diff mbox series

[RFC,net-next,03/13] virtio_ring: packed: harden dma unmap for indirect

Message ID 20240716064628.1950-4-xuanzhuo@linux.alibaba.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: support AF_XDP zero copy (tx) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 816 this patch: 816
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 821 this patch: 821
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 821 this patch: 821
netdev/checkpatch warning WARNING: line length of 87 exceeds 80 columns WARNING: line length of 88 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 22 this patch: 22
netdev/source_inline success Was 0 now: 0

Commit Message

Xuan Zhuo July 16, 2024, 6:46 a.m. UTC
1. this commit hardens dma unmap for indirect
2. the subsequent commit uses the struct extra to record whether the
   buffers need to be unmapped or not. So we need a struct extra for
   every desc, whatever it is indirect or not.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 57 ++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 28 deletions(-)
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 1e037da542b9..5fb94f735edb 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -81,7 +81,7 @@  struct vring_desc_state_split {
 
 struct vring_desc_state_packed {
 	void *data;			/* Data for callback. */
-	struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
+	struct vring_desc_extra *indir; /* Indirect descriptor, if any. */
 	u16 num;			/* Descriptor list length. */
 	u16 last;			/* The last desc state in a list. */
 };
@@ -1238,27 +1238,13 @@  static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
 	}
 }
 
-static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
-				    const struct vring_packed_desc *desc)
-{
-	u16 flags;
-
-	if (!vring_need_unmap_buffer(vq))
-		return;
-
-	flags = le16_to_cpu(desc->flags);
-
-	dma_unmap_page(vring_dma_dev(vq),
-		       le64_to_cpu(desc->addr),
-		       le32_to_cpu(desc->len),
-		       (flags & VRING_DESC_F_WRITE) ?
-		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
-}
-
 static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
+						       struct vring_desc_extra **pextra,
 						       gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
+	int i;
 
 	/*
 	 * We require lowmem mappings for the descriptors because
@@ -1267,7 +1253,14 @@  static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
 	 */
 	gfp &= ~__GFP_HIGHMEM;
 
-	desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
+	extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp);
+
+	desc = (struct vring_packed_desc *)&extra[total_sg];
+
+	for (i = 0; i < total_sg; i++)
+		extra[i].next = i + 1;
+
+	*pextra = extra;
 
 	return desc;
 }
@@ -1280,6 +1273,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 					 void *data,
 					 gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
 	struct scatterlist *sg;
 	unsigned int i, n, err_idx;
@@ -1287,7 +1281,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	dma_addr_t addr;
 
 	head = vq->packed.next_avail_idx;
-	desc = alloc_indirect_packed(total_sg, gfp);
+	desc = alloc_indirect_packed(total_sg, &extra, gfp);
 	if (!desc)
 		return -ENOMEM;
 
@@ -1313,6 +1307,12 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 			desc[i].addr = cpu_to_le64(addr);
 			desc[i].len = cpu_to_le32(sg->length);
 			i++;
+
+			if (unlikely(vq->use_dma_api)) {
+				extra[i].addr = addr;
+				extra[i].len = sg->length;
+				extra[i].flags = n < out_sgs ?  0 : VRING_DESC_F_WRITE;
+			}
 		}
 	}
 
@@ -1367,7 +1367,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	/* Store token and indirect buffer state. */
 	vq->packed.desc_state[id].num = 1;
 	vq->packed.desc_state[id].data = data;
-	vq->packed.desc_state[id].indir_desc = desc;
+	vq->packed.desc_state[id].indir = extra;
 	vq->packed.desc_state[id].last = id;
 
 	vq->num_added += 1;
@@ -1381,7 +1381,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	err_idx = i;
 
 	for (i = 0; i < err_idx; i++)
-		vring_unmap_desc_packed(vq, &desc[i]);
+		vring_unmap_extra_packed(vq, &extra[i]);
 
 free_desc:
 	kfree(desc);
@@ -1504,7 +1504,7 @@  static inline int virtqueue_add_packed(struct virtqueue *_vq,
 	/* Store token. */
 	vq->packed.desc_state[id].num = descs_used;
 	vq->packed.desc_state[id].data = data;
-	vq->packed.desc_state[id].indir_desc = ctx;
+	vq->packed.desc_state[id].indir = ctx;
 	vq->packed.desc_state[id].last = prev;
 
 	/*
@@ -1617,23 +1617,24 @@  static void detach_buf_packed(struct vring_virtqueue *vq,
 	}
 
 	if (vq->indirect) {
+		struct vring_desc_extra *extra;
 		u32 len;
 
 		/* Free the indirect table, if any, now that it's unmapped. */
-		desc = state->indir_desc;
-		if (!desc)
+		extra = state->indir;
+		if (!extra)
 			return;
 
 		if (vring_need_unmap_buffer(vq)) {
 			len = vq->packed.desc_extra[id].len;
 			for (i = 0; i < len / sizeof(struct vring_packed_desc);
 					i++)
-				vring_unmap_desc_packed(vq, &desc[i]);
+				vring_unmap_extra_packed(vq, &extra[i]);
 		}
 		kfree(desc);
-		state->indir_desc = NULL;
+		state->indir = NULL;
 	} else if (ctx) {
-		*ctx = state->indir_desc;
+		*ctx = state->indir;
 	}
 }