From: jiangkunkun <jiangkunkun@xxxxxxxxxx> When altering a translation table descriptor of some specific reasons, we require break-before-make procedure. But it might cause problems when the TTD is alive. The I/O streams might not tolerate translation faults. If the SMMU supports BBML level 1 or BBML level 2, we can change the block size without using break-before-make. This adds feature detection for BBML, none functional change. Co-developed-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx> Signed-off-by: Kunkun Jiang <jiangkunkun@xxxxxxxxxx> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 24 ++++++++++++++++++++- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 6 ++++++ include/linux/io-pgtable.h | 1 + 3 files changed, 30 insertions(+), 1 deletion(-) 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 8cc9d7536b08..9208881a571c 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -1947,7 +1947,7 @@ static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain, static int arm_smmu_domain_finalise(struct iommu_domain *domain, struct arm_smmu_master *master) { - int ret; + int ret, bbml; unsigned long ias, oas; enum io_pgtable_fmt fmt; struct io_pgtable_cfg pgtbl_cfg; @@ -1988,12 +1988,20 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain, return -EINVAL; } + if (smmu->features & ARM_SMMU_FEAT_BBML2) + bbml = 2; + else if (smmu->features & ARM_SMMU_FEAT_BBML1) + bbml = 1; + else + bbml = 0; + pgtbl_cfg = (struct io_pgtable_cfg) { .pgsize_bitmap = smmu->pgsize_bitmap, .ias = ias, .oas = oas, .httu_hd = smmu->features & ARM_SMMU_FEAT_HTTU_HD, .coherent_walk = smmu->features & ARM_SMMU_FEAT_COHERENCY, + .bbml = bbml, .tlb = &arm_smmu_flush_ops, .iommu_dev = smmu->dev, }; @@ -3328,6 +3336,20 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) /* IDR3 */ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3); + switch (FIELD_GET(IDR3_BBML, reg)) { + case IDR3_BBML0: + break; + case IDR3_BBML1: + smmu->features |= ARM_SMMU_FEAT_BBML1; + break; + case IDR3_BBML2: + smmu->features |= ARM_SMMU_FEAT_BBML2; + break; + default: + dev_err(smmu->dev, "unknown/unsupported BBM behavior level\n"); + return -ENXIO; + } + if (FIELD_GET(IDR3_RIL, reg)) smmu->features |= ARM_SMMU_FEAT_RANGE_INV; 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 e91bea44519e..11e526ab7239 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -55,6 +55,10 @@ #define IDR1_SIDSIZE GENMASK(5, 0) #define ARM_SMMU_IDR3 0xc +#define IDR3_BBML GENMASK(12, 11) +#define IDR3_BBML0 0 +#define IDR3_BBML1 1 +#define IDR3_BBML2 2 #define IDR3_RIL (1 << 10) #define ARM_SMMU_IDR5 0x14 @@ -612,6 +616,8 @@ struct arm_smmu_device { #define ARM_SMMU_FEAT_SVA (1 << 17) #define ARM_SMMU_FEAT_HTTU_HA (1 << 18) #define ARM_SMMU_FEAT_HTTU_HD (1 << 19) +#define ARM_SMMU_FEAT_BBML1 (1 << 20) +#define ARM_SMMU_FEAT_BBML2 (1 << 21) u32 features; #define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0) diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h index 1a00ea8562c7..26583beeb5d9 100644 --- a/include/linux/io-pgtable.h +++ b/include/linux/io-pgtable.h @@ -99,6 +99,7 @@ struct io_pgtable_cfg { unsigned int oas; bool httu_hd; bool coherent_walk; + int bbml; const struct iommu_flush_ops *tlb; struct device *iommu_dev; -- 2.19.1 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm