+static void
+vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
+{
+ struct vring_desc *dp, *dp_tail;
+ struct vq_desc_extra *dxp;
+ uint16_t desc_idx_last = desc_idx;
+
+ dp = &vq->vq_ring.desc[desc_idx];
+ dxp = &vq->vq_descx[desc_idx];
+ vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt + dxp->ndescs);
+ if ((dp->flags & VRING_DESC_F_INDIRECT) == 0) {
+ while (dp->flags & VRING_DESC_F_NEXT) {
+ desc_idx_last = dp->next;
+ dp = &vq->vq_ring.desc[dp->next];
+ }
+ }
+ dxp->ndescs = 0;
+
+ /*
+ * We must append the existing free chain, if any, to the end of
+ * newly freed chain. If the virtqueue was completely used, then
+ * head would be VQ_RING_DESC_CHAIN_END (ASSERTed above).
+ */
+ if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END) {
+ vq->vq_desc_head_idx = desc_idx;
+ } else {
+ dp_tail = &vq->vq_ring.desc[vq->vq_desc_tail_idx];
+ dp_tail->next = desc_idx;
+ }
+
+ vq->vq_desc_tail_idx = desc_idx_last;
+ dp->next = VQ_RING_DESC_CHAIN_END;
+}
+
+static uint16_t
+virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct rte_mbuf **rx_pkts,
+ uint32_t *len, uint16_t num)
+{
+ struct vring_used_elem *uep;
+ struct rte_mbuf *cookie;
+ uint16_t used_idx, desc_idx;
+ uint16_t i;
+
+ /* Caller does the check */
+ for (i = 0; i < num ; i++) {
+ used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
+ uep = &vq->vq_ring.used->ring[used_idx];
+ desc_idx = (uint16_t) uep->id;
+ len[i] = uep->len;
+ cookie = (struct rte_mbuf *)vq->vq_descx[desc_idx].cookie;
+
+ if (unlikely(cookie == NULL)) {
+ PMD_DRV_LOG(ERR, "vring descriptor with no mbuf cookie at %u\n",
+ vq->vq_used_cons_idx);
+ break;
+ }
+
+ rte_prefetch0(cookie);
+ rte_packet_prefetch(rte_pktmbuf_mtod(cookie, void *));
+ rx_pkts[i] = cookie;
+ vq->vq_used_cons_idx++;
+ vq_ring_free_chain(vq, desc_idx);
+ vq->vq_descx[desc_idx].cookie = NULL;
+ }
+
+ return i;
+}
+
+static void
+virtqueue_dequeue_pkt_tx(struct virtqueue *vq)
+{
+ struct vring_used_elem *uep;
+ uint16_t used_idx, desc_idx;
+
+ used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
+ uep = &vq->vq_ring.used->ring[used_idx];
+ desc_idx = (uint16_t) uep->id;
+ vq->vq_used_cons_idx++;
+ vq_ring_free_chain(vq, desc_idx);
+}
+
+
+static inline int
+virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
+{
+ struct vq_desc_extra *dxp;
+ struct virtio_hw *hw = vq->hw;
+ struct vring_desc *start_dp;
+ uint16_t needed = 1;
+ uint16_t head_idx, idx;
+
+ if (unlikely(vq->vq_free_cnt == 0))
+ return -ENOSPC;
+ if (unlikely(vq->vq_free_cnt < needed))
+ return -EMSGSIZE;
+
+ head_idx = vq->vq_desc_head_idx;
+ if (unlikely(head_idx >= vq->vq_nentries))
+ return -EFAULT;
+
+ idx = head_idx;
+ dxp = &vq->vq_descx[idx];
+ dxp->cookie = (void *)cookie;
+ dxp->ndescs = needed;
+
+ start_dp = vq->vq_ring.desc;
+ start_dp[idx].addr =
+ (uint64_t)(cookie->buf_physaddr + RTE_PKTMBUF_HEADROOM
+ - hw->vtnet_hdr_size);
+ start_dp[idx].len =
+ cookie->buf_len - RTE_PKTMBUF_HEADROOM + hw->vtnet_hdr_size;
+ start_dp[idx].flags = VRING_DESC_F_WRITE;
+ idx = start_dp[idx].next;
+ vq->vq_desc_head_idx = idx;
+ if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
+ vq->vq_desc_tail_idx = idx;
+ vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
+ vq_update_avail_ring(vq, head_idx);
+
+ return 0;
+}
+
+static int
+virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
+{
+ struct vq_desc_extra *dxp;
+ struct vring_desc *start_dp;
+ uint16_t seg_num = cookie->nb_segs;
+ uint16_t needed = 1 + seg_num;
+ uint16_t head_idx, idx;
+ uint16_t head_size = txvq->hw->vtnet_hdr_size;
+
+ if (unlikely(txvq->vq_free_cnt == 0))
+ return -ENOSPC;
+ if (unlikely(txvq->vq_free_cnt < needed))
+ return -EMSGSIZE;
+ head_idx = txvq->vq_desc_head_idx;
+ if (unlikely(head_idx >= txvq->vq_nentries))
+ return -EFAULT;
+
+ idx = head_idx;
+ dxp = &txvq->vq_descx[idx];
+ if (dxp->cookie != NULL)
+ rte_pktmbuf_free(dxp->cookie);
+ dxp->cookie = (void *)cookie;
+ dxp->ndescs = needed;
+
+ start_dp = txvq->vq_ring.desc;
+ start_dp[idx].addr =
+ txvq->virtio_net_hdr_mem + idx * head_size;
+ start_dp[idx].len = (uint32_t)head_size;
+ start_dp[idx].flags = VRING_DESC_F_NEXT;
+
+ for (; ((seg_num > 0) && (cookie != NULL)); seg_num--) {
+ idx = start_dp[idx].next;
+ start_dp[idx].addr = RTE_MBUF_DATA_DMA_ADDR(cookie);
+ start_dp[idx].len = cookie->data_len;
+ start_dp[idx].flags = VRING_DESC_F_NEXT;
+ cookie = cookie->next;
+ }
+
+ start_dp[idx].flags &= ~VRING_DESC_F_NEXT;
+ idx = start_dp[idx].next;
+ txvq->vq_desc_head_idx = idx;
+ if (txvq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
+ txvq->vq_desc_tail_idx = idx;
+ txvq->vq_free_cnt = (uint16_t)(txvq->vq_free_cnt - needed);
+ vq_update_avail_ring(txvq, head_idx);
+
+ return 0;
+}
+