vhost: add packed ring batch dequeue

Add batch dequeue function like enqueue function for packed ring, batch
dequeue function will not support chained descriptors, single packet
dequeue function will handle it.

Signed-off-by: Marvin Liu <yong.liu@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

lib/librte_vhost/vhost.h

@@ -39,6 +39,9 @@
 
 #define VHOST_LOG_CACHE_NR 32
 
+#define PACKED_DESC_SINGLE_DEQUEUE_FLAG (VRING_DESC_F_NEXT | \
+					 VRING_DESC_F_INDIRECT)
+
 #define PACKED_BATCH_SIZE (RTE_CACHE_LINE_SIZE / \
 			    sizeof(struct vring_packed_desc))
 #define PACKED_BATCH_MASK (PACKED_BATCH_SIZE - 1)

lib/librte_vhost/virtio_net.c

@@ -1635,6 +1635,117 @@ virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	return i;
 }
 
+static __rte_always_inline int
+vhost_reserve_avail_batch_packed(struct virtio_net *dev,
+				 struct vhost_virtqueue *vq,
+				 struct rte_mempool *mbuf_pool,
+				 struct rte_mbuf **pkts,
+				 uint16_t avail_idx,
+				 uintptr_t *desc_addrs,
+				 uint16_t *ids)
+{
+	bool wrap = vq->avail_wrap_counter;
+	struct vring_packed_desc *descs = vq->desc_packed;
+	struct virtio_net_hdr *hdr;
+	uint64_t lens[PACKED_BATCH_SIZE];
+	uint64_t buf_lens[PACKED_BATCH_SIZE];
+	uint32_t buf_offset = dev->vhost_hlen;
+	uint16_t flags, i;
+
+	if (unlikely(avail_idx & PACKED_BATCH_MASK))
+		return -1;
+	if (unlikely((avail_idx + PACKED_BATCH_SIZE) > vq->size))
+		return -1;
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		flags = descs[avail_idx + i].flags;
+		if (unlikely((wrap != !!(flags & VRING_DESC_F_AVAIL)) ||
+			     (wrap == !!(flags & VRING_DESC_F_USED))  ||
+			     (flags & PACKED_DESC_SINGLE_DEQUEUE_FLAG)))
+			return -1;
+	}
+
+	rte_smp_rmb();
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
+		lens[i] = descs[avail_idx + i].len;
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		desc_addrs[i] = vhost_iova_to_vva(dev, vq,
+						  descs[avail_idx + i].addr,
+						  &lens[i], VHOST_ACCESS_RW);
+	}
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		if (unlikely((lens[i] != descs[avail_idx + i].len)))
+			return -1;
+	}
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		pkts[i] = virtio_dev_pktmbuf_alloc(dev, mbuf_pool, lens[i]);
+		if (!pkts[i])
+			goto free_buf;
+	}
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
+		buf_lens[i] = pkts[i]->buf_len - pkts[i]->data_off;
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		if (unlikely(buf_lens[i] < (lens[i] - buf_offset)))
+			goto free_buf;
+	}
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+		pkts[i]->pkt_len = descs[avail_idx + i].len - buf_offset;
+		pkts[i]->data_len = pkts[i]->pkt_len;
+		ids[i] = descs[avail_idx + i].id;
+	}
+
+	if (virtio_net_with_host_offload(dev)) {
+		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
+			hdr = (struct virtio_net_hdr *)(desc_addrs[i]);
+			vhost_dequeue_offload(hdr, pkts[i]);
+		}
+	}
+
+	return 0;
+
+free_buf:
+	for (i = 0; i < PACKED_BATCH_SIZE; i++)
+		rte_pktmbuf_free(pkts[i]);
+
+	return -1;
+}
+
+static __rte_unused int
+virtio_dev_tx_batch_packed(struct virtio_net *dev,
+			   struct vhost_virtqueue *vq,
+			   struct rte_mempool *mbuf_pool,
+			   struct rte_mbuf **pkts)
+{
+	uint16_t avail_idx = vq->last_avail_idx;
+	uint32_t buf_offset = dev->vhost_hlen;
+	uintptr_t desc_addrs[PACKED_BATCH_SIZE];
+	uint16_t ids[PACKED_BATCH_SIZE];
+	uint16_t i;
+
+	if (vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool, pkts,
+					     avail_idx, desc_addrs, ids))
+		return -1;
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
+		rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
+
+	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
+		rte_memcpy(rte_pktmbuf_mtod_offset(pkts[i], void *, 0),
+			   (void *)(uintptr_t)(desc_addrs[i] + buf_offset),
+			   pkts[i]->pkt_len);
+
+	vq_inc_last_avail_packed(vq, PACKED_BATCH_SIZE);
+
+	return 0;
+}
+
 static __rte_always_inline int
 vhost_dequeue_single_packed(struct virtio_net *dev,
 			    struct vhost_virtqueue *vq,