diff options
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 13 | ||||
| -rw-r--r-- | include/uapi/linux/iommufd.h | 10 |
2 files changed, 22 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) diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index c218c89e0e2e..2c41920b641d 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -450,6 +450,16 @@ struct iommu_hwpt_vtd_s1 { * nested domain will translate the same as the nesting parent. The S1 will * install a Context Descriptor Table pointing at userspace memory translated * by the nesting parent. + * + * It's suggested to allocate a vDEVICE object carrying vSID and then re-attach + * the nested domain, as soon as the vSID is available in the VMM level: + * + * - when Cfg=translate, a vDEVICE must be allocated prior to attaching to the + * allocated nested domain, as CD/ATS invalidations and vevents need a vSID. + * - when Cfg=bypass/abort, a vDEVICE is not enforced during the nested domain + * attachment, to support a GBPA case where VM sets CR0.SMMUEN=0. However, if + * VM sets CR0.SMMUEN=1 while missing a vDEVICE object, kernel would fail to + * report events to the VM. E.g. F_TRANSLATION when guest STE.Cfg=abort. */ struct iommu_hwpt_arm_smmuv3 { __aligned_le64 ste[2]; |