lib/librte_vhost/virtio_net.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <stdint.h>
  35 #include <stdbool.h>
  36 #include <linux/virtio_net.h>
  37
  38 #include <rte_mbuf.h>
  39 #include <rte_memcpy.h>
  40 #include <rte_ether.h>
  41 #include <rte_ip.h>
  42 #include <rte_vhost.h>
  43 #include <rte_tcp.h>
  44 #include <rte_udp.h>
  45 #include <rte_sctp.h>
  46 #include <rte_arp.h>
  47
  48 #include "vhost.h"
  49
  50 #define MAX_PKT_BURST 32
  51
  52 static bool
  53 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
  54 {
  55         return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring;
  56 }
  57
  58 static __rte_always_inline void
  59 do_flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
  60                           uint16_t to, uint16_t from, uint16_t size)
  61 {
  62         rte_memcpy(&vq->used->ring[to],
  63                         &vq->shadow_used_ring[from],
  64                         size * sizeof(struct vring_used_elem));
  65         vhost_log_used_vring(dev, vq,
  66                         offsetof(struct vring_used, ring[to]),
  67                         size * sizeof(struct vring_used_elem));
  68 }
  69
  70 static __rte_always_inline void
  71 flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq)
  72 {
  73         uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
  74
  75         if (used_idx + vq->shadow_used_idx <= vq->size) {
  76                 do_flush_shadow_used_ring(dev, vq, used_idx, 0,
  77                                           vq->shadow_used_idx);
  78         } else {
  79                 uint16_t size;
  80
  81                 /* update used ring interval [used_idx, vq->size] */
  82                 size = vq->size - used_idx;
  83                 do_flush_shadow_used_ring(dev, vq, used_idx, 0, size);
  84
  85                 /* update the left half used ring interval [0, left_size] */
  86                 do_flush_shadow_used_ring(dev, vq, 0, size,
  87                                           vq->shadow_used_idx - size);
  88         }
  89         vq->last_used_idx += vq->shadow_used_idx;
  90
  91         rte_smp_wmb();
  92
  93         *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx;
  94         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
  95                 sizeof(vq->used->idx));
  96 }
  97
  98 static __rte_always_inline void
  99 update_shadow_used_ring(struct vhost_virtqueue *vq,
 100                          uint16_t desc_idx, uint16_t len)
 101 {
 102         uint16_t i = vq->shadow_used_idx++;
 103
 104         vq->shadow_used_ring[i].id  = desc_idx;
 105         vq->shadow_used_ring[i].len = len;
 106 }
 107
 108 /* avoid write operation when necessary, to lessen cache issues */
 109 #define ASSIGN_UNLESS_EQUAL(var, val) do {      \
 110         if ((var) != (val))                     \
 111                 (var) = (val);                  \
 112 } while (0)
 113
 114 static void
 115 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 116 {
 117         uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK;
 118
 119         if (m_buf->ol_flags & PKT_TX_TCP_SEG)
 120                 csum_l4 |= PKT_TX_TCP_CKSUM;
 121
 122         if (csum_l4) {
 123                 net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 124                 net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
 125
 126                 switch (csum_l4) {
 127                 case PKT_TX_TCP_CKSUM:
 128                         net_hdr->csum_offset = (offsetof(struct tcp_hdr,
 129                                                 cksum));
 130                         break;
 131                 case PKT_TX_UDP_CKSUM:
 132                         net_hdr->csum_offset = (offsetof(struct udp_hdr,
 133                                                 dgram_cksum));
 134                         break;
 135                 case PKT_TX_SCTP_CKSUM:
 136                         net_hdr->csum_offset = (offsetof(struct sctp_hdr,
 137                                                 cksum));
 138                         break;
 139                 }
 140         } else {
 141                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_start, 0);
 142                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0);
 143                 ASSIGN_UNLESS_EQUAL(net_hdr->flags, 0);
 144         }
 145
 146         /* IP cksum verification cannot be bypassed, then calculate here */
 147         if (m_buf->ol_flags & PKT_TX_IP_CKSUM) {
 148                 struct ipv4_hdr *ipv4_hdr;
 149
 150                 ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct ipv4_hdr *,
 151                                                    m_buf->l2_len);
 152                 ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
 153         }
 154
 155         if (m_buf->ol_flags & PKT_TX_TCP_SEG) {
 156                 if (m_buf->ol_flags & PKT_TX_IPV4)
 157                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 158                 else
 159                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 160                 net_hdr->gso_size = m_buf->tso_segsz;
 161                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 162                                         + m_buf->l4_len;
 163         } else {
 164                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0);
 165                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0);
 166                 ASSIGN_UNLESS_EQUAL(net_hdr->hdr_len, 0);
 167         }
 168 }
 169
 170 static __rte_always_inline int
 171 copy_mbuf_to_desc(struct virtio_net *dev, struct vring_desc *descs,
 172                   struct rte_mbuf *m, uint16_t desc_idx, uint32_t size)
 173 {
 174         uint32_t desc_avail, desc_offset;
 175         uint32_t mbuf_avail, mbuf_offset;
 176         uint32_t cpy_len;
 177         struct vring_desc *desc;
 178         uint64_t desc_addr;
 179         /* A counter to avoid desc dead loop chain */
 180         uint16_t nr_desc = 1;
 181
 182         desc = &descs[desc_idx];
 183         desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
 184         /*
 185          * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
 186          * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
 187          * otherwise stores offset on the stack instead of in a register.
 188          */
 189         if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
 190                 return -1;
 191
 192         rte_prefetch0((void *)(uintptr_t)desc_addr);
 193
 194         virtio_enqueue_offload(m, (struct virtio_net_hdr *)(uintptr_t)desc_addr);
 195         vhost_log_write(dev, desc->addr, dev->vhost_hlen);
 196         PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
 197
 198         desc_offset = dev->vhost_hlen;
 199         desc_avail  = desc->len - dev->vhost_hlen;
 200
 201         mbuf_avail  = rte_pktmbuf_data_len(m);
 202         mbuf_offset = 0;
 203         while (mbuf_avail != 0 || m->next != NULL) {
 204                 /* done with current mbuf, fetch next */
 205                 if (mbuf_avail == 0) {
 206                         m = m->next;
 207
 208                         mbuf_offset = 0;
 209                         mbuf_avail  = rte_pktmbuf_data_len(m);
 210                 }
 211
 212                 /* done with current desc buf, fetch next */
 213                 if (desc_avail == 0) {
 214                         if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
 215                                 /* Room in vring buffer is not enough */
 216                                 return -1;
 217                         }
 218                         if (unlikely(desc->next >= size || ++nr_desc > size))
 219                                 return -1;
 220
 221                         desc = &descs[desc->next];
 222                         desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
 223                         if (unlikely(!desc_addr))
 224                                 return -1;
 225
 226                         desc_offset = 0;
 227                         desc_avail  = desc->len;
 228                 }
 229
 230                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 231                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 232                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 233                         cpy_len);
 234                 vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
 235                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 236                              cpy_len, 0);
 237
 238                 mbuf_avail  -= cpy_len;
 239                 mbuf_offset += cpy_len;
 240                 desc_avail  -= cpy_len;
 241                 desc_offset += cpy_len;
 242         }
 243
 244         return 0;
 245 }
 246
 247 /**
 248  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 249  * be received from the physical port or from another virtio device. A packet
 250  * count is returned to indicate the number of packets that are successfully
 251  * added to the RX queue. This function works when the mbuf is scattered, but
 252  * it doesn't support the mergeable feature.
 253  */
 254 static __rte_always_inline uint32_t
 255 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 256               struct rte_mbuf **pkts, uint32_t count)
 257 {
 258         struct vhost_virtqueue *vq;
 259         uint16_t avail_idx, free_entries, start_idx;
 260         uint16_t desc_indexes[MAX_PKT_BURST];
 261         struct vring_desc *descs;
 262         uint16_t used_idx;
 263         uint32_t i, sz;
 264
 265         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 266         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
 267                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 268                         dev->vid, __func__, queue_id);
 269                 return 0;
 270         }
 271
 272         vq = dev->virtqueue[queue_id];
 273         if (unlikely(vq->enabled == 0))
 274                 return 0;
 275
 276         avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 277         start_idx = vq->last_used_idx;
 278         free_entries = avail_idx - start_idx;
 279         count = RTE_MIN(count, free_entries);
 280         count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
 281         if (count == 0)
 282                 return 0;
 283
 284         LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
 285                 dev->vid, start_idx, start_idx + count);
 286
 287         /* Retrieve all of the desc indexes first to avoid caching issues. */
 288         rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
 289         for (i = 0; i < count; i++) {
 290                 used_idx = (start_idx + i) & (vq->size - 1);
 291                 desc_indexes[i] = vq->avail->ring[used_idx];
 292                 vq->used->ring[used_idx].id = desc_indexes[i];
 293                 vq->used->ring[used_idx].len = pkts[i]->pkt_len +
 294                                                dev->vhost_hlen;
 295                 vhost_log_used_vring(dev, vq,
 296                         offsetof(struct vring_used, ring[used_idx]),
 297                         sizeof(vq->used->ring[used_idx]));
 298         }
 299
 300         rte_prefetch0(&vq->desc[desc_indexes[0]]);
 301         for (i = 0; i < count; i++) {
 302                 uint16_t desc_idx = desc_indexes[i];
 303                 int err;
 304
 305                 if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
 306                         descs = (struct vring_desc *)(uintptr_t)
 307                                 rte_vhost_gpa_to_vva(dev->mem,
 308                                         vq->desc[desc_idx].addr);
 309                         if (unlikely(!descs)) {
 310                                 count = i;
 311                                 break;
 312                         }
 313
 314                         desc_idx = 0;
 315                         sz = vq->desc[desc_idx].len / sizeof(*descs);
 316                 } else {
 317                         descs = vq->desc;
 318                         sz = vq->size;
 319                 }
 320
 321                 err = copy_mbuf_to_desc(dev, descs, pkts[i], desc_idx, sz);
 322                 if (unlikely(err)) {
 323                         used_idx = (start_idx + i) & (vq->size - 1);
 324                         vq->used->ring[used_idx].len = dev->vhost_hlen;
 325                         vhost_log_used_vring(dev, vq,
 326                                 offsetof(struct vring_used, ring[used_idx]),
 327                                 sizeof(vq->used->ring[used_idx]));
 328                 }
 329
 330                 if (i + 1 < count)
 331                         rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
 332         }
 333
 334         rte_smp_wmb();
 335
 336         *(volatile uint16_t *)&vq->used->idx += count;
 337         vq->last_used_idx += count;
 338         vhost_log_used_vring(dev, vq,
 339                 offsetof(struct vring_used, idx),
 340                 sizeof(vq->used->idx));
 341
 342         /* flush used->idx update before we read avail->flags. */
 343         rte_mb();
 344
 345         /* Kick the guest if necessary. */
 346         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 347                         && (vq->callfd >= 0))
 348                 eventfd_write(vq->callfd, (eventfd_t)1);
 349         return count;
 350 }
 351
 352 static __rte_always_inline int
 353 fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 354                          uint32_t avail_idx, uint32_t *vec_idx,
 355                          struct buf_vector *buf_vec, uint16_t *desc_chain_head,
 356                          uint16_t *desc_chain_len)
 357 {
 358         uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
 359         uint32_t vec_id = *vec_idx;
 360         uint32_t len    = 0;
 361         struct vring_desc *descs = vq->desc;
 362
 363         *desc_chain_head = idx;
 364
 365         if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
 366                 descs = (struct vring_desc *)(uintptr_t)
 367                         rte_vhost_gpa_to_vva(dev->mem, vq->desc[idx].addr);
 368                 if (unlikely(!descs))
 369                         return -1;
 370
 371                 idx = 0;
 372         }
 373
 374         while (1) {
 375                 if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
 376                         return -1;
 377
 378                 len += descs[idx].len;
 379                 buf_vec[vec_id].buf_addr = descs[idx].addr;
 380                 buf_vec[vec_id].buf_len  = descs[idx].len;
 381                 buf_vec[vec_id].desc_idx = idx;
 382                 vec_id++;
 383
 384                 if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
 385                         break;
 386
 387                 idx = descs[idx].next;
 388         }
 389
 390         *desc_chain_len = len;
 391         *vec_idx = vec_id;
 392
 393         return 0;
 394 }
 395
 396 /*
 397  * Returns -1 on fail, 0 on success
 398  */
 399 static inline int
 400 reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 401                                 uint32_t size, struct buf_vector *buf_vec,
 402                                 uint16_t *num_buffers, uint16_t avail_head)
 403 {
 404         uint16_t cur_idx;
 405         uint32_t vec_idx = 0;
 406         uint16_t tries = 0;
 407
 408         uint16_t head_idx = 0;
 409         uint16_t len = 0;
 410
 411         *num_buffers = 0;
 412         cur_idx  = vq->last_avail_idx;
 413
 414         while (size > 0) {
 415                 if (unlikely(cur_idx == avail_head))
 416                         return -1;
 417
 418                 if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec,
 419                                                 &head_idx, &len) < 0))
 420                         return -1;
 421                 len = RTE_MIN(len, size);
 422                 update_shadow_used_ring(vq, head_idx, len);
 423                 size -= len;
 424
 425                 cur_idx++;
 426                 tries++;
 427                 *num_buffers += 1;
 428
 429                 /*
 430                  * if we tried all available ring items, and still
 431                  * can't get enough buf, it means something abnormal
 432                  * happened.
 433                  */
 434                 if (unlikely(tries >= vq->size))
 435                         return -1;
 436         }
 437
 438         return 0;
 439 }
 440
 441 static __rte_always_inline int
 442 copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct rte_mbuf *m,
 443                             struct buf_vector *buf_vec, uint16_t num_buffers)
 444 {
 445         uint32_t vec_idx = 0;
 446         uint64_t desc_addr;
 447         uint32_t mbuf_offset, mbuf_avail;
 448         uint32_t desc_offset, desc_avail;
 449         uint32_t cpy_len;
 450         uint64_t hdr_addr, hdr_phys_addr;
 451         struct rte_mbuf *hdr_mbuf;
 452
 453         if (unlikely(m == NULL))
 454                 return -1;
 455
 456         desc_addr = rte_vhost_gpa_to_vva(dev->mem, buf_vec[vec_idx].buf_addr);
 457         if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr)
 458                 return -1;
 459
 460         hdr_mbuf = m;
 461         hdr_addr = desc_addr;
 462         hdr_phys_addr = buf_vec[vec_idx].buf_addr;
 463         rte_prefetch0((void *)(uintptr_t)hdr_addr);
 464
 465         LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
 466                 dev->vid, num_buffers);
 467
 468         desc_avail  = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
 469         desc_offset = dev->vhost_hlen;
 470
 471         mbuf_avail  = rte_pktmbuf_data_len(m);
 472         mbuf_offset = 0;
 473         while (mbuf_avail != 0 || m->next != NULL) {
 474                 /* done with current desc buf, get the next one */
 475                 if (desc_avail == 0) {
 476                         vec_idx++;
 477                         desc_addr = rte_vhost_gpa_to_vva(dev->mem,
 478                                         buf_vec[vec_idx].buf_addr);
 479                         if (unlikely(!desc_addr))
 480                                 return -1;
 481
 482                         /* Prefetch buffer address. */
 483                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 484                         desc_offset = 0;
 485                         desc_avail  = buf_vec[vec_idx].buf_len;
 486                 }
 487
 488                 /* done with current mbuf, get the next one */
 489                 if (mbuf_avail == 0) {
 490                         m = m->next;
 491
 492                         mbuf_offset = 0;
 493                         mbuf_avail  = rte_pktmbuf_data_len(m);
 494                 }
 495
 496                 if (hdr_addr) {
 497                         struct virtio_net_hdr_mrg_rxbuf *hdr;
 498
 499                         hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)
 500                                 hdr_addr;
 501                         virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
 502                         ASSIGN_UNLESS_EQUAL(hdr->num_buffers, num_buffers);
 503
 504                         vhost_log_write(dev, hdr_phys_addr, dev->vhost_hlen);
 505                         PRINT_PACKET(dev, (uintptr_t)hdr_addr,
 506                                      dev->vhost_hlen, 0);
 507
 508                         hdr_addr = 0;
 509                 }
 510
 511                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 512                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 513                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 514                         cpy_len);
 515                 vhost_log_write(dev, buf_vec[vec_idx].buf_addr + desc_offset,
 516                         cpy_len);
 517                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 518                         cpy_len, 0);
 519
 520                 mbuf_avail  -= cpy_len;
 521                 mbuf_offset += cpy_len;
 522                 desc_avail  -= cpy_len;
 523                 desc_offset += cpy_len;
 524         }
 525
 526         return 0;
 527 }
 528
 529 static __rte_always_inline uint32_t
 530 virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 531         struct rte_mbuf **pkts, uint32_t count)
 532 {
 533         struct vhost_virtqueue *vq;
 534         uint32_t pkt_idx = 0;
 535         uint16_t num_buffers;
 536         struct buf_vector buf_vec[BUF_VECTOR_MAX];
 537         uint16_t avail_head;
 538
 539         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 540         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
 541                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 542                         dev->vid, __func__, queue_id);
 543                 return 0;
 544         }
 545
 546         vq = dev->virtqueue[queue_id];
 547         if (unlikely(vq->enabled == 0))
 548                 return 0;
 549
 550         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 551         if (count == 0)
 552                 return 0;
 553
 554         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
 555
 556         vq->shadow_used_idx = 0;
 557         avail_head = *((volatile uint16_t *)&vq->avail->idx);
 558         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 559                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 560
 561                 if (unlikely(reserve_avail_buf_mergeable(dev, vq,
 562                                                 pkt_len, buf_vec, &num_buffers,
 563                                                 avail_head) < 0)) {
 564                         LOG_DEBUG(VHOST_DATA,
 565                                 "(%d) failed to get enough desc from vring\n",
 566                                 dev->vid);
 567                         vq->shadow_used_idx -= num_buffers;
 568                         break;
 569                 }
 570
 571                 LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 572                         dev->vid, vq->last_avail_idx,
 573                         vq->last_avail_idx + num_buffers);
 574
 575                 if (copy_mbuf_to_desc_mergeable(dev, pkts[pkt_idx],
 576                                                 buf_vec, num_buffers) < 0) {
 577                         vq->shadow_used_idx -= num_buffers;
 578                         break;
 579                 }
 580
 581                 vq->last_avail_idx += num_buffers;
 582         }
 583
 584         if (likely(vq->shadow_used_idx)) {
 585                 flush_shadow_used_ring(dev, vq);
 586
 587                 /* flush used->idx update before we read avail->flags. */
 588                 rte_mb();
 589
 590                 /* Kick the guest if necessary. */
 591                 if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 592                                 && (vq->callfd >= 0))
 593                         eventfd_write(vq->callfd, (eventfd_t)1);
 594         }
 595
 596         return pkt_idx;
 597 }
 598
 599 uint16_t
 600 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 601         struct rte_mbuf **pkts, uint16_t count)
 602 {
 603         struct virtio_net *dev = get_device(vid);
 604
 605         if (!dev)
 606                 return 0;
 607
 608         if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
 609                 return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 610         else
 611                 return virtio_dev_rx(dev, queue_id, pkts, count);
 612 }
 613
 614 static inline bool
 615 virtio_net_with_host_offload(struct virtio_net *dev)
 616 {
 617         if (dev->features &
 618                         ((1ULL << VIRTIO_NET_F_CSUM) |
 619                          (1ULL << VIRTIO_NET_F_HOST_ECN) |
 620                          (1ULL << VIRTIO_NET_F_HOST_TSO4) |
 621                          (1ULL << VIRTIO_NET_F_HOST_TSO6) |
 622                          (1ULL << VIRTIO_NET_F_HOST_UFO)))
 623                 return true;
 624
 625         return false;
 626 }
 627
 628 static void
 629 parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
 630 {
 631         struct ipv4_hdr *ipv4_hdr;
 632         struct ipv6_hdr *ipv6_hdr;
 633         void *l3_hdr = NULL;
 634         struct ether_hdr *eth_hdr;
 635         uint16_t ethertype;
 636
 637         eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
 638
 639         m->l2_len = sizeof(struct ether_hdr);
 640         ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
 641
 642         if (ethertype == ETHER_TYPE_VLAN) {
 643                 struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
 644
 645                 m->l2_len += sizeof(struct vlan_hdr);
 646                 ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
 647         }
 648
 649         l3_hdr = (char *)eth_hdr + m->l2_len;
 650
 651         switch (ethertype) {
 652         case ETHER_TYPE_IPv4:
 653                 ipv4_hdr = l3_hdr;
 654                 *l4_proto = ipv4_hdr->next_proto_id;
 655                 m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
 656                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 657                 m->ol_flags |= PKT_TX_IPV4;
 658                 break;
 659         case ETHER_TYPE_IPv6:
 660                 ipv6_hdr = l3_hdr;
 661                 *l4_proto = ipv6_hdr->proto;
 662                 m->l3_len = sizeof(struct ipv6_hdr);
 663                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 664                 m->ol_flags |= PKT_TX_IPV6;
 665                 break;
 666         default:
 667                 m->l3_len = 0;
 668                 *l4_proto = 0;
 669                 *l4_hdr = NULL;
 670                 break;
 671         }
 672 }
 673
 674 static __rte_always_inline void
 675 vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 676 {
 677         uint16_t l4_proto = 0;
 678         void *l4_hdr = NULL;
 679         struct tcp_hdr *tcp_hdr = NULL;
 680
 681         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 682                 return;
 683
 684         parse_ethernet(m, &l4_proto, &l4_hdr);
 685         if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 686                 if (hdr->csum_start == (m->l2_len + m->l3_len)) {
 687                         switch (hdr->csum_offset) {
 688                         case (offsetof(struct tcp_hdr, cksum)):
 689                                 if (l4_proto == IPPROTO_TCP)
 690                                         m->ol_flags |= PKT_TX_TCP_CKSUM;
 691                                 break;
 692                         case (offsetof(struct udp_hdr, dgram_cksum)):
 693                                 if (l4_proto == IPPROTO_UDP)
 694                                         m->ol_flags |= PKT_TX_UDP_CKSUM;
 695                                 break;
 696                         case (offsetof(struct sctp_hdr, cksum)):
 697                                 if (l4_proto == IPPROTO_SCTP)
 698                                         m->ol_flags |= PKT_TX_SCTP_CKSUM;
 699                                 break;
 700                         default:
 701                                 break;
 702                         }
 703                 }
 704         }
 705
 706         if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 707                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 708                 case VIRTIO_NET_HDR_GSO_TCPV4:
 709                 case VIRTIO_NET_HDR_GSO_TCPV6:
 710                         tcp_hdr = l4_hdr;
 711                         m->ol_flags |= PKT_TX_TCP_SEG;
 712                         m->tso_segsz = hdr->gso_size;
 713                         m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 714                         break;
 715                 default:
 716                         RTE_LOG(WARNING, VHOST_DATA,
 717                                 "unsupported gso type %u.\n", hdr->gso_type);
 718                         break;
 719                 }
 720         }
 721 }
 722
 723 #define RARP_PKT_SIZE   64
 724
 725 static int
 726 make_rarp_packet(struct rte_mbuf *rarp_mbuf, const struct ether_addr *mac)
 727 {
 728         struct ether_hdr *eth_hdr;
 729         struct arp_hdr  *rarp;
 730
 731         if (rarp_mbuf->buf_len < 64) {
 732                 RTE_LOG(WARNING, VHOST_DATA,
 733                         "failed to make RARP; mbuf size too small %u (< %d)\n",
 734                         rarp_mbuf->buf_len, RARP_PKT_SIZE);
 735                 return -1;
 736         }
 737
 738         /* Ethernet header. */
 739         eth_hdr = rte_pktmbuf_mtod_offset(rarp_mbuf, struct ether_hdr *, 0);
 740         memset(eth_hdr->d_addr.addr_bytes, 0xff, ETHER_ADDR_LEN);
 741         ether_addr_copy(mac, &eth_hdr->s_addr);
 742         eth_hdr->ether_type = htons(ETHER_TYPE_RARP);
 743
 744         /* RARP header. */
 745         rarp = (struct arp_hdr *)(eth_hdr + 1);
 746         rarp->arp_hrd = htons(ARP_HRD_ETHER);
 747         rarp->arp_pro = htons(ETHER_TYPE_IPv4);
 748         rarp->arp_hln = ETHER_ADDR_LEN;
 749         rarp->arp_pln = 4;
 750         rarp->arp_op  = htons(ARP_OP_REVREQUEST);
 751
 752         ether_addr_copy(mac, &rarp->arp_data.arp_sha);
 753         ether_addr_copy(mac, &rarp->arp_data.arp_tha);
 754         memset(&rarp->arp_data.arp_sip, 0x00, 4);
 755         memset(&rarp->arp_data.arp_tip, 0x00, 4);
 756
 757         rarp_mbuf->pkt_len  = rarp_mbuf->data_len = RARP_PKT_SIZE;
 758
 759         return 0;
 760 }
 761
 762 static __rte_always_inline void
 763 put_zmbuf(struct zcopy_mbuf *zmbuf)
 764 {
 765         zmbuf->in_use = 0;
 766 }
 767
 768 static __rte_always_inline int
 769 copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs,
 770                   uint16_t max_desc, struct rte_mbuf *m, uint16_t desc_idx,
 771                   struct rte_mempool *mbuf_pool)
 772 {
 773         struct vring_desc *desc;
 774         uint64_t desc_addr;
 775         uint32_t desc_avail, desc_offset;
 776         uint32_t mbuf_avail, mbuf_offset;
 777         uint32_t cpy_len;
 778         struct rte_mbuf *cur = m, *prev = m;
 779         struct virtio_net_hdr *hdr = NULL;
 780         /* A counter to avoid desc dead loop chain */
 781         uint32_t nr_desc = 1;
 782
 783         desc = &descs[desc_idx];
 784         if (unlikely((desc->len < dev->vhost_hlen)) ||
 785                         (desc->flags & VRING_DESC_F_INDIRECT))
 786                 return -1;
 787
 788         desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
 789         if (unlikely(!desc_addr))
 790                 return -1;
 791
 792         if (virtio_net_with_host_offload(dev)) {
 793                 hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
 794                 rte_prefetch0(hdr);
 795         }
 796
 797         /*
 798          * A virtio driver normally uses at least 2 desc buffers
 799          * for Tx: the first for storing the header, and others
 800          * for storing the data.
 801          */
 802         if (likely((desc->len == dev->vhost_hlen) &&
 803                    (desc->flags & VRING_DESC_F_NEXT) != 0)) {
 804                 desc = &descs[desc->next];
 805                 if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 806                         return -1;
 807
 808                 desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
 809                 if (unlikely(!desc_addr))
 810                         return -1;
 811
 812                 desc_offset = 0;
 813                 desc_avail  = desc->len;
 814                 nr_desc    += 1;
 815         } else {
 816                 desc_avail  = desc->len - dev->vhost_hlen;
 817                 desc_offset = dev->vhost_hlen;
 818         }
 819
 820         rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
 821
 822         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
 823
 824         mbuf_offset = 0;
 825         mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 826         while (1) {
 827                 uint64_t hpa;
 828
 829                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 830
 831                 /*
 832                  * A desc buf might across two host physical pages that are
 833                  * not continuous. In such case (gpa_to_hpa returns 0), data
 834                  * will be copied even though zero copy is enabled.
 835                  */
 836                 if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
 837                                         desc->addr + desc_offset, cpy_len)))) {
 838                         cur->data_len = cpy_len;
 839                         cur->data_off = 0;
 840                         cur->buf_addr = (void *)(uintptr_t)desc_addr;
 841                         cur->buf_physaddr = hpa;
 842
 843                         /*
 844                          * In zero copy mode, one mbuf can only reference data
 845                          * for one or partial of one desc buff.
 846                          */
 847                         mbuf_avail = cpy_len;
 848                 } else {
 849                         rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 850                                                            mbuf_offset),
 851                                 (void *)((uintptr_t)(desc_addr + desc_offset)),
 852                                 cpy_len);
 853                 }
 854
 855                 mbuf_avail  -= cpy_len;
 856                 mbuf_offset += cpy_len;
 857                 desc_avail  -= cpy_len;
 858                 desc_offset += cpy_len;
 859
 860                 /* This desc reaches to its end, get the next one */
 861                 if (desc_avail == 0) {
 862                         if ((desc->flags & VRING_DESC_F_NEXT) == 0)
 863                                 break;
 864
 865                         if (unlikely(desc->next >= max_desc ||
 866                                      ++nr_desc > max_desc))
 867                                 return -1;
 868                         desc = &descs[desc->next];
 869                         if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 870                                 return -1;
 871
 872                         desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
 873                         if (unlikely(!desc_addr))
 874                                 return -1;
 875
 876                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 877
 878                         desc_offset = 0;
 879                         desc_avail  = desc->len;
 880
 881                         PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
 882                 }
 883
 884                 /*
 885                  * This mbuf reaches to its end, get a new one
 886                  * to hold more data.
 887                  */
 888                 if (mbuf_avail == 0) {
 889                         cur = rte_pktmbuf_alloc(mbuf_pool);
 890                         if (unlikely(cur == NULL)) {
 891                                 RTE_LOG(ERR, VHOST_DATA, "Failed to "
 892                                         "allocate memory for mbuf.\n");
 893                                 return -1;
 894                         }
 895                         if (unlikely(dev->dequeue_zero_copy))
 896                                 rte_mbuf_refcnt_update(cur, 1);
 897
 898                         prev->next = cur;
 899                         prev->data_len = mbuf_offset;
 900                         m->nb_segs += 1;
 901                         m->pkt_len += mbuf_offset;
 902                         prev = cur;
 903
 904                         mbuf_offset = 0;
 905                         mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 906                 }
 907         }
 908
 909         prev->data_len = mbuf_offset;
 910         m->pkt_len    += mbuf_offset;
 911
 912         if (hdr)
 913                 vhost_dequeue_offload(hdr, m);
 914
 915         return 0;
 916 }
 917
 918 static __rte_always_inline void
 919 update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
 920                  uint32_t used_idx, uint32_t desc_idx)
 921 {
 922         vq->used->ring[used_idx].id  = desc_idx;
 923         vq->used->ring[used_idx].len = 0;
 924         vhost_log_used_vring(dev, vq,
 925                         offsetof(struct vring_used, ring[used_idx]),
 926                         sizeof(vq->used->ring[used_idx]));
 927 }
 928
 929 static __rte_always_inline void
 930 update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 931                 uint32_t count)
 932 {
 933         if (unlikely(count == 0))
 934                 return;
 935
 936         rte_smp_wmb();
 937         rte_smp_rmb();
 938
 939         vq->used->idx += count;
 940         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 941                         sizeof(vq->used->idx));
 942
 943         /* Kick guest if required. */
 944         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 945                         && (vq->callfd >= 0))
 946                 eventfd_write(vq->callfd, (eventfd_t)1);
 947 }
 948
 949 static __rte_always_inline struct zcopy_mbuf *
 950 get_zmbuf(struct vhost_virtqueue *vq)
 951 {
 952         uint16_t i;
 953         uint16_t last;
 954         int tries = 0;
 955
 956         /* search [last_zmbuf_idx, zmbuf_size) */
 957         i = vq->last_zmbuf_idx;
 958         last = vq->zmbuf_size;
 959
 960 again:
 961         for (; i < last; i++) {
 962                 if (vq->zmbufs[i].in_use == 0) {
 963                         vq->last_zmbuf_idx = i + 1;
 964                         vq->zmbufs[i].in_use = 1;
 965                         return &vq->zmbufs[i];
 966                 }
 967         }
 968
 969         tries++;
 970         if (tries == 1) {
 971                 /* search [0, last_zmbuf_idx) */
 972                 i = 0;
 973                 last = vq->last_zmbuf_idx;
 974                 goto again;
 975         }
 976
 977         return NULL;
 978 }
 979
 980 static __rte_always_inline bool
 981 mbuf_is_consumed(struct rte_mbuf *m)
 982 {
 983         while (m) {
 984                 if (rte_mbuf_refcnt_read(m) > 1)
 985                         return false;
 986                 m = m->next;
 987         }
 988
 989         return true;
 990 }
 991
 992 uint16_t
 993 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 994         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
 995 {
 996         struct virtio_net *dev;
 997         struct rte_mbuf *rarp_mbuf = NULL;
 998         struct vhost_virtqueue *vq;
 999         uint32_t desc_indexes[MAX_PKT_BURST];
1000         uint32_t used_idx;
1001         uint32_t i = 0;
1002         uint16_t free_entries;
1003         uint16_t avail_idx;
1004
1005         dev = get_device(vid);
1006         if (!dev)
1007                 return 0;
1008
1009         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {
1010                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
1011                         dev->vid, __func__, queue_id);
1012                 return 0;
1013         }
1014
1015         vq = dev->virtqueue[queue_id];
1016         if (unlikely(vq->enabled == 0))
1017                 return 0;
1018
1019         if (unlikely(dev->dequeue_zero_copy)) {
1020                 struct zcopy_mbuf *zmbuf, *next;
1021                 int nr_updated = 0;
1022
1023                 for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
1024                      zmbuf != NULL; zmbuf = next) {
1025                         next = TAILQ_NEXT(zmbuf, next);
1026
1027                         if (mbuf_is_consumed(zmbuf->mbuf)) {
1028                                 used_idx = vq->last_used_idx++ & (vq->size - 1);
1029                                 update_used_ring(dev, vq, used_idx,
1030                                                  zmbuf->desc_idx);
1031                                 nr_updated += 1;
1032
1033                                 TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
1034                                 rte_pktmbuf_free(zmbuf->mbuf);
1035                                 put_zmbuf(zmbuf);
1036                                 vq->nr_zmbuf -= 1;
1037                         }
1038                 }
1039
1040                 update_used_idx(dev, vq, nr_updated);
1041         }
1042
1043         /*
1044          * Construct a RARP broadcast packet, and inject it to the "pkts"
1045          * array, to looks like that guest actually send such packet.
1046          *
1047          * Check user_send_rarp() for more information.
1048          *
1049          * broadcast_rarp shares a cacheline in the virtio_net structure
1050          * with some fields that are accessed during enqueue and
1051          * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
1052          * result in false sharing between enqueue and dequeue.
1053          *
1054          * Prevent unnecessary false sharing by reading broadcast_rarp first
1055          * and only performing cmpset if the read indicates it is likely to
1056          * be set.
1057          */
1058
1059         if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
1060                         rte_atomic16_cmpset((volatile uint16_t *)
1061                                 &dev->broadcast_rarp.cnt, 1, 0))) {
1062
1063                 rarp_mbuf = rte_pktmbuf_alloc(mbuf_pool);
1064                 if (rarp_mbuf == NULL) {
1065                         RTE_LOG(ERR, VHOST_DATA,
1066                                 "Failed to allocate memory for mbuf.\n");
1067                         return 0;
1068                 }
1069
1070                 if (make_rarp_packet(rarp_mbuf, &dev->mac)) {
1071                         rte_pktmbuf_free(rarp_mbuf);
1072                         rarp_mbuf = NULL;
1073                 } else {
1074                         count -= 1;
1075                 }
1076         }
1077
1078         free_entries = *((volatile uint16_t *)&vq->avail->idx) -
1079                         vq->last_avail_idx;
1080         if (free_entries == 0)
1081                 goto out;
1082
1083         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
1084
1085         /* Prefetch available and used ring */
1086         avail_idx = vq->last_avail_idx & (vq->size - 1);
1087         used_idx  = vq->last_used_idx  & (vq->size - 1);
1088         rte_prefetch0(&vq->avail->ring[avail_idx]);
1089         rte_prefetch0(&vq->used->ring[used_idx]);
1090
1091         count = RTE_MIN(count, MAX_PKT_BURST);
1092         count = RTE_MIN(count, free_entries);
1093         LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n",
1094                         dev->vid, count);
1095
1096         /* Retrieve all of the head indexes first to avoid caching issues. */
1097         for (i = 0; i < count; i++) {
1098                 avail_idx = (vq->last_avail_idx + i) & (vq->size - 1);
1099                 used_idx  = (vq->last_used_idx  + i) & (vq->size - 1);
1100                 desc_indexes[i] = vq->avail->ring[avail_idx];
1101
1102                 if (likely(dev->dequeue_zero_copy == 0))
1103                         update_used_ring(dev, vq, used_idx, desc_indexes[i]);
1104         }
1105
1106         /* Prefetch descriptor index. */
1107         rte_prefetch0(&vq->desc[desc_indexes[0]]);
1108         for (i = 0; i < count; i++) {
1109                 struct vring_desc *desc;
1110                 uint16_t sz, idx;
1111                 int err;
1112
1113                 if (likely(i + 1 < count))
1114                         rte_prefetch0(&vq->desc[desc_indexes[i + 1]]);
1115
1116                 if (vq->desc[desc_indexes[i]].flags & VRING_DESC_F_INDIRECT) {
1117                         desc = (struct vring_desc *)(uintptr_t)
1118                                 rte_vhost_gpa_to_vva(dev->mem,
1119                                         vq->desc[desc_indexes[i]].addr);
1120                         if (unlikely(!desc))
1121                                 break;
1122
1123                         rte_prefetch0(desc);
1124                         sz = vq->desc[desc_indexes[i]].len / sizeof(*desc);
1125                         idx = 0;
1126                 } else {
1127                         desc = vq->desc;
1128                         sz = vq->size;
1129                         idx = desc_indexes[i];
1130                 }
1131
1132                 pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
1133                 if (unlikely(pkts[i] == NULL)) {
1134                         RTE_LOG(ERR, VHOST_DATA,
1135                                 "Failed to allocate memory for mbuf.\n");
1136                         break;
1137                 }
1138
1139                 err = copy_desc_to_mbuf(dev, desc, sz, pkts[i], idx, mbuf_pool);
1140                 if (unlikely(err)) {
1141                         rte_pktmbuf_free(pkts[i]);
1142                         break;
1143                 }
1144
1145                 if (unlikely(dev->dequeue_zero_copy)) {
1146                         struct zcopy_mbuf *zmbuf;
1147
1148                         zmbuf = get_zmbuf(vq);
1149                         if (!zmbuf) {
1150                                 rte_pktmbuf_free(pkts[i]);
1151                                 break;
1152                         }
1153                         zmbuf->mbuf = pkts[i];
1154                         zmbuf->desc_idx = desc_indexes[i];
1155
1156                         /*
1157                          * Pin lock the mbuf; we will check later to see
1158                          * whether the mbuf is freed (when we are the last
1159                          * user) or not. If that's the case, we then could
1160                          * update the used ring safely.
1161                          */
1162                         rte_mbuf_refcnt_update(pkts[i], 1);
1163
1164                         vq->nr_zmbuf += 1;
1165                         TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
1166                 }
1167         }
1168         vq->last_avail_idx += i;
1169
1170         if (likely(dev->dequeue_zero_copy == 0)) {
1171                 vq->last_used_idx += i;
1172                 update_used_idx(dev, vq, i);
1173         }
1174
1175 out:
1176         if (unlikely(rarp_mbuf != NULL)) {
1177                 /*
1178                  * Inject it to the head of "pkts" array, so that switch's mac
1179                  * learning table will get updated first.
1180                  */
1181                 memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *));
1182                 pkts[0] = rarp_mbuf;
1183                 i += 1;
1184         }
1185
1186         return i;
1187 }