[RFC PATCH v4 05/13] iommu/io-pgtable-arm: Add and realize sync_dirty_log ops

[Keqian Zhu]

From: Kunkun Jiang <jiangkunkun@xxxxxxxxxx>

During dirty log tracking, user will try to retrieve dirty log from
iommu if it supports hardware dirty log. Scan leaf TTD and treat it
is dirty if it's writable. As we just set DBM bit for stage1 mapping,
so check whether AP[2] is not set.

Co-developed-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
Signed-off-by: Kunkun Jiang <jiangkunkun@xxxxxxxxxx>
---
 drivers/iommu/io-pgtable-arm.c | 89 ++++++++++++++++++++++++++++++++++
 include/linux/io-pgtable.h     |  4 ++
 2 files changed, 93 insertions(+)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index b9f6e3370032..155d440099ab 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -877,6 +877,94 @@ static size_t arm_lpae_merge_page(struct io_pgtable_ops *ops, unsigned long iova
 	return __arm_lpae_merge_page(data, iova, paddr, size, lvl, ptep, prot);
 }
 
+static int __arm_lpae_sync_dirty_log(struct arm_lpae_io_pgtable *data,
+				     unsigned long iova, size_t size,
+				     int lvl, arm_lpae_iopte *ptep,
+				     unsigned long *bitmap,
+				     unsigned long base_iova,
+				     unsigned long bitmap_pgshift)
+{
+	arm_lpae_iopte pte;
+	struct io_pgtable *iop = &data->iop;
+	size_t base, next_size;
+	unsigned long offset;
+	int nbits, ret;
+
+	if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
+		return -EINVAL;
+
+	ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
+	pte = READ_ONCE(*ptep);
+	if (WARN_ON(!pte))
+		return -EINVAL;
+
+	if (size == ARM_LPAE_BLOCK_SIZE(lvl, data)) {
+		if (iopte_leaf(pte, lvl, iop->fmt)) {
+			if (pte & ARM_LPAE_PTE_AP_RDONLY)
+				return 0;
+
+			/* It is writable, set the bitmap */
+			nbits = size >> bitmap_pgshift;
+			offset = (iova - base_iova) >> bitmap_pgshift;
+			bitmap_set(bitmap, offset, nbits);
+			return 0;
+		}
+		/* Current level is table, traverse next level */
+		next_size = ARM_LPAE_BLOCK_SIZE(lvl + 1, data);
+		ptep = iopte_deref(pte, data);
+		for (base = 0; base < size; base += next_size) {
+			ret = __arm_lpae_sync_dirty_log(data, iova + base,
+					next_size, lvl + 1, ptep, bitmap,
+					base_iova, bitmap_pgshift);
+			if (ret)
+				return ret;
+		}
+		return 0;
+	} else if (iopte_leaf(pte, lvl, iop->fmt)) {
+		if (pte & ARM_LPAE_PTE_AP_RDONLY)
+			return 0;
+
+		/* Though the size is too small, also set bitmap */
+		nbits = size >> bitmap_pgshift;
+		offset = (iova - base_iova) >> bitmap_pgshift;
+		bitmap_set(bitmap, offset, nbits);
+		return 0;
+	}
+
+	/* Keep on walkin */
+	ptep = iopte_deref(pte, data);
+	return __arm_lpae_sync_dirty_log(data, iova, size, lvl + 1, ptep,
+			bitmap, base_iova, bitmap_pgshift);
+}
+
+static int arm_lpae_sync_dirty_log(struct io_pgtable_ops *ops,
+				   unsigned long iova, size_t size,
+				   unsigned long *bitmap,
+				   unsigned long base_iova,
+				   unsigned long bitmap_pgshift)
+{
+	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	arm_lpae_iopte *ptep = data->pgd;
+	int lvl = data->start_level;
+	long iaext = (s64)iova >> cfg->ias;
+
+	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
+		return -EINVAL;
+
+	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
+		iaext = ~iaext;
+	if (WARN_ON(iaext))
+		return -EINVAL;
+
+	if (data->iop.fmt != ARM_64_LPAE_S1 &&
+	    data->iop.fmt != ARM_32_LPAE_S1)
+		return -EINVAL;
+
+	return __arm_lpae_sync_dirty_log(data, iova, size, lvl, ptep,
+					 bitmap, base_iova, bitmap_pgshift);
+}
+
 static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
 {
 	unsigned long granule, page_sizes;
@@ -957,6 +1045,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
 		.iova_to_phys	= arm_lpae_iova_to_phys,
 		.split_block	= arm_lpae_split_block,
 		.merge_page	= arm_lpae_merge_page,
+		.sync_dirty_log	= arm_lpae_sync_dirty_log,
 	};
 
 	return data;
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index e77576d946a2..329fa99d9d96 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -171,6 +171,10 @@ struct io_pgtable_ops {
 			      size_t size);
 	size_t (*merge_page)(struct io_pgtable_ops *ops, unsigned long iova,
 			     phys_addr_t phys, size_t size, int prot);
+	int (*sync_dirty_log)(struct io_pgtable_ops *ops,
+			      unsigned long iova, size_t size,
+			      unsigned long *bitmap, unsigned long base_iova,
+			      unsigned long bitmap_pgshift);
 };
 
 /**
-- 
2.19.1