lib/librte_vhost/virtio_net.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2016 Intel Corporation
   3  */
   4
   5 #include <stdint.h>
   6 #include <stdbool.h>
   7 #include <linux/virtio_net.h>
   8
   9 #include <rte_mbuf.h>
  10 #include <rte_memcpy.h>
  11 #include <rte_ether.h>
  12 #include <rte_ip.h>
  13 #include <rte_vhost.h>
  14 #include <rte_tcp.h>
  15 #include <rte_udp.h>
  16 #include <rte_sctp.h>
  17 #include <rte_arp.h>
  18 #include <rte_spinlock.h>
  19 #include <rte_malloc.h>
  20
  21 #include "iotlb.h"
  22 #include "vhost.h"
  23
  24 #define MAX_PKT_BURST 32
  25
  26 #define MAX_BATCH_LEN 256
  27
  28 static  __rte_always_inline bool
  29 rxvq_is_mergeable(struct virtio_net *dev)
  30 {
  31         return dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF);
  32 }
  33
  34 static bool
  35 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
  36 {
  37         return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring;
  38 }
  39
  40 static __rte_always_inline void *
  41 alloc_copy_ind_table(struct virtio_net *dev, struct vhost_virtqueue *vq,
  42                 uint64_t desc_addr, uint64_t desc_len)
  43 {
  44         void *idesc;
  45         uint64_t src, dst;
  46         uint64_t len, remain = desc_len;
  47
  48         idesc = rte_malloc(__func__, desc_len, 0);
  49         if (unlikely(!idesc))
  50                 return 0;
  51
  52         dst = (uint64_t)(uintptr_t)idesc;
  53
  54         while (remain) {
  55                 len = remain;
  56                 src = vhost_iova_to_vva(dev, vq, desc_addr, &len,
  57                                 VHOST_ACCESS_RO);
  58                 if (unlikely(!src || !len)) {
  59                         rte_free(idesc);
  60                         return 0;
  61                 }
  62
  63                 rte_memcpy((void *)(uintptr_t)dst, (void *)(uintptr_t)src, len);
  64
  65                 remain -= len;
  66                 dst += len;
  67                 desc_addr += len;
  68         }
  69
  70         return idesc;
  71 }
  72
  73 static __rte_always_inline void
  74 free_ind_table(void *idesc)
  75 {
  76         rte_free(idesc);
  77 }
  78
  79 static __rte_always_inline void
  80 do_flush_shadow_used_ring_split(struct virtio_net *dev,
  81                         struct vhost_virtqueue *vq,
  82                         uint16_t to, uint16_t from, uint16_t size)
  83 {
  84         rte_memcpy(&vq->used->ring[to],
  85                         &vq->shadow_used_ring[from],
  86                         size * sizeof(struct vring_used_elem));
  87         vhost_log_cache_used_vring(dev, vq,
  88                         offsetof(struct vring_used, ring[to]),
  89                         size * sizeof(struct vring_used_elem));
  90 }
  91
  92 static __rte_always_inline void
  93 flush_shadow_used_ring_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
  94 {
  95         uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
  96
  97         if (used_idx + vq->shadow_used_idx <= vq->size) {
  98                 do_flush_shadow_used_ring_split(dev, vq, used_idx, 0,
  99                                           vq->shadow_used_idx);
 100         } else {
 101                 uint16_t size;
 102
 103                 /* update used ring interval [used_idx, vq->size] */
 104                 size = vq->size - used_idx;
 105                 do_flush_shadow_used_ring_split(dev, vq, used_idx, 0, size);
 106
 107                 /* update the left half used ring interval [0, left_size] */
 108                 do_flush_shadow_used_ring_split(dev, vq, 0, size,
 109                                           vq->shadow_used_idx - size);
 110         }
 111         vq->last_used_idx += vq->shadow_used_idx;
 112
 113         rte_smp_wmb();
 114
 115         vhost_log_cache_sync(dev, vq);
 116
 117         *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx;
 118         vq->shadow_used_idx = 0;
 119         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 120                 sizeof(vq->used->idx));
 121 }
 122
 123 static __rte_always_inline void
 124 update_shadow_used_ring_split(struct vhost_virtqueue *vq,
 125                          uint16_t desc_idx, uint16_t len)
 126 {
 127         uint16_t i = vq->shadow_used_idx++;
 128
 129         vq->shadow_used_ring[i].id  = desc_idx;
 130         vq->shadow_used_ring[i].len = len;
 131 }
 132
 133 static inline void
 134 do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq)
 135 {
 136         struct batch_copy_elem *elem = vq->batch_copy_elems;
 137         uint16_t count = vq->batch_copy_nb_elems;
 138         int i;
 139
 140         for (i = 0; i < count; i++) {
 141                 rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
 142                 vhost_log_cache_write(dev, vq, elem[i].log_addr, elem[i].len);
 143                 PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0);
 144         }
 145
 146         vq->batch_copy_nb_elems = 0;
 147 }
 148
 149 static inline void
 150 do_data_copy_dequeue(struct vhost_virtqueue *vq)
 151 {
 152         struct batch_copy_elem *elem = vq->batch_copy_elems;
 153         uint16_t count = vq->batch_copy_nb_elems;
 154         int i;
 155
 156         for (i = 0; i < count; i++)
 157                 rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
 158
 159         vq->batch_copy_nb_elems = 0;
 160 }
 161
 162 /* avoid write operation when necessary, to lessen cache issues */
 163 #define ASSIGN_UNLESS_EQUAL(var, val) do {      \
 164         if ((var) != (val))                     \
 165                 (var) = (val);                  \
 166 } while (0)
 167
 168 static __rte_always_inline void
 169 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 170 {
 171         uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK;
 172
 173         if (m_buf->ol_flags & PKT_TX_TCP_SEG)
 174                 csum_l4 |= PKT_TX_TCP_CKSUM;
 175
 176         if (csum_l4) {
 177                 net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 178                 net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
 179
 180                 switch (csum_l4) {
 181                 case PKT_TX_TCP_CKSUM:
 182                         net_hdr->csum_offset = (offsetof(struct tcp_hdr,
 183                                                 cksum));
 184                         break;
 185                 case PKT_TX_UDP_CKSUM:
 186                         net_hdr->csum_offset = (offsetof(struct udp_hdr,
 187                                                 dgram_cksum));
 188                         break;
 189                 case PKT_TX_SCTP_CKSUM:
 190                         net_hdr->csum_offset = (offsetof(struct sctp_hdr,
 191                                                 cksum));
 192                         break;
 193                 }
 194         } else {
 195                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_start, 0);
 196                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0);
 197                 ASSIGN_UNLESS_EQUAL(net_hdr->flags, 0);
 198         }
 199
 200         /* IP cksum verification cannot be bypassed, then calculate here */
 201         if (m_buf->ol_flags & PKT_TX_IP_CKSUM) {
 202                 struct ipv4_hdr *ipv4_hdr;
 203
 204                 ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct ipv4_hdr *,
 205                                                    m_buf->l2_len);
 206                 ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
 207         }
 208
 209         if (m_buf->ol_flags & PKT_TX_TCP_SEG) {
 210                 if (m_buf->ol_flags & PKT_TX_IPV4)
 211                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 212                 else
 213                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 214                 net_hdr->gso_size = m_buf->tso_segsz;
 215                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 216                                         + m_buf->l4_len;
 217         } else if (m_buf->ol_flags & PKT_TX_UDP_SEG) {
 218                 net_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 219                 net_hdr->gso_size = m_buf->tso_segsz;
 220                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len +
 221                         m_buf->l4_len;
 222         } else {
 223                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0);
 224                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0);
 225                 ASSIGN_UNLESS_EQUAL(net_hdr->hdr_len, 0);
 226         }
 227 }
 228
 229 static __rte_always_inline int
 230 fill_vec_buf_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 231                          uint32_t avail_idx, uint16_t *vec_idx,
 232                          struct buf_vector *buf_vec, uint16_t *desc_chain_head,
 233                          uint16_t *desc_chain_len, uint8_t perm)
 234 {
 235         uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
 236         uint16_t vec_id = *vec_idx;
 237         uint32_t len    = 0;
 238         uint64_t dlen, desc_avail, desc_iova;
 239         struct vring_desc *descs = vq->desc;
 240         struct vring_desc *idesc = NULL;
 241
 242         *desc_chain_head = idx;
 243
 244         if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
 245                 dlen = vq->desc[idx].len;
 246                 descs = (struct vring_desc *)(uintptr_t)
 247                         vhost_iova_to_vva(dev, vq, vq->desc[idx].addr,
 248                                                 &dlen,
 249                                                 VHOST_ACCESS_RO);
 250                 if (unlikely(!descs))
 251                         return -1;
 252
 253                 if (unlikely(dlen < vq->desc[idx].len)) {
 254                         /*
 255                          * The indirect desc table is not contiguous
 256                          * in process VA space, we have to copy it.
 257                          */
 258                         idesc = alloc_copy_ind_table(dev, vq,
 259                                         vq->desc[idx].addr, vq->desc[idx].len);
 260                         if (unlikely(!idesc))
 261                                 return -1;
 262
 263                         descs = idesc;
 264                 }
 265
 266                 idx = 0;
 267         }
 268
 269         while (1) {
 270                 if (unlikely(idx >= vq->size)) {
 271                         free_ind_table(idesc);
 272                         return -1;
 273                 }
 274
 275
 276                 len += descs[idx].len;
 277                 desc_avail = descs[idx].len;
 278                 desc_iova = descs[idx].addr;
 279
 280                 while (desc_avail) {
 281                         uint64_t desc_addr;
 282                         uint64_t desc_chunck_len = desc_avail;
 283
 284                         if (unlikely(vec_id >= BUF_VECTOR_MAX)) {
 285                                 free_ind_table(idesc);
 286                                 return -1;
 287                         }
 288
 289                         desc_addr = vhost_iova_to_vva(dev, vq,
 290                                         desc_iova,
 291                                         &desc_chunck_len,
 292                                         perm);
 293                         if (unlikely(!desc_addr)) {
 294                                 free_ind_table(idesc);
 295                                 return -1;
 296                         }
 297
 298                         buf_vec[vec_id].buf_iova = desc_iova;
 299                         buf_vec[vec_id].buf_addr = desc_addr;
 300                         buf_vec[vec_id].buf_len  = desc_chunck_len;
 301                         buf_vec[vec_id].desc_idx = idx;
 302
 303                         desc_avail -= desc_chunck_len;
 304                         desc_iova += desc_chunck_len;
 305                         vec_id++;
 306                 }
 307
 308                 if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
 309                         break;
 310
 311                 idx = descs[idx].next;
 312         }
 313
 314         *desc_chain_len = len;
 315         *vec_idx = vec_id;
 316
 317         if (unlikely(!!idesc))
 318                 free_ind_table(idesc);
 319
 320         return 0;
 321 }
 322
 323 /*
 324  * Returns -1 on fail, 0 on success
 325  */
 326 static inline int
 327 reserve_avail_buf_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 328                                 uint32_t size, struct buf_vector *buf_vec,
 329                                 uint16_t *num_buffers, uint16_t avail_head,
 330                                 uint16_t *nr_vec)
 331 {
 332         uint16_t cur_idx;
 333         uint16_t vec_idx = 0;
 334         uint16_t max_tries, tries = 0;
 335
 336         uint16_t head_idx = 0;
 337         uint16_t len = 0;
 338
 339         *num_buffers = 0;
 340         cur_idx  = vq->last_avail_idx;
 341
 342         if (rxvq_is_mergeable(dev))
 343                 max_tries = vq->size;
 344         else
 345                 max_tries = 1;
 346
 347         while (size > 0) {
 348                 if (unlikely(cur_idx == avail_head))
 349                         return -1;
 350
 351                 if (unlikely(fill_vec_buf_split(dev, vq, cur_idx,
 352                                                 &vec_idx, buf_vec,
 353                                                 &head_idx, &len,
 354                                                 VHOST_ACCESS_RW) < 0))
 355                         return -1;
 356                 len = RTE_MIN(len, size);
 357                 update_shadow_used_ring_split(vq, head_idx, len);
 358                 size -= len;
 359
 360                 cur_idx++;
 361                 tries++;
 362                 *num_buffers += 1;
 363
 364                 /*
 365                  * if we tried all available ring items, and still
 366                  * can't get enough buf, it means something abnormal
 367                  * happened.
 368                  */
 369                 if (unlikely(tries > max_tries))
 370                         return -1;
 371         }
 372
 373         *nr_vec = vec_idx;
 374
 375         return 0;
 376 }
 377
 378 static __rte_always_inline int
 379 copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
 380                             struct rte_mbuf *m, struct buf_vector *buf_vec,
 381                             uint16_t nr_vec, uint16_t num_buffers)
 382 {
 383         uint32_t vec_idx = 0;
 384         uint32_t mbuf_offset, mbuf_avail;
 385         uint32_t buf_offset, buf_avail;
 386         uint64_t buf_addr, buf_iova, buf_len;
 387         uint32_t cpy_len;
 388         uint64_t hdr_addr;
 389         struct rte_mbuf *hdr_mbuf;
 390         struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
 391         struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
 392         int error = 0;
 393
 394         if (unlikely(m == NULL)) {
 395                 error = -1;
 396                 goto out;
 397         }
 398
 399         buf_addr = buf_vec[vec_idx].buf_addr;
 400         buf_iova = buf_vec[vec_idx].buf_iova;
 401         buf_len = buf_vec[vec_idx].buf_len;
 402
 403         if (nr_vec > 1)
 404                 rte_prefetch0((void *)(uintptr_t)buf_vec[1].buf_addr);
 405
 406         if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
 407                 error = -1;
 408                 goto out;
 409         }
 410
 411         hdr_mbuf = m;
 412         hdr_addr = buf_addr;
 413         if (unlikely(buf_len < dev->vhost_hlen))
 414                 hdr = &tmp_hdr;
 415         else
 416                 hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
 417
 418         VHOST_LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
 419                 dev->vid, num_buffers);
 420
 421         if (unlikely(buf_len < dev->vhost_hlen)) {
 422                 buf_offset = dev->vhost_hlen - buf_len;
 423                 vec_idx++;
 424                 buf_addr = buf_vec[vec_idx].buf_addr;
 425                 buf_iova = buf_vec[vec_idx].buf_iova;
 426                 buf_len = buf_vec[vec_idx].buf_len;
 427                 buf_avail = buf_len - buf_offset;
 428         } else {
 429                 buf_offset = dev->vhost_hlen;
 430                 buf_avail = buf_len - dev->vhost_hlen;
 431         }
 432
 433         mbuf_avail  = rte_pktmbuf_data_len(m);
 434         mbuf_offset = 0;
 435         while (mbuf_avail != 0 || m->next != NULL) {
 436                 /* done with current buf, get the next one */
 437                 if (buf_avail == 0) {
 438                         vec_idx++;
 439                         if (unlikely(vec_idx >= nr_vec)) {
 440                                 error = -1;
 441                                 goto out;
 442                         }
 443
 444                         buf_addr = buf_vec[vec_idx].buf_addr;
 445                         buf_iova = buf_vec[vec_idx].buf_iova;
 446                         buf_len = buf_vec[vec_idx].buf_len;
 447
 448                         /* Prefetch next buffer address. */
 449                         if (vec_idx + 1 < nr_vec)
 450                                 rte_prefetch0((void *)(uintptr_t)
 451                                                 buf_vec[vec_idx + 1].buf_addr);
 452                         buf_offset = 0;
 453                         buf_avail  = buf_len;
 454                 }
 455
 456                 /* done with current mbuf, get the next one */
 457                 if (mbuf_avail == 0) {
 458                         m = m->next;
 459
 460                         mbuf_offset = 0;
 461                         mbuf_avail  = rte_pktmbuf_data_len(m);
 462                 }
 463
 464                 if (hdr_addr) {
 465                         virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
 466                         if (rxvq_is_mergeable(dev))
 467                                 ASSIGN_UNLESS_EQUAL(hdr->num_buffers,
 468                                                 num_buffers);
 469
 470                         if (unlikely(hdr == &tmp_hdr)) {
 471                                 uint64_t len;
 472                                 uint64_t remain = dev->vhost_hlen;
 473                                 uint64_t src = (uint64_t)(uintptr_t)hdr, dst;
 474                                 uint64_t iova = buf_vec[0].buf_iova;
 475                                 uint16_t hdr_vec_idx = 0;
 476
 477                                 while (remain) {
 478                                         len = remain;
 479                                         dst = buf_vec[hdr_vec_idx].buf_addr;
 480                                         rte_memcpy((void *)(uintptr_t)dst,
 481                                                         (void *)(uintptr_t)src,
 482                                                         len);
 483
 484                                         PRINT_PACKET(dev, (uintptr_t)dst,
 485                                                         (uint32_t)len, 0);
 486                                         vhost_log_cache_write(dev, vq,
 487                                                         iova, len);
 488
 489                                         remain -= len;
 490                                         iova += len;
 491                                         src += len;
 492                                         hdr_vec_idx++;
 493                                 }
 494                         } else {
 495                                 PRINT_PACKET(dev, (uintptr_t)hdr_addr,
 496                                                 dev->vhost_hlen, 0);
 497                                 vhost_log_cache_write(dev, vq,
 498                                                 buf_vec[0].buf_iova,
 499                                                 dev->vhost_hlen);
 500                         }
 501
 502                         hdr_addr = 0;
 503                 }
 504
 505                 cpy_len = RTE_MIN(buf_len, mbuf_avail);
 506
 507                 if (likely(cpy_len > MAX_BATCH_LEN ||
 508                                         vq->batch_copy_nb_elems >= vq->size)) {
 509                         rte_memcpy((void *)((uintptr_t)(buf_addr + buf_offset)),
 510                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 511                                 cpy_len);
 512                         vhost_log_cache_write(dev, vq, buf_iova + buf_offset,
 513                                         cpy_len);
 514                         PRINT_PACKET(dev, (uintptr_t)(buf_addr + buf_offset),
 515                                 cpy_len, 0);
 516                 } else {
 517                         batch_copy[vq->batch_copy_nb_elems].dst =
 518                                 (void *)((uintptr_t)(buf_addr + buf_offset));
 519                         batch_copy[vq->batch_copy_nb_elems].src =
 520                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
 521                         batch_copy[vq->batch_copy_nb_elems].log_addr =
 522                                 buf_iova + buf_offset;
 523                         batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
 524                         vq->batch_copy_nb_elems++;
 525                 }
 526
 527                 mbuf_avail  -= cpy_len;
 528                 mbuf_offset += cpy_len;
 529                 buf_avail  -= cpy_len;
 530                 buf_offset += cpy_len;
 531         }
 532
 533 out:
 534
 535         return error;
 536 }
 537
 538 static __rte_always_inline uint32_t
 539 virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 540         struct rte_mbuf **pkts, uint32_t count)
 541 {
 542         uint32_t pkt_idx = 0;
 543         uint16_t num_buffers;
 544         struct buf_vector buf_vec[BUF_VECTOR_MAX];
 545         uint16_t avail_head;
 546
 547         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
 548         avail_head = *((volatile uint16_t *)&vq->avail->idx);
 549
 550         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 551                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 552                 uint16_t nr_vec = 0;
 553
 554                 if (unlikely(reserve_avail_buf_split(dev, vq,
 555                                                 pkt_len, buf_vec, &num_buffers,
 556                                                 avail_head, &nr_vec) < 0)) {
 557                         VHOST_LOG_DEBUG(VHOST_DATA,
 558                                 "(%d) failed to get enough desc from vring\n",
 559                                 dev->vid);
 560                         vq->shadow_used_idx -= num_buffers;
 561                         break;
 562                 }
 563
 564                 rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
 565
 566                 VHOST_LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 567                         dev->vid, vq->last_avail_idx,
 568                         vq->last_avail_idx + num_buffers);
 569
 570                 if (copy_mbuf_to_desc(dev, vq, pkts[pkt_idx],
 571                                                 buf_vec, nr_vec,
 572                                                 num_buffers) < 0) {
 573                         vq->shadow_used_idx -= num_buffers;
 574                         break;
 575                 }
 576
 577                 vq->last_avail_idx += num_buffers;
 578         }
 579
 580         do_data_copy_enqueue(dev, vq);
 581
 582         if (likely(vq->shadow_used_idx)) {
 583                 flush_shadow_used_ring_split(dev, vq);
 584                 vhost_vring_call(dev, vq);
 585         }
 586
 587         return pkt_idx;
 588 }
 589
 590 static __rte_always_inline uint32_t
 591 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 592         struct rte_mbuf **pkts, uint32_t count)
 593 {
 594         struct vhost_virtqueue *vq;
 595
 596         VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 597         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
 598                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 599                         dev->vid, __func__, queue_id);
 600                 return 0;
 601         }
 602
 603         vq = dev->virtqueue[queue_id];
 604
 605         rte_spinlock_lock(&vq->access_lock);
 606
 607         if (unlikely(vq->enabled == 0))
 608                 goto out_access_unlock;
 609
 610         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 611                 vhost_user_iotlb_rd_lock(vq);
 612
 613         if (unlikely(vq->access_ok == 0))
 614                 if (unlikely(vring_translate(dev, vq) < 0))
 615                         goto out;
 616
 617         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 618         if (count == 0)
 619                 goto out;
 620
 621         count = virtio_dev_rx_split(dev, vq, pkts, count);
 622
 623 out:
 624         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 625                 vhost_user_iotlb_rd_unlock(vq);
 626
 627 out_access_unlock:
 628         rte_spinlock_unlock(&vq->access_lock);
 629
 630         return count;
 631 }
 632
 633 uint16_t
 634 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 635         struct rte_mbuf **pkts, uint16_t count)
 636 {
 637         struct virtio_net *dev = get_device(vid);
 638
 639         if (!dev)
 640                 return 0;
 641
 642         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 643                 RTE_LOG(ERR, VHOST_DATA,
 644                         "(%d) %s: built-in vhost net backend is disabled.\n",
 645                         dev->vid, __func__);
 646                 return 0;
 647         }
 648
 649         return virtio_dev_rx(dev, queue_id, pkts, count);
 650 }
 651
 652 static inline bool
 653 virtio_net_with_host_offload(struct virtio_net *dev)
 654 {
 655         if (dev->features &
 656                         ((1ULL << VIRTIO_NET_F_CSUM) |
 657                          (1ULL << VIRTIO_NET_F_HOST_ECN) |
 658                          (1ULL << VIRTIO_NET_F_HOST_TSO4) |
 659                          (1ULL << VIRTIO_NET_F_HOST_TSO6) |
 660                          (1ULL << VIRTIO_NET_F_HOST_UFO)))
 661                 return true;
 662
 663         return false;
 664 }
 665
 666 static void
 667 parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
 668 {
 669         struct ipv4_hdr *ipv4_hdr;
 670         struct ipv6_hdr *ipv6_hdr;
 671         void *l3_hdr = NULL;
 672         struct ether_hdr *eth_hdr;
 673         uint16_t ethertype;
 674
 675         eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
 676
 677         m->l2_len = sizeof(struct ether_hdr);
 678         ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
 679
 680         if (ethertype == ETHER_TYPE_VLAN) {
 681                 struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
 682
 683                 m->l2_len += sizeof(struct vlan_hdr);
 684                 ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
 685         }
 686
 687         l3_hdr = (char *)eth_hdr + m->l2_len;
 688
 689         switch (ethertype) {
 690         case ETHER_TYPE_IPv4:
 691                 ipv4_hdr = l3_hdr;
 692                 *l4_proto = ipv4_hdr->next_proto_id;
 693                 m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
 694                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 695                 m->ol_flags |= PKT_TX_IPV4;
 696                 break;
 697         case ETHER_TYPE_IPv6:
 698                 ipv6_hdr = l3_hdr;
 699                 *l4_proto = ipv6_hdr->proto;
 700                 m->l3_len = sizeof(struct ipv6_hdr);
 701                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 702                 m->ol_flags |= PKT_TX_IPV6;
 703                 break;
 704         default:
 705                 m->l3_len = 0;
 706                 *l4_proto = 0;
 707                 *l4_hdr = NULL;
 708                 break;
 709         }
 710 }
 711
 712 static __rte_always_inline void
 713 vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 714 {
 715         uint16_t l4_proto = 0;
 716         void *l4_hdr = NULL;
 717         struct tcp_hdr *tcp_hdr = NULL;
 718
 719         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 720                 return;
 721
 722         parse_ethernet(m, &l4_proto, &l4_hdr);
 723         if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 724                 if (hdr->csum_start == (m->l2_len + m->l3_len)) {
 725                         switch (hdr->csum_offset) {
 726                         case (offsetof(struct tcp_hdr, cksum)):
 727                                 if (l4_proto == IPPROTO_TCP)
 728                                         m->ol_flags |= PKT_TX_TCP_CKSUM;
 729                                 break;
 730                         case (offsetof(struct udp_hdr, dgram_cksum)):
 731                                 if (l4_proto == IPPROTO_UDP)
 732                                         m->ol_flags |= PKT_TX_UDP_CKSUM;
 733                                 break;
 734                         case (offsetof(struct sctp_hdr, cksum)):
 735                                 if (l4_proto == IPPROTO_SCTP)
 736                                         m->ol_flags |= PKT_TX_SCTP_CKSUM;
 737                                 break;
 738                         default:
 739                                 break;
 740                         }
 741                 }
 742         }
 743
 744         if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 745                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 746                 case VIRTIO_NET_HDR_GSO_TCPV4:
 747                 case VIRTIO_NET_HDR_GSO_TCPV6:
 748                         tcp_hdr = l4_hdr;
 749                         m->ol_flags |= PKT_TX_TCP_SEG;
 750                         m->tso_segsz = hdr->gso_size;
 751                         m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 752                         break;
 753                 case VIRTIO_NET_HDR_GSO_UDP:
 754                         m->ol_flags |= PKT_TX_UDP_SEG;
 755                         m->tso_segsz = hdr->gso_size;
 756                         m->l4_len = sizeof(struct udp_hdr);
 757                         break;
 758                 default:
 759                         RTE_LOG(WARNING, VHOST_DATA,
 760                                 "unsupported gso type %u.\n", hdr->gso_type);
 761                         break;
 762                 }
 763         }
 764 }
 765
 766 static __rte_always_inline void
 767 put_zmbuf(struct zcopy_mbuf *zmbuf)
 768 {
 769         zmbuf->in_use = 0;
 770 }
 771
 772 static __rte_always_inline int
 773 copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 774                   struct buf_vector *buf_vec, uint16_t nr_vec,
 775                   struct rte_mbuf *m, struct rte_mempool *mbuf_pool)
 776 {
 777         uint32_t buf_avail, buf_offset;
 778         uint64_t buf_addr, buf_iova, buf_len;
 779         uint32_t mbuf_avail, mbuf_offset;
 780         uint32_t cpy_len;
 781         struct rte_mbuf *cur = m, *prev = m;
 782         struct virtio_net_hdr tmp_hdr;
 783         struct virtio_net_hdr *hdr = NULL;
 784         /* A counter to avoid desc dead loop chain */
 785         uint16_t vec_idx = 0;
 786         struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
 787         int error = 0;
 788
 789         buf_addr = buf_vec[vec_idx].buf_addr;
 790         buf_iova = buf_vec[vec_idx].buf_iova;
 791         buf_len = buf_vec[vec_idx].buf_len;
 792
 793         if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
 794                 error = -1;
 795                 goto out;
 796         }
 797
 798         if (likely(nr_vec > 1))
 799                 rte_prefetch0((void *)(uintptr_t)buf_vec[1].buf_addr);
 800
 801         if (virtio_net_with_host_offload(dev)) {
 802                 if (unlikely(buf_len < sizeof(struct virtio_net_hdr))) {
 803                         uint64_t len;
 804                         uint64_t remain = sizeof(struct virtio_net_hdr);
 805                         uint64_t src;
 806                         uint64_t dst = (uint64_t)(uintptr_t)&tmp_hdr;
 807                         uint16_t hdr_vec_idx = 0;
 808
 809                         /*
 810                          * No luck, the virtio-net header doesn't fit
 811                          * in a contiguous virtual area.
 812                          */
 813                         while (remain) {
 814                                 len = remain;
 815                                 src = buf_vec[hdr_vec_idx].buf_addr;
 816                                 rte_memcpy((void *)(uintptr_t)dst,
 817                                                    (void *)(uintptr_t)src, len);
 818
 819                                 remain -= len;
 820                                 dst += len;
 821                                 hdr_vec_idx++;
 822                         }
 823
 824                         hdr = &tmp_hdr;
 825                 } else {
 826                         hdr = (struct virtio_net_hdr *)((uintptr_t)buf_addr);
 827                         rte_prefetch0(hdr);
 828                 }
 829         }
 830
 831         /*
 832          * A virtio driver normally uses at least 2 desc buffers
 833          * for Tx: the first for storing the header, and others
 834          * for storing the data.
 835          */
 836         if (unlikely(buf_len < dev->vhost_hlen)) {
 837                 buf_offset = dev->vhost_hlen - buf_len;
 838                 vec_idx++;
 839                 buf_addr = buf_vec[vec_idx].buf_addr;
 840                 buf_iova = buf_vec[vec_idx].buf_iova;
 841                 buf_len = buf_vec[vec_idx].buf_len;
 842                 buf_avail  = buf_len - buf_offset;
 843         } else if (buf_len == dev->vhost_hlen) {
 844                 if (unlikely(++vec_idx >= nr_vec))
 845                         goto out;
 846                 buf_addr = buf_vec[vec_idx].buf_addr;
 847                 buf_iova = buf_vec[vec_idx].buf_iova;
 848                 buf_len = buf_vec[vec_idx].buf_len;
 849
 850                 buf_offset = 0;
 851                 buf_avail = buf_len;
 852         } else {
 853                 buf_offset = dev->vhost_hlen;
 854                 buf_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
 855         }
 856
 857         rte_prefetch0((void *)(uintptr_t)
 858                         (buf_addr + buf_offset));
 859
 860         PRINT_PACKET(dev,
 861                         (uintptr_t)(buf_addr + buf_offset),
 862                         (uint32_t)buf_avail, 0);
 863
 864         mbuf_offset = 0;
 865         mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 866         while (1) {
 867                 uint64_t hpa;
 868
 869                 cpy_len = RTE_MIN(buf_avail, mbuf_avail);
 870
 871                 /*
 872                  * A desc buf might across two host physical pages that are
 873                  * not continuous. In such case (gpa_to_hpa returns 0), data
 874                  * will be copied even though zero copy is enabled.
 875                  */
 876                 if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
 877                                         buf_iova + buf_offset, cpy_len)))) {
 878                         cur->data_len = cpy_len;
 879                         cur->data_off = 0;
 880                         cur->buf_addr =
 881                                 (void *)(uintptr_t)(buf_addr + buf_offset);
 882                         cur->buf_iova = hpa;
 883
 884                         /*
 885                          * In zero copy mode, one mbuf can only reference data
 886                          * for one or partial of one desc buff.
 887                          */
 888                         mbuf_avail = cpy_len;
 889                 } else {
 890                         if (likely(cpy_len > MAX_BATCH_LEN ||
 891                                    vq->batch_copy_nb_elems >= vq->size ||
 892                                    (hdr && cur == m))) {
 893                                 rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 894                                                                    mbuf_offset),
 895                                            (void *)((uintptr_t)(buf_addr +
 896                                                            buf_offset)),
 897                                            cpy_len);
 898                         } else {
 899                                 batch_copy[vq->batch_copy_nb_elems].dst =
 900                                         rte_pktmbuf_mtod_offset(cur, void *,
 901                                                                 mbuf_offset);
 902                                 batch_copy[vq->batch_copy_nb_elems].src =
 903                                         (void *)((uintptr_t)(buf_addr +
 904                                                                 buf_offset));
 905                                 batch_copy[vq->batch_copy_nb_elems].len =
 906                                         cpy_len;
 907                                 vq->batch_copy_nb_elems++;
 908                         }
 909                 }
 910
 911                 mbuf_avail  -= cpy_len;
 912                 mbuf_offset += cpy_len;
 913                 buf_avail -= cpy_len;
 914                 buf_offset += cpy_len;
 915
 916                 /* This buf reaches to its end, get the next one */
 917                 if (buf_avail == 0) {
 918                         if (++vec_idx >= nr_vec)
 919                                 break;
 920
 921                         buf_addr = buf_vec[vec_idx].buf_addr;
 922                         buf_iova = buf_vec[vec_idx].buf_iova;
 923                         buf_len = buf_vec[vec_idx].buf_len;
 924
 925                         /*
 926                          * Prefecth desc n + 1 buffer while
 927                          * desc n buffer is processed.
 928                          */
 929                         if (vec_idx + 1 < nr_vec)
 930                                 rte_prefetch0((void *)(uintptr_t)
 931                                                 buf_vec[vec_idx + 1].buf_addr);
 932
 933                         buf_offset = 0;
 934                         buf_avail  = buf_len;
 935
 936                         PRINT_PACKET(dev, (uintptr_t)buf_addr,
 937                                         (uint32_t)buf_avail, 0);
 938                 }
 939
 940                 /*
 941                  * This mbuf reaches to its end, get a new one
 942                  * to hold more data.
 943                  */
 944                 if (mbuf_avail == 0) {
 945                         cur = rte_pktmbuf_alloc(mbuf_pool);
 946                         if (unlikely(cur == NULL)) {
 947                                 RTE_LOG(ERR, VHOST_DATA, "Failed to "
 948                                         "allocate memory for mbuf.\n");
 949                                 error = -1;
 950                                 goto out;
 951                         }
 952                         if (unlikely(dev->dequeue_zero_copy))
 953                                 rte_mbuf_refcnt_update(cur, 1);
 954
 955                         prev->next = cur;
 956                         prev->data_len = mbuf_offset;
 957                         m->nb_segs += 1;
 958                         m->pkt_len += mbuf_offset;
 959                         prev = cur;
 960
 961                         mbuf_offset = 0;
 962                         mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 963                 }
 964         }
 965
 966         prev->data_len = mbuf_offset;
 967         m->pkt_len    += mbuf_offset;
 968
 969         if (hdr)
 970                 vhost_dequeue_offload(hdr, m);
 971
 972 out:
 973
 974         return error;
 975 }
 976
 977 static __rte_always_inline struct zcopy_mbuf *
 978 get_zmbuf(struct vhost_virtqueue *vq)
 979 {
 980         uint16_t i;
 981         uint16_t last;
 982         int tries = 0;
 983
 984         /* search [last_zmbuf_idx, zmbuf_size) */
 985         i = vq->last_zmbuf_idx;
 986         last = vq->zmbuf_size;
 987
 988 again:
 989         for (; i < last; i++) {
 990                 if (vq->zmbufs[i].in_use == 0) {
 991                         vq->last_zmbuf_idx = i + 1;
 992                         vq->zmbufs[i].in_use = 1;
 993                         return &vq->zmbufs[i];
 994                 }
 995         }
 996
 997         tries++;
 998         if (tries == 1) {
 999                 /* search [0, last_zmbuf_idx) */
1000                 i = 0;
1001                 last = vq->last_zmbuf_idx;
1002                 goto again;
1003         }
1004
1005         return NULL;
1006 }
1007
1008 static __rte_always_inline bool
1009 mbuf_is_consumed(struct rte_mbuf *m)
1010 {
1011         while (m) {
1012                 if (rte_mbuf_refcnt_read(m) > 1)
1013                         return false;
1014                 m = m->next;
1015         }
1016
1017         return true;
1018 }
1019
1020 static __rte_always_inline void
1021 restore_mbuf(struct rte_mbuf *m)
1022 {
1023         uint32_t mbuf_size, priv_size;
1024
1025         while (m) {
1026                 priv_size = rte_pktmbuf_priv_size(m->pool);
1027                 mbuf_size = sizeof(struct rte_mbuf) + priv_size;
1028                 /* start of buffer is after mbuf structure and priv data */
1029
1030                 m->buf_addr = (char *)m + mbuf_size;
1031                 m->buf_iova = rte_mempool_virt2iova(m) + mbuf_size;
1032                 m = m->next;
1033         }
1034 }
1035
1036 static __rte_always_inline uint16_t
1037 virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
1038         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
1039 {
1040         uint16_t i;
1041         uint16_t free_entries;
1042
1043         if (unlikely(dev->dequeue_zero_copy)) {
1044                 struct zcopy_mbuf *zmbuf, *next;
1045                 int nr_updated = 0;
1046
1047                 for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
1048                      zmbuf != NULL; zmbuf = next) {
1049                         next = TAILQ_NEXT(zmbuf, next);
1050
1051                         if (mbuf_is_consumed(zmbuf->mbuf)) {
1052                                 update_shadow_used_ring_split(vq,
1053                                                 zmbuf->desc_idx, 0);
1054                                 nr_updated += 1;
1055
1056                                 TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
1057                                 restore_mbuf(zmbuf->mbuf);
1058                                 rte_pktmbuf_free(zmbuf->mbuf);
1059                                 put_zmbuf(zmbuf);
1060                                 vq->nr_zmbuf -= 1;
1061                         }
1062                 }
1063
1064                 flush_shadow_used_ring_split(dev, vq);
1065                 vhost_vring_call(dev, vq);
1066         }
1067
1068         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
1069
1070         free_entries = *((volatile uint16_t *)&vq->avail->idx) -
1071                         vq->last_avail_idx;
1072         if (free_entries == 0)
1073                 return 0;
1074
1075         VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
1076
1077         count = RTE_MIN(count, MAX_PKT_BURST);
1078         count = RTE_MIN(count, free_entries);
1079         VHOST_LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n",
1080                         dev->vid, count);
1081
1082         for (i = 0; i < count; i++) {
1083                 struct buf_vector buf_vec[BUF_VECTOR_MAX];
1084                 uint16_t head_idx, dummy_len;
1085                 uint16_t nr_vec = 0;
1086                 int err;
1087
1088                 if (unlikely(fill_vec_buf_split(dev, vq,
1089                                                 vq->last_avail_idx + i,
1090                                                 &nr_vec, buf_vec,
1091                                                 &head_idx, &dummy_len,
1092                                                 VHOST_ACCESS_RO) < 0))
1093                         break;
1094
1095                 if (likely(dev->dequeue_zero_copy == 0))
1096                         update_shadow_used_ring_split(vq, head_idx, 0);
1097
1098                 rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
1099
1100                 pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
1101                 if (unlikely(pkts[i] == NULL)) {
1102                         RTE_LOG(ERR, VHOST_DATA,
1103                                 "Failed to allocate memory for mbuf.\n");
1104                         break;
1105                 }
1106
1107                 err = copy_desc_to_mbuf(dev, vq, buf_vec, nr_vec, pkts[i],
1108                                 mbuf_pool);
1109                 if (unlikely(err)) {
1110                         rte_pktmbuf_free(pkts[i]);
1111                         break;
1112                 }
1113
1114                 if (unlikely(dev->dequeue_zero_copy)) {
1115                         struct zcopy_mbuf *zmbuf;
1116
1117                         zmbuf = get_zmbuf(vq);
1118                         if (!zmbuf) {
1119                                 rte_pktmbuf_free(pkts[i]);
1120                                 break;
1121                         }
1122                         zmbuf->mbuf = pkts[i];
1123                         zmbuf->desc_idx = head_idx;
1124
1125                         /*
1126                          * Pin lock the mbuf; we will check later to see
1127                          * whether the mbuf is freed (when we are the last
1128                          * user) or not. If that's the case, we then could
1129                          * update the used ring safely.
1130                          */
1131                         rte_mbuf_refcnt_update(pkts[i], 1);
1132
1133                         vq->nr_zmbuf += 1;
1134                         TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
1135                 }
1136         }
1137         vq->last_avail_idx += i;
1138
1139         if (likely(dev->dequeue_zero_copy == 0)) {
1140                 do_data_copy_dequeue(vq);
1141                 if (unlikely(i < count))
1142                         vq->shadow_used_idx = i;
1143                 flush_shadow_used_ring_split(dev, vq);
1144                 vhost_vring_call(dev, vq);
1145         }
1146
1147         return i;
1148 }
1149
1150 uint16_t
1151 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
1152         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
1153 {
1154         struct virtio_net *dev;
1155         struct rte_mbuf *rarp_mbuf = NULL;
1156         struct vhost_virtqueue *vq;
1157
1158         dev = get_device(vid);
1159         if (!dev)
1160                 return 0;
1161
1162         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
1163                 RTE_LOG(ERR, VHOST_DATA,
1164                         "(%d) %s: built-in vhost net backend is disabled.\n",
1165                         dev->vid, __func__);
1166                 return 0;
1167         }
1168
1169         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {
1170                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
1171                         dev->vid, __func__, queue_id);
1172                 return 0;
1173         }
1174
1175         vq = dev->virtqueue[queue_id];
1176
1177         if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0))
1178                 return 0;
1179
1180         if (unlikely(vq->enabled == 0))
1181                 goto out_access_unlock;
1182
1183         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1184                 vhost_user_iotlb_rd_lock(vq);
1185
1186         if (unlikely(vq->access_ok == 0))
1187                 if (unlikely(vring_translate(dev, vq) < 0))
1188                         goto out;
1189
1190         /*
1191          * Construct a RARP broadcast packet, and inject it to the "pkts"
1192          * array, to looks like that guest actually send such packet.
1193          *
1194          * Check user_send_rarp() for more information.
1195          *
1196          * broadcast_rarp shares a cacheline in the virtio_net structure
1197          * with some fields that are accessed during enqueue and
1198          * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
1199          * result in false sharing between enqueue and dequeue.
1200          *
1201          * Prevent unnecessary false sharing by reading broadcast_rarp first
1202          * and only performing cmpset if the read indicates it is likely to
1203          * be set.
1204          */
1205         if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
1206                         rte_atomic16_cmpset((volatile uint16_t *)
1207                                 &dev->broadcast_rarp.cnt, 1, 0))) {
1208
1209                 rarp_mbuf = rte_net_make_rarp_packet(mbuf_pool, &dev->mac);
1210                 if (rarp_mbuf == NULL) {
1211                         RTE_LOG(ERR, VHOST_DATA,
1212                                 "Failed to make RARP packet.\n");
1213                         return 0;
1214                 }
1215                 count -= 1;
1216         }
1217
1218         count = virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count);
1219
1220 out:
1221         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1222                 vhost_user_iotlb_rd_unlock(vq);
1223
1224 out_access_unlock:
1225         rte_spinlock_unlock(&vq->access_lock);
1226
1227         if (unlikely(rarp_mbuf != NULL)) {
1228                 /*
1229                  * Inject it to the head of "pkts" array, so that switch's mac
1230                  * learning table will get updated first.
1231                  */
1232                 memmove(&pkts[1], pkts, count * sizeof(struct rte_mbuf *));
1233                 pkts[0] = rarp_mbuf;
1234                 count += 1;
1235         }
1236
1237         return count;
1238 }