[dpdk-dev] [PATCH v2 3/6] vhost: log used vring changes

[Yuanhan Liu]

Introducing a vhost_log_write() wrapper, vhost_log_used_vring, to
log used vring changes.

Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Signed-off-by: Victor Kaplansky <victork at redhat.com
---
 lib/librte_vhost/rte_virtio_net.h |  3 +-
 lib/librte_vhost/vhost_rxtx.c     | 80 +++++++++++++++++++++++++++------------
 lib/librte_vhost/virtio-net.c     |  4 ++
 3 files changed, 62 insertions(+), 25 deletions(-)

diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index 5726683..0f83719 100644
--- a/lib/librte_vhost/rte_virtio_net.h
+++ b/lib/librte_vhost/rte_virtio_net.h
@@ -93,7 +93,8 @@ struct vhost_virtqueue {
 	int			callfd;			/**< Used to notify the guest (trigger interrupt). */
 	int			kickfd;			/**< Currently unused as polling mode is enabled. */
 	int			enabled;
-	uint64_t		reserved[16];		/**< Reserve some spaces for future extension. */
+	uint64_t		log_guest_addr;		/**< Physical address of used ring, for logging */
+	uint64_t		reserved[15];		/**< Reserve some spaces for future extension. */
 	struct buf_vector	buf_vec[BUF_VECTOR_MAX];	/**< for scatter RX. */
 } __rte_cache_aligned;
 
diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
index bbf3fac..f305acd 100644
--- a/lib/librte_vhost/vhost_rxtx.c
+++ b/lib/librte_vhost/vhost_rxtx.c
@@ -49,6 +49,16 @@ is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
 	return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
 }
 
+static inline void __attribute__((always_inline))
+vhost_log_used_vring(struct virtio_net *dev, struct vhost_virtqueue *vq,
+		     uint64_t offset, uint64_t len)
+{
+	uint64_t addr;
+
+	addr = vq->log_guest_addr + offset;
+	vhost_log_write(dev, addr, len);
+}
+
 /**
  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
  * be received from the physical port or from another virtio device. A packet
@@ -129,6 +139,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 		uint32_t offset = 0, vb_offset = 0;
 		uint32_t pkt_len, len_to_cpy, data_len, total_copied = 0;
 		uint8_t hdr = 0, uncompleted_pkt = 0;
+		uint16_t idx;
 
 		/* Get descriptor from available ring */
 		desc = &vq->desc[head[packet_success]];
@@ -200,16 +211,18 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 		}
 
 		/* Update used ring with desc information */
-		vq->used->ring[res_cur_idx & (vq->size - 1)].id =
-							head[packet_success];
+		idx = res_cur_idx & (vq->size - 1);
+		vq->used->ring[idx].id = head[packet_success];
 
 		/* Drop the packet if it is uncompleted */
 		if (unlikely(uncompleted_pkt == 1))
-			vq->used->ring[res_cur_idx & (vq->size - 1)].len =
-							vq->vhost_hlen;
+			vq->used->ring[idx].len = vq->vhost_hlen;
 		else
-			vq->used->ring[res_cur_idx & (vq->size - 1)].len =
-							pkt_len + vq->vhost_hlen;
+			vq->used->ring[idx].len = pkt_len + vq->vhost_hlen;
+
+		vhost_log_used_vring(dev, vq,
+			offsetof(struct vring_used, ring[idx]),
+			sizeof(vq->used->ring[idx]));
 
 		res_cur_idx++;
 		packet_success++;
@@ -236,6 +249,9 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 
 	*(volatile uint16_t *)&vq->used->idx += count;
 	vq->last_used_idx = res_end_idx;
+	vhost_log_used_vring(dev, vq,
+		offsetof(struct vring_used, idx),
+		sizeof(vq->used->idx));
 
 	/* flush used->idx update before we read avail->flags. */
 	rte_mb();
@@ -265,6 +281,7 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
 	uint32_t seg_avail;
 	uint32_t vb_avail;
 	uint32_t cpy_len, entry_len;
+	uint16_t idx;
 
 	if (pkt == NULL)
 		return 0;
@@ -302,16 +319,18 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
 	entry_len = vq->vhost_hlen;
 
 	if (vb_avail == 0) {
-		uint32_t desc_idx =
-			vq->buf_vec[vec_idx].desc_idx;
+		uint32_t desc_idx = vq->buf_vec[vec_idx].desc_idx;
+
+		if ((vq->desc[desc_idx].flags & VRING_DESC_F_NEXT) == 0) {
+			idx = cur_idx & (vq->size - 1);
 
-		if ((vq->desc[desc_idx].flags
-			& VRING_DESC_F_NEXT) == 0) {
 			/* Update used ring with desc information */
-			vq->used->ring[cur_idx & (vq->size - 1)].id
-				= vq->buf_vec[vec_idx].desc_idx;
-			vq->used->ring[cur_idx & (vq->size - 1)].len
-				= entry_len;
+			vq->used->ring[idx].id = vq->buf_vec[vec_idx].desc_idx;
+			vq->used->ring[idx].len = entry_len;
+
+			vhost_log_used_vring(dev, vq,
+					offsetof(struct vring_used, ring[idx]),
+					sizeof(vq->used->ring[idx]));
 
 			entry_len = 0;
 			cur_idx++;
@@ -354,10 +373,13 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
 			if ((vq->desc[vq->buf_vec[vec_idx].desc_idx].flags &
 				VRING_DESC_F_NEXT) == 0) {
 				/* Update used ring with desc information */
-				vq->used->ring[cur_idx & (vq->size - 1)].id
+				idx = cur_idx & (vq->size - 1);
+				vq->used->ring[idx].id
 					= vq->buf_vec[vec_idx].desc_idx;
-				vq->used->ring[cur_idx & (vq->size - 1)].len
-					= entry_len;
+				vq->used->ring[idx].len = entry_len;
+				vhost_log_used_vring(dev, vq,
+					offsetof(struct vring_used, ring[idx]),
+					sizeof(vq->used->ring[idx]));
 				entry_len = 0;
 				cur_idx++;
 				entry_success++;
@@ -390,16 +412,18 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
 
 					if ((vq->desc[desc_idx].flags &
 						VRING_DESC_F_NEXT) == 0) {
-						uint16_t wrapped_idx =
-							cur_idx & (vq->size - 1);
+						idx = cur_idx & (vq->size - 1);
 						/*
 						 * Update used ring with the
 						 * descriptor information
 						 */
-						vq->used->ring[wrapped_idx].id
+						vq->used->ring[idx].id
 							= desc_idx;
-						vq->used->ring[wrapped_idx].len
+						vq->used->ring[idx].len
 							= entry_len;
+						vhost_log_used_vring(dev, vq,
+							offsetof(struct vring_used, ring[idx]),
+							sizeof(vq->used->ring[idx]));
 						entry_success++;
 						entry_len = 0;
 						cur_idx++;
@@ -422,10 +446,13 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
 				 * This whole packet completes.
 				 */
 				/* Update used ring with desc information */
-				vq->used->ring[cur_idx & (vq->size - 1)].id
+				idx = cur_idx & (vq->size - 1);
+				vq->used->ring[idx].id
 					= vq->buf_vec[vec_idx].desc_idx;
-				vq->used->ring[cur_idx & (vq->size - 1)].len
-					= entry_len;
+				vq->used->ring[idx].len = entry_len;
+				vhost_log_used_vring(dev, vq,
+					offsetof(struct vring_used, ring[idx]),
+					sizeof(vq->used->ring[idx]));
 				entry_success++;
 				break;
 			}
@@ -653,6 +680,9 @@ rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
 		/* Update used index buffer information. */
 		vq->used->ring[used_idx].id = head[entry_success];
 		vq->used->ring[used_idx].len = 0;
+		vhost_log_used_vring(dev, vq,
+				offsetof(struct vring_used, ring[used_idx]),
+				sizeof(vq->used->ring[used_idx]));
 
 		/* Allocate an mbuf and populate the structure. */
 		m = rte_pktmbuf_alloc(mbuf_pool);
@@ -773,6 +803,8 @@ rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
 
 	rte_compiler_barrier();
 	vq->used->idx += entry_success;
+	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
+			sizeof(vq->used->idx));
 	/* Kick guest if required. */
 	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
 		eventfd_write(vq->callfd, (eventfd_t)1);
diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
index de78a0f..03044f6 100644
--- a/lib/librte_vhost/virtio-net.c
+++ b/lib/librte_vhost/virtio-net.c
@@ -666,12 +666,16 @@ set_vring_addr(struct vhost_device_ctx ctx, struct vhost_vring_addr *addr)
 		return -1;
 	}
 
+	vq->log_guest_addr = addr->log_guest_addr;
+
 	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address desc: %p\n",
 			dev->device_fh, vq->desc);
 	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address avail: %p\n",
 			dev->device_fh, vq->avail);
 	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address used: %p\n",
 			dev->device_fh, vq->used);
+	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") log_guest_addr: %"PRIx64"\n",
+			dev->device_fh, vq->log_guest_addr);
 
 	return 0;
 }
-- 
1.9.0