On Mon, Apr 21, 2025 at 11:22 AM Jason Wang <jasow...@redhat.com> wrote:
>
> On Thu, Apr 17, 2025 at 6:26 PM Cindy Lu <l...@redhat.com> wrote:
> >
> > For VDPA devices, Allow configurations where both the hardware MAC address
> > and QEMU command line MAC address are zero.
> > In this case, QEMU will automatically generate a random MAC address and
> > assign it to the hardware, and the VM will use this random MAC address as
> > its MAC address.
> >
> > Signed-off-by: Cindy Lu <l...@redhat.com>
> > ---
> > hw/net/virtio-net.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 808a2fe4d4..2d4ac20ee0 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -3772,7 +3772,18 @@ static bool virtio_net_check_vdpa_mac(VirtIONet *n,
> > uint8_t *hwmac,
> > return true;
> > }
> > }
> > + /*
> > + * 3. The hardware MAC address is 0,
> > + * and the MAC address in the QEMU command line is also 0.
>
> Can this happen? I'd expect qemu should check for invalid mac addresses.
>
If the QEMU command line does not specify the MAC address, it passes a
value of 0 to this function. Therefore, we may not need to add a check
here, as this value will be replaced with a random MAC address in the
subsequent process.
thanks
Cindy
> > + * In this situation, QEMU generates a random MAC address and
> > + * uses CVQ/set_config to assign it to the device.
> > + */
> > + if ((memcmp(hwmac, &zero, sizeof(MACAddr)) == 0) &&
> > + (memcmp(cmdline_mac, &zero, sizeof(MACAddr)) == 0)) {
> > + memcpy(&n->mac[0], &n->nic_conf.macaddr, sizeof(n->mac));
> >
> > + return true;
> > + }
> > return false;
> > }
> > static void virtio_net_device_realize(DeviceState *dev, Error **errp)
> > --
> > 2.45.0
> >
>
> Thanks
>
