Re: [dpdk-dev] [PATCH v2 2/3] vhost: call vDPA callback at the end of vring enable handler

[Tiwei Bie <tiwei.bie@intel.com>]

On Tue, Sep 17, 2019 at 05:09:47PM +0800, Andy Pei wrote:
> vDPA's set_vring_state callback would need to know the virtqueues'
> enable status to configure the hardware.
> 
> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
> Signed-off-by: Andy Pei <andy.pei@intel.com>
> ---
> v2:
>  add nr_active_vring as a parameter to ops function set_vring_state in
>  case of callback in set_vring_state() and avoid exposing new API.
> 
>  lib/librte_vhost/rte_vdpa.h   |  4 ++--
>  lib/librte_vhost/vhost_user.c | 27 +++++++++++++++++++++++++--
>  2 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/librte_vhost/rte_vdpa.h b/lib/librte_vhost/rte_vdpa.h
> index 9a3deb3..6e55d4d 100644
> --- a/lib/librte_vhost/rte_vdpa.h
> +++ b/lib/librte_vhost/rte_vdpa.h
> @@ -54,8 +54,8 @@ struct rte_vdpa_dev_ops {
>  	int (*dev_conf)(int vid);
>  	int (*dev_close)(int vid);
>  
> -	/** Enable/disable this vring */
> -	int (*set_vring_state)(int vid, int vring, int state);
> +	/** Enable/disable vring queue pairs */
> +	int (*set_vring_state)(int vid, int nr_active_vring);

We should avoid changing the API/ABI unless we have a very good
justification.

With the existing API, it should be easy to get the number of
active rings by maintaining a bitmap or something similar in
ifc driver.

Besides, please keep other maintainers got from get-maintainer.sh
in the Cc list as well.

Thanks,
Tiwei


>  
>  	/** Set features when changed */
>  	int (*set_features)(int vid);
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 0b72648..4d7de44 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1325,6 +1325,25 @@ static int vhost_user_set_vring_err(struct virtio_net **pdev __rte_unused,
>  	return RTE_VHOST_MSG_RESULT_REPLY;
>  }
>  
> +static uint16_t
> +vhost_get_active_vring_num(int vid)
> +{
> +	struct virtio_net *dev = get_device(vid);
> +	struct vhost_virtqueue *vq;
> +	uint16_t qid;
> +
> +	if (dev == NULL)
> +		return 0;
> +
> +	for (qid = 0; qid < dev->nr_vring; qid++) {
> +		vq = dev->virtqueue[qid];
> +		if (!vq->enabled)
> +			break;
> +	}
> +
> +	return qid;
> +}
> +
>  /*
>   * when virtio queues are ready to work, qemu will send us to
>   * enable the virtio queue pair.
> @@ -1339,6 +1358,7 @@ static int vhost_user_set_vring_err(struct virtio_net **pdev __rte_unused,
>  	int index = (int)msg->payload.state.index;
>  	struct rte_vdpa_device *vdpa_dev;
>  	int did = -1;
> +	int nr_active_vring;
>  
>  	RTE_LOG(INFO, VHOST_CONFIG,
>  		"set queue enable: %d to qp idx: %d\n",
> @@ -1346,8 +1366,6 @@ static int vhost_user_set_vring_err(struct virtio_net **pdev __rte_unused,
>  
>  	did = dev->vdpa_dev_id;
>  	vdpa_dev = rte_vdpa_get_device(did);
> -	if (vdpa_dev && vdpa_dev->ops->set_vring_state)
> -		vdpa_dev->ops->set_vring_state(dev->vid, index, enable);
>  
>  	if (dev->notify_ops->vring_state_changed)
>  		dev->notify_ops->vring_state_changed(dev->vid,
> @@ -1359,6 +1377,11 @@ static int vhost_user_set_vring_err(struct virtio_net **pdev __rte_unused,
>  
>  	dev->virtqueue[index]->enabled = enable;
>  
> +	if (vdpa_dev && vdpa_dev->ops->set_vring_state) {
> +		nr_active_vring = vhost_get_active_vring_num(dev->vid);
> +		vdpa_dev->ops->set_vring_state(dev->vid, nr_active_vring);
> +	}
> +
>  	return RTE_VHOST_MSG_RESULT_OK;
>  }
>  
> -- 
> 1.8.3.1
>