RE: [PATCH v1 16/21] net/virtio-user: allocate shadow control queue

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, November 30, 2022 11:57 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>;
> david.marchand@redhat.com; eperezma@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v1 16/21] net/virtio-user: allocate shadow control queue
> 
> If the backends supports control virtqueue, allocate a
> shadow control virtqueue, and implement the notify callback
> that writes into the kickfd.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  .../net/virtio/virtio_user/virtio_user_dev.c  | 47 ++++++++++++++++++-
>  .../net/virtio/virtio_user/virtio_user_dev.h  |  5 ++
>  drivers/net/virtio/virtio_user_ethdev.c       |  6 +++
>  3 files changed, 56 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index a3584e7735..16a0e07413 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -146,8 +146,9 @@ virtio_user_dev_set_features(struct virtio_user_dev
> *dev)
> 
>  	/* Strip VIRTIO_NET_F_MAC, as MAC address is handled in vdev init */
>  	features &= ~(1ull << VIRTIO_NET_F_MAC);
> -	/* Strip VIRTIO_NET_F_CTRL_VQ, as devices do not really need to know
> */
> -	features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
> +	/* Strip VIRTIO_NET_F_CTRL_VQ if the devices does not really support
> control VQ */
> +	if (!dev->hw_cvq)
> +		features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
>  	features &= ~(1ull << VIRTIO_NET_F_STATUS);
>  	ret = dev->ops->set_features(dev, features);
>  	if (ret < 0)
> @@ -911,6 +912,48 @@ virtio_user_handle_cq(struct virtio_user_dev *dev,
> uint16_t queue_idx)
>  	}
>  }
> 
> +static void
> +virtio_user_control_queue_notify(struct virtqueue *vq, void *cookie)
> +{
> +	struct virtio_user_dev *dev = cookie;
> +	uint64_t buf = 1;
> +
> +	if (write(dev->kickfds[vq->vq_queue_index], &buf, sizeof(buf)) < 0)
> +		PMD_DRV_LOG(ERR, "failed to kick backend: %s",
> +			    strerror(errno));
> +}
> +
> +int
> +virtio_user_dev_create_shadow_cvq(struct virtio_user_dev *dev, struct
> virtqueue *vq)
> +{
> +	char name[VIRTQUEUE_MAX_NAME_SZ];
> +	struct virtqueue *scvq;
> +
> +	snprintf(name, sizeof(name), "port%d_shadow_cvq", vq->hw->port_id);
> +	scvq = virtqueue_alloc(&dev->hw, vq->vq_queue_index, vq->vq_nentries,
> +			VTNET_CQ, SOCKET_ID_ANY, name);
> +	if (!scvq) {
> +		PMD_INIT_LOG(ERR, "(%s) Failed to alloc shadow control vq\n",
> dev->path);
> +		return -ENOMEM;
> +	}
> +
> +	scvq->cq.notify_queue = &virtio_user_control_queue_notify;
> +	scvq->cq.notify_cookie = dev;
> +	dev->scvq = scvq;
> +
> +	return 0;
> +}
> +
> +void
> +virtio_user_dev_destroy_shadow_cvq(struct virtio_user_dev *dev)
> +{
> +	if (!dev->scvq)
> +		return;
> +
> +	virtqueue_free(dev->scvq);
> +	dev->scvq = NULL;
> +}
> +
>  int
>  virtio_user_dev_set_status(struct virtio_user_dev *dev, uint8_t status)
>  {
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> index 3c5453eac0..e0db4faf3f 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> @@ -58,6 +58,9 @@ struct virtio_user_dev {
>  	pthread_mutex_t	mutex;
>  	bool		started;
> 
> +	bool			hw_cvq;
> +	struct virtqueue	*scvq;
> +
>  	void *backend_data;
>  };
> 
> @@ -74,6 +77,8 @@ void virtio_user_handle_cq(struct virtio_user_dev *dev,
> uint16_t queue_idx);
>  void virtio_user_handle_cq_packed(struct virtio_user_dev *dev,
>  				  uint16_t queue_idx);
>  uint8_t virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t
> q_pairs);
> +int virtio_user_dev_create_shadow_cvq(struct virtio_user_dev *dev, struct
> virtqueue *vq);
> +void virtio_user_dev_destroy_shadow_cvq(struct virtio_user_dev *dev);
>  int virtio_user_dev_set_status(struct virtio_user_dev *dev, uint8_t
> status);
>  int virtio_user_dev_update_status(struct virtio_user_dev *dev);
>  int virtio_user_dev_update_link_state(struct virtio_user_dev *dev);
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
> b/drivers/net/virtio/virtio_user_ethdev.c
> index 6c3e875793..626bd95b62 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -232,6 +232,9 @@ virtio_user_setup_queue(struct virtio_hw *hw, struct
> virtqueue *vq)
>  	else
>  		virtio_user_setup_queue_split(vq, dev);
> 
> +	if (dev->hw_cvq && hw->cvq && (virtnet_cq_to_vq(hw->cvq) == vq))
> +		return virtio_user_dev_create_shadow_cvq(dev, vq);
> +
>  	return 0;
>  }
> 
> @@ -251,6 +254,9 @@ virtio_user_del_queue(struct virtio_hw *hw, struct
> virtqueue *vq)
> 
>  	close(dev->callfds[vq->vq_queue_index]);
>  	close(dev->kickfds[vq->vq_queue_index]);
> +
> +	if (hw->cvq && (virtnet_cq_to_vq(hw->cvq) == vq) && dev->scvq)
> +		virtio_user_dev_destroy_shadow_cvq(dev);
>  }
> 
>  static void
> --
> 2.38.1

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