[dpdk-dev] [PATCH 07/17] vhost: export vhost vring info

[Maxime Coquelin]

On 03/03/2017 10:51 AM, Yuanhan Liu wrote:
> Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
> ---
>  lib/librte_vhost/rte_vhost_version.map |  1 +
>  lib/librte_vhost/rte_virtio_net.h      | 13 +++++++++++++
>  lib/librte_vhost/vhost.c               | 30 ++++++++++++++++++++++++++++++
>  lib/librte_vhost/vhost.h               |  2 ++
>  4 files changed, 46 insertions(+)
>
> diff --git a/lib/librte_vhost/rte_vhost_version.map b/lib/librte_vhost/rte_vhost_version.map
> index 85a2796..efde936 100644
> --- a/lib/librte_vhost/rte_vhost_version.map
> +++ b/lib/librte_vhost/rte_vhost_version.map
> @@ -37,5 +37,6 @@ DPDK_17.05 {
>  	rte_vhost_driver_set_features;
>  	rte_vhost_get_negotiated_features
>  	rte_vhost_get_vhost_memory;
> +	rte_vhost_get_vhost_vring;
>
>  } DPDK_16.07;
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index e7b1599..80209ad 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -80,6 +80,17 @@ struct rte_vhost_memory {
>  	struct rte_vhost_mem_region regions[0];
>  };
>
> +struct rte_vhost_vring {
> +	struct vring_desc	*desc;
> +	struct vring_avail	*avail;
> +	struct vring_used	*used;
> +	uint64_t		log_guest_addr;
> +
> +	int			callfd;
> +	int			kickfd;
> +	uint16_t		size;
> +};
> +
>  /**
>   * Device and vring operations.
>   */
> @@ -211,5 +222,7 @@ uint16_t rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>
>  int rte_vhost_get_vhost_memory(int vid, struct rte_vhost_memory **mem);
>  uint64_t rte_vhost_get_negotiated_features(int vid);
> +int rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
> +			      struct rte_vhost_vring *vring);
>
>  #endif /* _VIRTIO_NET_H_ */
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index 8046aef..b175f0e 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -375,6 +375,36 @@ struct virtio_net *
>  	return 0;
>  }
>
> +int
> +rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
> +			  struct rte_vhost_vring *vring)
> +{
> +	struct virtio_net *dev;
> +	struct vhost_virtqueue *vq;
> +
> +	dev = get_device(vid);
> +	if (!dev)
> +		return -1;
> +
> +	if (vring_idx > VHOST_MAX_VRING)
Shouldn't be ">=" ?

> +		return -1;
> +
> +	vq = dev->virtqueue[vring_idx];
> +	if (!vq)
> +		return -1;
> +
> +	vring->desc  = vq->desc;
> +	vring->avail = vq->avail;
> +	vring->used  = vq->used;
> +	vring->log_guest_addr  = vq->log_guest_addr;
> +
> +	vring->callfd  = vq->callfd;
> +	vring->kickfd  = vq->kickfd;
> +	vring->size    = vq->size;
> +
> +	return 0;
> +}
> +
>  uint16_t
>  rte_vhost_avail_entries(int vid, uint16_t queue_id)
>  {
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index ed7b2c9..b0ef0cc 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -138,6 +138,8 @@ struct vhost_virtqueue {
>  #ifndef VIRTIO_NET_F_MQ
>   #define VIRTIO_NET_F_MQ		22
>  #endif
> +
> +#define VHOST_MAX_VRING			0x100
Looking at the code, I'm not clear where this limitation comes from.
It seems that it can be up to 0x10000, no?

struct virtio_net {
...
	struct vhost_virtqueue	*virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];

with:
#ifdef VIRTIO_NET_F_MQ
  #define VHOST_MAX_QUEUE_PAIRS	VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX
  #define VHOST_SUPPORTS_MQ	(1ULL << VIRTIO_NET_F_MQ)
#else
  #define VHOST_MAX_QUEUE_PAIRS	1
  #define VHOST_SUPPORTS_MQ	0
#endif

and:
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000


Regards,
Maxime