On 6/3/26 23:17, Guanghui Feng wrote:
Extend the Generic Page Table framework to implement iova_to_phys_length.
Use pt_entry_oa_lg2sz() to determine PTE block size. Update
IOMMU_PT_DOMAIN_OPS macro to set .iova_to_phys_length.
Signed-off-by: Guanghui Feng <[email protected]>
Acked-by: Shiqiang Zhang <[email protected]>
Acked-by: Simon Guo <[email protected]>
---
drivers/iommu/generic_pt/iommu_pt.h | 84 +++++++++++++++++++++--------
include/linux/generic_pt/iommu.h | 13 ++---
2 files changed, 69 insertions(+), 28 deletions(-)
diff --git a/drivers/iommu/generic_pt/iommu_pt.h
b/drivers/iommu/generic_pt/iommu_pt.h
index dc91fb4e2f61..e362e819ef9c 100644
--- a/drivers/iommu/generic_pt/iommu_pt.h
+++ b/drivers/iommu/generic_pt/iommu_pt.h
@@ -145,13 +145,21 @@ static inline unsigned int compute_best_pgsize(struct
pt_state *pts,
pts->range->va, pts->range->last_va, oa);
}
-static __always_inline int __do_iova_to_phys(struct pt_range *range, void *arg,
- unsigned int level,
- struct pt_table_p *table,
- pt_level_fn_t descend_fn)
+struct iova_to_phys_length_data {
+ pt_oaddr_t phys;
+ size_t length;
+};
+
+static __always_inline int __do_iova_to_phys_length(struct pt_range *range,
+ void *arg, unsigned int level,
+ struct pt_table_p *table,
+ pt_level_fn_t descend_fn)
{
struct pt_state pts = pt_init(range, level, table);
- pt_oaddr_t *res = arg;
+ struct iova_to_phys_length_data *data = arg;
+ unsigned int entry_lg2sz;
+ size_t entry_sz;
+ pt_oaddr_t expected_oa;
switch (pt_load_single_entry(&pts)) {
case PT_ENTRY_EMPTY:
@@ -159,45 +167,77 @@ static __always_inline int __do_iova_to_phys(struct
pt_range *range, void *arg,
case PT_ENTRY_TABLE:
return pt_descend(&pts, arg, descend_fn);
case PT_ENTRY_OA:
- *res = pt_entry_oa_exact(&pts);
- return 0;
+ break;
}
- return -ENOENT;
+
+ data->phys = pt_entry_oa_exact(&pts);
+ entry_lg2sz = pt_entry_oa_lg2sz(&pts);
+ entry_sz = log2_to_int(entry_lg2sz);
+
+ /* Start with the full mapping size of the first entry */
+ data->length = entry_sz;
data->length doesn't account for iova offset. Is this by design? We
should document this clearly somewhere.
Sashiko reported the same issue too.
[Severity: High]
Does this calculation overstate the mapped length for unaligned IOVAs?
If the IOVA is not aligned to the PTE block size, pt_entry_oa_exact()
includes the intra-page offset in data->phys. However, data->length
is unconditionally initialized to the full entry_sz rather than
entry_sz - offset. Callers relying on mapped_length might operate
on out-of-bounds memory because data->phys + data->length extends
beyond the valid mapped physical memory by the unaligned offset amount.
+
+ /* Accumulate subsequent physically contiguous entries */
+ expected_oa = pt_entry_oa(&pts) + entry_sz;
+ pts.end_index = log2_to_int(pt_num_items_lg2(&pts));
+ pt_next_entry(&pts);
+
+ while (pts.index < pts.end_index) {
+ pt_load_entry(&pts);
+ if (pts.type != PT_ENTRY_OA)
+ break;
+ if (pt_entry_oa_lg2sz(&pts) != entry_lg2sz)
+ break;
+ if (pt_entry_oa(&pts) != expected_oa)
+ break;
+ data->length += entry_sz;
+ expected_oa += entry_sz;
+ pt_next_entry(&pts);
+ }
+
+ return 0;
}
-PT_MAKE_LEVELS(__iova_to_phys, __do_iova_to_phys);
+PT_MAKE_LEVELS(__iova_to_phys_length, __do_iova_to_phys_length);
/**
- * iova_to_phys() - Return the output address for the given IOVA
+ * iova_to_phys_length() - Translate IOVA returning phys and contiguous length
* @domain: Table to query
* @iova: IO virtual address to query
+ * @mapped_length: Output for the total contiguous mapped length in bytes
*
- * Determine the output address from the given IOVA. @iova may have any
- * alignment, the returned physical will be adjusted with any sub page offset.
+ * Walk the IOMMU page table to translate @iova to a physical address while
+ * also returning the total contiguous physically mapped length through
+ * @mapped_length. The function accumulates consecutive page table entries that
+ * are physically contiguous, so callers can determine the full contiguous
+ * mapping extent with a single call.
*
* Context: The caller must hold a read range lock that includes @iova.
*
- * Return: 0 if there is no translation for the given iova.
+ * Return: The physical address, or PHYS_ADDR_MAX if there is no translation.
*/
-phys_addr_t DOMAIN_NS(iova_to_phys)(struct iommu_domain *domain,
- dma_addr_t iova)
+phys_addr_t DOMAIN_NS(iova_to_phys_length)(struct iommu_domain *domain,
+ dma_addr_t iova,
+ size_t *mapped_length)
{
struct pt_iommu *iommu_table =
container_of(domain, struct pt_iommu, domain);
struct pt_range range;
- pt_oaddr_t res;
+ struct iova_to_phys_length_data data;
int ret;
ret = make_range(common_from_iommu(iommu_table), &range, iova, 1);
if (ret)
- return ret;
+ return PHYS_ADDR_MAX;
- ret = pt_walk_range(&range, __iova_to_phys, &res);
- /* PHYS_ADDR_MAX would be a better error code */
+ ret = pt_walk_range(&range, __iova_to_phys_length, &data);
if (ret)
- return 0;
- return res;
+ return PHYS_ADDR_MAX;
+
+ if (mapped_length)
+ *mapped_length = data.length;
+ return data.phys;
}
-EXPORT_SYMBOL_NS_GPL(DOMAIN_NS(iova_to_phys), "GENERIC_PT_IOMMU");
+EXPORT_SYMBOL_NS_GPL(DOMAIN_NS(iova_to_phys_length), "GENERIC_PT_IOMMU");
struct pt_iommu_dirty_args {
struct iommu_dirty_bitmap *dirty;
diff --git a/include/linux/generic_pt/iommu.h b/include/linux/generic_pt/iommu.h
index dd0edd02a48a..859b853e9dc7 100644
--- a/include/linux/generic_pt/iommu.h
+++ b/include/linux/generic_pt/iommu.h
@@ -249,8 +249,9 @@ struct pt_iommu_cfg {
/* Generate the exported function signatures from iommu_pt.h */
#define IOMMU_PROTOTYPES(fmt)
\
- phys_addr_t pt_iommu_##fmt##_iova_to_phys(struct iommu_domain *domain, \
- dma_addr_t iova); \
+ phys_addr_t pt_iommu_##fmt##_iova_to_phys_length(
\
+ struct iommu_domain *domain, dma_addr_t iova,
\
+ size_t *mapped_length);
\
int pt_iommu_##fmt##_read_and_clear_dirty( \
struct iommu_domain *domain, unsigned long iova, size_t size, \
unsigned long flags, struct iommu_dirty_bitmap *dirty); \
@@ -267,11 +268,11 @@ struct pt_iommu_cfg {
IOMMU_PROTOTYPES(fmt)
/*
- * A driver uses IOMMU_PT_DOMAIN_OPS to populate the iommu_domain_ops for the
- * iommu_pt
+ * A driver uses IOMMU_PT_DOMAIN_OPS to populate the iommu_domain_ops for
+ * the iommu_pt
*/
-#define IOMMU_PT_DOMAIN_OPS(fmt) \
- .iova_to_phys = &pt_iommu_##fmt##_iova_to_phys
+#define IOMMU_PT_DOMAIN_OPS(fmt) \
+ .iova_to_phys_length = &pt_iommu_##fmt##_iova_to_phys_length
#define IOMMU_PT_DIRTY_OPS(fmt) \
.read_and_clear_dirty = &pt_iommu_##fmt##_read_and_clear_dirty
Thanks,
baolu
