[dpdk-stable] [PATCH] vhost: fix shadowed descs not flushed

[Marvin Liu]

When ring size or enqueue packets not aligned with batch number, it is
possible that descs update still kept in shadowed used structure when
batched enqueue. Fix this issue by flushing remained shadowed used descs
before batch flush.

Fixes: f41516c309d ("vhost: flush batched enqueue descs directly")
Cc: stable at dpdk.org

Signed-off-by: Marvin Liu <yong.liu at intel.com>

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 210415904..39afb2b4d 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -43,6 +43,36 @@ is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
 	return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring;
 }
 
+static inline void
+do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq)
+{
+	struct batch_copy_elem *elem = vq->batch_copy_elems;
+	uint16_t count = vq->batch_copy_nb_elems;
+	int i;
+
+	for (i = 0; i < count; i++) {
+		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
+		vhost_log_cache_write_iova(dev, vq, elem[i].log_addr,
+					   elem[i].len);
+		PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0);
+	}
+
+	vq->batch_copy_nb_elems = 0;
+}
+
+static inline void
+do_data_copy_dequeue(struct vhost_virtqueue *vq)
+{
+	struct batch_copy_elem *elem = vq->batch_copy_elems;
+	uint16_t count = vq->batch_copy_nb_elems;
+	int i;
+
+	for (i = 0; i < count; i++)
+		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
+
+	vq->batch_copy_nb_elems = 0;
+}
+
 static __rte_always_inline void
 do_flush_shadow_used_ring_split(struct virtio_net *dev,
 			struct vhost_virtqueue *vq,
@@ -186,6 +216,11 @@ vhost_flush_enqueue_batch_packed(struct virtio_net *dev,
 	uint16_t i;
 	uint16_t flags;
 
+	if (vq->shadow_used_idx) {
+		do_data_copy_enqueue(dev, vq);
+		vhost_flush_enqueue_shadow_packed(dev, vq);
+	}
+
 	flags = PACKED_DESC_ENQUEUE_USED_FLAG(vq->used_wrap_counter);
 
 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
@@ -325,36 +360,6 @@ vhost_shadow_dequeue_single_packed_inorder(struct vhost_virtqueue *vq,
 	vq_inc_last_used_packed(vq, count);
 }
 
-static inline void
-do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq)
-{
-	struct batch_copy_elem *elem = vq->batch_copy_elems;
-	uint16_t count = vq->batch_copy_nb_elems;
-	int i;
-
-	for (i = 0; i < count; i++) {
-		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
-		vhost_log_cache_write_iova(dev, vq, elem[i].log_addr,
-					   elem[i].len);
-		PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0);
-	}
-
-	vq->batch_copy_nb_elems = 0;
-}
-
-static inline void
-do_data_copy_dequeue(struct vhost_virtqueue *vq)
-{
-	struct batch_copy_elem *elem = vq->batch_copy_elems;
-	uint16_t count = vq->batch_copy_nb_elems;
-	int i;
-
-	for (i = 0; i < count; i++)
-		rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
-
-	vq->batch_copy_nb_elems = 0;
-}
-
 static __rte_always_inline void
 vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
 				   struct vhost_virtqueue *vq,
-- 
2.17.1