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| author | Vasant Hegde <vasant.hegde@amd.com> | 2024-04-10 08:57:02 +0000 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2024-04-12 12:03:22 +0200 |
| commit | b650b38b006053ef96e90b8e3f7e6edc7845cd57 (patch) | |
| tree | 6bccfddd6b63773af33b517543490bd9a64dc390 | |
| parent | 84b1cec4fac5889b6d138d4b5ff6f2d5ef126c5e (diff) | |
| download | linux-b650b38b006053ef96e90b8e3f7e6edc7845cd57.tar.gz | |
iommu/amd: Do not enable SNP when V2 page table is enabled
DTE[Mode]=0 is not supported when SNP is enabled in the host. That means
to support SNP, IOMMU must be configured with V1 page table (See IOMMU
spec [1] for the details). If user passes kernel command line to configure
IOMMU domains with v2 page table (amd_iommu=pgtbl_v2) then disable SNP
as the user asked by not forcing the page table to v1.
[1] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/specifications/48882_IOMMU.pdf
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240410085702.31869-1-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/amd/init.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 33228c1c8980f3..a714eb08c08b5a 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -3232,28 +3232,29 @@ static void iommu_snp_enable(void) return; /* * The SNP support requires that IOMMU must be enabled, and is - * not configured in the passthrough mode. + * configured with V1 page table (DTE[Mode] = 0 is not supported). */ if (no_iommu || iommu_default_passthrough()) { pr_err("SNP: IOMMU disabled or configured in passthrough mode, SNP cannot be supported.\n"); - cc_platform_clear(CC_ATTR_HOST_SEV_SNP); - return; + goto disable_snp; + } + + if (amd_iommu_pgtable != AMD_IOMMU_V1) { + pr_warn("SNP: IOMMU is configured with V2 page table mode, SNP cannot be supported.\n"); + goto disable_snp; } amd_iommu_snp_en = check_feature(FEATURE_SNP); if (!amd_iommu_snp_en) { pr_err("SNP: IOMMU SNP feature not enabled, SNP cannot be supported.\n"); - cc_platform_clear(CC_ATTR_HOST_SEV_SNP); - return; + goto disable_snp; } pr_info("IOMMU SNP support enabled.\n"); + return; - /* Enforce IOMMU v1 pagetable when SNP is enabled. */ - if (amd_iommu_pgtable != AMD_IOMMU_V1) { - pr_warn("Forcing use of AMD IOMMU v1 page table due to SNP.\n"); - amd_iommu_pgtable = AMD_IOMMU_V1; - } +disable_snp: + cc_platform_clear(CC_ATTR_HOST_SEV_SNP); #endif } |