From: Rob Clark robdclark@chromium.org
Add an io-pgtable method to retrieve the raw PTEs that would be traversed for a given iova access.
Signed-off-by: Rob Clark robdclark@chromium.org --- drivers/iommu/io-pgtable-arm.c | 40 +++++++++++++++++++++++++++------- include/linux/io-pgtable.h | 9 ++++++++ 2 files changed, 41 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index dd9e47189d0d..c470fc0b3c2b 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -700,38 +700,61 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova, return arm_lpae_unmap_pages(ops, iova, size, 1, gather); }
-static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops, - unsigned long iova) +static int arm_lpae_pgtable_walk(struct io_pgtable_ops *ops, unsigned long iova, + void *_ptes, int *num_ptes) { struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops); arm_lpae_iopte pte, *ptep = data->pgd; + arm_lpae_iopte *ptes = _ptes; + int max_ptes = *num_ptes; int lvl = data->start_level;
+ *num_ptes = 0; + do { + if (*num_ptes >= max_ptes) + return -ENOSPC; + /* Valid IOPTE pointer? */ if (!ptep) - return 0; + return -EFAULT;
/* Grab the IOPTE we're interested in */ ptep += ARM_LPAE_LVL_IDX(iova, lvl, data); pte = READ_ONCE(*ptep);
+ ptes[(*num_ptes)++] = pte; + /* Valid entry? */ if (!pte) - return 0; + return -EFAULT;
/* Leaf entry? */ if (iopte_leaf(pte, lvl, data->iop.fmt)) - goto found_translation; + return 0;
/* Take it to the next level */ ptep = iopte_deref(pte, data); } while (++lvl < ARM_LPAE_MAX_LEVELS);
- /* Ran out of page tables to walk */ - return 0; + return -EFAULT; +} + +static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops, + unsigned long iova) +{ + struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops); + arm_lpae_iopte pte, ptes[ARM_LPAE_MAX_LEVELS]; + int lvl, num_ptes = ARM_LPAE_MAX_LEVELS; + int ret; + + ret = arm_lpae_pgtable_walk(ops, iova, ptes, &num_ptes); + if (ret) + return 0; + + pte = ptes[num_ptes - 1]; + lvl = num_ptes - 1 + data->start_level;
-found_translation: iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1); return iopte_to_paddr(pte, data) | iova; } @@ -816,6 +839,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg) .unmap = arm_lpae_unmap, .unmap_pages = arm_lpae_unmap_pages, .iova_to_phys = arm_lpae_iova_to_phys, + .pgtable_walk = arm_lpae_pgtable_walk, };
return data; diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h index 86af6f0a00a2..501f362a929c 100644 --- a/include/linux/io-pgtable.h +++ b/include/linux/io-pgtable.h @@ -148,6 +148,13 @@ struct io_pgtable_cfg { * @unmap: Unmap a physically contiguous memory region. * @unmap_pages: Unmap a range of virtually contiguous pages of the same size. * @iova_to_phys: Translate iova to physical address. + * @pgtable_walk: Return details of a page table walk for a given iova. + * This returns the array of PTEs in a format that is + * specific to the page table format. The number of + * PTEs can be format specific. The num_ptes parameter + * on input specifies the size of the ptes array, and + * on output the number of PTEs filled in (which depends + * on the number of PTEs walked to resolve the iova) * * These functions map directly onto the iommu_ops member functions with * the same names. @@ -165,6 +172,8 @@ 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 *ptes, int *num_ptes); };
/**