[PATCH v2] virtio-net: Add check for mac address while peer is vdpa

[Cindy Lu]

Sometime vdpa get an all 0 mac address from the hardware, this will cause the 
traffic down
So we add the check for this part.
if we get an 0 mac address we will use the default mac address instead

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 hw/net/virtio-net.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 9179013ac4..f1648fc47d 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -126,6 +126,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, 
uint8_t *config)
     VirtIONet *n = VIRTIO_NET(vdev);
     struct virtio_net_config netcfg;
     NetClientState *nc = qemu_get_queue(n->nic);
+    static const MACAddr zero = { .a = { 0, 0, 0, 0, 0, 0 } };
 
     int ret = 0;
     memset(&netcfg, 0 , sizeof(struct virtio_net_config));
@@ -151,7 +152,11 @@ static void virtio_net_get_config(VirtIODevice *vdev, 
uint8_t *config)
         ret = vhost_net_get_config(get_vhost_net(nc->peer), (uint8_t *)&netcfg,
                                    n->config_size);
         if (ret != -1) {
-            memcpy(config, &netcfg, n->config_size);
+            if (memcmp(&netcfg.mac, &zero, sizeof(zero)) != 0) {
+                memcpy(config, &netcfg, n->config_size);
+        } else {
+                error_report("Get an all zero mac address from hardware");
+            }
         }
     }
 }
-- 
2.21.3