drivers/net/virtio/virtio_rxtx_simple_altivec.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2015 Intel Corporation
   3  * Copyright(C) 2019 IBM Corporation
   4  */
   5
   6 #include <stdint.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <errno.h>
  11
  12 #include <altivec.h>
  13
  14 #include <rte_byteorder.h>
  15 #include <rte_branch_prediction.h>
  16 #include <rte_cycles.h>
  17 #include <rte_ether.h>
  18 #include <rte_ethdev_driver.h>
  19 #include <rte_errno.h>
  20 #include <rte_memory.h>
  21 #include <rte_mempool.h>
  22 #include <rte_malloc.h>
  23 #include <rte_mbuf.h>
  24 #include <rte_prefetch.h>
  25 #include <rte_string_fns.h>
  26
  27 #include "virtio_rxtx_simple.h"
  28
  29 #define RTE_VIRTIO_DESC_PER_LOOP 8
  30
  31 /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
  32  *
  33  * This routine is for non-mergeable RX, one desc for each guest buffer.
  34  * This routine is based on the RX ring layout optimization. Each entry in the
  35  * avail ring points to the desc with the same index in the desc ring and this
  36  * will never be changed in the driver.
  37  *
  38  * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
  39  */
  40 uint16_t
  41 virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
  42         uint16_t nb_pkts)
  43 {
  44         struct virtnet_rx *rxvq = rx_queue;
  45         struct virtqueue *vq = rxvq->vq;
  46         struct virtio_hw *hw = vq->hw;
  47         uint16_t nb_used;
  48         uint16_t desc_idx;
  49         struct vring_used_elem *rused;
  50         struct rte_mbuf **sw_ring;
  51         struct rte_mbuf **sw_ring_end;
  52         struct rte_mbuf **ref_rx_pkts;
  53         uint16_t nb_pkts_received = 0;
  54         const vector unsigned char zero = {0};
  55
  56         const vector unsigned char shuf_msk1 = {
  57                 0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  58                 4, 5, 0xFF, 0xFF, /* vlan tci */
  59                 4, 5,                   /* dat len */
  60                 0xFF, 0xFF,             /* vlan tci */
  61                 0xFF, 0xFF, 0xFF, 0xFF
  62         };
  63
  64         const vector unsigned char shuf_msk2 = {
  65                 0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  66                 12, 13, 0xFF, 0xFF,     /* pkt len */
  67                 12, 13,                 /* dat len */
  68                 0xFF, 0xFF,             /* vlan tci */
  69                 0xFF, 0xFF, 0xFF, 0xFF
  70         };
  71
  72         /*
  73          * Subtract the header length.
  74          *  In which case do we need the header length in used->len ?
  75          */
  76         const vector unsigned short len_adjust = {
  77                 0, 0,
  78                 (uint16_t)-vq->hw->vtnet_hdr_size, 0,
  79                 (uint16_t)-vq->hw->vtnet_hdr_size, 0,
  80                 0, 0
  81         };
  82
  83         if (unlikely(hw->started == 0))
  84                 return nb_pkts_received;
  85
  86         if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
  87                 return 0;
  88
  89         nb_used = VIRTQUEUE_NUSED(vq);
  90
  91         rte_compiler_barrier();
  92
  93         if (unlikely(nb_used == 0))
  94                 return 0;
  95
  96         nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
  97         nb_used = RTE_MIN(nb_used, nb_pkts);
  98
  99         desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
 100         rused = &vq->vq_split.ring.used->ring[desc_idx];
 101         sw_ring  = &vq->sw_ring[desc_idx];
 102         sw_ring_end = &vq->sw_ring[vq->vq_nentries];
 103
 104         rte_prefetch0(rused);
 105
 106         if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
 107                 virtio_rxq_rearm_vec(rxvq);
 108                 if (unlikely(virtqueue_kick_prepare(vq)))
 109                         virtqueue_notify(vq);
 110         }
 111
 112         ref_rx_pkts = rx_pkts;
 113         for (nb_pkts_received = 0;
 114                 nb_pkts_received < nb_used;) {
 115                 vector unsigned char desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
 116                 vector unsigned char mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
 117                 vector unsigned char pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
 118
 119                 mbp[0] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 0));
 120                 desc[0] = vec_vsx_ld(0, (unsigned char const *)(rused + 0));
 121                 *(vector unsigned char *)&rx_pkts[0] = mbp[0];
 122
 123                 mbp[1] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 2));
 124                 desc[1] = vec_vsx_ld(0, (unsigned char const *)(rused + 2));
 125                 *(vector unsigned char *)&rx_pkts[2] = mbp[1];
 126
 127                 mbp[2] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 4));
 128                 desc[2] = vec_vsx_ld(0, (unsigned char const *)(rused + 4));
 129                 *(vector unsigned char *)&rx_pkts[4] = mbp[2];
 130
 131                 mbp[3] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 6));
 132                 desc[3] = vec_vsx_ld(0, (unsigned char const *)(rused + 6));
 133                 *(vector unsigned char *)&rx_pkts[6] = mbp[3];
 134
 135                 pkt_mb[0] = vec_perm(desc[0], zero, shuf_msk1);
 136                 pkt_mb[1] = vec_perm(desc[0], zero, shuf_msk2);
 137                 pkt_mb[0] = (vector unsigned char)
 138                         ((vector unsigned short)pkt_mb[0] + len_adjust);
 139                 pkt_mb[1] = (vector unsigned char)
 140                         ((vector unsigned short)pkt_mb[1] + len_adjust);
 141                 *(vector unsigned char *)&rx_pkts[0]->rx_descriptor_fields1 =
 142                         pkt_mb[0];
 143                 *(vector unsigned char *)&rx_pkts[1]->rx_descriptor_fields1 =
 144                         pkt_mb[1];
 145
 146                 pkt_mb[2] = vec_perm(desc[1], zero, shuf_msk1);
 147                 pkt_mb[3] = vec_perm(desc[1], zero, shuf_msk2);
 148                 pkt_mb[2] = (vector unsigned char)
 149                         ((vector unsigned short)pkt_mb[2] + len_adjust);
 150                 pkt_mb[3] = (vector unsigned char)
 151                         ((vector unsigned short)pkt_mb[3] + len_adjust);
 152                 *(vector unsigned char *)&rx_pkts[2]->rx_descriptor_fields1 =
 153                         pkt_mb[2];
 154                 *(vector unsigned char *)&rx_pkts[3]->rx_descriptor_fields1 =
 155                         pkt_mb[3];
 156
 157                 pkt_mb[4] = vec_perm(desc[2], zero, shuf_msk1);
 158                 pkt_mb[5] = vec_perm(desc[2], zero, shuf_msk2);
 159                 pkt_mb[4] = (vector unsigned char)
 160                         ((vector unsigned short)pkt_mb[4] + len_adjust);
 161                 pkt_mb[5] = (vector unsigned char)
 162                         ((vector unsigned short)pkt_mb[5] + len_adjust);
 163                 *(vector unsigned char *)&rx_pkts[4]->rx_descriptor_fields1 =
 164                         pkt_mb[4];
 165                 *(vector unsigned char *)&rx_pkts[5]->rx_descriptor_fields1 =
 166                         pkt_mb[5];
 167
 168                 pkt_mb[6] = vec_perm(desc[3], zero, shuf_msk1);
 169                 pkt_mb[7] = vec_perm(desc[3], zero, shuf_msk2);
 170                 pkt_mb[6] = (vector unsigned char)
 171                         ((vector unsigned short)pkt_mb[6] + len_adjust);
 172                 pkt_mb[7] = (vector unsigned char)
 173                         ((vector unsigned short)pkt_mb[7] + len_adjust);
 174                 *(vector unsigned char *)&rx_pkts[6]->rx_descriptor_fields1 =
 175                         pkt_mb[6];
 176                 *(vector unsigned char *)&rx_pkts[7]->rx_descriptor_fields1 =
 177                         pkt_mb[7];
 178
 179                 if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
 180                         if (sw_ring + nb_used <= sw_ring_end)
 181                                 nb_pkts_received += nb_used;
 182                         else
 183                                 nb_pkts_received += sw_ring_end - sw_ring;
 184                         break;
 185                 } else {
 186                         if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
 187                                 sw_ring_end)) {
 188                                 nb_pkts_received += sw_ring_end - sw_ring;
 189                                 break;
 190                         } else {
 191                                 nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
 192
 193                                 rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
 194                                 sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
 195                                 rused   += RTE_VIRTIO_DESC_PER_LOOP;
 196                                 nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
 197                         }
 198                 }
 199         }
 200
 201         vq->vq_used_cons_idx += nb_pkts_received;
 202         vq->vq_free_cnt += nb_pkts_received;
 203         rxvq->stats.packets += nb_pkts_received;
 204         for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
 205                 virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
 206
 207         return nb_pkts_received;
 208 }