+ *desc_count = 0;
+ *len = 0;
+
+ while (1) {
+ if (unlikely(vec_id >= BUF_VECTOR_MAX))
+ return -1;
+
+ if (unlikely(*desc_count >= vq->size))
+ return -1;
+
+ *desc_count += 1;
+ *buf_id = descs[avail_idx].id;
+
+ if (descs[avail_idx].flags & VRING_DESC_F_INDIRECT) {
+ if (unlikely(fill_vec_buf_packed_indirect(dev, vq,
+ &descs[avail_idx],
+ &vec_id, buf_vec,
+ len, perm) < 0))
+ return -1;
+ } else {
+ *len += descs[avail_idx].len;
+
+ if (unlikely(map_one_desc(dev, vq, buf_vec, &vec_id,
+ descs[avail_idx].addr,
+ descs[avail_idx].len,
+ perm)))
+ return -1;
+ }
+
+ if ((descs[avail_idx].flags & VRING_DESC_F_NEXT) == 0)
+ break;
+
+ if (++avail_idx >= vq->size) {
+ avail_idx -= vq->size;
+ wrap_counter ^= 1;
+ }
+ }
+
+ *vec_idx = vec_id;
+
+ return 0;
+}
+
+/*
+ * Returns -1 on fail, 0 on success
+ */
+static inline int
+reserve_avail_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
+ uint32_t size, struct buf_vector *buf_vec,
+ uint16_t *nr_vec, uint16_t *num_buffers,
+ uint16_t *nr_descs)
+{
+ uint16_t avail_idx;
+ uint16_t vec_idx = 0;
+ uint16_t max_tries, tries = 0;
+
+ uint16_t buf_id = 0;
+ uint32_t len = 0;
+ uint16_t desc_count;
+
+ *num_buffers = 0;
+ avail_idx = vq->last_avail_idx;
+
+ 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, &vec_idx,
+ &buf_id, &len,
+ VHOST_ACCESS_RW) < 0))
+ return -1;
+
+ len = RTE_MIN(len, size);
+ update_shadow_used_ring_packed(vq, buf_id, len, desc_count);
+ size -= len;
+
+ avail_idx += desc_count;
+ if (avail_idx >= vq->size)
+ avail_idx -= vq->size;
+
+ *nr_descs += desc_count;
+ *num_buffers += 1;
+ }
+
+ *nr_vec = vec_idx;
+
+ return 0;
+}
+
+static __rte_always_inline int
+copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
+ struct rte_mbuf *m, struct buf_vector *buf_vec,
+ uint16_t nr_vec, uint16_t num_buffers)
+{
+ uint32_t vec_idx = 0;
+ uint32_t mbuf_offset, mbuf_avail;
+ uint32_t buf_offset, buf_avail;
+ uint64_t buf_addr, buf_iova, buf_len;
+ uint32_t cpy_len;
+ uint64_t hdr_addr;
+ struct rte_mbuf *hdr_mbuf;
+ struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
+ struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
+ int error = 0;
+
+ if (unlikely(m == NULL)) {
+ error = -1;
+ goto out;
+ }
+
+ buf_addr = buf_vec[vec_idx].buf_addr;
+ buf_iova = buf_vec[vec_idx].buf_iova;
+ buf_len = buf_vec[vec_idx].buf_len;
+
+ if (nr_vec > 1)
+ rte_prefetch0((void *)(uintptr_t)buf_vec[1].buf_addr);
+
+ if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
+ error = -1;
+ goto out;
+ }
+
+ hdr_mbuf = m;
+ hdr_addr = buf_addr;
+ if (unlikely(buf_len < dev->vhost_hlen))
+ hdr = &tmp_hdr;
+ else
+ hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
+
+ VHOST_LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
+ dev->vid, num_buffers);
+
+ if (unlikely(buf_len < dev->vhost_hlen)) {
+ buf_offset = dev->vhost_hlen - buf_len;
+ vec_idx++;
+ buf_addr = buf_vec[vec_idx].buf_addr;
+ buf_iova = buf_vec[vec_idx].buf_iova;
+ buf_len = buf_vec[vec_idx].buf_len;
+ buf_avail = buf_len - buf_offset;
+ } else {
+ buf_offset = dev->vhost_hlen;
+ buf_avail = buf_len - dev->vhost_hlen;
+ }
+
+ mbuf_avail = rte_pktmbuf_data_len(m);
+ mbuf_offset = 0;
+ while (mbuf_avail != 0 || m->next != NULL) {
+ /* done with current buf, get the next one */
+ if (buf_avail == 0) {
+ vec_idx++;
+ if (unlikely(vec_idx >= nr_vec)) {
+ error = -1;
+ goto out;
+ }
+
+ buf_addr = buf_vec[vec_idx].buf_addr;
+ buf_iova = buf_vec[vec_idx].buf_iova;
+ buf_len = buf_vec[vec_idx].buf_len;
+
+ /* Prefetch next buffer address. */
+ if (vec_idx + 1 < nr_vec)
+ rte_prefetch0((void *)(uintptr_t)
+ buf_vec[vec_idx + 1].buf_addr);
+ buf_offset = 0;
+ buf_avail = buf_len;
+ }
+
+ /* done with current mbuf, get the next one */
+ if (mbuf_avail == 0) {
+ m = m->next;
+
+ mbuf_offset = 0;
+ mbuf_avail = rte_pktmbuf_data_len(m);
+ }