On 12/11/18 11:38 AM, Ilya Maximets wrote:
On 05.12.2018 12:49, Maxime Coquelin wrote:A read barrier is required to ensure the ordering between available index and the descriptor reads is enforced. Fixes: 4796ad63ba1f ("examples/vhost: import userspace vhost application") Cc: [email protected] Reported-by: Jason Wang <[email protected]> Signed-off-by: Maxime Coquelin <[email protected]> --- lib/librte_vhost/virtio_net.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)I'd like to have a bit more details about a bad scenario in a commit message because it's not an obvious change at a first glance.
Sure, I'll rework the commit message in the v2.
Otherwise, Acked-by: Ilya Maximets <[email protected]>
Thanks, Maxime
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index 5e1a1a727..f11ebb54f 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -791,6 +791,12 @@ virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq, rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]); avail_head = *((volatile uint16_t *)&vq->avail->idx);+ /*+ * The ordering between avail index and + * desc reads needs to be enforced. + */ + rte_smp_rmb(); + for (pkt_idx = 0; pkt_idx < count; pkt_idx++) { uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen; uint16_t nr_vec = 0; @@ -1373,6 +1379,12 @@ virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq, if (free_entries == 0) return 0;+ /*+ * The ordering between avail index and + * desc reads needs to be enforced. + */ + rte_smp_rmb(); + VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);count = RTE_MIN(count, MAX_PKT_BURST);
