Bit 1 of the IVFS IVInfo field indicates that IOMMU has been used for pre-boot DMA protection. Export this information to the kernel to allow other drivers to use it. Link: https://www.amd.com/system/files/TechDocs/48882_IOMMU.pdf Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> --- drivers/iommu/amd/amd_iommu_types.h | 1 + drivers/iommu/amd/init.c | 18 ++++++++++++++++++ include/linux/amd-iommu.h | 5 +++++ 3 files changed, 24 insertions(+) diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h index 47108ed44fbb..68e51213f119 100644 --- a/drivers/iommu/amd/amd_iommu_types.h +++ b/drivers/iommu/amd/amd_iommu_types.h @@ -407,6 +407,7 @@ /* IOMMU IVINFO */ #define IOMMU_IVINFO_OFFSET 36 #define IOMMU_IVINFO_EFRSUP BIT(0) +#define IOMMU_IVINFO_DMA_REMAP BIT(1) /* IOMMU Feature Reporting Field (for IVHD type 10h */ #define IOMMU_FEAT_GASUP_SHIFT 6 diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 7bfe37e52e21..e9b669592dfc 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -182,6 +182,7 @@ u32 amd_iommu_max_pasid __read_mostly = ~0; bool amd_iommu_v2_present __read_mostly; static bool amd_iommu_pc_present __read_mostly; +static bool amdr_ivrs_remap_support __read_mostly; bool amd_iommu_force_isolation __read_mostly; @@ -326,6 +327,8 @@ static void __init early_iommu_features_init(struct amd_iommu *iommu, { if (amd_iommu_ivinfo & IOMMU_IVINFO_EFRSUP) iommu->features = h->efr_reg; + if (amd_iommu_ivinfo & IOMMU_IVINFO_DMA_REMAP) + amdr_ivrs_remap_support = true; } /* Access to l1 and l2 indexed register spaces */ @@ -3269,6 +3272,21 @@ struct amd_iommu *get_amd_iommu(unsigned int idx) return NULL; } +/* + * ivrs_remap_support - Is %IOMMU_IVINFO_DMA_REMAP set in IVRS table + * + * Returns true if the platform has %IOMMU_IVINFO_DMA_REMAP% set in the IOMMU + * IVRS IVInfo field. + * Presence of this flag indicates to the OS/HV that the IOMMU is used for + * Preboot DMA protection and device accessed memory should be remapped after + * the OS has loaded. + */ +bool amd_ivrs_remap_support(void) +{ + return amdr_ivrs_remap_support; +} +EXPORT_SYMBOL_GPL(amd_ivrs_remap_support); + /**************************************************************************** * * IOMMU EFR Performance Counter support functionality. This code allows diff --git a/include/linux/amd-iommu.h b/include/linux/amd-iommu.h index 58e6c3806c09..d07b9fed6474 100644 --- a/include/linux/amd-iommu.h +++ b/include/linux/amd-iommu.h @@ -170,6 +170,7 @@ amd_iommu_update_ga(int cpu, bool is_run, void *data); extern int amd_iommu_activate_guest_mode(void *data); extern int amd_iommu_deactivate_guest_mode(void *data); +extern bool amd_ivrs_remap_support(void); #else /* defined(CONFIG_AMD_IOMMU) && defined(CONFIG_IRQ_REMAP) */ @@ -194,6 +195,10 @@ static inline int amd_iommu_deactivate_guest_mode(void *data) { return 0; } +static inline bool amd_ivrs_remap_support(void) +{ + return false; +} #endif /* defined(CONFIG_AMD_IOMMU) && defined(CONFIG_IRQ_REMAP) */ int amd_iommu_get_num_iommus(void); -- 2.34.1
