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         uint16_t nb_pkts_received = 0;
  53         const vector unsigned char zero = {0};
  54
  55         const vector unsigned char shuf_msk1 = {
  56                 0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  57                 4, 5, 0xFF, 0xFF, /* vlan tci */
  58                 4, 5,                   /* dat len */
  59                 0xFF, 0xFF,             /* vlan tci */
  60                 0xFF, 0xFF, 0xFF, 0xFF
  61         };
  62
  63         const vector unsigned char shuf_msk2 = {
  64                 0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
  65                 12, 13, 0xFF, 0xFF,     /* pkt len */
  66                 12, 13,                 /* dat len */
  67                 0xFF, 0xFF,             /* vlan tci */
  68                 0xFF, 0xFF, 0xFF, 0xFF
  69         };
  70
  71         /*
  72          * Subtract the header length.
  73          *  In which case do we need the header length in used->len ?
  74          */
  75         const vector unsigned short len_adjust = {
  76                 0, 0,
  77                 (uint16_t)-vq->hw->vtnet_hdr_size, 0,
  78                 (uint16_t)-vq->hw->vtnet_hdr_size, 0,
  79                 0, 0
  80         };
  81
  82         if (unlikely(hw->started == 0))
  83                 return nb_pkts_received;
  84
  85         if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
  86                 return 0;
  87
  88         nb_used = VIRTQUEUE_NUSED(vq);
  89
  90         rte_compiler_barrier();
  91
  92         if (unlikely(nb_used == 0))
  93                 return 0;
  94
  95         nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
  96         nb_used = RTE_MIN(nb_used, nb_pkts);
  97
  98         desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
  99         rused = &vq->vq_split.ring.used->ring[desc_idx];
 100         sw_ring  = &vq->sw_ring[desc_idx];
 101         sw_ring_end = &vq->sw_ring[vq->vq_nentries];
 102
 103         rte_prefetch0(rused);
 104
 105         if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
 106                 virtio_rxq_rearm_vec(rxvq);
 107                 if (unlikely(virtqueue_kick_prepare(vq)))
 108                         virtqueue_notify(vq);
 109         }
 110
 111         for (nb_pkts_received = 0;
 112                 nb_pkts_received < nb_used;) {
 113                 vector unsigned char desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
 114                 vector unsigned char mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
 115                 vector unsigned char pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
 116
 117                 mbp[0] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 0));
 118                 desc[0] = vec_vsx_ld(0, (unsigned char const *)(rused + 0));
 119                 *(vector unsigned char *)&rx_pkts[0] = mbp[0];
 120
 121                 mbp[1] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 2));
 122                 desc[1] = vec_vsx_ld(0, (unsigned char const *)(rused + 2));
 123                 *(vector unsigned char *)&rx_pkts[2] = mbp[1];
 124
 125                 mbp[2] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 4));
 126                 desc[2] = vec_vsx_ld(0, (unsigned char const *)(rused + 4));
 127                 *(vector unsigned char *)&rx_pkts[4] = mbp[2];
 128
 129                 mbp[3] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 6));
 130                 desc[3] = vec_vsx_ld(0, (unsigned char const *)(rused + 6));
 131                 *(vector unsigned char *)&rx_pkts[6] = mbp[3];
 132
 133                 pkt_mb[0] = vec_perm(desc[0], zero, shuf_msk1);
 134                 pkt_mb[1] = vec_perm(desc[0], zero, shuf_msk2);
 135                 pkt_mb[0] = (vector unsigned char)
 136                         ((vector unsigned short)pkt_mb[0] + len_adjust);
 137                 pkt_mb[1] = (vector unsigned char)
 138                         ((vector unsigned short)pkt_mb[1] + len_adjust);
 139                 *(vector unsigned char *)&rx_pkts[0]->rx_descriptor_fields1 =
 140                         pkt_mb[0];
 141                 *(vector unsigned char *)&rx_pkts[1]->rx_descriptor_fields1 =
 142                         pkt_mb[1];
 143
 144                 pkt_mb[2] = vec_perm(desc[1], zero, shuf_msk1);
 145                 pkt_mb[3] = vec_perm(desc[1], zero, shuf_msk2);
 146                 pkt_mb[2] = (vector unsigned char)
 147                         ((vector unsigned short)pkt_mb[2] + len_adjust);
 148                 pkt_mb[3] = (vector unsigned char)
 149                         ((vector unsigned short)pkt_mb[3] + len_adjust);
 150                 *(vector unsigned char *)&rx_pkts[2]->rx_descriptor_fields1 =
 151                         pkt_mb[2];
 152                 *(vector unsigned char *)&rx_pkts[3]->rx_descriptor_fields1 =
 153                         pkt_mb[3];
 154
 155                 pkt_mb[4] = vec_perm(desc[2], zero, shuf_msk1);
 156                 pkt_mb[5] = vec_perm(desc[2], zero, shuf_msk2);
 157                 pkt_mb[4] = (vector unsigned char)
 158                         ((vector unsigned short)pkt_mb[4] + len_adjust);
 159                 pkt_mb[5] = (vector unsigned char)
 160                         ((vector unsigned short)pkt_mb[5] + len_adjust);
 161                 *(vector unsigned char *)&rx_pkts[4]->rx_descriptor_fields1 =
 162                         pkt_mb[4];
 163                 *(vector unsigned char *)&rx_pkts[5]->rx_descriptor_fields1 =
 164                         pkt_mb[5];
 165
 166                 pkt_mb[6] = vec_perm(desc[3], zero, shuf_msk1);
 167                 pkt_mb[7] = vec_perm(desc[3], zero, shuf_msk2);
 168                 pkt_mb[6] = (vector unsigned char)
 169                         ((vector unsigned short)pkt_mb[6] + len_adjust);
 170                 pkt_mb[7] = (vector unsigned char)
 171                         ((vector unsigned short)pkt_mb[7] + len_adjust);
 172                 *(vector unsigned char *)&rx_pkts[6]->rx_descriptor_fields1 =
 173                         pkt_mb[6];
 174                 *(vector unsigned char *)&rx_pkts[7]->rx_descriptor_fields1 =
 175                         pkt_mb[7];
 176
 177                 if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
 178                         if (sw_ring + nb_used <= sw_ring_end)
 179                                 nb_pkts_received += nb_used;
 180                         else
 181                                 nb_pkts_received += sw_ring_end - sw_ring;
 182                         break;
 183                 } else {
 184                         if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
 185                                 sw_ring_end)) {
 186                                 nb_pkts_received += sw_ring_end - sw_ring;
 187                                 break;
 188                         } else {
 189                                 nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
 190
 191                                 rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
 192                                 sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
 193                                 rused   += RTE_VIRTIO_DESC_PER_LOOP;
 194                                 nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
 195                         }
 196                 }
 197         }
 198
 199         vq->vq_used_cons_idx += nb_pkts_received;
 200         vq->vq_free_cnt += nb_pkts_received;
 201         rxvq->stats.packets += nb_pkts_received;
 202         return nb_pkts_received;
 203 }