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Merge branch 'virtio-net-fixes-for-mergeable-xdp-receive-path'

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Bui Quang Minh says:

====================
virtio-net: fixes for mergeable XDP receive path

This series contains fixes for XDP receive path in virtio-net
- Patch 1: add a missing check for the received data length with our
allocated buffer size in mergeable mode.
- Patch 2: remove a redundant truesize check with PAGE_SIZE in mergeable
mode
- Patch 3: make the current repeated code use the check_mergeable_len to
check for received data length in mergeable mode
====================

Link: https://patch.msgid.link/20250630144212.48471-1-minhquangbui99@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Paolo Abeni
2025-07-03 10:56:57 +02:00
parent bd475eeaaf 7d4a119e45
commit c9cbbe7ab6
1 changed files with 42 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/net/virtio_net.c
+42 -33
View File
@@ -778,6 +778,26 @@ static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx)
return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1);
}
static int check_mergeable_len(struct net_device *dev, void *mrg_ctx,
unsigned int len)
{
unsigned int headroom, tailroom, room, truesize;
truesize = mergeable_ctx_to_truesize(mrg_ctx);
headroom = mergeable_ctx_to_headroom(mrg_ctx);
tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
room = SKB_DATA_ALIGN(headroom + tailroom);
if (len > truesize - room) {
pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
dev->name, len, (unsigned long)(truesize - room));
DEV_STATS_INC(dev, rx_length_errors);
return -1;
}
return 0;
}
static struct sk_buff *virtnet_build_skb(void *buf, unsigned int buflen,
unsigned int headroom,
unsigned int len)
@@ -1797,7 +1817,8 @@ static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
* across multiple buffers (num_buf > 1), and we make sure buffers
* have enough headroom.
*/
static struct page *xdp_linearize_page(struct receive_queue *rq,
static struct page *xdp_linearize_page(struct net_device *dev,
struct receive_queue *rq,
int *num_buf,
struct page *p,
int offset,
@@ -1817,18 +1838,27 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
memcpy(page_address(page) + page_off, page_address(p) + offset, *len);
page_off += *len;
/* Only mergeable mode can go inside this while loop. In small mode,
* *num_buf == 1, so it cannot go inside.
*/
while (--*num_buf) {
unsigned int buflen;
void *buf;
void *ctx;
int off;
buf = virtnet_rq_get_buf(rq, &buflen, NULL);
buf = virtnet_rq_get_buf(rq, &buflen, &ctx);
if (unlikely(!buf))
goto err_buf;
p = virt_to_head_page(buf);
off = buf - page_address(p);
if (check_mergeable_len(dev, ctx, buflen)) {
put_page(p);
goto err_buf;
}
/* guard against a misconfigured or uncooperative backend that
* is sending packet larger than the MTU.
*/
@@ -1917,7 +1947,7 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
headroom = vi->hdr_len + header_offset;
buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
xdp_page = xdp_linearize_page(rq, &num_buf, page,
xdp_page = xdp_linearize_page(dev, rq, &num_buf, page,
offset, header_offset,
&tlen);
if (!xdp_page)
@@ -2126,10 +2156,9 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
struct virtnet_rq_stats *stats)
{
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
unsigned int headroom, tailroom, room;
unsigned int truesize, cur_frag_size;
struct skb_shared_info *shinfo;
unsigned int xdp_frags_truesz = 0;
unsigned int truesize;
struct page *page;
skb_frag_t *frag;
int offset;
@@ -2172,21 +2201,14 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
page = virt_to_head_page(buf);
offset = buf - page_address(page);
truesize = mergeable_ctx_to_truesize(ctx);
headroom = mergeable_ctx_to_headroom(ctx);
tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
room = SKB_DATA_ALIGN(headroom + tailroom);
cur_frag_size = truesize;
xdp_frags_truesz += cur_frag_size;
if (unlikely(len > truesize - room || cur_frag_size > PAGE_SIZE)) {
if (check_mergeable_len(dev, ctx, len)) {
put_page(page);
pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
dev->name, len, (unsigned long)(truesize - room));
DEV_STATS_INC(dev, rx_length_errors);
goto err;
}
truesize = mergeable_ctx_to_truesize(ctx);
xdp_frags_truesz += truesize;
frag = &shinfo->frags[shinfo->nr_frags++];
skb_frag_fill_page_desc(frag, page, offset, len);
if (page_is_pfmemalloc(page))
@@ -2252,7 +2274,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
*/
if (!xdp_prog->aux->xdp_has_frags) {
/* linearize data for XDP */
xdp_page = xdp_linearize_page(rq, num_buf,
xdp_page = xdp_linearize_page(vi->dev, rq, num_buf,
*page, offset,
XDP_PACKET_HEADROOM,
len);
@@ -2400,18 +2422,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
struct sk_buff *head_skb, *curr_skb;
unsigned int truesize = mergeable_ctx_to_truesize(ctx);
unsigned int headroom = mergeable_ctx_to_headroom(ctx);
unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
head_skb = NULL;
u64_stats_add(&stats->bytes, len - vi->hdr_len);
if (unlikely(len > truesize - room)) {
pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
dev->name, len, (unsigned long)(truesize - room));
DEV_STATS_INC(dev, rx_length_errors);
if (check_mergeable_len(dev, ctx, len))
goto err_skb;
}
if (unlikely(vi->xdp_enabled)) {
struct bpf_prog *xdp_prog;
@@ -2446,17 +2462,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
u64_stats_add(&stats->bytes, len);
page = virt_to_head_page(buf);
truesize = mergeable_ctx_to_truesize(ctx);
headroom = mergeable_ctx_to_headroom(ctx);
tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
room = SKB_DATA_ALIGN(headroom + tailroom);
if (unlikely(len > truesize - room)) {
pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
dev->name, len, (unsigned long)(truesize - room));
DEV_STATS_INC(dev, rx_length_errors);
if (check_mergeable_len(dev, ctx, len))
goto err_skb;
}
truesize = mergeable_ctx_to_truesize(ctx);
curr_skb = virtnet_skb_append_frag(head_skb, curr_skb, page,
buf, len, truesize);
if (!curr_skb)