Re: [PATCH v5 8/9] iommu/arm-smmu-v3: Change how the tlbi describes the invalidation
From: Jason Gunthorpe <jgg@nvidia.com>
Date: 2026-09-09 15:57:39
Also in:
linux-doc, linux-iommu, linux-patches, stable
Subsystem:
arm smmu drivers, arm smmu sva support, iommu subsystem, the rest · Maintainers:
Will Deacon, Joerg Roedel, Linus Torvalds
On Mon, Sep 07, 2026 at 12:34:29PM -0300, Jason Gunthorpe wrote:
quoted
quoted
+ tlbi.leaf_levels_bitmap = BIT((ilog2(gather->pgsize) - tg) / (tg - 3));Having some page table macros would be helpful (and in other places in this patch)At least this one gets deleted in the next series, so I left it like this deliberately. Was there something else you saw that had duplication?
I ended up with this:
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 07ba4e7910ab84..fc9622cdbac808 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c@@ -155,7 +155,7 @@ static void arm_smmu_mm_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn, */ .table_levels_bitmap = 0xfe, }; - u8 pmd_lg2sz = (tgsz_lg2 - 3) * 1 + tgsz_lg2; + u8 pmd_lg2sz = arm_smmu_pt_level_to_lg2sz(tgsz_lg2, 1); /* * If the size is small then we can infer the invalidation is PTE only
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 2a159be751891e..8dd5d30c569771 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -2485,7 +2485,7 @@ static void arm_smmu_tlb_inv_context(void *cookie) static bool arm_smmu_ttl_addr_aligned(u64 address, unsigned int tg, unsigned int ttl) { - unsigned int pgsz_lg2 = (tg - 3) * (3 - ttl) + tg; + unsigned int pgsz_lg2 = arm_smmu_pt_level_to_lg2sz(tg, 3 - ttl); return !(address & GENMASK_U64(pgsz_lg2 - 1, 0)); }
@@ -2497,6 +2497,16 @@ struct arm_smmu_ril_range { unsigned int scale; }; +static unsigned int arm_smmu_ril_calc_scale(u64 num_tg) +{ + return fls64((num_tg - 1) / (CMDQ_TLBI_RANGE_NUM_MAX + 1)); +} + +static u64 arm_smmu_ril_calc_num(u64 num_tg, unsigned int scale) +{ + return DIV_ROUND_UP_ULL(num_tg, 1ULL << scale); +} + /* * Initialize the smallest RIL covering num_tg and ending at last_tg. */
@@ -2507,8 +2517,8 @@ static struct arm_smmu_ril_range arm_smmu_ril_init_end(u64 last_tg, u64 num_tg) if (!num_tg) return ril; - ril.scale = fls64((num_tg - 1) / 32); - ril.num = DIV_ROUND_UP_ULL(num_tg, 1ULL << ril.scale); + ril.scale = arm_smmu_ril_calc_scale(num_tg); + ril.num = arm_smmu_ril_calc_num(num_tg, ril.scale); ril.start_tg = last_tg - ((ril.num << ril.scale) - 1); return ril; }
@@ -2654,7 +2664,7 @@ static void arm_smmu_tlbi_calc_range(struct arm_smmu_tlbi *tlbi, * Unlike other IOMMUs the spec has no alignment requirement on the * address beyond alignment to tg (so long as TTL=0). */ - first.scale = fls64((num_tg - 1) / 32); + first.scale = arm_smmu_ril_calc_scale(num_tg); if (first.scale > scale_max) { /* Range too large for a single command do full invalidation */ tlbi->range.use_full_inv = true;
@@ -2666,7 +2676,7 @@ static void arm_smmu_tlbi_calc_range(struct arm_smmu_tlbi *tlbi, * Produce a single invalidation by rounding up and disabling * the trailer. */ - first.num = DIV_ROUND_UP_ULL(num_tg, 1ULL << first.scale); + first.num = arm_smmu_ril_calc_num(num_tg, first.scale); trail.num = 0; } else { /*
@@ -2694,11 +2704,10 @@ static void arm_smmu_tlbi_calc_range(struct arm_smmu_tlbi *tlbi, static u8 arm_smmu_tlbi_calc_stride(struct arm_smmu_tlbi *tlbi) { u8 combined = tlbi->table_levels_bitmap | tlbi->leaf_levels_bitmap; - u8 tg_szlg2 = tlbi->tgsz_lg2; if (WARN_ON(!combined)) return U8_MAX; - return (tg_szlg2 - 3) * __ffs(combined) + tg_szlg2; + return arm_smmu_pt_level_to_lg2sz(tlbi->tgsz_lg2, __ffs(combined)); } /*
@@ -2972,7 +2981,8 @@ static void arm_smmu_tlb_inv_walk(unsigned long iova, size_t size, .start = iova, .last = iova + size - 1, }; - u8 table_levels = BIT((ilog2(size) - tgsz_lg2) / (tgsz_lg2 - 3)); + u8 table_levels = + BIT(arm_smmu_pt_lg2sz_to_level(tgsz_lg2, ilog2(size))); tlbi.table_levels_bitmap = table_levels; tlbi.leaf_levels_bitmap = table_levels - 1;
@@ -4247,10 +4257,12 @@ static void arm_smmu_flush_iotlb_all(struct iommu_domain *domain) } /* - * Called by io-pgtable-arm.c for each run of same pgsize leaf only - * invalidation. If it has to change to a different leaf level then it flushes - * the gather and starts a fresh one. Thus this always targets only a single - * leaf level. + * io-pgtable-arm.c calls this function either under + * arm_smmu_tlb_inv_page_nosync() or via the normal iommu code to flush the + * gather. Due to how iommu_iotlb_gather_add_page() works the gather will end up + * with a single uniform pgsize leaf. If it has to change to a different leaf + * level then it flushes the gather and starts a fresh one. Thus this always + * targets only a single leaf level. */ static void arm_smmu_iotlb_sync(struct iommu_domain *domain, struct iommu_iotlb_gather *gather)
@@ -4266,7 +4278,8 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain, if (WARN_ON(gather->pgsize < BIT(tg))) return; - tlbi.leaf_levels_bitmap = BIT((ilog2(gather->pgsize) - tg) / (tg - 3)); + tlbi.leaf_levels_bitmap = + BIT(arm_smmu_pt_lg2sz_to_level(tg, ilog2(gather->pgsize))); arm_smmu_domain_tlbi(&tlbi, smmu_domain); }
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 8b251a188810c9..70d732a96be27f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h@@ -810,12 +810,24 @@ static inline struct arm_smmu_invs *arm_smmu_invs_alloc(size_t num_invs) return new_invs; } +/* Generic page-table level 0 is the leaf-only level. */ +static inline unsigned int arm_smmu_pt_level_to_lg2sz(unsigned int tgsz_lg2, + unsigned int level) +{ + return tgsz_lg2 + (tgsz_lg2 - ilog2(sizeof(u64))) * level; +} + +static inline unsigned int arm_smmu_pt_lg2sz_to_level(unsigned int tgsz_lg2, + unsigned int lg2sz) +{ + return (lg2sz - tgsz_lg2) / (tgsz_lg2 - ilog2(sizeof(u64))); +} + struct arm_smmu_tlbi { unsigned long start; unsigned long last; /* Base Translation Granule of the page table */ u8 tgsz_lg2; - bool leaf_only; /* * Level bitmaps use iommupt numbering: bit 0 is the leaf-only level * (ARM level 3), bit 1 is the next level up (ARM level 2), etc. These