Re: [PATCH 1/3] virtio_net: Add the check for vdpa's mac address

[Yan Vugenfirer]

Do we check that the MAC from the command line or HW was formed
correctly and doesn't include multicast bit?

Best regards,
Yan.


On Tue, Aug 6, 2024 at 12:45 PM Cindy Lu <lulu@redhat.com> wrote:
>
> On Tue, 6 Aug 2024 at 11:07, Jason Wang <jasowang@redhat.com> wrote:
> >
> > On Tue, Aug 6, 2024 at 8:58 AM Cindy Lu <lulu@redhat.com> wrote:
> > >
> > > When using a VDPA device, it is important to ensure that
> > > the MAC address in the hardware matches the MAC address
> > > from the QEMU command line.
> > > This will allow the device to boot.
> > >
> > > Signed-off-by: Cindy Lu <lulu@redhat.com>
> > > ---
> > >  hw/net/virtio-net.c | 33 +++++++++++++++++++++++++++++----
> > >  1 file changed, 29 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > > index 9c7e85caea..7f51bd0dd3 100644
> > > --- a/hw/net/virtio-net.c
> > > +++ b/hw/net/virtio-net.c
> > > @@ -3579,12 +3579,36 @@ static bool 
> > > failover_hide_primary_device(DeviceListener *listener,
> > >      /* failover_primary_hidden is set during feature negotiation */
> > >      return qatomic_read(&n->failover_primary_hidden);
> > >  }
> > > +static bool virtio_net_check_vdpa_mac(NetClientState *nc, VirtIONet *n, 
> > > MACAddr *cmdline_mac,
> > > +                                     Error **errp)
> > > +{
> > > +       struct virtio_net_config hwcfg = {};
> > > +       static const MACAddr zero = { .a = { 0, 0, 0, 0, 0, 0 } };
> > > +
> > > +       vhost_net_get_config(get_vhost_net(nc->peer), (uint8_t *)&hwcfg, 
> > > ETH_ALEN);
> > > +
> > > +    /*
> > > +     * For VDPA device: Only two situations are acceptable:
> > > +     * 1.The hardware MAC address is the same as the QEMU command line 
> > > MAC
> > > +     *   address, and both of them are not 0.
> >
> > I guess there should be a bullet 2?
> >
> yes, there is a section 2, will change this code here
> Thanks
> cindy
> > > +     */
> > > +
> > > +       if (memcmp(&hwcfg.mac, &zero, sizeof(MACAddr)) != 0) {
> > > +               if ((memcmp(&hwcfg.mac, cmdline_mac, sizeof(MACAddr)) == 
> > > 0)) {
> > > +                       return true;
> > > +               }
> > > +       }
> > > +       error_setg(errp, "vDPA device's mac != the mac address from qemu 
> > > cmdline"
> > > +                        "Please check the the vdpa device's setting.");
> >
> > For error messages I think it's better to use english instead of "!="
> > to describe the issue.
> >
> > >
> > > +       return false;
> > > +}
> > >  static void virtio_net_device_realize(DeviceState *dev, Error **errp)
> > >  {
> > >      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > >      VirtIONet *n = VIRTIO_NET(dev);
> > >      NetClientState *nc;
> > > +    MACAddr macaddr_cmdline;
> > >      int i;
> > >
> > >      if (n->net_conf.mtu) {
> > > @@ -3692,6 +3716,7 @@ static void virtio_net_device_realize(DeviceState 
> > > *dev, Error **errp)
> > >      virtio_net_add_queue(n, 0);
> > >
> > >      n->ctrl_vq = virtio_add_queue(vdev, 64, virtio_net_handle_ctrl);
> > > +    memcpy(&macaddr_cmdline, &n->nic_conf.macaddr, sizeof(n->mac));
> > >      qemu_macaddr_default_if_unset(&n->nic_conf.macaddr);
> > >      memcpy(&n->mac[0], &n->nic_conf.macaddr, sizeof(n->mac));
> > >      n->status = VIRTIO_NET_S_LINK_UP;
> > > @@ -3739,10 +3764,10 @@ static void virtio_net_device_realize(DeviceState 
> > > *dev, Error **errp)
> > >      nc->rxfilter_notify_enabled = 1;
> > >
> > >     if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) 
> > > {
> > > -        struct virtio_net_config netcfg = {};
> > > -        memcpy(&netcfg.mac, &n->nic_conf.macaddr, ETH_ALEN);
> > > -        vhost_net_set_config(get_vhost_net(nc->peer),
> > > -            (uint8_t *)&netcfg, 0, ETH_ALEN, 
> > > VHOST_SET_CONFIG_TYPE_FRONTEND);
> > > +          if (!virtio_net_check_vdpa_mac(nc, n, &macaddr_cmdline, errp)) 
> > > {
> > > +                  virtio_cleanup(vdev);
> > > +                  return;
> > > +          }
> >
> > Any reason we remove vhost_net_set_config() here? It is not described
> > in the commit or does it belong to another patch?
> >
> > Thanks
> >
> as we discussed before， the MAC address in hardware should have a
> "higher priority"
> than the MAC address in qemu cmdline. So I remove the set_config there,
> the MAC address from the hardware will overwrite the MAC in qemu
> cmdline. so don't need to set_config to hardware now
> Thanks,
> cindy
> > >      }
> > >      QTAILQ_INIT(&n->rsc_chains);
> > >      n->qdev = dev;
> > > --
> > > 2.45.0
> > >
> >
>
>