Re: [Qemu-devel] [QEMU PATCH v2] virtio-net: introduce a new macaddr control

[Amos Kong <akong@redhat.com>]

On Thu, Jan 17, 2013 at 01:45:11PM +0800, Amos Kong wrote:
> On Thu, Jan 17, 2013 at 11:49:20AM +1030, Rusty Russell wrote:
> > akong@redhat.com writes:
> > > @@ -349,6 +351,14 @@ static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
> > >  {
> > >      struct virtio_net_ctrl_mac mac_data;
> > >  
> > > +    if (cmd == VIRTIO_NET_CTRL_MAC_ADDR_SET && elem->out_num == 2 &&
> > > +        elem->out_sg[1].iov_len == ETH_ALEN) {
> > > +        /* Set MAC address */
> > > +        memcpy(n->mac, elem->out_sg[1].iov_base, elem->out_sg[1].iov_len);
> > > +        qemu_format_nic_info_str(&n->nic->nc, n->mac);
> > > +        return VIRTIO_NET_OK;
> > > +    }
> > 
> > Does the rest of the net device still rely on the layout of descriptors?
> 
> No, only info string of net client relies on n->mac

I misunderstood. There is no clear limitation of how much descriptor are
used for each vq command, but many commands rely on the layout of
descriptiors. eg:

virtio-net:
   VIRTIO_NET_CTRL_RX_PROMISC
   VIRTIO_NET_CTRL_RX_ALLMULTI
   VIRTIO_NET_CTRL_MAC_TABLE_SET
   etc
 
> > If so, OK, we'll fix them all together.  If not, this introduces a new
> > one.
> > 
> > Cheers,
> > Rusty.