Re: [PATCH v6 3/4] virtio_net: Add second acceptable configuration for MAC setup

[Cindy Lu <lulu@redhat.com>]

On Tue, Apr 8, 2025 at 2:48 PM Jason Wang <jasowang@redhat.com> wrote:
>
> On Tue, Apr 8, 2025 at 2:13 PM Cindy Lu <lulu@redhat.com> wrote:
> >
> > For VDPA devices, Allow configurations where the hardware MAC address
> > is non-zero while the MAC address in the QEMU command line is zero.
> >
> > Signed-off-by: Cindy Lu <lulu@redhat.com>
> > ---
> >  hw/net/virtio-net.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 94ee21d1fc..45b63eb9de 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -3769,6 +3769,20 @@ static bool virtio_net_check_vdpa_mac(NetClientState *nc, VirtIONet *n,
> >          if ((memcmp(&hwcfg.mac, cmdline_mac, sizeof(MACAddr)) == 0)) {
> >              return true;
> >          }
> > +        /*
> > +         * 2. The hardware MAC address is NOT 0 and the MAC address in
> > +         *  the QEMU command line is 0.
> > +         *  In this situation, we use the hardware MAC address overwrite
> > +         *  the QEMU command line address saved in VirtIONet->mac[0].
> > +         *  In the following process, QEMU will use this MAC address
> > +         *  in VirtIONet to complete the initialization.
> > +         */
>
> Let's describe how this can interact with the trick done in
> virtio_net_get_config().
>
Sure, will do
Thanks
cindy
> > +        if (memcmp(cmdline_mac, &zero, sizeof(MACAddr)) == 0) {
> > +            /* overwrite the mac address with hardware address */
> > +            memcpy(&n->mac[0], &hwcfg.mac, sizeof(n->mac));
> > +            memcpy(&n->nic_conf.macaddr, &hwcfg.mac, sizeof(n->mac));
> > +            return true;
> > +        }
> >      }
> >      error_setg(errp,
> >                 "vDPA device's MAC address %02x:%02x:%02x:%02x:%02x:%02x "
> > --
> > 2.45.0
> >
>
> Thanks
>