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Subject[PATCH v3 7/7] iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled
Date
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 f5695ccb7c81..4c9b96160a8b 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3448,7 +3448,12 @@ __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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