linux-kernel - [PATCH v11 2/4] iommu/io-pgtable-arm: Re-use the pgtable walk for iova_to

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Message-ID: <20241210165127.600817-3-robdclark@gmail.com>
Date: Tue, 10 Dec 2024 08:51:20 -0800
From: Rob Clark <robdclark@...il.com>
To: iommu@...ts.linux.dev
Cc: linux-arm-msm@...r.kernel.org,
	freedreno@...ts.freedesktop.org,
	Mostafa Saleh <smostafa@...gle.com>,
	Will Deacon <will@...nel.org>,
	Rob Clark <robdclark@...omium.org>,
	Robin Murphy <robin.murphy@....com>,
	Joerg Roedel <joro@...tes.org>,
	linux-arm-kernel@...ts.infradead.org (moderated list:ARM SMMU DRIVERS),
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v11 2/4] iommu/io-pgtable-arm: Re-use the pgtable walk for iova_to_phys

From: Rob Clark <robdclark@...omium.org>

Re-use the generic pgtable walk path.

Signed-off-by: Rob Clark <robdclark@...omium.org>
Reviewed-by: Mostafa Saleh <smostafa@...gle.com>
---
 drivers/iommu/io-pgtable-arm.c | 74 +++++++++++++++++-----------------
 1 file changed, 37 insertions(+), 37 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 7e9c0f8ae138..88b128c77893 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -712,42 +712,6 @@ 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)
-{
-	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
-	arm_lpae_iopte pte, *ptep = data->pgd;
-	int lvl = data->start_level;
-
-	do {
-		/* Valid IOPTE pointer? */
-		if (!ptep)
-			return 0;
-
-		/* Grab the IOPTE we're interested in */
-		ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
-		pte = READ_ONCE(*ptep);
-
-		/* Valid entry? */
-		if (!pte)
-			return 0;
-
-		/* Leaf entry? */
-		if (iopte_leaf(pte, lvl, data->iop.fmt))
-			goto found_translation;
-
-		/* 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;
-
-found_translation:
-	iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
-	return iopte_to_paddr(pte, data) | iova;
-}
-
 struct io_pgtable_walk_data {
 	struct io_pgtable		*iop;
 	void				*data;
@@ -763,6 +727,41 @@ static int __arm_lpae_iopte_walk(struct arm_lpae_io_pgtable *data,
 				 arm_lpae_iopte *ptep,
 				 int lvl);
 
+struct iova_to_phys_data {
+	arm_lpae_iopte pte;
+	int lvl;
+};
+
+static int visit_iova_to_phys(struct io_pgtable_walk_data *walk_data, int lvl,
+			      arm_lpae_iopte *ptep, size_t size)
+{
+	struct iova_to_phys_data *data = walk_data->data;
+	data->pte = *ptep;
+	data->lvl = lvl;
+	return 0;
+}
+
+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 iova_to_phys_data d;
+	struct io_pgtable_walk_data walk_data = {
+		.data = &d,
+		.visit = visit_iova_to_phys,
+		.addr = iova,
+		.end = iova + 1,
+	};
+	int ret;
+
+	ret = __arm_lpae_iopte_walk(data, &walk_data, data->pgd, data->start_level);
+	if (ret)
+		return 0;
+
+	iova &= (ARM_LPAE_BLOCK_SIZE(d.lvl, data) - 1);
+	return iopte_to_paddr(d.pte, data) | iova;
+}
+
 static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
 			    struct io_pgtable_walk_data *walk_data,
 			    arm_lpae_iopte *ptep, int lvl)
@@ -780,8 +779,9 @@ static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
 		return 0;
 	}
 
-	if (WARN_ON(!iopte_table(pte, lvl)))
+	if (!iopte_table(pte, lvl)) {
 		return -EINVAL;
+	}
 
 	ptep = iopte_deref(pte, data);
 	return __arm_lpae_iopte_walk(data, walk_data, ptep, lvl + 1);
-- 
2.47.1