Commit aff028a8 authored by Rob Clark's avatar Rob Clark Committed by Will Deacon
Browse files

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



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: default avatarRob Clark <robdclark@chromium.org>
Reviewed-by: default avatarMostafa 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: default avatarWill Deacon <will@kernel.org>
parent d9e589e6

drivers/iommu/io-pgtable-arm.c

+23 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/io-pgtable.h

+11 −0
Original line number Diff line number Diff line
@@ -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,