From: Robin Murphy <robin.murphy@xxxxxxx> commit 1d9777b9f3d55b4b6faf186ba4f1d6fb560c0523 upstream 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 <robin.murphy@xxxxxxx> Reviewed-by: Nicolin Chen <nicolinc@xxxxxxxxxx> Link: https://lore.kernel.org/r/136c3f4a3a84cc14a5a1978ace57dfd3ed67b688.1683731256.git.robin.murphy@xxxxxxx Signed-off-by: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 + 2 files changed, 5 insertions(+) --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -3703,6 +3703,10 @@ static int arm_smmu_device_hw_probe(stru 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)) --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -646,6 +646,7 @@ 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)
