* [Bug 1295] Virtio driver, packed mode, the first desc misses the next flag, causing the message to be sent abnormally
@ 2023-10-07 3:37 bugzilla
2023-11-28 16:25 ` bugzilla
0 siblings, 1 reply; 2+ messages in thread
From: bugzilla @ 2023-10-07 3:37 UTC (permalink / raw)
To: dev
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https://bugs.dpdk.org/show_bug.cgi?id=1295
Bug ID: 1295
Summary: Virtio driver, packed mode, the first desc misses the
next flag, causing the message to be sent abnormally
Product: DPDK
Version: 23.07
Hardware: All
OS: All
Status: UNCONFIRMED
Severity: major
Priority: Normal
Component: vhost/virtio
Assignee: dev@dpdk.org
Reporter: fengjiang_liu@163.com
Target Milestone: ---
In the virtio_xmit_pkts_packed sending interface, when the virio header and pkt
payload are added in two descs, the desc of the virtio-header is missing
VRING_DESC_F_NEXT flag, resulting in the virio header and pkt payload being
considered to be two pkts, resulting in an exception.
static inline void
virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
uint16_t needed, int use_indirect, int can_push,
int in_order)
{
struct virtio_tx_region *txr = txvq->hdr_mz->addr;
struct vq_desc_extra *dxp;
struct virtqueue *vq = virtnet_txq_to_vq(txvq);
struct vring_packed_desc *start_dp, *head_dp;
uint16_t idx, id, head_idx, head_flags;
int16_t head_size = vq->hw->vtnet_hdr_size;
struct virtio_net_hdr *hdr;
uint16_t prev;
bool prepend_header = false;
uint16_t seg_num = cookie->nb_segs;
id = in_order ? vq->vq_avail_idx : vq->vq_desc_head_idx;
dxp = &vq->vq_descx[id];
dxp->ndescs = needed;
dxp->cookie = cookie;
head_idx = vq->vq_avail_idx;
idx = head_idx;
prev = head_idx;
start_dp = vq->vq_packed.ring.desc;
head_dp = &vq->vq_packed.ring.desc[idx];
head_flags = cookie->next ? VRING_DESC_F_NEXT : 0;
====>branch1： mbuf is not buffer-list, next == NULL, so No next flag
set
head_flags |= vq->vq_packed.cached_flags;
if (can_push) {
/* prepend cannot fail, checked by caller */
hdr = rte_pktmbuf_mtod_offset(cookie, struct virtio_net_hdr *,
-head_size);
prepend_header = true;
/* if offload disabled, it is not zeroed below, do it now */
if (!vq->hw->has_tx_offload)
virtqueue_clear_net_hdr(hdr);
} else if (use_indirect) {
/* setup tx ring slot to point to indirect
* descriptor list stored in reserved region.
*
* the first slot in indirect ring is already preset
* to point to the header in reserved region
*/
start_dp[idx].addr = txvq->hdr_mem +
RTE_PTR_DIFF(&txr[idx].tx_packed_indir, txr);
start_dp[idx].len = (seg_num + 1) * sizeof(struct
vring_packed_desc);
/* Packed descriptor id needs to be restored when inorder. */
if (in_order)
start_dp[idx].id = idx;
/* reset flags for indirect desc */
head_flags = VRING_DESC_F_INDIRECT;
head_flags |= vq->vq_packed.cached_flags;
hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
/* loop below will fill in rest of the indirect elements */
start_dp = txr[idx].tx_packed_indir;
idx = 1;
} else {
/* setup first tx ring slot to point to header
* stored in reserved region.
*/
start_dp[idx].addr = txvq->hdr_mem +
RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
start_dp[idx].len = vq->hw->vtnet_hdr_size;
hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
====>branch2： Add virtio header desc, no next flag set
idx++;
if (idx >= vq->vq_nentries) {
idx -= vq->vq_nentries;
vq->vq_packed.cached_flags ^=
VRING_PACKED_DESC_F_AVAIL_USED;
}
}
if (vq->hw->has_tx_offload)
virtqueue_xmit_offload(hdr, cookie);
do {
uint16_t flags;
start_dp[idx].addr = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
start_dp[idx].len = cookie->data_len;
if (prepend_header) {
start_dp[idx].addr -= head_size;
start_dp[idx].len += head_size;
prepend_header = false;
}
if (likely(idx != head_idx)) {
flags = cookie->next ? VRING_DESC_F_NEXT : 0;
flags |= vq->vq_packed.cached_flags;
start_dp[idx].flags = flags;
}
prev = idx;
idx++;
if (idx >= vq->vq_nentries) {
idx -= vq->vq_nentries;
vq->vq_packed.cached_flags ^=
VRING_PACKED_DESC_F_AVAIL_USED;
}
} while ((cookie = cookie->next) != NULL);
start_dp[prev].id = id;
if (use_indirect) {
idx = head_idx;
if (++idx >= vq->vq_nentries) {
idx -= vq->vq_nentries;
vq->vq_packed.cached_flags ^=
VRING_PACKED_DESC_F_AVAIL_USED;
}
}
vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
vq->vq_avail_idx = idx;
if (!in_order) {
vq->vq_desc_head_idx = dxp->next;
if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
vq->vq_desc_tail_idx = VQ_RING_DESC_CHAIN_END;
}
===》head_flags ：no next flag set
virtqueue_store_flags_packed(head_dp, head_flags,
vq->hw->weak_barriers);
}
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