[ovs-dev] [PATCH] netdev-dpdk : vhost-user port link state fix

[Zoltán Balogh]

Hi,

OVS reports that link state of a vhost-user port (type=dpdkvhostuser) is DOWN, even when traffic is running through the port between a Virtual Machine and the vSwitch.
Changing admin state with the "ovs-ofctl mod-port <BR> <PORT> up/down" command over OpenFlow does affect neither the reported link state nor the traffic. 

The patch below does the flowing:
 - Triggers link state change by altering netdev's change_seq member. 
 - Controls sending/receiving of packets through vhost-user port according to the port's current admin state.
 - Sets admin state of newly created vhost-user port to UP.

Signed-off-by: Zoltán Balogh <zoltan.balogh at ericsson.com>
Co-authored-by: Jan Scheurich <jan.scheurich at ericsson.com>
Signed-off-by: Jan Scheurich <jan.scheurich at ericsson.com>

---

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index af86d19..155efe1 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -772,6 +772,8 @@ netdev_dpdk_init(struct netdev *netdev, unsigned int port_no,
         }
     } else {
         netdev_dpdk_alloc_txq(dev, OVS_VHOST_MAX_QUEUE_NUM);
+        /* Enable DPDK_DEV_VHOST device and set promiscuous mode flag. */
+        dev->flags = NETDEV_UP | NETDEV_PROMISC;
     }
 
     ovs_list_push_back(&dpdk_list, &dev->list_node);
@@ -1256,6 +1258,21 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq,
         return EAGAIN;
     }
 
+    /* Delete received packets if device is disabled. */
+    if (OVS_UNLIKELY(!(dev->flags & NETDEV_UP))) {
+        uint16_t i;
+
+        VLOG_WARN_RL(&rl, "error receiving Ethernet packet on %s: %s",
+                     netdev_rxq_get_name(rxq), ovs_strerror(ENONET));
+
+        for (i = 0; i < nb_rx; i++) {
+            dp_packet_delete(packets[i]);
+        }
+
+        *c = 0;
+        return EAGAIN;
+    }
+
     rte_spinlock_lock(&dev->stats_lock);
     netdev_dpdk_vhost_update_rx_counters(&dev->stats, packets, nb_rx);
     rte_spinlock_unlock(&dev->stats_lock);
@@ -1516,6 +1533,23 @@ static int
 netdev_dpdk_vhost_send(struct netdev *netdev, int qid, struct dp_packet **pkts,
                  int cnt, bool may_steal)
 {
+    struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
+
+    /* Do not send anything if device is disabled. */
+    if (OVS_UNLIKELY(!(dev->flags & NETDEV_UP))) {
+        int i;
+
+        VLOG_WARN_RL(&rl, "error sending Ethernet packet on %s: %s",
+                     netdev_get_name(netdev), ovs_strerror(ENONET));
+
+        if (may_steal) {
+            for (i = 0; i < cnt; i++) {
+                dp_packet_delete(pkts[i]);
+            }
+        }
+        return ENONET;
+    }
+
     if (OVS_UNLIKELY(pkts[0]->source != DPBUF_DPDK)) {
         int i;
 
@@ -2004,6 +2038,23 @@ netdev_dpdk_update_flags__(struct netdev_dpdk *dev,
         if (!(dev->flags & NETDEV_UP)) {
             rte_eth_dev_stop(dev->port_id);
         }
+    } else {
+        /* If DPDK_DEV_VHOST device's NETDEV_UP flag was changed and vhost is
+         * running then change netdev's change_seq to trigger link state
+         * update. */
+        struct virtio_net *virtio_dev = netdev_dpdk_get_virtio(dev);
+
+        if ((NETDEV_UP & ((*old_flagsp ^ on) | (*old_flagsp ^ off)))
+            && is_vhost_running(virtio_dev)) {
+            netdev_change_seq_changed(&dev->up);
+
+            /* Clear statistics if device is getting up. */
+            if (NETDEV_UP & on) {
+                rte_spinlock_lock(&dev->stats_lock);
+                memset(&dev->stats, 0x00, sizeof(dev->stats));
+                rte_spinlock_unlock(&dev->stats_lock);
+            }
+        }
     }
 
     return 0;
@@ -2226,6 +2277,7 @@ new_device(struct virtio_net *virtio_dev)
             virtio_dev->flags |= VIRTIO_DEV_RUNNING;
             /* Disable notifications. */
             set_irq_status(virtio_dev);
+            netdev_change_seq_changed(&dev->up);
             ovs_mutex_unlock(&dev->mutex);
             break;
         }
@@ -2277,6 +2329,7 @@ destroy_device(volatile struct virtio_net *virtio_dev)
             ovsrcu_set(&dev->virtio_dev, NULL);
             netdev_dpdk_txq_map_clear(dev);
             exists = true;
+            netdev_change_seq_changed(&dev->up);
             ovs_mutex_unlock(&dev->mutex);
             break;
         }