text: /* SPDX-License-Identifier: BSD-3-Clause
   * Copyright(c) 2016 Cavium, Inc
   */
  
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <errno.h>
  
  #include <rte_byteorder.h>
  #include <rte_branch_prediction.h>
  #include <rte_cycles.h>
  #include <rte_ether.h>
  #include <rte_ethdev_driver.h>
  #include <rte_errno.h>
  #include <rte_memory.h>
  #include <rte_mempool.h>
  #include <rte_malloc.h>
  #include <rte_mbuf.h>
  #include <rte_prefetch.h>
  #include <rte_string_fns.h>
  #include <rte_vect.h>
  
  #include "virtio_rxtx_simple.h"
  
  #define RTE_VIRTIO_DESC_PER_LOOP 8
  
  /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
   *
   * This routine is for non-mergeable RX, one desc for each guest buffer.
   * This routine is based on the RX ring layout optimization. Each entry in the
   * avail ring points to the desc with the same index in the desc ring and this
   * will never be changed in the driver.
   *
   * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
   */
  uint16_t
  virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
  	uint16_t nb_pkts)
  {
  	struct virtnet_rx *rxvq = rx_queue;
  	struct virtqueue *vq = rxvq->vq;
  	struct virtio_hw *hw = vq->hw;
  	uint16_t nb_used;
  	uint16_t desc_idx;
  	struct vring_used_elem *rused;
  	struct rte_mbuf **sw_ring;
  	struct rte_mbuf **sw_ring_end;
  	uint16_t nb_pkts_received = 0;
  
  	uint8x16_t shuf_msk1 = {
  		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  		4, 5, 0xFF, 0xFF,       /* pkt len */
  		4, 5,                   /* dat len */
  		0xFF, 0xFF,             /* vlan tci */
  		0xFF, 0xFF, 0xFF, 0xFF
  	};
  
  	uint8x16_t shuf_msk2 = {
  		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  		12, 13, 0xFF, 0xFF,     /* pkt len */
  		12, 13,                 /* dat len */
  		0xFF, 0xFF,             /* vlan tci */
  		0xFF, 0xFF, 0xFF, 0xFF
  	};
  
  	/* Subtract the header length.
  	 *  In which case do we need the header length in used->len ?
  	 */
  	uint16x8_t len_adjust = {
  		0, 0,
  		(uint16_t)vq->hw->vtnet_hdr_size, 0,
  		(uint16_t)vq->hw->vtnet_hdr_size,
  		0,
  		0, 0
  	};
  
  	if (unlikely(hw->started == 0))
  		return nb_pkts_received;
  
  	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
  		return 0;
  
  	nb_used = VIRTQUEUE_NUSED(vq);
  
  	rte_rmb();
  
  	if (unlikely(nb_used == 0))
  		return 0;
  
  	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
  	nb_used = RTE_MIN(nb_used, nb_pkts);
  
  	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
  	rused = &vq->vq_split.ring.used->ring[desc_idx];
  	sw_ring  = &vq->sw_ring[desc_idx];
  	sw_ring_end = &vq->sw_ring[vq->vq_nentries];
  
  	rte_prefetch_non_temporal(rused);
  
  	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
  		virtio_rxq_rearm_vec(rxvq);
  		if (unlikely(virtqueue_kick_prepare(vq)))
  			virtqueue_notify(vq);
  	}
  
  	for (nb_pkts_received = 0;
  		nb_pkts_received < nb_used;) {
  		uint64x2_t desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
  		uint64x2_t mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
  		uint64x2_t pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
  
  		mbp[0] = vld1q_u64((uint64_t *)(sw_ring + 0));
  		desc[0] = vld1q_u64((uint64_t *)(rused + 0));
  		vst1q_u64((uint64_t *)&rx_pkts[0], mbp[0]);
  
  		mbp[1] = vld1q_u64((uint64_t *)(sw_ring + 2));
  		desc[1] = vld1q_u64((uint64_t *)(rused + 2));
  		vst1q_u64((uint64_t *)&rx_pkts[2], mbp[1]);
  
  		mbp[2] = vld1q_u64((uint64_t *)(sw_ring + 4));
  		desc[2] = vld1q_u64((uint64_t *)(rused + 4));
  		vst1q_u64((uint64_t *)&rx_pkts[4], mbp[2]);
  
  		mbp[3] = vld1q_u64((uint64_t *)(sw_ring + 6));
  		desc[3] = vld1q_u64((uint64_t *)(rused + 6));
  		vst1q_u64((uint64_t *)&rx_pkts[6], mbp[3]);
  
  		pkt_mb[1] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[0]), shuf_msk2));
  		pkt_mb[0] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[0]), shuf_msk1));
  		pkt_mb[1] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[1]), len_adjust));
  		pkt_mb[0] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[0]), len_adjust));
  		vst1q_u64((void *)&rx_pkts[1]->rx_descriptor_fields1,
  			pkt_mb[1]);
  		vst1q_u64((void *)&rx_pkts[0]->rx_descriptor_fields1,
  			pkt_mb[0]);
  
  		pkt_mb[3] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[1]), shuf_msk2));
  		pkt_mb[2] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[1]), shuf_msk1));
  		pkt_mb[3] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[3]), len_adjust));
  		pkt_mb[2] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[2]), len_adjust));
  		vst1q_u64((void *)&rx_pkts[3]->rx_descriptor_fields1,
  			pkt_mb[3]);
  		vst1q_u64((void *)&rx_pkts[2]->rx_descriptor_fields1,
  			pkt_mb[2]);
  
  		pkt_mb[5] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[2]), shuf_msk2));
  		pkt_mb[4] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[2]), shuf_msk1));
  		pkt_mb[5] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[5]), len_adjust));
  		pkt_mb[4] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[4]), len_adjust));
  		vst1q_u64((void *)&rx_pkts[5]->rx_descriptor_fields1,
  			pkt_mb[5]);
  		vst1q_u64((void *)&rx_pkts[4]->rx_descriptor_fields1,
  			pkt_mb[4]);
  
  		pkt_mb[7] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[3]), shuf_msk2));
  		pkt_mb[6] = vreinterpretq_u64_u8(vqtbl1q_u8(
  				vreinterpretq_u8_u64(desc[3]), shuf_msk1));
  		pkt_mb[7] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[7]), len_adjust));
  		pkt_mb[6] = vreinterpretq_u64_u16(vsubq_u16(
  				vreinterpretq_u16_u64(pkt_mb[6]), len_adjust));
  		vst1q_u64((void *)&rx_pkts[7]->rx_descriptor_fields1,
  			pkt_mb[7]);
  		vst1q_u64((void *)&rx_pkts[6]->rx_descriptor_fields1,
  			pkt_mb[6]);
  
  		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
  			if (sw_ring + nb_used <= sw_ring_end)
  				nb_pkts_received += nb_used;
  			else
  				nb_pkts_received += sw_ring_end - sw_ring;
  			break;
  		} else {
  			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
  				sw_ring_end)) {
  				nb_pkts_received += sw_ring_end - sw_ring;
  				break;
  			} else {
  				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
  
  				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
  				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
  				rused   += RTE_VIRTIO_DESC_PER_LOOP;
  				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
  			}
  		}
  	}
  
  	vq->vq_used_cons_idx += nb_pkts_received;
  	vq->vq_free_cnt += nb_pkts_received;
  	rxvq->stats.packets += nb_pkts_received;
  	return nb_pkts_received;
  }
  