Re: [PATCH v7 11/12] vdpa: Add virtio-net mac address via CVQ at start

[Eugenio Perez Martin]

On Tue, Aug 9, 2022 at 9:16 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Fri, Aug 5, 2022 at 2:29 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > This is needed so the destination vdpa device see the same state a the
> > guest set in the source.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> > v6:
> > * Map and unmap command buffers at the start and end of device usage.
> >
> > v5:
> > * Rename s/start/load/
> > * Use independent NetClientInfo to only add load callback on cvq.
> > ---
> >  net/vhost-vdpa.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 43 insertions(+)
> >
> > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> > index 10843e6d97..4f1524c2e9 100644
> > --- a/net/vhost-vdpa.c
> > +++ b/net/vhost-vdpa.c
> > @@ -363,11 +363,54 @@ static ssize_t vhost_vdpa_net_cvq_add(VhostVDPAState 
> > *s, size_t out_len,
> >      return vhost_svq_poll(svq);
> >  }
> >
> > +static int vhost_vdpa_net_load(NetClientState *nc)
> > +{
> > +    VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
> > +    struct vhost_vdpa *v = &s->vhost_vdpa;
> > +    VirtIONet *n;
> > +    uint64_t features;
> > +
> > +    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
> > +
> > +    if (!v->shadow_vqs_enabled) {
> > +        return 0;
> > +    }
> > +
> > +    n = VIRTIO_NET(v->dev->vdev);
> > +    features = v->dev->vdev->host_features;
> > +    if (features & BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR)) {
> > +        const struct virtio_net_ctrl_hdr ctrl = {
> > +            .class = VIRTIO_NET_CTRL_MAC,
> > +            .cmd = VIRTIO_NET_CTRL_MAC_ADDR_SET,
> > +        };
>
> Can we build this directly from the cmd_out_buffer?
>
> > +        char *cursor = s->cvq_cmd_out_buffer;
> > +        ssize_t dev_written;
> > +        virtio_net_ctrl_ack state;
>
> I think we can read the status directly from the cmd_in_buffer.
>

Directly casting it to virtio_net_ctrl_ack? Sure.

Thanks!

> Thanks
>
> > +
> > +        memcpy(cursor, &ctrl, sizeof(ctrl));
> > +        cursor += sizeof(ctrl);
> > +        memcpy(cursor, n->mac, sizeof(n->mac));
> > +        cursor += sizeof(n->mac);
> > +
> > +        dev_written = vhost_vdpa_net_cvq_add(s, sizeof(ctrl) + 
> > sizeof(n->mac),
> > +                                             sizeof(state));
> > +        if (unlikely(dev_written < 0)) {
> > +            return dev_written;
> > +        }
> > +
> > +        memcpy(&state, s->cvq_cmd_in_buffer, sizeof(state));
> > +        return state == VIRTIO_NET_OK ? 0 : -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> >  static NetClientInfo net_vhost_vdpa_cvq_info = {
> >      .type = NET_CLIENT_DRIVER_VHOST_VDPA,
> >      .size = sizeof(VhostVDPAState),
> >      .receive = vhost_vdpa_receive,
> >      .prepare = vhost_vdpa_net_cvq_prepare,
> > +    .load = vhost_vdpa_net_load,
> >      .stop = vhost_vdpa_net_cvq_stop,
> >      .cleanup = vhost_vdpa_cleanup,
> >      .has_vnet_hdr = vhost_vdpa_has_vnet_hdr,
> > --
> > 2.31.1
> >
>