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iommu/io-pgtable-arm: Add way to debug pgtable walk

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Add an io-pgtable method to walk the pgtable returning the raw PTEs that
would be traversed for a given iova access.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20241210165127.600817-4-robdclark@gmail.com
[will: Removed 'arm_lpae_io_pgtable_walk_data::level' per Mostafa]
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Rob Clark 2024-12-10 08:51:21 -08:00 • committed by Will Deacon
parent d9e589e6ad
commit aff028a819
2 changed files with 34 additions and 0 deletions
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23
drivers/iommu/io-pgtable-arm.c
View file

@ -754,6 +754,28 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
return iopte_to_paddr(d.pte, data) | iova;
}
static int visit_pgtable_walk(struct io_pgtable_walk_data *walk_data, int lvl,
arm_lpae_iopte *ptep, size_t size)
{
struct arm_lpae_io_pgtable_walk_data *data = walk_data->data;
data->ptes[lvl] = *ptep;
return 0;
}
static int arm_lpae_pgtable_walk(struct io_pgtable_ops *ops, unsigned long iova,
void *wd)
{
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
struct io_pgtable_walk_data walk_data = {
.data = wd,
.visit = visit_pgtable_walk,
.addr = iova,
.end = iova + 1,
};
return __arm_lpae_iopte_walk(data, &walk_data, data->pgd, data->start_level);
}
static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
struct io_pgtable_walk_data *walk_data,
arm_lpae_iopte *ptep, int lvl)
@ -929,6 +951,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
.unmap_pages = arm_lpae_unmap_pages,
.iova_to_phys = arm_lpae_iova_to_phys,
.read_and_clear_dirty = arm_lpae_read_and_clear_dirty,
.pgtable_walk = arm_lpae_pgtable_walk,
};
return data;

11
include/linux/io-pgtable.h
View file

@ -180,12 +180,22 @@ struct io_pgtable_cfg {
};
};
/**
* struct arm_lpae_io_pgtable_walk_data - information from a pgtable walk
*
* @ptes: The recorded PTE values from the walk
*/
struct arm_lpae_io_pgtable_walk_data {
u64 ptes[4];
};
/**
* struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
*
* @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.
* @pgtable_walk: (optional) Perform a page table walk for a given iova.
*
* These functions map directly onto the iommu_ops member functions with
* the same names.
@ -199,6 +209,7 @@ struct io_pgtable_ops {
struct iommu_iotlb_gather *gather);
phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
unsigned long iova);
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,
unsigned long flags,