAL ; +if (cap->args[0 ] & ~KVM_BUS_LOCK_DETECTION_VALID_MODE ) +break ; + +if ((cap->args[0 ] &KVM_BUS_LOCK_DETECTION_OFF ) && + (cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT )) +break ; + +if (kvm_has_bus_lock_exit && + cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT ) + kvm->arch.bus_lock_exit = true; + r =0 ; +break ;default : r = -EINVAL ;break ;@@ -7772,12 +7793,16 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)struct kvm_run *kvm_run = vcpu->run; kvm_run->if_flag = (kvm_get_rflags (vcpu) &X86_EFLAGS_IF ) !=0 ; - kvm_run->flags =is_smm (vcpu) ?KVM_RUN_X86_SMM :0 ; kvm_run->cr8 =kvm_get_cr8 (vcpu); kvm_run->apic_base =kvm_get_apic_base (vcpu); kvm_run->ready_for_interrupt_injection =pic_in_kernel (vcpu->kvm) ||kvm_vcpu_ready_for_interrupt_injection (vcpu); + +if (is_smm (vcpu)) + kvm_run->flags |=KVM_RUN_X86_SMM ; +else + kvm_run->flags &= ~KVM_RUN_X86_SMM ; }static void update_cr8_intercept (struct kvm_vcpu *vcpu)arch/x86/kvm/x86.h +0
-0
arch/x86/kvm/x86.h static inline bool kvm_cstate_in_guest(struct kvm *kvm) · line 338
Quoted 4 lines
arch/x86/kvm/x86.h +1
-0@@ -335,6 +335,11 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm)return kvm->arch.cstate_in_guest; } +static inline bool kvm_bus_lock_exit_enabled (struct kvm *kvm)
I don't see any point in adding an accessor for a bool.
Quoted 28 lines
arch/x86/kvm/x86.h +4
-0+{ +return kvm->arch.bus_lock_exit; +} + DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);static inline void kvm_before_interrupt (struct kvm_vcpu *vcpu)include/uapi/linux/kvm.h +2
-0@@ -248,6 +248,7 @@ struct kvm_hyperv_exit {#define KVM_EXIT_IOAPIC_EOI 26#define KVM_EXIT_HYPERV 27#define KVM_EXIT_ARM_NISV 28 +#define KVM_EXIT_BUS_LOCK 29/* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -1035,6 +1036,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_LAST_CPU 184#define KVM_CAP_SMALLER_MAXPHYADDR 185#define KVM_CAP_S390_DIAG318 186 +#define KVM_CAP_X86_BUS_LOCK_EXIT 187#ifdef KVM_CAP_IRQ_ROUTING
include/uapi/linux/kvm.h struct kvm_hyperv_eventfd { · line 1697
Quoted 7 lines
include/uapi/linux/kvm.h +4
-0@@ -1689,4 +1691,9 @@ struct kvm_hyperv_eventfd {#define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0)#define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) +#define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) +#define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) +#define KVM_BUS_LOCK_DETECTION_VALID_MODE (KVM_BUS_LOCK_DETECTION_OFF | \ + KVM_BUS_LOCK_DETECTION_EXIT)
I don't think we want to define KVM_BUS_LOCK_DETECTION_VALID_MODE in the uapi header, that should be kernel only.
Quoted 5 lines
include/uapi/linux/kvm.h +1
-0+#endif /* __LINUX_KVM_H */ Signature · 1 line
2.17.1
Re: [RFC v3 2/2] KVM: VMX: Enable bus lock VM exit
Thank you for comments. Will clean up my code.
Quoted 362 lines · Sean Christopherson
arch/x86/include/asm/kvm_host.h struct kvm_arch { · line 965
Quoted 10 lines · Chenyi Qiang
arch/x86/include/asm/kvm_host.h +2
-0@@ -961,6 +961,9 @@ struct kvm_arch {bool guest_can_read_msr_platform_info;bool exception_payload_enabled; +/* Set when bus lock vm exit is enabled by user */ +bool bus_lock_exit;Maybe
bus_lock_detection_enabled? Then you don't need the comment or the accessor.arch/x86/include/asm/kvm_host.h extern u8 kvm_tsc_scaling_ratio_frac_bits; · line 1354
Quoted 10 lines
arch/x86/include/asm/kvm_host.h +3
-0+struct kvm_pmu_event_filter *pmu_event_filter;struct task_struct *nx_lpage_recovery_thread; };@@ -1347,6 +1350,8 @@ extern u8 kvm_tsc_scaling_ratio_frac_bits;extern u64 kvm_max_tsc_scaling_ratio;/* 1ull << kvm_tsc_scaling_ratio_frac_bits */ extern u64 kvm_default_tsc_scaling_ratio; +/* bus lock detection supported */ +extern bool kvm_has_bus_lock_exit;Hrm, it'd be nice to somehow squeeze this into
kvm_cpu_caps, but I can't think of a clever/clean way to do so.Quoted 101 lines
arch/x86/include/asm/kvm_host.h +0
-0extern u64 kvm_mce_cap_supported;arch/x86/include/asm/vmx.h +1
-0@@ -73,6 +73,7 @@#define SECONDARY_EXEC_PT_USE_GPA VMCS_CONTROL_BIT(PT_USE_GPA)#define SECONDARY_EXEC_TSC_SCALING VMCS_CONTROL_BIT(TSC_SCALING)#define SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE VMCS_CONTROL_BIT(USR_WAIT_PAUSE) +#define SECONDARY_EXEC_BUS_LOCK_DETECTION VMCS_CONTROL_BIT(BUS_LOCK_DETECTION)#define PIN_BASED_EXT_INTR_MASK VMCS_CONTROL_BIT(INTR_EXITING)#define PIN_BASED_NMI_EXITING VMCS_CONTROL_BIT(NMI_EXITING)arch/x86/include/asm/vmxfeatures.h +1
-0@@ -83,5 +83,6 @@#define VMX_FEATURE_TSC_SCALING ( 2*32+ 25)/* Scale hardware TSC when read in guest */ #define VMX_FEATURE_USR_WAIT_PAUSE ( 2*32+ 26)/* Enable TPAUSE, UMONITOR, UMWAIT in guest */ #define VMX_FEATURE_ENCLV_EXITING ( 2*32+ 28)/* "" VM-Exit on ENCLV (leaf dependent) */ +#define VMX_FEATURE_BUS_LOCK_DETECTION ( 2*32+ 30)/* VM-Exit when bus lock caused */ #endif /* _ASM_X86_VMXFEATURES_H */ arch/x86/include/uapi/asm/kvm.h +1
-0@@ -111,6 +111,7 @@ struct kvm_ioapic_state {#define KVM_NR_IRQCHIPS 3#define KVM_RUN_X86_SMM (1 << 0) +#define KVM_RUN_BUS_LOCK (1 << 1)/* for KVM_GET_REGS and KVM_SET_REGS */ struct kvm_regs {arch/x86/include/uapi/asm/vmx.h +3
-1@@ -88,6 +88,7 @@#define EXIT_REASON_XRSTORS 64#define EXIT_REASON_UMWAIT 67#define EXIT_REASON_TPAUSE 68 +#define EXIT_REASON_BUS_LOCK 74#define VMX_EXIT_REASONS \ { EXIT_REASON_EXCEPTION_NMI, "EXCEPTION_NMI" }, \@@ -148,7 +149,8 @@ { EXIT_REASON_XSAVES, "XSAVES" }, \ { EXIT_REASON_XRSTORS, "XRSTORS" }, \ { EXIT_REASON_UMWAIT, "UMWAIT" }, \ - { EXIT_REASON_TPAUSE, "TPAUSE" } + { EXIT_REASON_TPAUSE, "TPAUSE" }, \ + { EXIT_REASON_BUS_LOCK, "BUS_LOCK" } #define VMX_EXIT_REASON_FLAGS \ { VMX_EXIT_REASONS_FAILED_VMENTRY, "FAILED_VMENTRY" }arch/x86/kvm/vmx/capabilities.h +6
-0@@ -262,6 +262,12 @@ static inline bool cpu_has_vmx_tsc_scaling(void)SECONDARY_EXEC_TSC_SCALING ; } +static inline bool cpu_has_vmx_bus_lock_detection (void ) +{ +return vmcs_config.cpu_based_2nd_exec_ctrl & +SECONDARY_EXEC_BUS_LOCK_DETECTION ; +} +static inline bool cpu_has_vmx_apicv (void ) { return cpu_has_vmx_apic_register_virt() &&arch/x86/kvm/vmx/vmx.c +5
-1@@ -2461,7 +2461,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE |SECONDARY_EXEC_PT_USE_GPA |SECONDARY_EXEC_PT_CONCEAL_VMX | -SECONDARY_EXEC_ENABLE_VMFUNC ; +SECONDARY_EXEC_ENABLE_VMFUNC | +SECONDARY_EXEC_BUS_LOCK_DETECTION ;if (cpu_has_sgx ()) opt2 |=SECONDARY_EXEC_ENCLS_EXITING ; if (adjust_vmx_controls(min2, opt2,@@ -4244,6 +4245,9 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx) } } +if (!kvm_bus_lock_exit_enabled (vmx->vcpu.kvm)) + exec_control &= ~SECONDARY_EXEC_BUS_LOCK_DETECTION ; + vmx->secondary_exec_control = exec_control; }arch/x86/kvm/vmx/vmx.c static int handle_encls(struct kvm_vcpu *vcpu) · line 5696
Quoted 8 lines
arch/x86/kvm/vmx/vmx.c +5
-0@@ -5685,6 +5689,14 @@ static int handle_encls(struct kvm_vcpu *vcpu)return 1 ; } +static int handle_bus_lock (struct kvm_vcpu *vcpu) +{ +struct kvm_run *kvm_run = vcpu->run; + + kvm_run->exit_reason =KVM_EXIT_BUS_LOCK ;No need for
kvm_run, "vcpu->run->exit_reason=KVM_EXIT_BUS_LOCK" will do.Quoted 24 lines
arch/x86/kvm/vmx/vmx.c +5
-1+return 0 ; +} +/* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs @@ -5741,6 +5753,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { [EXIT_REASON_VMFUNC] = handle_vmx_instruction, [EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer, [EXIT_REASON_ENCLS] = handle_encls, + [EXIT_REASON_BUS_LOCK] = handle_bus_lock, }; static const int kvm_vmx_max_exit_handlers =@@ -5979,7 +5992,7 @@ void dump_vmcs(void)* The guest has exited. See if we can fix it or if we need userspace * assistance. */ -static int vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) +static int __vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) {struct vcpu_vmx *vmx =to_vmx (vcpu);union vmx_exit_reason exit_reason = vmx->exit_reason;arch/x86/kvm/vmx/vmx.c static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) · line 6149
Quoted 6 lines
arch/x86/kvm/vmx/vmx.c +3
-0@@ -6131,6 +6144,28 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)return 0 ; } +static int vmx_handle_exit (struct kvm_vcpu *vcpu,fastpath_t exit_fastpath) +{ +struct vcpu_vmx *vmx =to_vmx (vcpu);Personal preference, but I'd probably skip the local 'vmx' variable since there's only a single user, i.e. "to_vmx(vcpu)->exit_reason....".
arch/x86/kvm/vmx/vmx.c static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) · line 6156
Quoted 7 lines
arch/x86/kvm/vmx/vmx.c +7
-0+int ret =__vmx_handle_exit (vcpu, exit_fastpath); + +/* +* Even when current exit reason is handled by KVM +* internally, we still needs to exit to user space +* when bus lock detected to inform that there is a +* bus lock in guest. Run these lines out to the edge of 80 chars, wrapping this aggressively just adds extra lines.
Quoted 16 lines
arch/x86/kvm/vmx/vmx.c +12
-0+*/ +if (vmx->exit_reason.bus_lock_detected) { +if (ret >0 ) + vcpu->run->exit_reason =KVM_EXIT_BUS_LOCK ; +else + vcpu->run->flags |=KVM_RUN_BUS_LOCK ; +return 0 ; + } + vcpu->run->flags &= ~KVM_RUN_BUS_LOCK ; +return ret; +} +/* * Software based L1D cache flush which is used when microcode providing * the cache control MSR is not loaded. arch/x86/kvm/vmx/vmx.c static __init int hardware_setup(void) · line 8136
Quoted 5 lines
arch/x86/kvm/vmx/vmx.c +2
-0@@ -8097,6 +8132,9 @@ static __init int hardware_setup(void) kvm_tsc_scaling_ratio_frac_bits =48 ; } +if (cpu_has_vmx_bus_lock_detection ()) + kvm_has_bus_lock_exit = true;Or simply:
kvm_has_bus_lock_exit = cpu_has_vmx_bus_lock_detection();Quoted 31 lines
arch/x86/kvm/vmx/vmx.c +1
-0+set_bit (0 , vmx_vpid_bitmap);/* 0 is reserved for host */ if (enable_ept)arch/x86/kvm/vmx/vmx.h +1
-1@@ -105,7 +105,7 @@ union vmx_exit_reason { u32 reserved23 : 1; u32 reserved24 : 1; u32 reserved25 : 1; - u32 reserved26 : 1; + u32 bus_lock_detected : 1; u32 enclave_mode : 1; u32 smi_pending_mtf : 1; u32 smi_from_vmx_root : 1;arch/x86/kvm/x86.c +2
-0@@ -134,6 +134,8 @@ u64 __read_mostly kvm_max_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_max_tsc_scaling_ratio);u64 __read_mostly kvm_default_tsc_scaling_ratio;EXPORT_SYMBOL_GPL (kvm_default_tsc_scaling_ratio); +bool __read_mostly kvm_has_bus_lock_exit; +EXPORT_SYMBOL_GPL (kvm_has_bus_lock_exit);/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */ static u32 __read_mostly tsc_tolerance_ppm =250 ;arch/x86/kvm/x86.c int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) · line 3583
Quoted 4 lines
arch/x86/kvm/x86.c +1
-0@@ -3578,6 +3580,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_SMALLER_MAXPHYADDR : r = (int ) allow_smaller_maxphyaddr;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT :Hmm, it might make more sense to do:
if (kvm_has_bus_lock_exit) r = KVM_BUS_LOCK_DETECTION_OFF | KVM_BUS_LOCK_DETECTION_EXIT; else r = 0;On the other hand I can see it being useful for userspace to know that KVM itself supports bus lock detection, but hardware does not.
Quoted 51 lines
arch/x86/kvm/x86.c +23
-1+ r |=KVM_BUS_LOCK_DETECTION_OFF ; +if (kvm_has_bus_lock_exit) + r |=KVM_BUS_LOCK_DETECTION_EXIT ; +break ;default :break ; }@@ -5030,6 +5037,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, kvm->arch.exception_payload_enabled = cap->args[0 ]; r =0 ;break ; +case KVM_CAP_X86_BUS_LOCK_EXIT : + r = -EINVAL ; +if (cap->args[0 ] & ~KVM_BUS_LOCK_DETECTION_VALID_MODE ) +break ; + +if ((cap->args[0 ] &KVM_BUS_LOCK_DETECTION_OFF ) && + (cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT )) +break ; + +if (kvm_has_bus_lock_exit && + cap->args[0 ] &KVM_BUS_LOCK_DETECTION_EXIT ) + kvm->arch.bus_lock_exit = true; + r =0 ; +break ;default : r = -EINVAL ;break ;@@ -7772,12 +7793,16 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)struct kvm_run *kvm_run = vcpu->run; kvm_run->if_flag = (kvm_get_rflags (vcpu) &X86_EFLAGS_IF ) !=0 ; - kvm_run->flags =is_smm (vcpu) ?KVM_RUN_X86_SMM :0 ; kvm_run->cr8 =kvm_get_cr8 (vcpu); kvm_run->apic_base =kvm_get_apic_base (vcpu); kvm_run->ready_for_interrupt_injection =pic_in_kernel (vcpu->kvm) ||kvm_vcpu_ready_for_interrupt_injection (vcpu); + +if (is_smm (vcpu)) + kvm_run->flags |=KVM_RUN_X86_SMM ; +else + kvm_run->flags &= ~KVM_RUN_X86_SMM ; }static void update_cr8_intercept (struct kvm_vcpu *vcpu)arch/x86/kvm/x86.h +0
-0arch/x86/kvm/x86.h static inline bool kvm_cstate_in_guest(struct kvm *kvm) · line 338
Quoted 4 lines
arch/x86/kvm/x86.h +1
-0@@ -335,6 +335,11 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm)return kvm->arch.cstate_in_guest; } +static inline bool kvm_bus_lock_exit_enabled (struct kvm *kvm)I don't see any point in adding an accessor for a bool.
Quoted 28 lines
arch/x86/kvm/x86.h +4
-0+{ +return kvm->arch.bus_lock_exit; +} + DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);static inline void kvm_before_interrupt (struct kvm_vcpu *vcpu)include/uapi/linux/kvm.h +2
-0@@ -248,6 +248,7 @@ struct kvm_hyperv_exit {#define KVM_EXIT_IOAPIC_EOI 26#define KVM_EXIT_HYPERV 27#define KVM_EXIT_ARM_NISV 28 +#define KVM_EXIT_BUS_LOCK 29/* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -1035,6 +1036,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_LAST_CPU 184#define KVM_CAP_SMALLER_MAXPHYADDR 185#define KVM_CAP_S390_DIAG318 186 +#define KVM_CAP_X86_BUS_LOCK_EXIT 187#ifdef KVM_CAP_IRQ_ROUTING include/uapi/linux/kvm.h struct kvm_hyperv_eventfd { · line 1697
Quoted 7 lines
include/uapi/linux/kvm.h +4
-0@@ -1689,4 +1691,9 @@ struct kvm_hyperv_eventfd {#define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0)#define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) +#define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) +#define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) +#define KVM_BUS_LOCK_DETECTION_VALID_MODE (KVM_BUS_LOCK_DETECTION_OFF | \ + KVM_BUS_LOCK_DETECTION_EXIT)I don't think we want to define
KVM_BUS_LOCK_DETECTION_VALID_MODEin the uapi header, that should be kernel only.Quoted 5 lines
include/uapi/linux/kvm.h +1
-0+#endif /* __LINUX_KVM_H */ Signature · 1 line
2.17.1