- /*check that we have enough buffers*/
- if (unlikely(count > free_entries))
- count = free_entries;
-
- if (count == 0)
- return 0;
-
- res_end_idx = res_base_idx + count;
- /* vq->last_used_idx_res is atomically updated. */
- success = rte_atomic16_cmpset(&vq->last_used_idx_res, res_base_idx,
- res_end_idx);
- } while (unlikely(success == 0));
- res_cur_idx = res_base_idx;
- LOG_DEBUG(DATA, "(%"PRIu64") Current Index %d| End Index %d\n", dev->device_fh, res_cur_idx, res_end_idx);
-
- /* Prefetch available ring to retrieve indexes. */
- rte_prefetch0(&vq->avail->ring[res_cur_idx & (vq->size - 1)]);
-
- /* Check if the VIRTIO_NET_F_MRG_RXBUF feature is enabled. */
- mergeable = dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF);
-
- /* Retrieve all of the head indexes first to avoid caching issues. */
- for (head_idx = 0; head_idx < count; head_idx++)
- head[head_idx] = vq->avail->ring[(res_cur_idx + head_idx) & (vq->size - 1)];
-
- /*Prefetch descriptor index. */
- rte_prefetch0(&vq->desc[head[packet_success]]);
-
- while (res_cur_idx != res_end_idx) {
- /* Get descriptor from available ring */
- desc = &vq->desc[head[packet_success]];
-
- buff = pkts[packet_success];
-
- /* Convert from gpa to vva (guest physical addr -> vhost virtual addr) */
- buff_addr = gpa_to_vva(dev, desc->addr);
- /* Prefetch buffer address. */
- rte_prefetch0((void*)(uintptr_t)buff_addr);
-
- if (mergeable && (mrg_count != 0)) {
- desc->len = packet_len = rte_pktmbuf_data_len(buff);
- } else {
- /* Copy virtio_hdr to packet and increment buffer address */
- buff_hdr_addr = buff_addr;
- packet_len = rte_pktmbuf_data_len(buff) + vq->vhost_hlen;
-
- /*
- * If the descriptors are chained the header and data are placed in
- * separate buffers.
- */
- if (desc->flags & VRING_DESC_F_NEXT) {
- desc->len = vq->vhost_hlen;
- desc = &vq->desc[desc->next];
- /* Buffer address translation. */
- buff_addr = gpa_to_vva(dev, desc->addr);
- desc->len = rte_pktmbuf_data_len(buff);
- } else {
- buff_addr += vq->vhost_hlen;
- desc->len = packet_len;
- }
- }
-
- PRINT_PACKET(dev, (uintptr_t)buff_addr, rte_pktmbuf_data_len(buff), 0);
-
- /* Update used ring with desc information */
- vq->used->ring[res_cur_idx & (vq->size - 1)].id = head[packet_success];
- vq->used->ring[res_cur_idx & (vq->size - 1)].len = packet_len;
-
- /* Copy mbuf data to buffer */
- rte_memcpy((void *)(uintptr_t)buff_addr, (const void*)buff->pkt.data, rte_pktmbuf_data_len(buff));
-
- res_cur_idx++;
- packet_success++;
-
- /* If mergeable is disabled then a header is required per buffer. */
- if (!mergeable) {
- rte_memcpy((void *)(uintptr_t)buff_hdr_addr, (const void*)&virtio_hdr, vq->vhost_hlen);
- PRINT_PACKET(dev, (uintptr_t)buff_hdr_addr, vq->vhost_hlen, 1);
- } else {
- mrg_count++;
- /* Merge buffer can only handle so many buffers at a time. Tell the guest if this limit is reached. */
- if ((mrg_count == MAX_MRG_PKT_BURST) || (res_cur_idx == res_end_idx)) {
- virtio_hdr.num_buffers = mrg_count;
- LOG_DEBUG(DATA, "(%"PRIu64") RX: Num merge buffers %d\n", dev->device_fh, virtio_hdr.num_buffers);
- rte_memcpy((void *)(uintptr_t)buff_hdr_addr, (const void*)&virtio_hdr, vq->vhost_hlen);
- PRINT_PACKET(dev, (uintptr_t)buff_hdr_addr, vq->vhost_hlen, 1);
- mrg_count = 0;
- }
- }
- if (res_cur_idx < res_end_idx) {
- /* Prefetch descriptor index. */
- rte_prefetch0(&vq->desc[head[packet_success]]);
- }