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

[Jason Wang]

在 2022/7/16 19:34, Eugenio Pérez 写道:
> 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>
> ---
>   net/vhost-vdpa.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 52 insertions(+), 1 deletion(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 0183fce353..2873be2ba4 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -383,7 +383,7 @@ static virtio_net_ctrl_ack 
> vhost_vdpa_net_svq_add(VhostShadowVirtqueue *svq,
>       return VIRTIO_NET_OK;
>   }
>   
> -static int vhost_vdpa_start_control_svq(struct vhost_vdpa *v)
> +static int vhost_vdpa_enable_control_svq(struct vhost_vdpa *v)
>   {
>       struct vhost_vring_state state = {
>           .index = v->dev->vq_index,
> @@ -395,6 +395,57 @@ static int vhost_vdpa_start_control_svq(struct vhost_vdpa 
> *v)
>       return r < 0 ? -errno : r;
>   }
>   
> +static int vhost_vdpa_start_control_svq(struct vhost_vdpa *v)
> +{
> +
> +    VirtIONet *n = VIRTIO_NET(v->dev->vdev);
> +    uint64_t features = v->dev->vdev->host_features;
> +    VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, 0);
> +    VhostVDPAState *s = container_of(v, VhostVDPAState, vhost_vdpa);
> +    int r;
> +
> +    r = vhost_vdpa_enable_control_svq(v);
> +    if (unlikely(r < 0)) {
> +        return r;
> +    }
> +
> +    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,
> +        };
> +        uint8_t mac[6];
> +        const struct iovec out[] = {
> +            {
> +                .iov_base = (void *)&ctrl,
> +                .iov_len = sizeof(ctrl),
> +            },{
> +                .iov_base = mac,
> +                .iov_len = sizeof(mac),
> +            },
> +        };
> +        struct iovec dev_buffers[2] = {
> +            { .iov_base = s->cvq_cmd_out_buffer },
> +            { .iov_base = s->cvq_cmd_in_buffer },
> +        };
> +        bool ok;
> +        virtio_net_ctrl_ack state;
> +
> +        ok = vhost_vdpa_net_cvq_map_sg(s, out, ARRAY_SIZE(out), dev_buffers);
> +        if (unlikely(!ok)) {
> +            return -1;
> +        }
> +
> +        memcpy(mac, n->mac, sizeof(mac));
> +        state = vhost_vdpa_net_svq_add(svq, dev_buffers);
> +        vhost_vdpa_cvq_unmap_buf(v, dev_buffers[0].iov_base);
> +        vhost_vdpa_cvq_unmap_buf(v, dev_buffers[1].iov_base);


Any reason we do per buffer unmap instead of the sg unmap here?

Thanks


> +        return state == VIRTIO_NET_OK ? 0 : 1;
> +    }
> +
> +    return 0;
> +}
> +
>   /**
>    * Do not forward commands not supported by SVQ. Otherwise, the device could
>    * accept it and qemu would not know how to update the device model.