RE: [PATCH v7 1/3] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

From: Liu, Yi L yi.l.liu@intel.com Sent: Friday, November 17, 2023 9:18 PM

This adds the data structure for flushing iotlb for the nested domain allocated with IOMMU_HWPT_DATA_VTD_S1 type.

This only supports invalidating IOTLB, but no for device-TLB as device-TLB invalidation will be covered automatically in the IOTLB invalidation if the underlying IOMMU driver has enabled ATS for the affected device.

"no for device-TLB" is misleading. Here just say that cache invalidation request applies to both IOTLB and device TLB (if ATS is enabled ...)

+/**

• • enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d

• •                                       stage-1 cache invalidation
    

• • @IOMMU_VTD_INV_FLAGS_LEAF: The LEAF flag indicates whether only

the

• •                        leaf PTE caching needs to be invalidated
    

• •                        and other paging structure caches can be
    

• •                        preserved.
    

remove the words after 'and'

+/**

• • struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation

• •                                   (IOMMU_HWPT_DATA_VTD_S1)
    

• • @addr: The start address of the addresses to be invalidated. It needs

• •    to be 4KB aligned.
    

remove "of the addresses"

• • @npages: Number of contiguous 4K pages to be invalidated.
• • @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
• • @__reserved: Must be 0
• • The Intel VT-d specific invalidation data for user-managed stage-1 cache
• • invalidation in nested translation. Userspace uses this structure to
• • tell the impacted cache scope after modifying the stage-1 page table.
• • Invalidating all the caches related to the page table by setting @addr
• • to be 0 and @npages to be __aligned_u64(-1). This includes the
• • corresponding device-TLB if ATS is enabled on the attached devices.

put words about device-TLB to last paragraph. Putting it here is confusing as if it only applies to invalidate-all.