[PATCH 2/9] iommu/io-pgtable: introduce iova_to_phys_length in io_pgtable_ops
From: Guanghui Feng
Date: Sun May 31 2026 - 05:38:24 EST
Add iova_to_phys_length to struct io_pgtable_ops alongside iova_to_phys.
The new callback additionally returns the block/page size of the PTE
entry through the mapped_length parameter.
Implement in all three io-pgtable backends:
- ARM LPAE: returns ARM_LPAE_BLOCK_SIZE at the resolved level
- ARM v7s: returns block size derived from level mask
- DART: returns pgsize_bitmap (single fixed page size)
The old iova_to_phys is kept as a thin wrapper for backward compat.
Signed-off-by: Guanghui Feng <guanghuifeng@xxxxxxxxxxxxxxxxx>
Acked-by: Shiqiang Zhang <shiyu.zsq@xxxxxxxxxxxxxxxxx>
Acked-by: Simon Guo <wei.guo.simon@xxxxxxxxxxxxxxxxx>
---
drivers/iommu/io-pgtable-arm-v7s.c | 30 ++++++++++++++++++++++++------
drivers/iommu/io-pgtable-arm.c | 19 ++++++++++++++++++-
drivers/iommu/io-pgtable-dart.c | 26 +++++++++++++++++++++-----
include/linux/io-pgtable.h | 7 +++++++
4 files changed, 70 insertions(+), 12 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 40e33257d3c2..54e8cc673eb6 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -641,13 +641,25 @@ static size_t arm_v7s_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova
return unmapped;
}
+static phys_addr_t arm_v7s_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length);
+
static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
unsigned long iova)
+{
+ return arm_v7s_iova_to_phys_length(ops, iova, NULL);
+}
+
+static phys_addr_t arm_v7s_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length)
{
struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
arm_v7s_iopte *ptep = data->pgd, pte;
int lvl = 0;
u32 mask;
+ size_t blk_size;
do {
ptep += ARM_V7S_LVL_IDX(iova, ++lvl, &data->iop.cfg);
@@ -661,6 +673,11 @@ static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
mask = ARM_V7S_LVL_MASK(lvl);
if (arm_v7s_pte_is_cont(pte, lvl))
mask *= ARM_V7S_CONT_PAGES;
+
+ blk_size = ~mask + 1U;
+ if (mapped_length)
+ *mapped_length = blk_size;
+
return iopte_to_paddr(pte, lvl, &data->iop.cfg) | (iova & ~mask);
}
@@ -714,6 +731,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
.map_pages = arm_v7s_map_pages,
.unmap_pages = arm_v7s_unmap_pages,
.iova_to_phys = arm_v7s_iova_to_phys,
+ .iova_to_phys_length = arm_v7s_iova_to_phys_length,
};
/* We have to do this early for __arm_v7s_alloc_table to work... */
@@ -837,13 +855,13 @@ static int __init arm_v7s_do_selftests(void)
* Initial sanity checks.
* Empty page tables shouldn't provide any translations.
*/
- if (ops->iova_to_phys(ops, 42))
+ if (ops->iova_to_phys_length(ops, 42, NULL))
return __FAIL(ops);
- if (ops->iova_to_phys(ops, SZ_1G + 42))
+ if (ops->iova_to_phys_length(ops, SZ_1G + 42, NULL))
return __FAIL(ops);
- if (ops->iova_to_phys(ops, SZ_2G + 42))
+ if (ops->iova_to_phys_length(ops, SZ_2G + 42, NULL))
return __FAIL(ops);
/*
@@ -864,7 +882,7 @@ static int __init arm_v7s_do_selftests(void)
&mapped))
return __FAIL(ops);
- if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
+ if (ops->iova_to_phys_length(ops, iova + 42, NULL) != (iova + 42))
return __FAIL(ops);
iova += SZ_16M;
@@ -878,7 +896,7 @@ static int __init arm_v7s_do_selftests(void)
if (ops->unmap_pages(ops, iova, size, 1, NULL) != size)
return __FAIL(ops);
- if (ops->iova_to_phys(ops, iova + 42))
+ if (ops->iova_to_phys_length(ops, iova + 42, NULL))
return __FAIL(ops);
/* Remap full block */
@@ -886,7 +904,7 @@ static int __init arm_v7s_do_selftests(void)
GFP_KERNEL, &mapped))
return __FAIL(ops);
- if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
+ if (ops->iova_to_phys_length(ops, iova + 42, NULL) != (iova + 42))
return __FAIL(ops);
iova += SZ_16M;
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 0208e5897c29..e2ea84669fbf 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -731,8 +731,19 @@ static int visit_iova_to_phys(struct io_pgtable_walk_data *walk_data, int lvl,
return 0;
}
+static phys_addr_t arm_lpae_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length);
+
static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
unsigned long iova)
+{
+ return arm_lpae_iova_to_phys_length(ops, iova, NULL);
+}
+
+static phys_addr_t arm_lpae_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length)
{
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
struct iova_to_phys_data d;
@@ -742,13 +753,18 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
.addr = iova,
.end = iova + 1,
};
+ size_t block_size;
int ret;
ret = __arm_lpae_iopte_walk(data, &walk_data, data->pgd, data->start_level);
if (ret)
return 0;
- iova &= (ARM_LPAE_BLOCK_SIZE(d.lvl, data) - 1);
+ block_size = ARM_LPAE_BLOCK_SIZE(d.lvl, data);
+ if (mapped_length)
+ *mapped_length = block_size;
+
+ iova &= (block_size - 1);
return iopte_to_paddr(d.pte, data) | iova;
}
@@ -948,6 +964,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
.map_pages = arm_lpae_map_pages,
.unmap_pages = arm_lpae_unmap_pages,
.iova_to_phys = arm_lpae_iova_to_phys,
+ .iova_to_phys_length = arm_lpae_iova_to_phys_length,
.read_and_clear_dirty = arm_lpae_read_and_clear_dirty,
.pgtable_walk = arm_lpae_pgtable_walk,
};
diff --git a/drivers/iommu/io-pgtable-dart.c b/drivers/iommu/io-pgtable-dart.c
index cbc5d6aa2daa..fa250f5d16ed 100644
--- a/drivers/iommu/io-pgtable-dart.c
+++ b/drivers/iommu/io-pgtable-dart.c
@@ -333,11 +333,23 @@ static size_t dart_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova,
return i * pgsize;
}
+static phys_addr_t dart_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length);
+
static phys_addr_t dart_iova_to_phys(struct io_pgtable_ops *ops,
- unsigned long iova)
+ unsigned long iova)
+{
+ return dart_iova_to_phys_length(ops, iova, NULL);
+}
+
+static phys_addr_t dart_iova_to_phys_length(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length)
{
struct dart_io_pgtable *data = io_pgtable_ops_to_data(ops);
dart_iopte pte, *ptep;
+ size_t pgsize;
ptep = dart_get_last(data, iova);
@@ -350,7 +362,10 @@ static phys_addr_t dart_iova_to_phys(struct io_pgtable_ops *ops,
pte = READ_ONCE(*ptep);
/* Found translation */
if (pte) {
- iova &= (data->iop.cfg.pgsize_bitmap - 1);
+ pgsize = data->iop.cfg.pgsize_bitmap;
+ if (mapped_length)
+ *mapped_length = pgsize;
+ iova &= (pgsize - 1);
return iopte_to_paddr(pte, data) | iova;
}
@@ -397,9 +412,10 @@ dart_alloc_pgtable(struct io_pgtable_cfg *cfg)
data->bits_per_level = bits_per_level;
data->iop.ops = (struct io_pgtable_ops) {
- .map_pages = dart_map_pages,
- .unmap_pages = dart_unmap_pages,
- .iova_to_phys = dart_iova_to_phys,
+ .map_pages = dart_map_pages,
+ .unmap_pages = dart_unmap_pages,
+ .iova_to_phys = dart_iova_to_phys,
+ .iova_to_phys_length = dart_iova_to_phys_length,
};
return data;
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index e19872e37e06..42bcdd309b88 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -203,6 +203,10 @@ struct arm_lpae_io_pgtable_walk_data {
* @map_pages: Map a physically contiguous range of pages of the same size.
* @unmap_pages: Unmap a range of virtually contiguous pages of the same size.
* @iova_to_phys: Translate iova to physical address.
+ * @iova_to_phys_length: Translate iova to physical address and return the
+ * remaining mapped length from iova to the end of the
+ * mapping entry via @mapped_length. If @mapped_length is
+ * NULL, only the physical address is returned.
* @pgtable_walk: (optional) Perform a page table walk for a given iova.
* @read_and_clear_dirty: Record dirty info per IOVA. If an IOVA is dirty,
* clear its dirty state from the PTE unless the
@@ -220,6 +224,9 @@ struct io_pgtable_ops {
struct iommu_iotlb_gather *gather);
phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
unsigned long iova);
+ phys_addr_t (*iova_to_phys_length)(struct io_pgtable_ops *ops,
+ unsigned long iova,
+ size_t *mapped_length);
int (*pgtable_walk)(struct io_pgtable_ops *ops, unsigned long iova, void *wd);
int (*read_and_clear_dirty)(struct io_pgtable_ops *ops,
unsigned long iova, size_t size,
--
2.43.7