Am Thursday 02 April 2009 18:06:25 schrieb Alex Williamson:
> On Thu, 2009-04-02 at 13:33 +0200, Christian Borntraeger wrote:
> > I read this as the mac config field is optional (similar to all the optional
> > fields we added in virtio_blk later).
[...]
> Sorry for the breakage. My interpretation of the virtio-net config
> space was that the mac field was always present and the host had
> programmed a valid value when the F_MAC feature is available. However,
> from the history of the flag, it seems like you're interpretation is
> likely correct. Setting the config value from the randomly generated
> mac was largely opportunistic since there's no userspace that doesn't
> provide a mac by default. So perhaps we can drop that and gate the
> set_mac_address entry point as shown below. How does this look?
> Thanks,
that patch would solve the my problem. Thanks.
In addition, I will change our hypervisor sample code, to provide the
config space even if we do not set a MAC address in the host. Better
safe than sorry.
[...]
> virtio_net: Set the mac config only when VIRITO_NET_F_MAC
>
> VIRTIO_NET_F_MAC indicates the presence of the mac field in config
> space, not the validity of the value it contains. Allow the mac to be
> changed at runtime, but only push the change into config space with the
> VIRTIO_NET_F_MAC feature present.
>
> Signed-off-by: Alex Williamson <alex.william...@hp.com>
Acked-by: Christian Borntraeger <borntrae...@de.ibm.com>
> --
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index a6f1e19..9c82a39 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -575,8 +575,9 @@ static int virtnet_set_mac_address(struct net_device
> *dev, void *p)
> if (ret)
> return ret;
>
> - vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
> - dev->dev_addr, dev->addr_len);
> + if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
> + vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
> + dev->dev_addr, dev->addr_len);
>
> return 0;
> }
> @@ -876,11 +877,8 @@ static int virtnet_probe(struct virtio_device *vdev)
> vdev->config->get(vdev,
> offsetof(struct virtio_net_config, mac),
> dev->dev_addr, dev->addr_len);
> - } else {
> + } else
> random_ether_addr(dev->dev_addr);
> - vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
> - dev->dev_addr, dev->addr_len);
> - }
>
> /* Set up our device-specific information */
> vi = netdev_priv(dev);
--
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