[RFC 23/27] vhost: add support for virtqueue state get event

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Friday, March 31, 2023 11:43 PM
> To: dev at dpdk.org; david.marchand at redhat.com; Xia, Chenbo
> <chenbo.xia at intel.com>; mkp at redhat.com; fbl at redhat.com;
> jasowang at redhat.com; Liang, Cunming <cunming.liang at intel.com>; Xie, Yongji
> <xieyongji at bytedance.com>; echaudro at redhat.com; eperezma at redhat.com;
> amorenoz at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
> Subject: [RFC 23/27] vhost: add support for virtqueue state get event
> 
> This patch adds support for VDUSE_GET_VQ_STATE event
> handling, which consists in providing the backend last
> available index for the specified virtqueue.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/vhost/vduse.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
> index 2a183130d3..36028b7315 100644
> --- a/lib/vhost/vduse.c
> +++ b/lib/vhost/vduse.c
> @@ -133,6 +133,7 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>  	struct virtio_net *dev = arg;
>  	struct vduse_dev_request req;
>  	struct vduse_dev_response resp;
> +	struct vhost_virtqueue *vq;
>  	int ret;
> 
>  	memset(&resp, 0, sizeof(resp));
> @@ -155,6 +156,13 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>  			req.type);
> 
>  	switch (req.type) {
> +	case VDUSE_GET_VQ_STATE:
> +		vq = dev->virtqueue[req.vq_state.index];
> +		VHOST_LOG_CONFIG(dev->ifname, INFO, "\tvq index: %u,
> avail_index: %u\n",
> +				req.vq_state.index, vq->last_avail_idx);
> +		resp.vq_state.split.avail_index = vq->last_avail_idx;
> +		resp.result = VDUSE_REQ_RESULT_OK;
> +		break;
>  	default:
>  		resp.result = VDUSE_REQ_RESULT_FAILED;
>  		break;
> --
> 2.39.2

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>