From 1e8be08d1c91d52a9b51d424db78ddbf88660bbb Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 30 Oct 2024 21:20:53 -0300 Subject: iommu/arm-smmu-v3: Support IOMMU_DOMAIN_NESTED For SMMUv3 a IOMMU_DOMAIN_NESTED is composed of a S2 iommu_domain acting as the parent and a user provided STE fragment that defines the CD table and related data with addresses translated by the S2 iommu_domain. The kernel only permits userspace to control certain allowed bits of the STE that are safe for user/guest control. IOTLB maintenance is a bit subtle here, the S1 implicitly includes the S2 translation, but there is no way of knowing which S1 entries refer to a range of S2. For the IOTLB we follow ARM's guidance and issue a CMDQ_OP_TLBI_NH_ALL to flush all ASIDs from the VMID after flushing the S2 on any change to the S2. The IOMMU_DOMAIN_NESTED can only be created from inside a VIOMMU as the invalidation path relies on the VIOMMU to translate virtual stream ID used in the invalidation commands for the CD table and ATS. Link: https://patch.msgid.link/r/9-v4-9e99b76f3518+3a8-smmuv3_nesting_jgg@nvidia.com Reviewed-by: Nicolin Chen Reviewed-by: Kevin Tian Reviewed-by: Jerry Snitselaar Reviewed-by: Donald Dutile Signed-off-by: Nicolin Chen Tested-by: Nicolin Chen Signed-off-by: Jason Gunthorpe --- include/uapi/linux/iommufd.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index 7cb13a29969d..b6baaa1e55b1 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -421,6 +421,26 @@ struct iommu_hwpt_vtd_s1 { __u32 __reserved; }; +/** + * struct iommu_hwpt_arm_smmuv3 - ARM SMMUv3 nested STE + * (IOMMU_HWPT_DATA_ARM_SMMUV3) + * + * @ste: The first two double words of the user space Stream Table Entry for + * the translation. Must be little-endian. + * Allowed fields: (Refer to "5.2 Stream Table Entry" in SMMUv3 HW Spec) + * - word-0: V, Cfg, S1Fmt, S1ContextPtr, S1CDMax + * - word-1: S1DSS, S1CIR, S1COR, S1CSH, S1STALLD + * + * -EIO will be returned if @ste is not legal or contains any non-allowed field. + * Cfg can be used to select a S1, Bypass or Abort configuration. A Bypass + * 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. + */ +struct iommu_hwpt_arm_smmuv3 { + __aligned_le64 ste[2]; +}; + /** * enum iommu_hwpt_data_type - IOMMU HWPT Data Type * @IOMMU_HWPT_DATA_NONE: no data -- cgit v1.2.3