Messages in this thread | | | Date | Wed, 29 Jun 2022 18:54:34 +0700 | Subject | Re: [PATCH v3 7/7] iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled | From | "Suthikulpanit, Suravee" <> |
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On 6/23/2022 3:23 PM, Joerg Roedel wrote: > On Wed, Jun 22, 2022 at 12:11:31PM -0500, Suravee Suthikulpanit wrote: >> bool amd_iommu_v2_supported(void) >> { >> - return amd_iommu_v2_present; >> + /* >> + * Since DTE[Mode]=0 is prohibited on SNP-enabled system >> + * (i.e. EFR[SNPSup]=1), IOMMUv2 page table cannot be used without >> + * setting up IOMMUv1 page table. >> + */ >> + return amd_iommu_v2_present && !amd_iommu_snp_en; > > IOMMU_v2 APIs could actually be supported with GIOV and IOMMUv2 > page-tables in-use, no? > We can support IOMMUv2 iff the v1 table is also setup (i.e. DTE[Mode] != 0). Currently w/ IOMMU_v2 APIs, the IOMMU sets the mode to zero. Therefore, we cannot support this use case.
Best Regards, Suravee
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