<html>
<head>
<base href="https://bugs.dpdk.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8" class="bz_new_table">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_UNCONFIRMED "
title="UNCONFIRMED - Virtio driver, packed mode, the first desc misses the next flag, causing the message to be sent abnormally"
href="https://bugs.dpdk.org/show_bug.cgi?id=1295">1295</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Virtio driver, packed mode, the first desc misses the next flag, causing the message to be sent abnormally
</td>
</tr>
<tr>
<th>Product</th>
<td>DPDK
</td>
</tr>
<tr>
<th>Version</th>
<td>23.07
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>UNCONFIRMED
</td>
</tr>
<tr>
<th>Severity</th>
<td>major
</td>
</tr>
<tr>
<th>Priority</th>
<td>Normal
</td>
</tr>
<tr>
<th>Component</th>
<td>vhost/virtio
</td>
</tr>
<tr>
<th>Assignee</th>
<td>dev@dpdk.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>fengjiang_liu@163.com
</td>
</tr>
<tr>
<th>Target Milestone</th>
<td>---
</td>
</tr></table>
<p>
<div class="bz_comment_block">
<pre class="bz_comment_text">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);
}
</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the assignee for the bug.</li>
</ul>
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
<link itemprop="url" href="https://bugs.dpdk.org/show_bug.cgi?id=1295">
<meta itemprop="name" content="View bug">
</div>
<meta itemprop="description" content="Bugzilla bug update notification">
</div>
</body>
</html>