iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled

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>
Link: https://lore.kernel.org/r/20220713225651.20758-10-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 538c750..d864961 100644 (file)
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3458,7 +3458,12 @@ __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);