[dpdk-dev] [PATCH v5 07/11] net/virtio: implement transmit path for packed queues

[Jens Freimann]

This implements the transmit path for devices with
support for packed virtqueues.

Add the feature bit and enable code to
add buffers to vring and mark descriptors as available.

Signed-off-by: Jens Freiman <jfreimann at redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c |   8 +-
 drivers/net/virtio/virtio_ethdev.h |   2 +
 drivers/net/virtio/virtio_rxtx.c   | 113 ++++++++++++++++++++++++++++-
 3 files changed, 121 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index ad91f7f82..d2c5755bb 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -384,6 +384,8 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t vtpci_queue_idx)
 	vq->hw = hw;
 	vq->vq_queue_index = vtpci_queue_idx;
 	vq->vq_nentries = vq_size;
+	if (vtpci_packed_queue(hw))
+		vq->vq_ring.avail_wrap_counter = 1;
 
 	/*
 	 * Reserve a memzone for vring elements
@@ -1338,7 +1340,11 @@ set_rxtx_funcs(struct rte_eth_dev *eth_dev)
 		eth_dev->rx_pkt_burst = &virtio_recv_pkts;
 	}
 
-	if (hw->use_inorder_tx) {
+	if (vtpci_packed_queue(hw)) {
+		PMD_INIT_LOG(INFO, "virtio: using virtio 1.1 Tx path on port %u",
+			eth_dev->data->port_id);
+		eth_dev->tx_pkt_burst = virtio_xmit_pkts_packed;
+	} else if (hw->use_inorder_tx) {
 		PMD_INIT_LOG(INFO, "virtio: using inorder Tx path on port %u",
 			eth_dev->data->port_id);
 		eth_dev->tx_pkt_burst = virtio_xmit_pkts_inorder;
diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index b726ad108..04161b461 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -79,6 +79,8 @@ uint16_t virtio_recv_mergeable_pkts_inorder(void *rx_queue,
 
 uint16_t virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 		uint16_t nb_pkts);
+uint16_t virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts,
+		uint16_t nb_pkts);
 
 uint16_t virtio_xmit_pkts_inorder(void *tx_queue, struct rte_mbuf **tx_pkts,
 		uint16_t nb_pkts);
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index eb891433e..12787070e 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -38,6 +38,112 @@
 #define  VIRTIO_DUMP_PACKET(m, len) do { } while (0)
 #endif
 
+
+/* Cleanup from completed transmits. */
+static void
+virtio_xmit_cleanup_packed(struct virtqueue *vq)
+{
+	uint16_t idx;
+	uint16_t size = vq->vq_nentries;
+	struct vring_desc_packed *desc = vq->vq_ring.desc_packed;
+	struct vq_desc_extra *dxp;
+
+	idx = vq->vq_used_cons_idx;
+	while (desc_is_used(&desc[idx], &vq->vq_ring) &&
+	       vq->vq_free_cnt < size) {
+		dxp = &vq->vq_descx[idx];
+		vq->vq_free_cnt += dxp->ndescs;
+		idx = dxp->ndescs;
+		idx = idx >= size ? idx - size : idx;
+	}
+}
+
+uint16_t
+virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts,
+		     uint16_t nb_pkts)
+{
+	struct virtnet_tx *txvq = tx_queue;
+	struct virtqueue *vq = txvq->vq;
+	uint16_t i;
+	struct vring_desc_packed *desc = vq->vq_ring.desc_packed;
+	uint16_t idx, prev;
+	struct vq_desc_extra *dxp;
+
+	if (unlikely(nb_pkts < 1))
+		return nb_pkts;
+
+	PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
+
+	if (likely(vq->vq_free_cnt < vq->vq_free_thresh))
+		virtio_xmit_cleanup_packed(vq);
+
+	for (i = 0; i < nb_pkts; i++) {
+		struct rte_mbuf *txm = tx_pkts[i];
+		struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
+		uint16_t head_idx;
+		int wrap_counter;
+		int descs_used;
+
+		if (unlikely(txm->nb_segs + 1 > vq->vq_free_cnt)) {
+			virtio_xmit_cleanup_packed(vq);
+
+			if (unlikely(txm->nb_segs + 1 > vq->vq_free_cnt)) {
+				PMD_TX_LOG(ERR,
+					   "No free tx descriptors to transmit");
+				break;
+			}
+		}
+
+		txvq->stats.bytes += txm->pkt_len;
+
+		vq->vq_free_cnt -= txm->nb_segs + 1;
+
+		wrap_counter = vq->vq_ring.avail_wrap_counter;
+		idx = vq->vq_avail_idx; 
+		head_idx = idx;
+
+		dxp = &vq->vq_descx[idx];
+		if (dxp->cookie != NULL)
+			rte_pktmbuf_free(dxp->cookie);
+		dxp->cookie = txm;
+
+		desc[idx].addr  = txvq->virtio_net_hdr_mem +
+				  RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
+		desc[idx].len   = vq->hw->vtnet_hdr_size;
+		desc[idx].flags = VRING_DESC_F_NEXT |
+			VRING_DESC_F_AVAIL(vq->vq_ring.avail_wrap_counter) |
+			VRING_DESC_F_USED(!vq->vq_ring.avail_wrap_counter);
+		descs_used = 1;
+
+		do {
+			idx = update_pq_avail_index(vq);
+			desc[idx].addr  = VIRTIO_MBUF_DATA_DMA_ADDR(txm, vq);
+			desc[idx].len   = txm->data_len;
+			desc[idx].flags = VRING_DESC_F_NEXT |
+				VRING_DESC_F_AVAIL(vq->vq_ring.avail_wrap_counter) |
+				VRING_DESC_F_USED(!vq->vq_ring.avail_wrap_counter);
+			descs_used++;
+		} while ((txm = txm->next) != NULL);
+
+		desc[idx].flags &= ~VRING_DESC_F_NEXT;
+
+		rte_smp_wmb();
+		prev = (idx > 0 ? idx : vq->vq_nentries) - 1;
+		desc[prev].index = head_idx; //FIXME
+		desc[head_idx].flags =
+			(VRING_DESC_F_AVAIL(wrap_counter) |
+			 VRING_DESC_F_USED(!wrap_counter));
+
+		vq->vq_descx[head_idx].ndescs = descs_used;
+		idx = update_pq_avail_index(vq);
+	}
+
+	txvq->stats.packets += i;
+	txvq->stats.errors  += nb_pkts - i;
+
+	return i;
+}
+
 int
 virtio_dev_rx_queue_done(void *rxq, uint16_t offset)
 {
@@ -736,7 +842,12 @@ virtio_dev_tx_queue_setup_finish(struct rte_eth_dev *dev,
 	if (hw->use_inorder_tx)
 		vq->vq_ring.desc[vq->vq_nentries - 1].next = 0;
 
-	VIRTQUEUE_DUMP(vq);
+	if (vtpci_packed_queue(hw)) {
+		vq->vq_ring.avail_wrap_counter = 1;
+	}
+
+	if (!vtpci_packed_queue(hw))
+		VIRTQUEUE_DUMP(vq);
 
 	return 0;
 }
-- 
2.17.1