From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Coquelin Subject: [PATCH 1/5] vhost: enforce avail index and desc read ordering Date: Wed, 5 Dec 2018 10:49:53 +0100 Message-ID: <20181205094957.1938-2-maxime.coquelin@redhat.com> References: <20181205094957.1938-1-maxime.coquelin@redhat.com> Cc: Maxime Coquelin , stable@dpdk.org To: dev@dpdk.org, jfreimann@redhat.com, tiwei.bie@intel.com, zhihong.wang@intel.com, jasowang@redhat.com Return-path: In-Reply-To: <20181205094957.1938-1-maxime.coquelin@redhat.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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: stable@dpdk.org Reported-by: Jason Wang Signed-off-by: Maxime Coquelin --- lib/librte_vhost/virtio_net.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) 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); -- 2.17.2