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iommu/amd: Report SEV-TIO support 

The SEV-TIO switch in the AMD BIOS is reported to the OS via
the IOMMU Extended Feature 2 register (EFR2), bit 1.

Add helper to parse the bit and report the feature presence.

Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://patch.msgid.link/20251202024449.542361-4-aik@amd.com
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
pull/1354/merge
Alexey Kardashevskiy 2025-12-02 13:44:48 +11:00 committed by Dan Williams
parent c3859de858
commit eeb934137d
3 changed files with 12 additions and 0 deletions
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1
drivers/iommu/amd/amd_iommu_types.h
View File

@ -107,6 +107,7 @@
/* Extended Feature 2 Bits */ /* Extended Feature 2 Bits */
#define FEATURE_SEVSNPIO_SUP BIT_ULL(1)
#define FEATURE_SNPAVICSUP GENMASK_ULL(7, 5) #define FEATURE_SNPAVICSUP GENMASK_ULL(7, 5)
#define FEATURE_SNPAVICSUP_GAM(x) \ #define FEATURE_SNPAVICSUP_GAM(x) \
(FIELD_GET(FEATURE_SNPAVICSUP, x) == 0x1) (FIELD_GET(FEATURE_SNPAVICSUP, x) == 0x1)

9
drivers/iommu/amd/init.c
View File

@ -2252,6 +2252,9 @@ static void print_iommu_info(void)
if (check_feature(FEATURE_SNP)) if (check_feature(FEATURE_SNP))
pr_cont(" SNP"); pr_cont(" SNP");
if (check_feature2(FEATURE_SEVSNPIO_SUP))
pr_cont(" SEV-TIO");
pr_cont("\n"); pr_cont("\n");
} }
@ -4015,4 +4018,10 @@ int amd_iommu_snp_disable(void)
return 0; return 0;
} }
EXPORT_SYMBOL_GPL(amd_iommu_snp_disable); EXPORT_SYMBOL_GPL(amd_iommu_snp_disable);
bool amd_iommu_sev_tio_supported(void)
{
return check_feature2(FEATURE_SEVSNPIO_SUP);
}
EXPORT_SYMBOL_GPL(amd_iommu_sev_tio_supported);
#endif #endif

2
include/linux/amd-iommu.h
View File

@ -18,10 +18,12 @@ struct task_struct;
struct pci_dev; struct pci_dev;
extern void amd_iommu_detect(void); extern void amd_iommu_detect(void);
extern bool amd_iommu_sev_tio_supported(void);
#else /* CONFIG_AMD_IOMMU */ #else /* CONFIG_AMD_IOMMU */
static inline void amd_iommu_detect(void) { } static inline void amd_iommu_detect(void) { }
static inline bool amd_iommu_sev_tio_supported(void) { return false; }
#endif /* CONFIG_AMD_IOMMU */ #endif /* CONFIG_AMD_IOMMU */