Re: [PATCH net-next v2 13/14] sfc: update vdpa device MAC address

[Gautam Dawar]

On 3/10/23 10:35, Jason Wang wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On Tue, Mar 7, 2023 at 7:38 PM Gautam Dawar <gautam.dawar@xxxxxxx> wrote:
> > As the VF MAC address can now be updated using `devlink port function set`
> What happens if we run this while the vpda is being used by a VM?
IIUC, updating the MAC address using devlink interface requires 
unbinding the device from driver and hence updating the MAC while vdpa 
device is in-use won't be possible. It can only be done via control vq 
VIRTIO_NET_CTRL_MAC_ADDR_SET command, when available.
> > interface, fetch the vdpa device MAC address from the underlying VF during
> > vdpa device creation.
> >
> > Signed-off-by: Gautam Dawar <gautam.dawar@xxxxxxx>
> > ---
> >   drivers/net/ethernet/sfc/ef100_vdpa.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.c b/drivers/net/ethernet/sfc/ef100_vdpa.c
> > index 30ca4ab00175..32182a01f6a5 100644
> > --- a/drivers/net/ethernet/sfc/ef100_vdpa.c
> > +++ b/drivers/net/ethernet/sfc/ef100_vdpa.c
> > @@ -272,6 +272,18 @@ static int get_net_config(struct ef100_vdpa_nic *vdpa_nic)
> >          vdpa_nic->net_config.max_virtqueue_pairs =
> >                  cpu_to_efx_vdpa16(vdpa_nic, vdpa_nic->max_queue_pairs);
> >
> > +       rc = ef100_get_mac_address(efx, vdpa_nic->mac_address,
> > +                                  efx->client_id, true);
> > +       if (rc) {
> > +               dev_err(&vdpa_nic->vdpa_dev.dev,
> > +                       "%s: Get MAC for vf:%u failed:%d\n", __func__,
> > +                       vdpa_nic->vf_index, rc);
> > +               return rc;
> > +       }
> Can this override what is provisioned by the userspace?

No, this was carefully avoided by overwriting the userspace provisioned 
MAC in ef100_vdpa_create():

        rc = get_net_config(vdpa_nic);
        if (rc)
                goto err_put_device;

        if (mac) {
                ether_addr_copy(vdpa_nic->mac_address, mac);
                vdpa_nic->mac_configured = true;
        }

> Thanks
>
>
> > +
> > +       if (is_valid_ether_addr(vdpa_nic->mac_address))
> > +               vdpa_nic->mac_configured = true;
> > +
> >          rc = efx_vdpa_get_mtu(efx, &mtu);
> >          if (rc) {
> >                  dev_err(&vdpa_nic->vdpa_dev.dev,
> > --
> > 2.30.1