Commit eeb93413 authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Dan Williams
Browse files

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: default avatarAlexey Kardashevskiy <aik@amd.com>
Link: https://patch.msgid.link/20251202024449.542361-4-aik@amd.com


Acked-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Reviewed-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Acked-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent c3859de8

drivers/iommu/amd/amd_iommu_types.h

+1 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ 




/* Extended Feature 2 Bits */

#define FEATURE_SEVSNPIO_SUP	BIT_ULL(1)

#define FEATURE_SNPAVICSUP	GENMASK_ULL(7, 5)

#define FEATURE_SNPAVICSUP_GAM(x) \

	(FIELD_GET(FEATURE_SNPAVICSUP, x) == 0x1)

drivers/iommu/amd/init.c

+9 −0
Original line number Diff line number Diff line
@@ -2252,6 +2252,9 @@ static void print_iommu_info(void) 
		if (check_feature(FEATURE_SNP))

			pr_cont(" SNP");



		if (check_feature2(FEATURE_SEVSNPIO_SUP))

			pr_cont(" SEV-TIO");



		pr_cont("\n");

	}
@@ -4015,4 +4018,10 @@ int amd_iommu_snp_disable(void) 
	return 0;

}

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

include/linux/amd-iommu.h

+2 −0
Original line number Diff line number Diff line
@@ -18,10 +18,12 @@ struct task_struct; 
struct pci_dev;



extern void amd_iommu_detect(void);

extern bool amd_iommu_sev_tio_supported(void);



#else /* CONFIG_AMD_IOMMU */



static inline void amd_iommu_detect(void) { }

static inline bool amd_iommu_sev_tio_supported(void) { return false; }



#endif /* CONFIG_AMD_IOMMU */