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Message-ID: <20240717163627.43423-2-robdclark@gmail.com>
Date: Wed, 17 Jul 2024 09:36:21 -0700
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org,
iommu@...ts.linux.dev,
Will Deacon <will@...nel.org>,
Rob Clark <robdclark@...omium.org>,
Joerg Roedel <jroedel@...e.de>,
Robin Murphy <robin.murphy@....com>,
Joerg Roedel <joro@...tes.org>,
Jason Gunthorpe <jgg@...pe.ca>,
Lu Baolu <baolu.lu@...ux.intel.com>,
Kevin Tian <kevin.tian@...el.com>,
Boris Brezillon <boris.brezillon@...labora.com>,
Joao Martins <joao.m.martins@...cle.com>,
linux-arm-kernel@...ts.infradead.org (moderated list:ARM SMMU DRIVERS),
linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v6 1/2] iommu/io-pgtable-arm: Add way to debug pgtable walk
From: Rob Clark <robdclark@...omium.org>
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@...omium.org>
Acked-by: Joerg Roedel <jroedel@...e.de>
---
drivers/iommu/io-pgtable-arm.c | 36 +++++++++++++++++++++++++---------
include/linux/io-pgtable.h | 17 ++++++++++++++++
2 files changed, 44 insertions(+), 9 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 3d23b924cec1..e70803940b46 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -690,9 +690,11 @@ static size_t arm_lpae_unmap_pages(struct io_pgtable_ops *ops, unsigned long iov
data->start_level, ptep);
}
-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 *_wd)
{
+ struct arm_lpae_io_pgtable_walk_data *wd = _wd;
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
arm_lpae_iopte pte, *ptep = data->pgd;
int lvl = data->start_level;
@@ -700,7 +702,7 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
do {
/* Valid IOPTE pointer? */
if (!ptep)
- return 0;
+ return -ENOENT;
/* Grab the IOPTE we're interested in */
ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
@@ -708,22 +710,37 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
/* Valid entry? */
if (!pte)
- return 0;
+ return -ENOENT;
- /* Leaf entry? */
+ wd->ptes[wd->level++] = pte;
+
+ /* Leaf entry? If so, we've found the translation */
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 -ENOENT;
+}
+
+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);
+ struct arm_lpae_io_pgtable_walk_data wd = {};
+ int ret, lvl;
+
+ ret = arm_lpae_pgtable_walk(ops, iova, &wd);
+ if (ret)
+ return 0;
+
+ lvl = wd.level + data->start_level;
-found_translation:
iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
- return iopte_to_paddr(pte, data) | iova;
+ return iopte_to_paddr(wd.ptes[wd.level - 1], data) | iova;
}
static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
@@ -804,6 +821,7 @@ 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,
+ .pgtable_walk = arm_lpae_pgtable_walk,
};
return data;
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index 86cf1f7ae389..df6f6e58310c 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -171,12 +171,28 @@ struct io_pgtable_cfg {
};
};
+/**
+ * struct arm_lpae_io_pgtable_walk_data - information from a pgtable walk
+ *
+ * @ptes: The recorded PTE values from the walk
+ * @level: The level of the last PTE
+ *
+ * @level also specifies the last valid index in @ptes
+ */
+struct arm_lpae_io_pgtable_walk_data {
+ u64 ptes[4];
+ int level;
+};
+
/**
* 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. The
+ * type for the wd parameter is specific to pgtable type, as
+ * the PTE size and number of levels differs per pgtable type.
*
* These functions map directly onto the iommu_ops member functions with
* the same names.
@@ -190,6 +206,7 @@ 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,
--
2.45.2
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