[dpdk-dev] [PATCH v5 2/4] vhost: add support for packed ring in async vhost

Maxime Coquelin maxime.coquelin at redhat.com
Tue Apr 13 10:36:43 CEST 2021



On 4/12/21 1:34 PM, Cheng Jiang wrote:
> For now async vhost data path only supports split ring structure. In
> order to make async vhost compatible with virtio 1.1 spec this patch
> enables packed ring in async vhost data path.
> 
> Signed-off-by: Cheng Jiang <Cheng1.jiang at intel.com>
> ---
>  lib/librte_vhost/rte_vhost_async.h |   1 +
>  lib/librte_vhost/vhost.c           |  27 +-
>  lib/librte_vhost/vhost.h           |   7 +-
>  lib/librte_vhost/virtio_net.c      | 438 +++++++++++++++++++++++++++--
>  4 files changed, 448 insertions(+), 25 deletions(-)
> 
> diff --git a/lib/librte_vhost/rte_vhost_async.h b/lib/librte_vhost/rte_vhost_async.h
> index c855ff875..6faa31f5a 100644
> --- a/lib/librte_vhost/rte_vhost_async.h
> +++ b/lib/librte_vhost/rte_vhost_async.h
> @@ -89,6 +89,7 @@ struct rte_vhost_async_channel_ops {
>  struct async_inflight_info {
>  	struct rte_mbuf *mbuf;
>  	uint16_t descs; /* num of descs inflight */
> +	uint16_t nr_buffers; /* num of buffers inflight for packed ring */
>  };
>  
>  /**
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index a70fe01d8..8c9935c0f 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -342,15 +342,21 @@ vhost_free_async_mem(struct vhost_virtqueue *vq)
>  {
>  	if (vq->async_pkts_info)
>  		rte_free(vq->async_pkts_info);
> -	if (vq->async_descs_split)
> +	if (vq->async_buffers_packed) {
> +		rte_free(vq->async_buffers_packed);
> +		vq->async_buffers_packed = NULL;
> +	}
> +	if (vq->async_descs_split) {

You can remove the check, rte_free is safe with NULL pointers.
You can do the same for the other ones in this function.

>  		rte_free(vq->async_descs_split);
> +		vq->async_descs_split = NULL;
> +	}
> +
>  	if (vq->it_pool)
>  		rte_free(vq->it_pool);
>  	if (vq->vec_pool)
>  		rte_free(vq->vec_pool);
>  
>  	vq->async_pkts_info = NULL;
> -	vq->async_descs_split = NULL;
>  	vq->it_pool = NULL;
>  	vq->vec_pool = NULL;
>  }
> @@ -1627,9 +1633,9 @@ int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
>  		return -1;
>  
>  	/* packed queue is not supported */
> -	if (unlikely(vq_is_packed(dev) || !f.async_inorder)) {
> +	if (unlikely(!f.async_inorder)) {
>  		VHOST_LOG_CONFIG(ERR,
> -			"async copy is not supported on packed queue or non-inorder mode "
> +			"async copy is not supported on non-inorder mode "
>  			"(vid %d, qid: %d)\n", vid, queue_id);
>  		return -1;
>  	}
> @@ -1667,11 +1673,18 @@ int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
>  	vq->vec_pool = rte_malloc_socket(NULL,
>  			VHOST_MAX_ASYNC_VEC * sizeof(struct iovec),
>  			RTE_CACHE_LINE_SIZE, node);
> -	vq->async_descs_split = rte_malloc_socket(NULL,
> +	if (vq_is_packed(dev)) {
> +		vq->async_buffers_packed = rte_malloc_socket(NULL,
> +			vq->size * sizeof(struct vring_used_elem_packed),
> +			RTE_CACHE_LINE_SIZE, node);
> +	} else {
> +		vq->async_descs_split = rte_malloc_socket(NULL,
>  			vq->size * sizeof(struct vring_used_elem),
>  			RTE_CACHE_LINE_SIZE, node);
> -	if (!vq->async_descs_split || !vq->async_pkts_info ||
> -		!vq->it_pool || !vq->vec_pool) {
> +	}
> +
> +	if (!vq->async_buffers_packed || !vq->async_descs_split ||
> +		!vq->async_pkts_info || !vq->it_pool || !vq->vec_pool) {
>  		vhost_free_async_mem(vq);
>  		VHOST_LOG_CONFIG(ERR,
>  				"async register failed: cannot allocate memory for vq data "
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index f628714c2..fe131ae8f 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -201,9 +201,14 @@ struct vhost_virtqueue {
>  	uint16_t	async_pkts_idx;
>  	uint16_t	async_pkts_inflight_n;
>  	uint16_t	async_last_pkts_n;
> -	struct vring_used_elem  *async_descs_split;
> +	union {
> +		struct vring_used_elem  *async_descs_split;
> +		struct vring_used_elem_packed *async_buffers_packed;
> +	};
>  	uint16_t async_desc_idx;
> +	uint16_t async_packed_buffer_idx;

Don't dupplicate variable names, async_desc_idx can be reused for packed
ring. Also, they are representing the same thing, why use desc in one
case and buffer in the other?

>  	uint16_t last_async_desc_idx;
> +	uint16_t last_async_buffer_idx;

Same remark here.

>  	/* vq async features */
>  	bool		async_inorder;
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index c43ab0093..410be9678 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -363,14 +363,14 @@ vhost_shadow_dequeue_single_packed_inorder(struct vhost_virtqueue *vq,
>  }
>  
>  static __rte_always_inline void
> -vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
> -				   struct vhost_virtqueue *vq,
> -				   uint32_t len[],
> -				   uint16_t id[],
> -				   uint16_t count[],
> +vhost_shadow_enqueue_packed(struct vhost_virtqueue *vq,
> +				   uint32_t *len,
> +				   uint16_t *id,
> +				   uint16_t *count,
>  				   uint16_t num_buffers)
>  {
>  	uint16_t i;
> +
>  	for (i = 0; i < num_buffers; i++) {
>  		/* enqueue shadow flush action aligned with batch num */
>  		if (!vq->shadow_used_idx)
> @@ -382,6 +382,17 @@ vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
>  		vq->shadow_aligned_idx += count[i];
>  		vq->shadow_used_idx++;
>  	}
> +}
> +
> +static __rte_always_inline void
> +vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
> +				   struct vhost_virtqueue *vq,
> +				   uint32_t *len,
> +				   uint16_t *id,
> +				   uint16_t *count,
> +				   uint16_t num_buffers)
> +{
> +	vhost_shadow_enqueue_packed(vq, len, id, count, num_buffers);
>  
>  	if (vq->shadow_aligned_idx >= PACKED_BATCH_SIZE) {
>  		do_data_copy_enqueue(dev, vq);
> @@ -1481,6 +1492,62 @@ shadow_ring_store(struct vhost_virtqueue *vq,  void *shadow_ring, void *d_ring,
>  	}
>  }
>  
> +static __rte_always_inline void
> +vhost_update_used_packed(struct vhost_virtqueue *vq,
> +			struct vring_used_elem_packed *shadow_ring,
> +			uint16_t count)
> +{
> +	if (count == 0)
> +		return;

Move this after the variables declaration.

> +
> +	int i;
> +	uint16_t used_idx = vq->last_used_idx;
> +	uint16_t head_idx = vq->last_used_idx;
> +	uint16_t head_flags = 0;
> +
> +	/* Split loop in two to save memory barriers */
> +	for (i = 0; i < count; i++) {
> +		vq->desc_packed[used_idx].id = shadow_ring[i].id;
> +		vq->desc_packed[used_idx].len = shadow_ring[i].len;
> +
> +		used_idx += shadow_ring[i].count;
> +		if (used_idx >= vq->size)
> +			used_idx -= vq->size;
> +	}
> +
> +	/* The ordering for storing desc flags needs to be enforced. */
> +	rte_atomic_thread_fence(__ATOMIC_RELEASE);
> +
> +	for (i = 0; i < count; i++) {
> +		uint16_t flags;
> +
> +		if (vq->shadow_used_packed[i].len)
> +			flags = VRING_DESC_F_WRITE;
> +		else
> +			flags = 0;
> +
> +		if (vq->used_wrap_counter) {
> +			flags |= VRING_DESC_F_USED;
> +			flags |= VRING_DESC_F_AVAIL;
> +		} else {
> +			flags &= ~VRING_DESC_F_USED;
> +			flags &= ~VRING_DESC_F_AVAIL;
> +		}
> +
> +		if (i > 0) {
> +			vq->desc_packed[vq->last_used_idx].flags = flags;
> +
> +		} else {
> +			head_idx = vq->last_used_idx;
> +			head_flags = flags;
> +		}
> +
> +		vq_inc_last_used_packed(vq, shadow_ring[i].count);
> +	}
> +
> +	vq->desc_packed[head_idx].flags = head_flags;
> +}
> +
>  static __rte_noinline uint32_t
>  virtio_dev_rx_async_submit_split(struct virtio_net *dev,
>  	struct vhost_virtqueue *vq, uint16_t queue_id,
> @@ -1656,6 +1723,294 @@ virtio_dev_rx_async_submit_split(struct virtio_net *dev,
>  	return pkt_idx;
>  }
>  
> +static __rte_always_inline int
> +vhost_enqueue_async_single_packed(struct virtio_net *dev,
> +			    struct vhost_virtqueue *vq,
> +			    struct rte_mbuf *pkt,
> +			    struct buf_vector *buf_vec,
> +			    uint16_t *nr_descs,
> +			    uint16_t *nr_buffers,
> +			    struct vring_packed_desc *async_descs,
> +			    struct iovec *src_iovec, struct iovec *dst_iovec,
> +			    struct rte_vhost_iov_iter *src_it,
> +			    struct rte_vhost_iov_iter *dst_it)
> +{
> +	uint16_t nr_vec = 0;
> +	uint16_t avail_idx = vq->last_avail_idx;
> +	uint16_t max_tries, tries = 0;
> +	uint16_t buf_id = 0;
> +	uint32_t len = 0;
> +	uint16_t desc_count = 0;
> +	uint32_t size = pkt->pkt_len + sizeof(struct virtio_net_hdr_mrg_rxbuf);
> +	uint32_t buffer_len[vq->size];
> +	uint16_t buffer_buf_id[vq->size];
> +	uint16_t buffer_desc_count[vq->size];
> +	*nr_buffers = 0;
> +
> +	if (rxvq_is_mergeable(dev))
> +		max_tries = vq->size - 1;
> +	else
> +		max_tries = 1;
> +
> +	while (size > 0) {
> +		/*
> +		 * if we tried all available ring items, and still
> +		 * can't get enough buf, it means something abnormal
> +		 * happened.
> +		 */
> +		if (unlikely(++tries > max_tries))
> +			return -1;
> +
> +		if (unlikely(fill_vec_buf_packed(dev, vq,
> +						avail_idx, &desc_count,
> +						buf_vec, &nr_vec,
> +						&buf_id, &len,
> +						VHOST_ACCESS_RW) < 0))
> +			return -1;
> +
> +		len = RTE_MIN(len, size);
> +		size -= len;
> +
> +		buffer_len[*nr_buffers] = len;
> +		buffer_buf_id[*nr_buffers] = buf_id;
> +		buffer_desc_count[*nr_buffers] = desc_count;
> +		*nr_buffers += 1;
> +
> +		*nr_descs += desc_count;
> +		avail_idx += desc_count;
> +		if (avail_idx >= vq->size)
> +			avail_idx -= vq->size;
> +	}
> +
> +	if (async_mbuf_to_desc(dev, vq, pkt, buf_vec, nr_vec, *nr_buffers,
> +		src_iovec, dst_iovec, src_it, dst_it) < 0)
> +		return -1;
> +	/* store descriptors for DMA */
> +	if (avail_idx >= *nr_descs)
> +		rte_memcpy(async_descs,
> +			&vq->desc_packed[vq->last_avail_idx],
> +			*nr_descs * sizeof(struct vring_packed_desc));

Please add brackets for the 'if' since there are for the 'else'.

> +	else {
> +		uint16_t nr_copy = vq->size - vq->last_avail_idx;
> +		rte_memcpy(async_descs,
> +			&vq->desc_packed[vq->last_avail_idx],
> +			nr_copy * sizeof(struct vring_packed_desc));
> +		rte_memcpy(async_descs + nr_copy,
> +			vq->desc_packed, (*nr_descs - nr_copy) *
> +			sizeof(struct vring_packed_desc));
> +	}
> +
> +	vhost_shadow_enqueue_packed(vq, buffer_len, buffer_buf_id,
> +					   buffer_desc_count, *nr_buffers);
> +
> +	return 0;
> +}
> +
> +static __rte_always_inline int16_t
> +virtio_dev_rx_async_single_packed(struct virtio_net *dev,
> +			    struct vhost_virtqueue *vq,
> +			    struct rte_mbuf *pkt,
> +			    uint16_t *nr_descs, uint16_t *nr_buffers,
> +			    struct vring_packed_desc *async_descs,
> +			    struct iovec *src_iovec, struct iovec *dst_iovec,
> +			    struct rte_vhost_iov_iter *src_it,
> +			    struct rte_vhost_iov_iter *dst_it)
> +{
> +	struct buf_vector buf_vec[BUF_VECTOR_MAX];
> +	*nr_descs = 0;
> +	*nr_buffers = 0;
> +
> +	if (unlikely(vhost_enqueue_async_single_packed(dev, vq, pkt, buf_vec,
> +						 nr_descs,
> +						 nr_buffers,
> +						 async_descs,
> +						 src_iovec, dst_iovec,
> +						 src_it, dst_it) < 0)) {
> +		VHOST_LOG_DATA(DEBUG,
> +				"(%d) failed to get enough desc from vring\n",
> +				dev->vid);
> +		return -1;
> +	}
> +
> +	VHOST_LOG_DATA(DEBUG, "(%d) current index %d | end index %d\n",
> +			dev->vid, vq->last_avail_idx,
> +			vq->last_avail_idx + *nr_descs);
> +
> +	return 0;
> +}
> +
> +static __rte_noinline uint32_t
> +virtio_dev_rx_async_submit_packed(struct virtio_net *dev,
> +	struct vhost_virtqueue *vq, uint16_t queue_id,
> +	struct rte_mbuf **pkts, uint32_t count,
> +	struct rte_mbuf **comp_pkts, uint32_t *comp_count)
> +{
> +	uint32_t pkt_idx = 0, pkt_burst_idx = 0;
> +	uint16_t async_descs_idx = 0;
> +	uint16_t num_buffers;
> +	uint16_t num_desc;
> +
> +	struct rte_vhost_iov_iter *it_pool = vq->it_pool;
> +	struct iovec *vec_pool = vq->vec_pool;
> +	struct rte_vhost_async_desc tdes[MAX_PKT_BURST];
> +	struct iovec *src_iovec = vec_pool;
> +	struct iovec *dst_iovec = vec_pool + (VHOST_MAX_ASYNC_VEC >> 1);
> +	struct rte_vhost_iov_iter *src_it = it_pool;
> +	struct rte_vhost_iov_iter *dst_it = it_pool + 1;
> +	uint16_t slot_idx = 0;
> +	uint16_t segs_await = 0;
> +	uint16_t iovec_idx = 0, it_idx = 0;
> +	struct async_inflight_info *pkts_info = vq->async_pkts_info;
> +	uint32_t n_pkts = 0, pkt_err = 0;
> +	uint32_t num_async_pkts = 0, num_done_pkts = 0;
> +	struct vring_packed_desc async_descs[vq->size];
> +
> +	rte_prefetch0(&vq->desc_packed[vq->last_avail_idx & (vq->size - 1)]);

The size of the ring is not necessarily a power of two with packed ring.

> +
> +	for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
> +		if (unlikely(virtio_dev_rx_async_single_packed(dev, vq,
> +						pkts[pkt_idx],
> +						&num_desc, &num_buffers,
> +						&async_descs[async_descs_idx],
> +						&src_iovec[iovec_idx],
> +						&dst_iovec[iovec_idx],
> +						&src_it[it_idx],
> +						&dst_it[it_idx]) < 0))
> +			break;
> +
> +		VHOST_LOG_DATA(DEBUG, "(%d) current index %d | end index %d\n",
> +			dev->vid, vq->last_avail_idx,
> +			vq->last_avail_idx + num_desc);
> +
> +		slot_idx = (vq->async_pkts_idx + num_async_pkts) &
> +			(vq->size - 1);

Same here.

> +		if (src_it[it_idx].count) {
> +			uint16_t from, to;
> +
> +			async_descs_idx += num_desc;
> +			async_fill_desc(&tdes[pkt_burst_idx++], &src_it[it_idx],
> +					&dst_it[it_idx]);
> +			pkts_info[slot_idx].descs = num_desc;
> +			pkts_info[slot_idx].nr_buffers = num_buffers;
> +			pkts_info[slot_idx].mbuf = pkts[pkt_idx];
> +			num_async_pkts++;
> +			iovec_idx += src_it[it_idx].nr_segs;
> +			it_idx += 2;
> +
> +			segs_await += src_it[it_idx].nr_segs;
> +
> +			/**
> +			 * recover shadow used ring and keep DMA-occupied
> +			 * descriptors.
> +			 */
> +			from = vq->shadow_used_idx - num_buffers;
> +			to = vq->async_packed_buffer_idx & (vq->size - 1);
> +			shadow_ring_store(vq, vq->shadow_used_packed,
> +					vq->async_buffers_packed,
> +					from, to, num_buffers,
> +					sizeof(struct vring_used_elem_packed));
> +
> +			vq->async_packed_buffer_idx += num_buffers;
> +			vq->shadow_used_idx -= num_buffers;
> +		} else

Brackets needed.

> +			comp_pkts[num_done_pkts++] = pkts[pkt_idx];
> +
> +		vq_inc_last_avail_packed(vq, num_desc);
> +
> +		/*
> +		 * conditions to trigger async device transfer:
> +		 * - buffered packet number reaches transfer threshold
> +		 * - unused async iov number is less than max vhost vector
> +		 */
> +		if (unlikely(pkt_burst_idx >= VHOST_ASYNC_BATCH_THRESHOLD ||
> +			((VHOST_MAX_ASYNC_VEC >> 1) - segs_await <
> +			BUF_VECTOR_MAX))) {
> +			n_pkts = vq->async_ops.transfer_data(dev->vid,
> +					queue_id, tdes, 0, pkt_burst_idx);
> +			iovec_idx = 0;
> +			it_idx = 0;
> +			segs_await = 0;
> +			vq->async_pkts_inflight_n += n_pkts;
> +
> +			if (unlikely(n_pkts < pkt_burst_idx)) {
> +				/*
> +				 * log error packets number here and do actual
> +				 * error processing when applications poll
> +				 * completion
> +				 */
> +				pkt_err = pkt_burst_idx - n_pkts;
> +				pkt_burst_idx = 0;
> +				pkt_idx++;
> +				break;
> +			}
> +
> +			pkt_burst_idx = 0;
> +		}
> +	}
> +
> +	if (pkt_burst_idx) {
> +		n_pkts = vq->async_ops.transfer_data(dev->vid,
> +				queue_id, tdes, 0, pkt_burst_idx);
> +		vq->async_pkts_inflight_n += n_pkts;
> +
> +		if (unlikely(n_pkts < pkt_burst_idx))
> +			pkt_err = pkt_burst_idx - n_pkts;
> +	}
> +
> +	do_data_copy_enqueue(dev, vq);
> +
> +	if (unlikely(pkt_err)) {
> +		uint16_t descs_err = 0;
> +		uint16_t buffers_err = 0;
> +
> +		num_async_pkts -= pkt_err;
> +		pkt_idx -= pkt_err;
> +	/* calculate the sum of buffers and descs of DMA-error packets. */
> +		while (pkt_err-- > 0) {
> +			descs_err +=
> +				pkts_info[slot_idx & (vq->size - 1)].descs;

The size of the ring is not necessarily a power of two with packed ring.

> +			buffers_err +=
> +				pkts_info[slot_idx & (vq->size - 1)].nr_buffers;

Ditto.

> +			slot_idx--;
> +		}
> +
> +		vq->async_packed_buffer_idx -= buffers_err;
> +
> +		if (vq->last_avail_idx >= descs_err) {
> +			vq->last_avail_idx -= descs_err;
> +
> +			rte_memcpy(&vq->desc_packed[vq->last_avail_idx],
> +				&async_descs[async_descs_idx - descs_err],
> +				descs_err * sizeof(struct vring_packed_desc));
> +		} else {
> +			uint16_t nr_copy;
> +
> +			vq->last_avail_idx = vq->last_avail_idx + vq->size
> +						- descs_err;
> +			nr_copy = vq->size - vq->last_avail_idx;
> +			rte_memcpy(&vq->desc_packed[vq->last_avail_idx],
> +				&async_descs[async_descs_idx - descs_err],
> +				nr_copy * sizeof(struct vring_packed_desc));
> +			descs_err -= nr_copy;
> +			rte_memcpy(vq->desc_packed,
> +				&async_descs[async_descs_idx - descs_err],
> +				descs_err * sizeof(struct vring_packed_desc));
> +			vq->avail_wrap_counter ^= 1;
> +		}
> +
> +		num_done_pkts = pkt_idx - num_async_pkts;
> +	}

This error handling could be moved in a dedicated function.

> +	vq->async_pkts_idx += num_async_pkts;
> +	*comp_count = num_done_pkts;
> +
> +	if (likely(vq->shadow_used_idx)) {
> +		vhost_flush_enqueue_shadow_packed(dev, vq);
> +		vhost_vring_call_packed(dev, vq);
> +	}
> +
> +	return pkt_idx;
> +}

Above function is very big and complex, it should be possible to split
it in several ones to make it maintainable.

> +
>  static __rte_always_inline void
>  write_back_completed_descs_split(struct vhost_virtqueue *vq, uint16_t n_descs)
>  {
> @@ -1693,12 +2048,40 @@ write_back_completed_descs_split(struct vhost_virtqueue *vq, uint16_t n_descs)
>  	} while (nr_left > 0);
>  }
>  
> +static __rte_always_inline void
> +write_back_completed_descs_packed(struct vhost_virtqueue *vq,
> +				uint16_t n_buffers)
> +{
> +	uint16_t nr_left = n_buffers;
> +	uint16_t from, to;
> +
> +	do {
> +		from = vq->last_async_buffer_idx &
> +						(vq->size - 1);
> +		to = (from + nr_left) & (vq->size - 1);

The size of the ring is not necessarily a power of two with packed ring.

> +		if (to > from) {
> +			vhost_update_used_packed(vq,
> +				vq->async_buffers_packed + from,
> +				to - from);
> +			vq->last_async_buffer_idx += nr_left;
> +			nr_left = 0;
> +		} else {
> +			vhost_update_used_packed(vq,
> +				vq->async_buffers_packed + from,
> +				vq->size - from);
> +			vq->last_async_buffer_idx +=
> +						vq->size - from;
> +			nr_left -= vq->size - from;
> +		}
> +	} while (nr_left > 0);
> +}
> +
>  uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
>  		struct rte_mbuf **pkts, uint16_t count)
>  {
>  	struct virtio_net *dev = get_device(vid);
>  	struct vhost_virtqueue *vq;
> -	uint16_t n_pkts_cpl = 0, n_pkts_put = 0, n_descs = 0;
> +	uint16_t n_pkts_cpl = 0, n_pkts_put = 0, n_descs = 0, n_buffers = 0;
>  	uint16_t start_idx, pkts_idx, vq_size;
>  	struct async_inflight_info *pkts_info;
>  	uint16_t from, i;
> @@ -1740,21 +2123,41 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
>  		goto done;
>  	}
>  
> -	for (i = 0; i < n_pkts_put; i++) {
> -		from = (start_idx + i) & (vq_size - 1);
> -		n_descs += pkts_info[from].descs;
> -		pkts[i] = pkts_info[from].mbuf;
> +	if (vq_is_packed(dev)) {
> +		for (i = 0; i < n_pkts_put; i++) {
> +			from = (start_idx + i) & (vq_size - 1);

Unlike split ring, packed ring size is not necessarily a power of 2.

> +			n_buffers += pkts_info[from].nr_buffers;
> +			pkts[i] = pkts_info[from].mbuf;
> +		}
> +	} else {
> +		for (i = 0; i < n_pkts_put; i++) {
> +			from = (start_idx + i) & (vq_size - 1);
> +			n_descs += pkts_info[from].descs;
> +			pkts[i] = pkts_info[from].mbuf;
> +		}
>  	}
> +
>  	vq->async_last_pkts_n = n_pkts_cpl - n_pkts_put;
>  	vq->async_pkts_inflight_n -= n_pkts_put;
>  
>  	if (likely(vq->enabled && vq->access_ok)) {
> -		write_back_completed_descs_split(vq, n_descs);
> +		if (vq_is_packed(dev)) {
> +			write_back_completed_descs_packed(vq, n_buffers);
>  
> -		__atomic_add_fetch(&vq->used->idx, n_descs, __ATOMIC_RELEASE);
> -		vhost_vring_call_split(dev, vq);
> -	} else
> -		vq->last_async_desc_idx += n_descs;
> +			vhost_vring_call_packed(dev, vq);
> +		} else {
> +			write_back_completed_descs_split(vq, n_descs);
> +
> +			__atomic_add_fetch(&vq->used->idx, n_descs,
> +					__ATOMIC_RELEASE);
> +			vhost_vring_call_split(dev, vq);
> +		}
> +	} else {
> +		if (vq_is_packed(dev))
> +			vq->last_async_buffer_idx += n_buffers;
> +		else
> +			vq->last_async_desc_idx += n_descs;
> +	}
>  
>  done:
>  	rte_spinlock_unlock(&vq->access_lock);
> @@ -1795,9 +2198,10 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, uint16_t queue_id,
>  	if (count == 0)
>  		goto out;
>  
> -	/* TODO: packed queue not implemented */
>  	if (vq_is_packed(dev))
> -		nb_tx = 0;
> +		nb_tx = virtio_dev_rx_async_submit_packed(dev,
> +				vq, queue_id, pkts, count, comp_pkts,
> +				comp_count);
>  	else
>  		nb_tx = virtio_dev_rx_async_submit_split(dev,
>  				vq, queue_id, pkts, count, comp_pkts,
> 



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