From: Robin Murphy Date: Wed, 10 May 2023 15:38:45 +0000 (+0100) Subject: iommu/arm-smmu-v3: Add explicit feature for nesting X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1d9777b9f3d55b4b6faf186ba4f1d6fb560c0523;p=linux.git iommu/arm-smmu-v3: Add explicit feature for nesting In certain cases we may want to refuse to allow nested translation even when both stages are implemented, so let's add an explicit feature for nesting support which we can control in its own right. For now this merely serves as documentation, but it means a nice convenient check will be ready and waiting for the future nesting code. Signed-off-by: Robin Murphy Reviewed-by: Nicolin Chen Link: https://lore.kernel.org/r/136c3f4a3a84cc14a5a1978ace57dfd3ed67b688.1683731256.git.robin.murphy@arm.com Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index b0ccd735f8bb3..7e08ec55df2ac 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -3674,6 +3674,10 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) smmu->ias = max(smmu->ias, smmu->oas); + if ((smmu->features & ARM_SMMU_FEAT_TRANS_S1) && + (smmu->features & ARM_SMMU_FEAT_TRANS_S2)) + smmu->features |= ARM_SMMU_FEAT_NESTING; + arm_smmu_device_iidr_probe(smmu); if (arm_smmu_sva_supported(smmu)) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index 1555c82203816..dcab85698a4e2 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -645,6 +645,7 @@ struct arm_smmu_device { #define ARM_SMMU_FEAT_BTM (1 << 16) #define ARM_SMMU_FEAT_SVA (1 << 17) #define ARM_SMMU_FEAT_E2H (1 << 18) +#define ARM_SMMU_FEAT_NESTING (1 << 19) u32 features; #define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0)