diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2025-11-03 09:27:55 -0800 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2025-11-26 14:04:04 -0400 |
| commit | 81c45c62dc3eefd83af8eb8df10e45705e8e3a47 (patch) | |
| tree | d948cfd6840701a96dc9c2f89733fca4f188e192 /drivers | |
| parent | ac3fd01e4c1efce8f2c054cdeb2ddd2fc0fb150d (diff) | |
iommu/arm-smmu-v3-iommufd: Allow attaching nested domain for GBPA cases
A vDEVICE has been a hard requirement for attaching a nested domain to the
device. This makes sense when installing a guest STE, since a vSID must be
present and given to the kernel during the vDEVICE allocation.
But, when CR0.SMMUEN is disabled, VM doesn't really need a vSID to program
the vSMMU behavior as GBPA will take effect, in which case the vSTE in the
nested domain could have carried the bypass or abort configuration in GBPA
register. Thus, having such a hard requirement doesn't work well for GBPA.
Skip vmaster allocation in arm_smmu_attach_prepare_vmaster() for an abort
or bypass vSTE. Note that device on this attachment won't report vevents.
Update the uAPI doc accordingly.
Link: https://patch.msgid.link/r/20251103172755.2026145-1-nicolinc@nvidia.com
Tested-by: Shameer Kolothum <skolothumtho@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Tested-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c index 8cd8929bbfdf..e5fbbdbdea24 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c @@ -99,6 +99,8 @@ static void arm_smmu_make_nested_domain_ste( int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state, struct arm_smmu_nested_domain *nested_domain) { + unsigned int cfg = + FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(nested_domain->ste[0])); struct arm_smmu_vmaster *vmaster; unsigned long vsid; int ret; @@ -107,8 +109,17 @@ int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state, ret = iommufd_viommu_get_vdev_id(&nested_domain->vsmmu->core, state->master->dev, &vsid); - if (ret) + /* + * Attaching to a translate nested domain must allocate a vDEVICE prior, + * as CD/ATS invalidations and vevents require a vSID to work properly. + * A abort/bypass domain is allowed to attach w/o vmaster for GBPA case. + */ + if (ret) { + if (cfg == STRTAB_STE_0_CFG_ABORT || + cfg == STRTAB_STE_0_CFG_BYPASS) + return 0; return ret; + } vmaster = kzalloc(sizeof(*vmaster), GFP_KERNEL); if (!vmaster) |