Re: [PATCH v2 0/3] amd : iommu : Initial IOMMU support for SNP
On Wed, Sep 23, 2020 at 12:13:44PM +, Suravee Suthikulpanit wrote: > Suravee Suthikulpanit (3): > iommu: amd: Use 4K page for completion wait write-back semaphore > iommu: amd: Add support for RMP_PAGE_FAULT and RMP_HW_ERR > iommu: amd: Re-purpose Exclusion range registers to support SNP CWWB Applied, thanks. I am slightly concerned about the re-purposing of the exclusion-range registers based on a feature bit being set. This makes the hardware incompatible to older IOMMU drivers which do not check the FEATURE_SNP bit. It will probably work in this case, as the firmware on systems with IOMMU-SNP support will not declare exclusion ranges at all and exclusion-ranges in the IOMMU hardware have been a bad idea since forever, but it would have been nicer if hardware actually provided a bit to enable this behavior. Regards, Joerg ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
[PATCH v2 0/3] amd : iommu : Initial IOMMU support for SNP
Introducing support for AMD Secure Nested Paging (SNP) with IOMMU, which mainly affects the use of IOMMU Exclusion Base and Range Limit registers. Note that these registers are no longer used by Linux IOMMU driver. Patch 2 and 3 are SNP-specific, and discuss detail of the implementation. In order to support SNP, the current Completion Wait Write-back logic is modified (patch 1/4). This change is independent from SNP. Please see the following white paper for more info on SNP: https://www.amd.com/system/files/TechDocs/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf Changes from V1: (https://lkml.org/lkml/2020/9/16/455) - Patch 2/3: Fix up per Joerg's comments Thank you, Suravee Suravee Suthikulpanit (3): iommu: amd: Use 4K page for completion wait write-back semaphore iommu: amd: Add support for RMP_PAGE_FAULT and RMP_HW_ERR iommu: amd: Re-purpose Exclusion range registers to support SNP CWWB drivers/iommu/amd/amd_iommu_types.h | 6 +- drivers/iommu/amd/init.c| 44 ++ drivers/iommu/amd/iommu.c | 90 + 3 files changed, 127 insertions(+), 13 deletions(-) -- 2.17.1 ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
