On Fri, Aug 27, 2021 at 12:17:18PM +0200, Pierre Morel wrote:
> To communicate in both directions with a VIRTIO device we need
> to add the incoming communication to the VIRTIO level.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> ---
> lib/virtio.c | 32 ++++++++++++++++++++++++++++++++
> lib/virtio.h | 2 ++
> 2 files changed, 34 insertions(+)
>
> diff --git a/lib/virtio.c b/lib/virtio.c
> index e10153b9..b84bc680 100644
> --- a/lib/virtio.c
> +++ b/lib/virtio.c
> @@ -47,6 +47,38 @@ void vring_init_virtqueue(struct vring_virtqueue *vq, unsigned index,
> vq->data[i] = NULL;
> }
>
> +int virtqueue_add_inbuf(struct virtqueue *_vq, char *buf, unsigned int len)
> +{
> + struct vring_virtqueue *vq = to_vvq(_vq);
> + unsigned int avail;
> + int head;
> +
> + assert(buf);
> + assert(len);
> +
> + if (!vq->vq.num_free)
> + return -1;
> +
> + --vq->vq.num_free;
> +
> + head = vq->free_head;
> +
> + vq->vring.desc[head].flags = 0;
> + vq->vring.desc[head].addr = virt_to_phys(buf);
> + vq->vring.desc[head].len = len;
> +
> + vq->free_head = vq->vring.desc[head].next;
> +
> + vq->data[head] = buf;
> +
> + avail = (vq->vring.avail->idx & (vq->vring.num - 1));
> + vq->vring.avail->ring[avail] = head;
> + wmb(); /* be sure to update the ring before updating the idx */
> + vq->vring.avail->idx++;
> + vq->num_added++;
> +
> + return 0;
> +}
> int virtqueue_add_outbuf(struct virtqueue *_vq, char *buf, unsigned int len)
> {
> struct vring_virtqueue *vq = to_vvq(_vq);
> diff --git a/lib/virtio.h b/lib/virtio.h
> index 2c31fdc7..44b727f8 100644
> --- a/lib/virtio.h
> +++ b/lib/virtio.h
> @@ -141,6 +141,8 @@ extern void vring_init_virtqueue(struct vring_virtqueue *vq, unsigned index,
> const char *name);
> extern int virtqueue_add_outbuf(struct virtqueue *vq, char *buf,
> unsigned int len);
> +extern int virtqueue_add_inbuf(struct virtqueue *vq, char *buf,
> + unsigned int len);
> extern bool virtqueue_kick(struct virtqueue *vq);
> extern void detach_buf(struct vring_virtqueue *vq, unsigned head);
> extern void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len);
> --
> 2.25.1
>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
