[PATCH v5 1/1] virtio-net: Add check for mac address while peer is vdpa

[Cindy Lu]

While peer is vdpa, sometime qemu get an all zero mac address from the hardware,
This is not a legal value. Add the check for this.if we get an zero mac address.
qemu will use the default mac address or the mac address from qemu cmdline

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 hw/net/virtio-net.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 9179013ac4..8f36ca5066 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));
@@ -151,6 +152,15 @@ 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) {
+            /*
+             * Here is a work around, the 0 mac address is not a legal value.
+             * if we got this from hardware, qemu will use the mac address
+             * saved in VirtIONet->mac.
+             */
+            if (memcmp(&netcfg.mac, &zero, sizeof(zero)) == 0) {
+                info_report("Get an all zero mac address from hardware");
+                memcpy(netcfg.mac, n->mac, ETH_ALEN);
+            }
             memcpy(config, &netcfg, n->config_size);
         }
     }
-- 
2.21.3