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

[Jason Wang <jasowang@redhat.com>]

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 <lulu@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;
>