We can access the CVQ header through `struct virtio_net_ctrl_hdr`,
instead of accessing it through a `uint8_t` pointer,
which improves the code's readability and maintainability.

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
 net/vhost-vdpa.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index e80d4b4ef3..a84eb088a0 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -928,6 +928,7 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
 {
     VhostVDPAState *s = opaque;
     size_t in_len;
+    const struct virtio_net_ctrl_hdr *ctrl;
     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
     /* Out buffer sent to both the vdpa device and the device model */
     struct iovec out = {
@@ -943,7 +944,9 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
     out.iov_len = iov_to_buf(elem->out_sg, elem->out_num, 0,
                              s->cvq_cmd_out_buffer,
                              vhost_vdpa_net_cvq_cmd_len());
-    if (*(uint8_t *)s->cvq_cmd_out_buffer == VIRTIO_NET_CTRL_ANNOUNCE) {
+
+    ctrl = s->cvq_cmd_out_buffer;
+    if (ctrl->class == VIRTIO_NET_CTRL_ANNOUNCE) {
         /*
          * Guest announce capability is emulated by qemu, so don't forward to
          * the device.
-- 
2.25.1

On Fri, Jul 7, 2023 at 5:27 PM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> We can access the CVQ header through `struct virtio_net_ctrl_hdr`,
> instead of accessing it through a `uint8_t` pointer,
> which improves the code's readability and maintainability.
>
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> ---
>  net/vhost-vdpa.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index e80d4b4ef3..a84eb088a0 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -928,6 +928,7 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
>  {
>      VhostVDPAState *s = opaque;
>      size_t in_len;
> +    const struct virtio_net_ctrl_hdr *ctrl;
>      virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
>      /* Out buffer sent to both the vdpa device and the device model */
>      struct iovec out = {
> @@ -943,7 +944,9 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
>      out.iov_len = iov_to_buf(elem->out_sg, elem->out_num, 0,
>                               s->cvq_cmd_out_buffer,
>                               vhost_vdpa_net_cvq_cmd_len());
> -    if (*(uint8_t *)s->cvq_cmd_out_buffer == VIRTIO_NET_CTRL_ANNOUNCE) {
> +
> +    ctrl = s->cvq_cmd_out_buffer;
> +    if (ctrl->class == VIRTIO_NET_CTRL_ANNOUNCE) {
>          /*
>           * Guest announce capability is emulated by qemu, so don't forward to
>           * the device.
> --
> 2.25.1
>