[v5,26/26] vhost: add VDUSE device stop

  This patch adds VDUSE device stop and cleanup of its
virtqueues.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 doc/guides/rel_notes/release_23_07.rst |  7 +++
 lib/vhost/vduse.c                      | 72 +++++++++++++++++++++++---
 2 files changed, 71 insertions(+), 8 deletions(-)
  

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, June 6, 2023 4:19 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>;
> david.marchand@redhat.com; mkp@redhat.com; fbl@redhat.com;
> jasowang@redhat.com; Liang, Cunming <cunming.liang@intel.com>; Xie, Yongji
> <xieyongji@bytedance.com>; echaudro@redhat.com; eperezma@redhat.com;
> amorenoz@redhat.com; lulu@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v5 26/26] vhost: add VDUSE device stop
> 
> This patch adds VDUSE device stop and cleanup of its
> virtqueues.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  doc/guides/rel_notes/release_23_07.rst |  7 +++
>  lib/vhost/vduse.c                      | 72 +++++++++++++++++++++++---
>  2 files changed, 71 insertions(+), 8 deletions(-)
> 
> diff --git a/doc/guides/rel_notes/release_23_07.rst
> b/doc/guides/rel_notes/release_23_07.rst
> index 7034fb664c..0f44c859da 100644
> --- a/doc/guides/rel_notes/release_23_07.rst
> +++ b/doc/guides/rel_notes/release_23_07.rst
> @@ -67,6 +67,13 @@ New Features
>    Introduced ``rte_vhost_driver_set_max_queue_num()`` to be able to limit
> the
>    maximum number of supported queue pairs, required for VDUSE support.
> 
> +* **Added VDUSE support into Vhost library.**
> +
> +  VDUSE aims at implementing vDPA devices in userspace. It can be used as
> an
> +  alternative to Vhost-user when using Vhost-vDPA, but also enable
> providing a
> +  virtio-net netdev to the host when using Virtio-vDPA driver. A
> limitation in
> +  this release is the lack of reconnection support.
> +
> 
>  Removed Items
>  -------------
> diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
> index d3759077ff..a509daf80c 100644
> --- a/lib/vhost/vduse.c
> +++ b/lib/vhost/vduse.c
> @@ -252,6 +252,44 @@ vduse_vring_setup(struct virtio_net *dev, unsigned
> int index)
>  	}
>  }
> 
> +static void
> +vduse_vring_cleanup(struct virtio_net *dev, unsigned int index)
> +{
> +	struct vhost_virtqueue *vq = dev->virtqueue[index];
> +	struct vduse_vq_eventfd vq_efd;
> +	int ret;
> +
> +	if (vq == dev->cvq && vq->kickfd >= 0) {
> +		fdset_del(&vduse.fdset, vq->kickfd);
> +		fdset_pipe_notify(&vduse.fdset);
> +	}
> +
> +	vq_efd.index = index;
> +	vq_efd.fd = VDUSE_EVENTFD_DEASSIGN;
> +
> +	ret = ioctl(dev->vduse_dev_fd, VDUSE_VQ_SETUP_KICKFD, &vq_efd);
> +	if (ret)
> +		VHOST_LOG_CONFIG(dev->ifname, ERR, "Failed to cleanup kickfd
> for VQ %u: %s\n",
> +				index, strerror(errno));
> +
> +	close(vq->kickfd);
> +	vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
> +
> +	vring_invalidate(dev, vq);
> +
> +	rte_free(vq->batch_copy_elems);
> +	vq->batch_copy_elems = NULL;
> +
> +	rte_free(vq->shadow_used_split);
> +	vq->shadow_used_split = NULL;
> +
> +	vq->enabled = false;
> +	vq->ready = false;
> +	vq->size = 0;
> +	vq->last_used_idx = 0;
> +	vq->last_avail_idx = 0;
> +}
> +
>  static void
>  vduse_device_start(struct virtio_net *dev)
>  {
> @@ -304,6 +342,23 @@ vduse_device_start(struct virtio_net *dev)
>  	}
>  }
> 
> +static void
> +vduse_device_stop(struct virtio_net *dev)
> +{
> +	unsigned int i;
> +
> +	VHOST_LOG_CONFIG(dev->ifname, INFO, "Stopping device...\n");
> +
> +	vhost_destroy_device_notify(dev);
> +
> +	dev->flags &= ~VIRTIO_DEV_READY;
> +
> +	for (i = 0; i < dev->nr_vring; i++)
> +		vduse_vring_cleanup(dev, i);
> +
> +	vhost_user_iotlb_flush_all(dev);
> +}
> +
>  static void
>  vduse_events_handler(int fd, void *arg, int *remove __rte_unused)
>  {
> @@ -311,6 +366,7 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>  	struct vduse_dev_request req;
>  	struct vduse_dev_response resp;
>  	struct vhost_virtqueue *vq;
> +	uint8_t old_status = dev->status;
>  	int ret;
> 
>  	memset(&resp, 0, sizeof(resp));
> @@ -339,6 +395,7 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>  	case VDUSE_SET_STATUS:
>  		VHOST_LOG_CONFIG(dev->ifname, INFO, "\tnew status: 0x%08x\n",
>  				req.s.status);
> +		old_status = dev->status;
>  		dev->status = req.s.status;
>  		resp.result = VDUSE_REQ_RESULT_OK;
>  		break;
> @@ -363,8 +420,12 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>  		return;
>  	}
> 
> -	if (dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK)
> -		vduse_device_start(dev);
> +	if ((old_status ^ dev->status) & VIRTIO_DEVICE_STATUS_DRIVER_OK) {
> +		if (dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK)
> +			vduse_device_start(dev);
> +		else
> +			vduse_device_stop(dev);
> +	}
> 
>  	VHOST_LOG_CONFIG(dev->ifname, INFO, "Request %s (%u) handled
> successfully\n",
>  			vduse_req_id_to_str(req.type), req.type);
> @@ -560,12 +621,7 @@ vduse_device_destroy(const char *path)
>  	if (vid == RTE_MAX_VHOST_DEVICE)
>  		return -1;
> 
> -	if (dev->cvq && dev->cvq->kickfd >= 0) {
> -		fdset_del(&vduse.fdset, dev->cvq->kickfd);
> -		fdset_pipe_notify(&vduse.fdset);
> -		close(dev->cvq->kickfd);
> -		dev->cvq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
> -	}
> +	vduse_device_stop(dev);
> 
>  	fdset_del(&vduse.fdset, dev->vduse_dev_fd);
>  	fdset_pipe_notify(&vduse.fdset);
> --
> 2.40.1

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