For VDPA devices, Allow configurations where the hardware MAC address
is non-zero while the MAC address in the QEMU command line is zero.
In this case, QEMU will use the hardware MAC address from the device.

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 0b6a4e5634..808a2fe4d4 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -3757,6 +3757,20 @@ static bool virtio_net_check_vdpa_mac(VirtIONet *n, uint8_t *hwmac,
         if ((memcmp(hwmac, 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 case,qemu will use the hardware MAC address overwrite
+         *  the QEMU command line MAC address saved in VirtIONet->mac[0].
+         *  In the following process, QEMU will use this MAC address
+         *  to complete the initialization.
+         */
+        if (memcmp(cmdline_mac, &zero, sizeof(MACAddr)) == 0) {
+            /* overwrite the mac address with hardware address */
+            memcpy(&n->mac[0], hwmac, sizeof(n->mac));
+            memcpy(&n->nic_conf.macaddr, hwmac, sizeof(n->mac));
+            return true;
+        }
     }
 
     return false;
-- 
2.45.0

On Thu, Apr 17, 2025 at 6:25 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.
> In this case, QEMU will use the hardware MAC address from the device.
>
> 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 0b6a4e5634..808a2fe4d4 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -3757,6 +3757,20 @@ static bool virtio_net_check_vdpa_mac(VirtIONet *n, uint8_t *hwmac,
>          if ((memcmp(hwmac, 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 case,qemu will use the hardware MAC address overwrite
> +         *  the QEMU command line MAC address saved in VirtIONet->mac[0].
> +         *  In the following process, QEMU will use this MAC address
> +         *  to complete the initialization.
> +         */
> +        if (memcmp(cmdline_mac, &zero, sizeof(MACAddr)) == 0) {
> +            /* overwrite the mac address with hardware address */
> +            memcpy(&n->mac[0], hwmac, sizeof(n->mac));
> +            memcpy(&n->nic_conf.macaddr, hwmac, sizeof(n->mac));

I'm not sure I get here, shouldn't we need to call get_config() here?

Thanks

> +            return true;
> +        }
>      }
>
>      return false;
> --
> 2.45.0
>

On Mon, Apr 21, 2025 at 11:19 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Thu, Apr 17, 2025 at 6:25 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.
> > In this case, QEMU will use the hardware MAC address from the device.
> >
> > 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 0b6a4e5634..808a2fe4d4 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -3757,6 +3757,20 @@ static bool virtio_net_check_vdpa_mac(VirtIONet *n, uint8_t *hwmac,
> >          if ((memcmp(hwmac, 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 case,qemu will use the hardware MAC address overwrite
> > +         *  the QEMU command line MAC address saved in VirtIONet->mac[0].
> > +         *  In the following process, QEMU will use this MAC address
> > +         *  to complete the initialization.
> > +         */
> > +        if (memcmp(cmdline_mac, &zero, sizeof(MACAddr)) == 0) {
> > +            /* overwrite the mac address with hardware address */
> > +            memcpy(&n->mac[0], hwmac, sizeof(n->mac));
> > +            memcpy(&n->nic_conf.macaddr, hwmac, sizeof(n->mac));
>
> I'm not sure I get here, shouldn't we need to call get_config() here?
>
> Thanks
>
I made a small change to this function: get_config() is called in
virtio_net_device_realize() before check_mac(), so we don't need to
call it again.
Thanks
Cindy
> > +            return true;
> > +        }
> >      }
> >
> >      return false;
> > --
> > 2.45.0
> >
>