+
+int
+rte_vdpa_relay_vring_used(int vid, uint16_t qid, void *vring_m)
+{
+ struct virtio_net *dev = get_device(vid);
+ uint16_t idx, idx_m, desc_id;
+ struct vhost_virtqueue *vq;
+ struct vring_desc desc;
+ struct vring_desc *desc_ring;
+ struct vring_desc *idesc = NULL;
+ struct vring *s_vring;
+ uint64_t dlen;
+ uint32_t nr_descs;
+ int ret;
+
+ if (!dev || !vring_m)
+ return -1;
+
+ if (qid >= dev->nr_vring)
+ return -1;
+
+ if (vq_is_packed(dev))
+ return -1;
+
+ s_vring = (struct vring *)vring_m;
+ vq = dev->virtqueue[qid];
+ idx = vq->used->idx;
+ idx_m = s_vring->used->idx;
+ ret = (uint16_t)(idx_m - idx);
+
+ while (idx != idx_m) {
+ /* copy used entry, used ring logging is not covered here */
+ vq->used->ring[idx & (vq->size - 1)] =
+ s_vring->used->ring[idx & (vq->size - 1)];
+
+ desc_id = vq->used->ring[idx & (vq->size - 1)].id;
+ desc_ring = vq->desc;
+ nr_descs = vq->size;
+
+ if (unlikely(desc_id >= vq->size))
+ return -1;
+
+ if (vq->desc[desc_id].flags & VRING_DESC_F_INDIRECT) {
+ dlen = vq->desc[desc_id].len;
+ nr_descs = dlen / sizeof(struct vring_desc);
+ if (unlikely(nr_descs > vq->size))
+ return -1;
+
+ desc_ring = (struct vring_desc *)(uintptr_t)
+ vhost_iova_to_vva(dev, vq,
+ vq->desc[desc_id].addr, &dlen,
+ VHOST_ACCESS_RO);
+ if (unlikely(!desc_ring))
+ return -1;
+
+ if (unlikely(dlen < vq->desc[desc_id].len)) {
+ idesc = vhost_alloc_copy_ind_table(dev, vq,
+ vq->desc[desc_id].addr,
+ vq->desc[desc_id].len);
+ if (unlikely(!idesc))
+ return -1;
+
+ desc_ring = idesc;
+ }
+
+ desc_id = 0;
+ }
+
+ /* dirty page logging for DMA writeable buffer */
+ do {
+ if (unlikely(desc_id >= vq->size))
+ goto fail;
+ if (unlikely(nr_descs-- == 0))
+ goto fail;
+ desc = desc_ring[desc_id];
+ if (desc.flags & VRING_DESC_F_WRITE)
+ vhost_log_write(dev, desc.addr, desc.len);
+ desc_id = desc.next;
+ } while (desc.flags & VRING_DESC_F_NEXT);
+
+ if (unlikely(idesc)) {
+ free_ind_table(idesc);
+ idesc = NULL;
+ }
+
+ idx++;
+ }
+
+ rte_smp_wmb();
+ vq->used->idx = idx_m;
+
+ if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
+ vring_used_event(s_vring) = idx_m;
+
+ return ret;
+
+fail:
+ if (unlikely(idesc))
+ free_ind_table(idesc);
+ return -1;
+}