Re: [dpdk-dev] [PATCH v5 03/15] vhost: vring address setup for packed queues

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

On Fri, Jun 22, 2018 at 03:43:15PM +0200, Maxime Coquelin wrote:
> From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> 
> Add code to set up packed queues when enabled.
> 
> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> Signed-off-by: Jens Freimann <jfreiman@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/librte_vhost/vhost.c      | 44 ++++++++++++++++++++++++++++++++++++++-----
>  lib/librte_vhost/vhost.h      |  7 ++++++-
>  lib/librte_vhost/vhost_user.c | 29 +++++++++++++++++++++++++++-
>  3 files changed, 73 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index afded4952..a85c6646f 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -23,6 +23,7 @@
>  #include "iotlb.h"
>  #include "vhost.h"
>  #include "vhost_user.h"
> +#include "virtio-packed.h"
>  
>  struct virtio_net *vhost_devices[MAX_VHOST_DEVICE];
>  
> @@ -115,14 +116,11 @@ free_device(struct virtio_net *dev)
>  	rte_free(dev);
>  }
>  
> -int
> -vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +static int
> +vring_translate_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
>  {
>  	uint64_t req_size, size;
>  
> -	if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
> -		goto out;
> -
>  	req_size = sizeof(struct vring_desc) * vq->size;
>  	size = req_size;
>  	vq->desc = (struct vring_desc *)(uintptr_t)vhost_iova_to_vva(dev, vq,
> @@ -153,6 +151,40 @@ vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
>  	if (!vq->used || size != req_size)
>  		return -1;
>  
> +	return 0;
> +}
> +
> +static int
> +vring_translate_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{
> +	uint64_t req_size, size;
> +
> +	req_size = sizeof(struct vring_desc_packed) * vq->size;
> +	size = req_size;
> +	vq->desc_packed =
> +		(struct vring_desc_packed *)(uintptr_t)vhost_iova_to_vva(dev,
> +					vq, vq->ring_addrs.desc_user_addr,
> +					&size, VHOST_ACCESS_RW);
> +	if (!vq->desc || size != req_size)

Should check vq->desc_packed instead of vq->desc.

> +		return -1;

Also need to get vq->driver_event and vq->device_event.
Maybe shouldn't do it in this patch. But it's missing
in the whole patch set.

> +
> +	return 0;
> +}
> +
> +int
> +vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{
> +
> +	if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
> +		goto out;
> +
> +	if (vq_is_packed(dev)) {
> +		if (vring_translate_packed(dev, vq) < 0)
> +			return -1;
> +	} else {
> +		if (vring_translate_split(dev, vq) < 0)
> +			return -1;
> +	}
>  out:
>  	vq->access_ok = 1;
>  
> @@ -234,6 +266,8 @@ alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
>  	dev->virtqueue[vring_idx] = vq;
>  	init_vring_queue(dev, vring_idx);
>  	rte_spinlock_init(&vq->access_lock);
> +	vq->avail_wrap_counter = 1;
> +	vq->used_wrap_counter = 1;
>  
>  	dev->nr_vring += 1;
>  
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 34a614c97..671b4b3bf 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -84,7 +84,10 @@ struct log_cache_entry {
>   * Structure contains variables relevant to RX/TX virtqueues.
>   */
>  struct vhost_virtqueue {
> -	struct vring_desc	*desc;
> +	union {
> +		struct vring_desc	*desc;
> +		struct vring_desc_packed   *desc_packed;
> +	};
>  	struct vring_avail	*avail;
>  	struct vring_used	*used;
>  	uint32_t		size;
> @@ -122,6 +125,8 @@ struct vhost_virtqueue {
>  
>  	struct batch_copy_elem	*batch_copy_elems;
>  	uint16_t		batch_copy_nb_elems;
> +	uint16_t		used_wrap_counter;
> +	uint16_t		avail_wrap_counter;

Not quite sure about this. Do you think it will be
better to define wrap counters as bool (as only 0 or
1 are available)?

>  
>  	struct log_cache_entry log_cache[VHOST_LOG_CACHE_NR];
>  	uint16_t log_cache_nb_elem;
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 947290fc3..b6097c085 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -39,6 +39,7 @@
>  #include "iotlb.h"
>  #include "vhost.h"
>  #include "vhost_user.h"
> +#include "virtio-packed.h"
>  
>  #define VIRTIO_MIN_MTU 68
>  #define VIRTIO_MAX_MTU 65535
> @@ -477,6 +478,30 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  	struct vhost_vring_addr *addr = &vq->ring_addrs;
>  	uint64_t len;
>  
> +	if (vq_is_packed(dev)) {
> +		len = sizeof(struct vring_desc_packed) * vq->size;
> +		vq->desc_packed = (struct vring_desc_packed *) ring_addr_to_vva
> +			(dev, vq, addr->desc_user_addr, &len);
> +		vq->desc = NULL;

`vq->desc = NULL` will set vq->desc_packed to NULL.

> +		vq->avail = NULL;
> +		vq->used = NULL;
> +		vq->log_guest_addr = 0;
> +		if (vq->desc_packed == 0 ||

It's better to compare with NULL.

> +				len != sizeof(struct vring_desc_packed) *
> +				vq->size) {
> +			RTE_LOG(DEBUG, VHOST_CONFIG,
> +				"(%d) failed to map desc_packed ring.\n",
> +				dev->vid);
> +			return dev;
> +		}
> +
> +		dev = numa_realloc(dev, vq_index);
> +		vq = dev->virtqueue[vq_index];
> +		addr = &vq->ring_addrs;
> +
> +		return dev;
> +	}
> +
>  	/* The addresses are converted from QEMU virtual to Vhost virtual. */
>  	if (vq->desc && vq->avail && vq->used)
>  		return dev;
> @@ -490,6 +515,7 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
>  			dev->vid);
>  		return dev;
>  	}
> +	vq->desc_packed = NULL;

It seems that above assignment isn't needed.

>  
>  	dev = numa_realloc(dev, vq_index);
>  	vq = dev->virtqueue[vq_index];
> @@ -888,7 +914,8 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *pmsg)
>  static int
>  vq_is_ready(struct vhost_virtqueue *vq)
>  {
> -	return vq && vq->desc && vq->avail && vq->used &&
> +	return vq &&
> +	       (vq->desc_packed || (vq->desc && vq->avail && vq->used)) &&
>  	       vq->kickfd != VIRTIO_UNINITIALIZED_EVENTFD &&
>  	       vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD;
>  }
> -- 
> 2.14.4
>