Re: [Qemu-devel] [PATCH RFC v6 15/20] virtio-net: no writeable mac for virtio-1

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Tue, 20 Jan 2015 11:19:47 +0000
Stefan Hajnoczi <stefanha@gmail.com> wrote:

> On Thu, Dec 11, 2014 at 02:25:17PM +0100, Cornelia Huck wrote:
> > Devices operating as virtio 1.0 may not allow writes to the mac
> > address in config space.
> > 
> > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> > ---
> >  hw/net/virtio-net.c |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index d6d1b98..ebbea60 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -87,6 +87,7 @@ static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)
> >      memcpy(&netcfg, config, n->config_size);
> >  
> >      if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR) &&
> 
> I don't see VIRTIO_NET_F_CTRL_MAC_ADDR (23) in the VIRTIO 1.0 "5.1.3.1
> Legacy Interface: Feature bits" section.  Should it be there just so
> people don't try to reuse bit 23 in the future?

But this isn't a legacy flag. Virtio-1 devices simply may not
manipulate the mac address directly even if this feature has not been
negotiated.

> 
> The patch itself:
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>