Messages in this thread Patch in this message | | | From | Suravee Suthikulpanit <> | Subject | [PATCH v4 9/9] iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled | Date | Wed, 13 Jul 2022 17:56:51 -0500 |
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The IOMMUv2 APIs (for supporting shared virtual memory with PASID) configures the domain with IOMMU v2 page table, and sets DTE[Mode]=0. This configuration cannot be supported on SNP-enabled system.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> --- drivers/iommu/amd/init.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 959595c49656..2cfac23d34a6 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -3455,7 +3455,12 @@ __setup("ivrs_acpihid", parse_ivrs_acpihid); 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; } EXPORT_SYMBOL(amd_iommu_v2_supported); -- 2.32.0
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