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

[Cindy Lu <lulu@redhat.com>]

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