iommufd: Iterate the cache invalidation array in the core
Subsystems (4)
v5 cover iommufd: Iterate the cache invalidation array in the core
The vIOMMU cache_invalidate() and the nested-HWPT cache_invalidate_user() ops are each handed the full user invalidation array and must report, via array->entry_num, how many of its entries they handled. That makes every driver open-code the same array walk, with real downsides:
- each driver carries its own loop and sub-array bookkeeping;
- the ARM SMMUv3 driver allocates a buffer sized to the whole array just to iterate over it;
- hand-rolling the loop left the ARM SMMUv3 driver with two long-standing bugs:
1) on a conversion failure it counts commands that it converted but never issued, so user space skips invalidations that never reached the cmdq;
2) it rejects a zero-length array, which the uAPI documents as a valid request that only probes the data type.
The walk is identical for every driver, so move it into the iommufd core.
The core now drives the iteration:
- it invokes the op on a sub-array starting at the first not-yet-handled entry;
- the op handles one chunk from the front of that sub-array and reports the count via array->entry_num;
- the core advances and re-invokes until the whole array is consumed or the op returns an error.
A driver then only has to handle one bounded chunk per call, e.g. the ARM SMMUv3 op copies a single cmdq batch into a fixed on-stack buffer and drops its whole-array allocation. An op still handling the entire array in one call keeps working, so each driver converts independently.
All the bugs fixed here are long-standing ones rather than regressions in this cycle, so the series targets for-next, not for-rc. The stable tag on the second patch takes care of the backport.
This is on Github:
https://github.com/nicolinc/iommufd/commits/iommufd_invalidation_loop-v5
[Note to Jason and Will]
This is based on the arm/smmu/updates branch, which integrates Ashish's CFGI/TLBI-repeat series. I've run Sashiko locally: v5 is still clean.
Changelog
v5
* Rebase on top of arm/smmu/updates branch
* Add "Reviewed-by" from Jason and Pranjal
* Patch-1: Drop the Fixes and Cc stable tags
* Patch-2: Reject an unsupported opcode in the validation helper
* Patch-2: Add an explicit NSNH_ALL case to the allowlist switch
v4
https://lore.kernel.org/all/[email protected]/
* Add "Reviewed-by" from Baolu and Pranjal
* Split the DS support out of the reject patch into a new patch-1, also listing DS in the iommu_hw_info_arm_smmuv3 kdoc
* Patch-2: Add "!!" to the bool range assignment
* Patch-2: Factor the allowlist into arm_vsmmu_validate_user_cmd()
v3
https://lore.kernel.org/all/[email protected]/
* Patch-1: Add a minimal FEAT_DS detection and allow the two DS-only range encodings on a DS-capable SMMU
* Patch-1: Mask the host's scale value to keep its 5-bit truncation
v2
https://lore.kernel.org/all/[email protected]/
* Add "Reviewed-by" from Kevin to patches 2-5
* Patch-1: Allow the ATC_INV Global bit gated on ssid_bits, correcting the wrong every-device claim: per the spec it only broadens a single device's invalidation across its PASIDs
* Patch-1: Move the FEAT_ATS check into the allowlist switch
* Patch-1: Gate the TTL range field on FEAT_RANGE_INV too
* Patch-1: Accept only asid_bits of the ASID field
* Patch-1: Reject Reserved range field value combinations
* Patch-1: Reject an ATC_INV Size above 52
* Patch-1: Add local smmu and data variables to simplify the long lines
* Patch-1: Document the valid-command contract in the uAPI header
* Patch-1: Note that unchecked out-of-range values are UNPREDICTABLE
* Patch-1: Note that SSID/Global are IGNORED, not RES0, when SSV == 0
* Patch-2: Consolidate the two invalidation loops into one
* Patch-2: Multiply by the size_t entry_len to avoid a u32 overflow
* Patch-3/5: Return 0 directly on a zero-length array
* Patch-4: Use a processed counter and an out label like the mock driver
v1
https://lore.kernel.org/all/[email protected]/
Nicolin Chen (6):
iommu/arm-smmu-v3: Support IDR5.DS and widen the TLBI SCALE field iommu/arm-smmu-v3-iommufd: Reject unsupported bits in invalidation
commands
iommufd: Iterate the cache invalidation array in the core iommufd/selftest: Convert cache invalidation mocks to the core array
loop
iommu/arm-smmu-v3-iommufd: Convert cache invalidation to the core
array loop
iommu/vt-d: Convert nested cache invalidation to the core array loop
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 4 +- include/linux/iommu.h | 6 +- include/linux/iommufd.h | 2 + include/uapi/linux/iommufd.h | 8 +- .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 197 ++++++++++++++---- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 6 +- drivers/iommu/intel/nested.c | 54 ++--- drivers/iommu/iommufd/hw_pagetable.c | 25 ++- drivers/iommu/iommufd/selftest.c | 147 +++++++------ 9 files changed, 292 insertions(+), 157 deletions(-)
base-commit: a86c36163c9722545d27e92bdad8418fdcaa8b1d
Signature · 1 line
2.43.0
PATCH v5 1/6 iommu/arm-smmu-v3: Support IDR5.DS and widen the TLBI SCALE field
An SMMU implementing SMMU_IDR5.DS extends the range invalidation commands:
the SCALE field grows a 6th bit, raising its maximum value from 31 to 39, and TTL == 0b01 becomes a valid level hint for a 16KB translation granule.
Add a new ARM_SMMU_FEAT_DS feature detecting the DS bit, and widen the CMDQ_TLBI_0_SCALE field to its architectural 6 bits. Mask the scale value explicitly in arm_smmu_cmdq_batch_add_range(), so the range invalidation path emits the same commands as before, keeping the pre-existing 5-bit truncation of a scale above 31.
Also list DS as a valid IDR5 field in the iommu_hw_info_arm_smmuv3 kdoc:
iommufd has always reported the raw IDR5 register, so a VMM may conclude from that bit alone that it can expose DS to its guest.
--- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 4 +++- include/uapi/linux/iommufd.h | 4 ++-- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 6 +++++- 3 files changed, 10 insertions(+), 4 deletions(-)
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +3 -1
@@ -64,6 +64,7 @@ struct arm_vsmmu;#define ARM_SMMU_IDR5 0x14#define IDR5_STALL_MAX GENMASK(31, 16) +#define IDR5_DS (1 << 7)#define IDR5_GRAN64K (1 << 6)#define IDR5_GRAN16K (1 << 5)#define IDR5_GRAN4K (1 << 4)
@@ -415,7 +416,7 @@ struct arm_smmu_cmd {#define CMDQ_TLBI_0_NUM GENMASK_ULL(16, 12)#define CMDQ_TLBI_RANGE_NUM_MAX 31 -#define CMDQ_TLBI_0_SCALE GENMASK_ULL(24, 20) +#define CMDQ_TLBI_0_SCALE GENMASK_ULL(25, 20)#define CMDQ_TLBI_0_VMID GENMASK_ULL(47, 32)#define CMDQ_TLBI_0_ASID GENMASK_ULL(63, 48)#define CMDQ_TLBI_1_LEAF (1UL << 0)
@@ -922,6 +923,7 @@ struct arm_smmu_device {#define ARM_SMMU_FEAT_HD (1 << 22)#define ARM_SMMU_FEAT_S2FWB (1 << 23)#define ARM_SMMU_FEAT_BBML2 (1 << 24) +#define ARM_SMMU_FEAT_DS (1 << 25)u32 features;#define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0)
include/uapi/linux/iommufd.h +2 -2
@@ -605,7 +605,7 @@ enum iommu_hw_info_arm_smmuv3_flags {* idr[0]: ST_LEVEL, TERM_MODEL, STALL_MODEL, TTENDIAN , CD2L, ASID16, TTF * idr[1]: SIDSIZE, SSIDSIZE * idr[3]: BBML, RIL -* idr[5]: VAX, GRAN64K, GRAN16K, GRAN4K +* idr[5]: VAX, GRAN64K, GRAN16K, GRAN4K, DS * * - S1P should be assumed to be true if a NESTED HWPT can be created * - VFIO/iommufd only support platforms with COHACC, it should be assumed to be
@@ -613,7 +613,7 @@ enum iommu_hw_info_arm_smmuv3_flags {* - ATS is a per-device property. If the VMM describes any devices as ATS * capable in ACPI/DT it should set the corresponding idr. * -* This list may expand in future (eg E0PD, AIE, PBHA, D128, DS etc). It is +* This list may expand in future (eg E0PD, AIE, PBHA, D128 etc). It is * important that VMMs do not read bits outside the list to allow for * compatibility with future kernels. Several features in the SMMUv3 * architecture are not currently supported by the kernel for nesting: HTTU,
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +5 -1
@@ -2511,9 +2511,10 @@ static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,/* Determine how many chunks of 2^scale size we have */ num = (num_pages >> scale) &CMDQ_TLBI_RANGE_NUM_MAX ; +/* Keep the pre-DS 5-bit truncation when scale > 31 */ cmd->data[0 ] = orig_data0 |FIELD_PREP (CMDQ_TLBI_0_NUM , num -1 ) | -FIELD_PREP (CMDQ_TLBI_0_SCALE , scale); +FIELD_PREP (CMDQ_TLBI_0_SCALE , scale &0x1f );/* range is num * 2^scale * pgsize */ inv_range = num << (scale + tg);
@@ -5192,6 +5193,9 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)/* Maximum number of outstanding stalls */ smmu->evtq.max_stalls =FIELD_GET (IDR5_STALL_MAX , reg); +if (reg &IDR5_DS ) + smmu->features |=ARM_SMMU_FEAT_DS ; +/* Page sizes */ if (reg &IDR5_GRAN64K ) smmu->pgsize_bitmap |=SZ_64K |SZ_512M ;
Signature · 1 line
2.43.0
PATCH v5 2/6 iommu/arm-smmu-v3-iommufd: Reject unsupported bits in invalidation commands
In reply to Nicolin ChenThe arm_vsmmu_cache_invalidate() op hands a guest's invalidation commands to the trusted main command queue after enforcing only the VMID or the SID, and passes the rest of the command through to the queue unchanged.
That lets a guest set bits the host never meant to forward: a reserved or undefined bit makes a command malformed; per the Arm SMMUv3 specification, in its section 4.1.3 "Command errors", a CERROR_ILL is raised, among other cases, when:
A valid command opcode is used and a Reserved or undefined field is optionally detected as non-zero, which results in the command being treated as malformed.
Restrict each opcode to the fields that the driver supports and reject the command with -EIO if it sets any other bit, before the command reaches the queue. This stops the host from forwarding any bit whose meaning it does not control. Document this contract in the uAPI header, so user space must take the responsibility to forward valid commands only.
Some fields and whole opcodes are legal only on an SMMU that implements the matching feature, so accept them conditionally:
- NUM, SCALE, TG and TTL need FEAT_RANGE_INV.
- SCALE bit 25, for values above 31, and TTL == 0b01 with a 16KB TG need SMMU_IDR5.DS, gated on ARM_SMMU_FEAT_DS so that a VMM exposing DS from the reported IDR5 register keeps working.
- ASID is limited to asid_bits, since its upper 8 bits are RES0 on an SMMU that only supports 8-bit ASIDs.
- ATC_INV needs FEAT_ATS. Per the specification's section 4.5 "ATS and PRI", CMD_ATC_INV is ILLEGAL when:
SMMU_IDR0.ATS == 0 and this command is issued on a Non-secure or Secure Command queue.
- SSV, SSID and Global need a non-zero ssid_bits. Without it, setting them is not illegal but CONSTRAINED UNPREDICTABLE, which a guest should not be able to provoke. Global also takes effect only when SSV == 1, broadening the invalidation from the one SSID to all the PASIDs of the single device that the SID field addresses.
Some values inside the accepted fields are Reserved too:
- NUM == 0, SCALE == 0 and TTL == 0 together are a Reserved combination and cause a CERROR_ILL.
- NUM, SCALE and TTL turn RES0 when TG == 0.
- An ATC_INV Size above 52, the invalidate-all span, is permitted to raise a CERROR_ILL.
Reject these Reserved values the same way. In contrast, an out-of-range address or ID value is defined as CONSTRAINED UNPREDICTABLE that would be scoped to the guest itself, so it does not deserve a check.
--- include/uapi/linux/iommufd.h | 4 +- .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 129 ++++++++++++++++-- 2 files changed, 121 insertions(+), 12 deletions(-)
include/uapi/linux/iommufd.h +3 -1
@@ -920,7 +920,9 @@ struct iommu_hwpt_vtd_s1_invalidate {* CMDQ_OP_CFGI_CD * CMDQ_OP_CFGI_CD_ALL * -* -EIO will be returned if the command is not supported. +* User space must forward only valid commands: the kernel rejects, with +* -EIO, any command carrying an unsupported opcode, an unsupported field, +* or a field value that the underlying SMMU hardware does not implement. */ struct iommu_viommu_arm_smmuv3_invalidate {__aligned_le64 cmd[2 ];
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c +118 -11
157 lines not on this page · raw message
Signature · 1 line
2.43.0
PATCH v5 3/6 iommufd: Iterate the cache invalidation array in the core
In reply to Nicolin ChenThe cache invalidation ops, cache_invalidate_user() for a nested HWPT and the cache_invalidate() for a vIOMMU, are each handed the full user request array and report how many of the array entries they handled by setting the array->entry_num. Every driver therefore implements its own loop over the array, and a driver wanting to process that array in fixed-size chunks (e.g. to issue commands out of a fixed-size on-stack buffer) has to carry the loop and its sub-array bookkeeping all on its own.
Move the iteration into the iommufd core instead. Invoke the op with a sub-array that starts at the first not-yet-handled entry, let it handle a prefix of that sub-array and report the count via array->entry_num, then advance the base pointer and re-invoke the op until the entire array has been consumed or until the op returns an error along the way.
A driver that handles the entire window in one single call, as all of the current drivers happen to do, finishes the loop in just one pass, so this does not change any of the existing behavior. It instead lets each of the drivers convert to bounded chunk processing on its own, done by each of the subsequent changes.
--- include/linux/iommu.h | 6 ++++-- include/linux/iommufd.h | 2 ++ drivers/iommu/iommufd/hw_pagetable.c | 25 +++++++++++++++---------- 3 files changed, 21 insertions(+), 12 deletions(-)
include/linux/iommu.h +4 -2
@@ -773,8 +773,10 @@ struct iommu_ops {* passes in the cache invalidation requests, in form * of a driver data structure. The driver must update * array->entry_num to report the number of handled -* invalidation requests. The driver data structure -* must be defined in include/uapi/linux/iommufd.h +* invalidation requests. A driver may handle fewer than +* the requested, in which case the core re-invokes the +* op for the remainder. The driver data structure must +* be defined in include/uapi/linux/iommufd.h * @iova_to_phys: translate iova to physical address * @enforce_cache_coherency: Prevent any kind of DMA from bypassing IOMMU_CACHE, * including no-snoop TLPs on PCIe or other platform
include/linux/iommufd.h +2 -0
@@ -154,6 +154,8 @@ struct iommufd_hw_queue {* The @array passes in the cache invalidation requests, in * form of a driver data structure. A driver must update the * array->entry_num to report the number of handled requests. +* A driver may handle fewer than the requested entry_num, in +* which case the core re-invokes the op for the remainder. * The data structure of the array entry must be defined in * include/uapi/linux/iommufd.h * @vdevice_size: Size of the driver-defined vDEVICE structure per this vIOMMU
drivers/iommu/iommufd/hw_pagetable.c +15 -10
@@ -501,6 +501,8 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd) .entry_len = cmd->entry_len, .entry_num = cmd->entry_num, }; +struct iommufd_hw_pagetable *hwpt =NULL ; +struct iommufd_viommu *viommu =NULL ;struct iommufd_object *pt_obj;u32 done_num =0 ;int rc;
@@ -527,31 +529,34 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd) goto out; }if (pt_obj->type ==IOMMUFD_OBJ_HWPT_NESTED ) { -struct iommufd_hw_pagetable *hwpt = - container_of(pt_obj, struct iommufd_hw_pagetable, obj); - + hwpt = container_of(pt_obj, struct iommufd_hw_pagetable, obj);if (!hwpt->domain->ops || !hwpt->domain->ops->cache_invalidate_user) { rc = -EOPNOTSUPP ; goto out_put_pt; } - rc = hwpt->domain->ops->cache_invalidate_user (hwpt->domain, - &data_array); }else if (pt_obj->type ==IOMMUFD_OBJ_VIOMMU ) { -struct iommufd_viommu *viommu = - container_of(pt_obj, struct iommufd_viommu, obj); - + viommu = container_of(pt_obj, struct iommufd_viommu, obj);if (!viommu->ops || !viommu->ops->cache_invalidate) { rc = -EOPNOTSUPP ; goto out_put_pt; } - rc = viommu->ops->cache_invalidate (viommu, &data_array); }else { rc = -EINVAL ; goto out_put_pt; } - done_num = data_array.entry_num; +do { +if (viommu) + rc = viommu->ops->cache_invalidate (viommu, &data_array); +else + rc = hwpt->domain->ops->cache_invalidate_user ( + hwpt->domain, &data_array); + + done_num += data_array.entry_num; + data_array.uptr += data_array.entry_num * data_array.entry_len; + data_array.entry_num = cmd->entry_num - done_num; + }while (!rc && done_num != cmd->entry_num); out_put_pt:iommufd_put_object (ucmd->ictx, pt_obj);
Signature · 1 line
2.43.0
PATCH v5 4/6 iommufd/selftest: Convert cache invalidation mocks to the core array loop
In reply to Nicolin ChenThe vIOMMU and the nested-domain selftest invalidation mocks each used to walk the whole request array on their own, with the vIOMMU mock even allocating a buffer sized to the entire array in order to do so first.
The iommufd core now iterates the request array itself and re-invokes the op with the not-yet-handled sub-array, so handle just a single request per call out of the front of that sub-array and report one handled entry via the array->entry_num. Drop both of the loops and the kzalloc_objs() in the viommu callback function, and keep returning a success for an empty array as a probe of the selftest data type.
--- drivers/iommu/iommufd/selftest.c | 147 +++++++++++++++---------------- 1 file changed, 72 insertions(+), 75 deletions(-)
drivers/iommu/iommufd/selftest.c +72 -75
@@ -631,70 +631,63 @@ mock_viommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,static int mock_viommu_cache_invalidate (struct iommufd_viommu *viommu,struct iommu_user_data_array *array) { -struct iommu_viommu_invalidate_selftest *cmds; -struct iommu_viommu_invalidate_selftest *cur; -struct iommu_viommu_invalidate_selftest *end; -int rc; +struct iommu_viommu_invalidate_selftest cmd; +struct mock_dev *mdev; +struct device *dev; +u32 processed =0 ; +int rc =0 ; +int i; -/* A zero-length array is allowed to validate the array type */ -if (array->entry_num ==0 && - array->type ==IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST ) { - array->entry_num =0 ; -return 0 ; +if (array->type !=IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST ) { + rc = -EINVAL ; + goto out; } - cmds =kzalloc_objs (*cmds, array->entry_num); -if (!cmds) -return -ENOMEM ; - cur = cmds; - end = cmds + array->entry_num; +/* +* The core re-invokes this op for the remaining requests, so handle one +* request per call. A zero-length array only probes the type, validated +* above. +*/ +if (!array->entry_num) +return 0 ; -static_assert (sizeof (*cmds) ==3 *sizeof (u32)); - rc =iommu_copy_struct_from_full_user_array ( - cmds,sizeof (*cmds), array, -IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST ); + rc =iommu_copy_struct_from_user_array ( + &cmd, array,IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST ,0 , + cache_id);if (rc) goto out; -while (cur != end) { -struct mock_dev *mdev; -struct device *dev; -int i; - -if (cur->flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL ) { - rc = -EOPNOTSUPP ; - goto out; - } - -if (cur->cache_id >MOCK_DEV_CACHE_ID_MAX ) { - rc = -EINVAL ; - goto out; - } +if (cmd.flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL ) { + rc = -EOPNOTSUPP ; + goto out; + } -xa_lock (&viommu->vdevs); - dev =iommufd_viommu_find_dev (viommu, - (unsigned long )cur->vdev_id); -if (!dev) { -xa_unlock (&viommu->vdevs); - rc = -EINVAL ; - goto out; - } - mdev = container_of(dev, struct mock_dev, dev); +if (cmd.cache_id >MOCK_DEV_CACHE_ID_MAX ) { + rc = -EINVAL ; + goto out; + } -if (cur->flags &IOMMU_TEST_INVALIDATE_FLAG_ALL ) { -/* Invalidate all cache entries and ignore cache_id */ -for (i =0 ; i <MOCK_DEV_CACHE_NUM ; i++) - mdev->cache[i] =0 ; - }else { - mdev->cache[cur->cache_id] =0 ; - } +xa_lock (&viommu->vdevs); + dev =iommufd_viommu_find_dev (viommu, (unsigned long )cmd.vdev_id); +if (!dev) {xa_unlock (&viommu->vdevs); - - cur++; + rc = -EINVAL ; + goto out; + } + mdev = container_of(dev, struct mock_dev, dev); + +if (cmd.flags &IOMMU_TEST_INVALIDATE_FLAG_ALL ) { +/* Invalidate all cache entries and ignore cache_id */ +for (i =0 ; i <MOCK_DEV_CACHE_NUM ; i++) + mdev->cache[i] =0 ; + }else { + mdev->cache[cmd.cache_id] =0 ; } +xa_unlock (&viommu->vdevs); + + processed =1 ; out: - array->entry_num = cur - cmds; -kfree (cmds); + array->entry_num = processed;return rc; }
@@ -875,42 +868,46 @@ mock_domain_cache_invalidate_user(struct iommu_domain *domain,struct mock_iommu_domain_nested *mock_nested =to_mock_nested (domain);struct iommu_hwpt_invalidate_selftest inv;u32 processed =0 ; -int i =0 , j;int rc =0 ; +int i;if (array->type !=IOMMU_HWPT_INVALIDATE_DATA_SELFTEST ) { rc = -EINVAL ; goto out; } -for ( ; i < array->entry_num; i++) { - rc =iommu_copy_struct_from_user_array (&inv, array, -IOMMU_HWPT_INVALIDATE_DATA_SELFTEST , - i, iotlb_id); -if (rc) -break ; +/* +* The core re-invokes this op for the remaining requests, so handle one +* request per call. A zero-length array only probes the type, validated +* above. +*/ +if (!array->entry_num) +return 0 ; -if (inv.flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL ) { - rc = -EOPNOTSUPP ; -break ; - } + rc =iommu_copy_struct_from_user_array ( + &inv, array,IOMMU_HWPT_INVALIDATE_DATA_SELFTEST ,0 , iotlb_id); +if (rc) + goto out; -if (inv.iotlb_id >MOCK_NESTED_DOMAIN_IOTLB_ID_MAX ) { - rc = -EINVAL ; -break ; - } +if (inv.flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL ) { + rc = -EOPNOTSUPP ; + goto out; + } -if (inv.flags &IOMMU_TEST_INVALIDATE_FLAG_ALL ) { -/* Invalidate all mock iotlb entries and ignore iotlb_id */ -for (j =0 ; j <MOCK_NESTED_DOMAIN_IOTLB_NUM ; j++) - mock_nested->iotlb[j] =0 ; - }else { - mock_nested->iotlb[inv.iotlb_id] =0 ; - } +if (inv.iotlb_id >MOCK_NESTED_DOMAIN_IOTLB_ID_MAX ) { + rc = -EINVAL ; + goto out; + } - processed++; +if (inv.flags &IOMMU_TEST_INVALIDATE_FLAG_ALL ) { +/* Invalidate all mock iotlb entries and ignore iotlb_id */ +for (i =0 ; i <MOCK_NESTED_DOMAIN_IOTLB_NUM ; i++) + mock_nested->iotlb[i] =0 ; + }else { + mock_nested->iotlb[inv.iotlb_id] =0 ; } + processed =1 ; out: array->entry_num = processed;return rc;
Signature · 1 line
2.43.0
PATCH v5 5/6 iommu/arm-smmu-v3-iommufd: Convert cache invalidation to the core array loop
In reply to Nicolin Chenarm_vsmmu_cache_invalidate() allocated a buffer for the entire user request array, walked the array converting each of the commands, and issued those converted commands to the cmdq in CMDQ_BATCH_ENTRIES sized chunks, carrying the sub-array bookkeeping all on its own.
The iommufd core now iterates the invalidation array and re-invokes the op with the not-yet-handled sub-array, so the driver only has to proceed with a single chunk per call.
Instead of a per-array allocation, use a fixed on-stack batch to copy from the userspace array. If the copy fails due to nonzero padding (VMM violates the ABI), fail the entire batch.
Convert the whole batch before issuing any of it: a malformed command is a userspace bug, so the first illegal command fails the batch as a unit, issuing nothing and leaving array->entry_num at zero, the same way the copy above bails on nonzero padding. A batch that converts cleanly is issued in full, so the op returns either a handled count with no error or zero with an error.
A zero-length array now returns success once the data type gets validated, matching the documented probe behavior, rather than the -EINVAL that the full-array copy helper would previously return.
This also fixes two long-standing bugs:
1) On a conversion failure the old code reported commands that it had converted but not yet issued, so user space advanced its consumer index past invalidations that never reached the cmdq.
2) A zero-length array was rejected with -EINVAL, although the uAPI documents it as a valid request that only probes the data type.
--- .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 68 +++++++++++-------- 1 file changed, 38 insertions(+), 30 deletions(-)
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c +38 -30
@@ -464,49 +464,57 @@ int arm_vsmmu_cache_invalidate(struct iommufd_viommu *viommu, struct iommu_user_data_array *array) { struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core); +struct arm_vsmmu_invalidation_cmd cmds[CMDQ_BATCH_ENTRIES -1 ];struct arm_smmu_device *smmu = vsmmu->smmu; -struct arm_vsmmu_invalidation_cmd *last; -struct arm_vsmmu_invalidation_cmd *cmds; -struct arm_vsmmu_invalidation_cmd *cur; -struct arm_vsmmu_invalidation_cmd *end; +struct iommu_user_data_array batch = { + .type = array->type, + .uptr = array->uptr, + .entry_len = array->entry_len, + }; +u32 processed =0 ;int ret; - - cmds =kzalloc_objs (*cmds, array->entry_num); -if (!cmds) -return -ENOMEM ; - cur = cmds; - end = cmds + array->entry_num; +u32 i;static_assert (sizeof (*cmds) ==2 *sizeof (u64)); + +if (array->type !=IOMMU_VIOMMU_INVALIDATE_DATA_ARM_SMMUV3 ) { + ret = -EINVAL ; + goto out; + } + +/* A zero-length array only probes the type, validated above */ +if (!array->entry_num) +return 0 ; + +/* +* The core re-invokes this op for the remaining requests, so copy one +* cmdq batch worth of commands into a fixed on-stack buffer rather than +* allocating for the whole array. +*/ + batch.entry_num =min_t (u32, array->entry_num,ARRAY_SIZE (cmds)); ret =iommu_copy_struct_from_full_user_array ( - cmds,sizeof (*cmds), array, + cmds,sizeof (*cmds), &batch,IOMMU_VIOMMU_INVALIDATE_DATA_ARM_SMMUV3 );if (ret) goto out; - last = cmds; -while (cur != end) { - ret =arm_vsmmu_convert_user_cmd (vsmmu, cur); +/* +* Convert the whole batch. Sending an illegal command is a VMM bug, so +* a single one fails the entire batch, issuing nothing. +*/ +for (i =0 ; i < batch.entry_num; i++) { + ret =arm_vsmmu_convert_user_cmd (vsmmu, &cmds[i]);if (ret) goto out; - -/* FIXME work in blocks of CMDQ_BATCH_ENTRIES and copy each block? */ - cur++; -if (cur != end && (cur - last) !=CMDQ_BATCH_ENTRIES -1 ) -continue ; - -/* FIXME always uses the main cmdq rather than trying to group by type */ - ret =__arm_smmu_cmdq_issue_cmdlist (smmu, &smmu->cmdq, &last->cmd, - cur - last, true); -if (ret) { - cur--; - goto out; - } - last = cur; } + +/* FIXME always uses the main cmdq rather than trying to group by type */ + ret =__arm_smmu_cmdq_issue_cmdlist (smmu, &smmu->cmdq, &cmds->cmd, + batch.entry_num, true); +if (!ret) + processed = batch.entry_num; out: - array->entry_num = cur - cmds; -kfree (cmds); + array->entry_num = processed;return ret; }
Signature · 1 line
2.43.0
PATCH v5 6/6 iommu/vt-d: Convert nested cache invalidation to the core array loop
In reply to Nicolin Chenintel_nested_cache_invalidate_user() used to walk the whole request array on its own, copying and then flushing one single entry at a time.
The iommufd core now iterates the request array itself and re-invokes the op with the not-yet-handled sub-array, so handle just a single request per call out of the front of that sub-array and report one handled entry via the array->entry_num. An empty array keeps returning a success, used as a probe of IOMMU_HWPT_INVALIDATE_DATA_VTD_S1 support.
--- drivers/iommu/intel/nested.c | 54 ++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 24 deletions(-)
drivers/iommu/intel/nested.c +30 -24
@@ -93,7 +93,7 @@ static int intel_nested_cache_invalidate_user(struct iommu_domain *domain, {struct dmar_domain *dmar_domain =to_dmar_domain (domain);struct iommu_hwpt_vtd_s1_invalidate inv_entry; -u32 index, processed =0 ; +u32 processed =0 ;int ret =0 ;if (array->type !=IOMMU_HWPT_INVALIDATE_DATA_VTD_S1 ) {
@@ -101,31 +101,37 @@ static int intel_nested_cache_invalidate_user(struct iommu_domain *domain, goto out; } -for (index =0 ; index < array->entry_num; index++) { - ret =iommu_copy_struct_from_user_array (&inv_entry, array, -IOMMU_HWPT_INVALIDATE_DATA_VTD_S1 , - index, __reserved); -if (ret) -break ; - -if ((inv_entry.flags & ~IOMMU_VTD_INV_FLAGS_LEAF ) || - inv_entry.__reserved) { - ret = -EOPNOTSUPP ; -break ; - } - -if (!IS_ALIGNED (inv_entry.addr,VTD_PAGE_SIZE ) || - ((inv_entry.npages ==U64_MAX ) && inv_entry.addr)) { - ret = -EINVAL ; -break ; - } - -cache_tag_flush_range (dmar_domain, inv_entry.addr, - inv_entry.addr +nrpages_to_size (inv_entry.npages) -1 , - inv_entry.flags &IOMMU_VTD_INV_FLAGS_LEAF ); - processed++; +/* +* The core re-invokes this op for the remaining requests, so handle one +* request per call. A zero-length array only probes the type, validated +* above. +*/ +if (!array->entry_num) +return 0 ; + + ret =iommu_copy_struct_from_user_array ( + &inv_entry, array,IOMMU_HWPT_INVALIDATE_DATA_VTD_S1 ,0 , + __reserved); +if (ret) + goto out; + +if ((inv_entry.flags & ~IOMMU_VTD_INV_FLAGS_LEAF ) || + inv_entry.__reserved) { + ret = -EOPNOTSUPP ; + goto out; + } + +if (!IS_ALIGNED (inv_entry.addr,VTD_PAGE_SIZE ) || + (inv_entry.npages ==U64_MAX && inv_entry.addr)) { + ret = -EINVAL ; + goto out; } +cache_tag_flush_range (dmar_domain, inv_entry.addr, + inv_entry.addr + +nrpages_to_size (inv_entry.npages) -1 , + inv_entry.flags &IOMMU_VTD_INV_FLAGS_LEAF ); + processed =1 ; out: array->entry_num = processed;return ret;
Signature · 1 line
2.43.0
Will Deacon
maintainerQuoted 16 lines · Nicolin Chen
The vIOMMU
cache_invalidate()and the nested-HWPTcache_invalidate_user()ops are each handed the full user invalidation array and must report, viaarray->entry_num, how many of its entries they handled. That makes every driver open-code the same array walk, with real downsides:- each driver carries its own loop and sub-array bookkeeping;
- the ARM SMMUv3 driver allocates a buffer sized to the whole array just to iterate over it;
- hand-rolling the loop left the ARM SMMUv3 driver with two long-standing bugs:
1) on a conversion failure it counts commands that it converted but never issued, so user space skips invalidations that never reached the cmdq;
2) it rejects a zero-length array, which the uAPI documents as a valid request that only probes the data type.
Quoted 1 line
[...]
Applied first patch to iommu (arm/smmu/updates), thanks!
[1/6] iommu/arm-smmu-v3: Support IDR5.DS and widen the TLBI SCALE field
https://git.kernel.org/iommu/c/773f2b9e3670
Cheers,
Signature · 5 lines
Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev