Re: [PATCH 1/3] virtio-net: Set mac address to hardware if the peer is vdpa

[Jason Wang]

On 2020/9/17 下午11:58, Cindy Lu wrote:
If the peer's type is vdpa,set the mac address to NIC in 
virtio_net_device_realize,
Also sometime vdpa get an all 0 macaddress 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 <l...@redhat.com>
---
  hw/net/virtio-net.c | 12 +++++++++++-
  1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index cb0d27084c..7db9da1482 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");


This is probably a hint that MAC is not properly provisioned.

So I guess we can leave this as is, or simply warn until the management 
interface is finalized.


+            }
          }
      }
  }
@@ -3399,6 +3404,11 @@ static void virtio_net_device_realize(DeviceState *dev, 
Error **errp)
      nc = qemu_get_queue(n->nic);
      nc->rxfilter_notify_enabled = 1;
  
+   if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) {
+        struct virtio_net_config netcfg = {};
+        memcpy(&netcfg.mac, &n->nic_conf.macaddr, ETH_ALEN);
+        virtio_net_set_config(vdev, (uint8_t *)&netcfg);


Won't this overwrite all other fields in the netcfg? I think we should 
only touch mac part.

Thanks


+    }
      QTAILQ_INIT(&n->rsc_chains);
      n->qdev = dev;