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_virtio_net.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 #define VHOST_LOG_PAGE  4096
  52
  53 static inline void __attribute__((always_inline))
  54 vhost_log_page(uint8_t *log_base, uint64_t page)
  55 {
  56         log_base[page / 8] |= 1 << (page % 8);
  57 }
  58
  59 static inline void __attribute__((always_inline))
  60 vhost_log_write(struct virtio_net *dev, uint64_t addr, uint64_t len)
  61 {
  62         uint64_t page;
  63
  64         if (likely(((dev->features & (1ULL << VHOST_F_LOG_ALL)) == 0) ||
  65                    !dev->log_base || !len))
  66                 return;
  67
  68         if (unlikely(dev->log_size <= ((addr + len - 1) / VHOST_LOG_PAGE / 8)))
  69                 return;
  70
  71         /* To make sure guest memory updates are committed before logging */
  72         rte_smp_wmb();
  73
  74         page = addr / VHOST_LOG_PAGE;
  75         while (page * VHOST_LOG_PAGE < addr + len) {
  76                 vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page);
  77                 page += 1;
  78         }
  79 }
  80
  81 static inline void __attribute__((always_inline))
  82 vhost_log_used_vring(struct virtio_net *dev, struct vhost_virtqueue *vq,
  83                      uint64_t offset, uint64_t len)
  84 {
  85         vhost_log_write(dev, vq->log_guest_addr + offset, len);
  86 }
  87
  88 static bool
  89 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
  90 {
  91         return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
  92 }
  93
  94 static inline void __attribute__((always_inline))
  95 do_flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
  96                           uint16_t to, uint16_t from, uint16_t size)
  97 {
  98         rte_memcpy(&vq->used->ring[to],
  99                         &vq->shadow_used_ring[from],
 100                         size * sizeof(struct vring_used_elem));
 101         vhost_log_used_vring(dev, vq,
 102                         offsetof(struct vring_used, ring[to]),
 103                         size * sizeof(struct vring_used_elem));
 104 }
 105
 106 static inline void __attribute__((always_inline))
 107 flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq)
 108 {
 109         uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
 110
 111         if (used_idx + vq->shadow_used_idx <= vq->size) {
 112                 do_flush_shadow_used_ring(dev, vq, used_idx, 0,
 113                                           vq->shadow_used_idx);
 114         } else {
 115                 uint16_t size;
 116
 117                 /* update used ring interval [used_idx, vq->size] */
 118                 size = vq->size - used_idx;
 119                 do_flush_shadow_used_ring(dev, vq, used_idx, 0, size);
 120
 121                 /* update the left half used ring interval [0, left_size] */
 122                 do_flush_shadow_used_ring(dev, vq, 0, size,
 123                                           vq->shadow_used_idx - size);
 124         }
 125         vq->last_used_idx += vq->shadow_used_idx;
 126
 127         rte_smp_wmb();
 128
 129         *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx;
 130         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 131                 sizeof(vq->used->idx));
 132 }
 133
 134 static inline void __attribute__((always_inline))
 135 update_shadow_used_ring(struct vhost_virtqueue *vq,
 136                          uint16_t desc_idx, uint16_t len)
 137 {
 138         uint16_t i = vq->shadow_used_idx++;
 139
 140         vq->shadow_used_ring[i].id  = desc_idx;
 141         vq->shadow_used_ring[i].len = len;
 142 }
 143
 144 static void
 145 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 146 {
 147         if (m_buf->ol_flags & PKT_TX_L4_MASK) {
 148                 net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 149                 net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
 150
 151                 switch (m_buf->ol_flags & PKT_TX_L4_MASK) {
 152                 case PKT_TX_TCP_CKSUM:
 153                         net_hdr->csum_offset = (offsetof(struct tcp_hdr,
 154                                                 cksum));
 155                         break;
 156                 case PKT_TX_UDP_CKSUM:
 157                         net_hdr->csum_offset = (offsetof(struct udp_hdr,
 158                                                 dgram_cksum));
 159                         break;
 160                 case PKT_TX_SCTP_CKSUM:
 161                         net_hdr->csum_offset = (offsetof(struct sctp_hdr,
 162                                                 cksum));
 163                         break;
 164                 }
 165         }
 166
 167         if (m_buf->ol_flags & PKT_TX_TCP_SEG) {
 168                 if (m_buf->ol_flags & PKT_TX_IPV4)
 169                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 170                 else
 171                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 172                 net_hdr->gso_size = m_buf->tso_segsz;
 173                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 174                                         + m_buf->l4_len;
 175         }
 176 }
 177
 178 static inline void
 179 copy_virtio_net_hdr(struct virtio_net *dev, uint64_t desc_addr,
 180                     struct virtio_net_hdr_mrg_rxbuf hdr)
 181 {
 182         if (dev->vhost_hlen == sizeof(struct virtio_net_hdr_mrg_rxbuf))
 183                 *(struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr = hdr;
 184         else
 185                 *(struct virtio_net_hdr *)(uintptr_t)desc_addr = hdr.hdr;
 186 }
 187
 188 static inline int __attribute__((always_inline))
 189 copy_mbuf_to_desc(struct virtio_net *dev, struct vring_desc *descs,
 190                   struct rte_mbuf *m, uint16_t desc_idx, uint32_t size)
 191 {
 192         uint32_t desc_avail, desc_offset;
 193         uint32_t mbuf_avail, mbuf_offset;
 194         uint32_t cpy_len;
 195         struct vring_desc *desc;
 196         uint64_t desc_addr;
 197         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 198         /* A counter to avoid desc dead loop chain */
 199         uint16_t nr_desc = 1;
 200
 201         desc = &descs[desc_idx];
 202         desc_addr = gpa_to_vva(dev, desc->addr);
 203         /*
 204          * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
 205          * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
 206          * otherwise stores offset on the stack instead of in a register.
 207          */
 208         if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
 209                 return -1;
 210
 211         rte_prefetch0((void *)(uintptr_t)desc_addr);
 212
 213         virtio_enqueue_offload(m, &virtio_hdr.hdr);
 214         copy_virtio_net_hdr(dev, desc_addr, virtio_hdr);
 215         vhost_log_write(dev, desc->addr, dev->vhost_hlen);
 216         PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
 217
 218         desc_offset = dev->vhost_hlen;
 219         desc_avail  = desc->len - dev->vhost_hlen;
 220
 221         mbuf_avail  = rte_pktmbuf_data_len(m);
 222         mbuf_offset = 0;
 223         while (mbuf_avail != 0 || m->next != NULL) {
 224                 /* done with current mbuf, fetch next */
 225                 if (mbuf_avail == 0) {
 226                         m = m->next;
 227
 228                         mbuf_offset = 0;
 229                         mbuf_avail  = rte_pktmbuf_data_len(m);
 230                 }
 231
 232                 /* done with current desc buf, fetch next */
 233                 if (desc_avail == 0) {
 234                         if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
 235                                 /* Room in vring buffer is not enough */
 236                                 return -1;
 237                         }
 238                         if (unlikely(desc->next >= size || ++nr_desc > size))
 239                                 return -1;
 240
 241                         desc = &descs[desc->next];
 242                         desc_addr = gpa_to_vva(dev, desc->addr);
 243                         if (unlikely(!desc_addr))
 244                                 return -1;
 245
 246                         desc_offset = 0;
 247                         desc_avail  = desc->len;
 248                 }
 249
 250                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 251                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 252                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 253                         cpy_len);
 254                 vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
 255                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 256                              cpy_len, 0);
 257
 258                 mbuf_avail  -= cpy_len;
 259                 mbuf_offset += cpy_len;
 260                 desc_avail  -= cpy_len;
 261                 desc_offset += cpy_len;
 262         }
 263
 264         return 0;
 265 }
 266
 267 /**
 268  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 269  * be received from the physical port or from another virtio device. A packet
 270  * count is returned to indicate the number of packets that are succesfully
 271  * added to the RX queue. This function works when the mbuf is scattered, but
 272  * it doesn't support the mergeable feature.
 273  */
 274 static inline uint32_t __attribute__((always_inline))
 275 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 276               struct rte_mbuf **pkts, uint32_t count)
 277 {
 278         struct vhost_virtqueue *vq;
 279         uint16_t avail_idx, free_entries, start_idx;
 280         uint16_t desc_indexes[MAX_PKT_BURST];
 281         struct vring_desc *descs;
 282         uint16_t used_idx;
 283         uint32_t i, sz;
 284
 285         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 286         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
 287                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 288                         dev->vid, __func__, queue_id);
 289                 return 0;
 290         }
 291
 292         vq = dev->virtqueue[queue_id];
 293         if (unlikely(vq->enabled == 0))
 294                 return 0;
 295
 296         avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 297         start_idx = vq->last_used_idx;
 298         free_entries = avail_idx - start_idx;
 299         count = RTE_MIN(count, free_entries);
 300         count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
 301         if (count == 0)
 302                 return 0;
 303
 304         LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
 305                 dev->vid, start_idx, start_idx + count);
 306
 307         /* Retrieve all of the desc indexes first to avoid caching issues. */
 308         rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
 309         for (i = 0; i < count; i++) {
 310                 used_idx = (start_idx + i) & (vq->size - 1);
 311                 desc_indexes[i] = vq->avail->ring[used_idx];
 312                 vq->used->ring[used_idx].id = desc_indexes[i];
 313                 vq->used->ring[used_idx].len = pkts[i]->pkt_len +
 314                                                dev->vhost_hlen;
 315                 vhost_log_used_vring(dev, vq,
 316                         offsetof(struct vring_used, ring[used_idx]),
 317                         sizeof(vq->used->ring[used_idx]));
 318         }
 319
 320         rte_prefetch0(&vq->desc[desc_indexes[0]]);
 321         for (i = 0; i < count; i++) {
 322                 uint16_t desc_idx = desc_indexes[i];
 323                 int err;
 324
 325                 if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
 326                         descs = (struct vring_desc *)(uintptr_t)gpa_to_vva(dev,
 327                                         vq->desc[desc_idx].addr);
 328                         if (unlikely(!descs)) {
 329                                 count = i;
 330                                 break;
 331                         }
 332
 333                         desc_idx = 0;
 334                         sz = vq->desc[desc_idx].len / sizeof(*descs);
 335                 } else {
 336                         descs = vq->desc;
 337                         sz = vq->size;
 338                 }
 339
 340                 err = copy_mbuf_to_desc(dev, descs, pkts[i], desc_idx, sz);
 341                 if (unlikely(err)) {
 342                         used_idx = (start_idx + i) & (vq->size - 1);
 343                         vq->used->ring[used_idx].len = dev->vhost_hlen;
 344                         vhost_log_used_vring(dev, vq,
 345                                 offsetof(struct vring_used, ring[used_idx]),
 346                                 sizeof(vq->used->ring[used_idx]));
 347                 }
 348
 349                 if (i + 1 < count)
 350                         rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
 351         }
 352
 353         rte_smp_wmb();
 354
 355         *(volatile uint16_t *)&vq->used->idx += count;
 356         vq->last_used_idx += count;
 357         vhost_log_used_vring(dev, vq,
 358                 offsetof(struct vring_used, idx),
 359                 sizeof(vq->used->idx));
 360
 361         /* flush used->idx update before we read avail->flags. */
 362         rte_mb();
 363
 364         /* Kick the guest if necessary. */
 365         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 366                         && (vq->callfd >= 0))
 367                 eventfd_write(vq->callfd, (eventfd_t)1);
 368         return count;
 369 }
 370
 371 static inline int __attribute__((always_inline))
 372 fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 373                          uint32_t avail_idx, uint32_t *vec_idx,
 374                          struct buf_vector *buf_vec, uint16_t *desc_chain_head,
 375                          uint16_t *desc_chain_len)
 376 {
 377         uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
 378         uint32_t vec_id = *vec_idx;
 379         uint32_t len    = 0;
 380         struct vring_desc *descs = vq->desc;
 381
 382         *desc_chain_head = idx;
 383
 384         if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
 385                 descs = (struct vring_desc *)(uintptr_t)
 386                                         gpa_to_vva(dev, vq->desc[idx].addr);
 387                 if (unlikely(!descs))
 388                         return -1;
 389
 390                 idx = 0;
 391         }
 392
 393         while (1) {
 394                 if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
 395                         return -1;
 396
 397                 len += descs[idx].len;
 398                 buf_vec[vec_id].buf_addr = descs[idx].addr;
 399                 buf_vec[vec_id].buf_len  = descs[idx].len;
 400                 buf_vec[vec_id].desc_idx = idx;
 401                 vec_id++;
 402
 403                 if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
 404                         break;
 405
 406                 idx = descs[idx].next;
 407         }
 408
 409         *desc_chain_len = len;
 410         *vec_idx = vec_id;
 411
 412         return 0;
 413 }
 414
 415 /*
 416  * Returns -1 on fail, 0 on success
 417  */
 418 static inline int
 419 reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 420                                 uint32_t size, struct buf_vector *buf_vec,
 421                                 uint16_t *num_buffers, uint16_t avail_head)
 422 {
 423         uint16_t cur_idx;
 424         uint32_t vec_idx = 0;
 425         uint16_t tries = 0;
 426
 427         uint16_t head_idx = 0;
 428         uint16_t len = 0;
 429
 430         *num_buffers = 0;
 431         cur_idx  = vq->last_avail_idx;
 432
 433         while (size > 0) {
 434                 if (unlikely(cur_idx == avail_head))
 435                         return -1;
 436
 437                 if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec,
 438                                                 &head_idx, &len) < 0))
 439                         return -1;
 440                 len = RTE_MIN(len, size);
 441                 update_shadow_used_ring(vq, head_idx, len);
 442                 size -= len;
 443
 444                 cur_idx++;
 445                 tries++;
 446                 *num_buffers += 1;
 447
 448                 /*
 449                  * if we tried all available ring items, and still
 450                  * can't get enough buf, it means something abnormal
 451                  * happened.
 452                  */
 453                 if (unlikely(tries >= vq->size))
 454                         return -1;
 455         }
 456
 457         return 0;
 458 }
 459
 460 static inline int __attribute__((always_inline))
 461 copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct rte_mbuf *m,
 462                             struct buf_vector *buf_vec, uint16_t num_buffers)
 463 {
 464         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 465         uint32_t vec_idx = 0;
 466         uint64_t desc_addr;
 467         uint32_t mbuf_offset, mbuf_avail;
 468         uint32_t desc_offset, desc_avail;
 469         uint32_t cpy_len;
 470         uint64_t hdr_addr, hdr_phys_addr;
 471         struct rte_mbuf *hdr_mbuf;
 472
 473         if (unlikely(m == NULL))
 474                 return -1;
 475
 476         desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
 477         if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr)
 478                 return -1;
 479
 480         hdr_mbuf = m;
 481         hdr_addr = desc_addr;
 482         hdr_phys_addr = buf_vec[vec_idx].buf_addr;
 483         rte_prefetch0((void *)(uintptr_t)hdr_addr);
 484
 485         virtio_hdr.num_buffers = num_buffers;
 486         LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
 487                 dev->vid, num_buffers);
 488
 489         desc_avail  = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
 490         desc_offset = dev->vhost_hlen;
 491
 492         mbuf_avail  = rte_pktmbuf_data_len(m);
 493         mbuf_offset = 0;
 494         while (mbuf_avail != 0 || m->next != NULL) {
 495                 /* done with current desc buf, get the next one */
 496                 if (desc_avail == 0) {
 497                         vec_idx++;
 498                         desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
 499                         if (unlikely(!desc_addr))
 500                                 return -1;
 501
 502                         /* Prefetch buffer address. */
 503                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 504                         desc_offset = 0;
 505                         desc_avail  = buf_vec[vec_idx].buf_len;
 506                 }
 507
 508                 /* done with current mbuf, get the next one */
 509                 if (mbuf_avail == 0) {
 510                         m = m->next;
 511
 512                         mbuf_offset = 0;
 513                         mbuf_avail  = rte_pktmbuf_data_len(m);
 514                 }
 515
 516                 if (hdr_addr) {
 517                         virtio_enqueue_offload(hdr_mbuf, &virtio_hdr.hdr);
 518                         copy_virtio_net_hdr(dev, hdr_addr, virtio_hdr);
 519                         vhost_log_write(dev, hdr_phys_addr, dev->vhost_hlen);
 520                         PRINT_PACKET(dev, (uintptr_t)hdr_addr,
 521                                      dev->vhost_hlen, 0);
 522
 523                         hdr_addr = 0;
 524                 }
 525
 526                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 527                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 528                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 529                         cpy_len);
 530                 vhost_log_write(dev, buf_vec[vec_idx].buf_addr + desc_offset,
 531                         cpy_len);
 532                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 533                         cpy_len, 0);
 534
 535                 mbuf_avail  -= cpy_len;
 536                 mbuf_offset += cpy_len;
 537                 desc_avail  -= cpy_len;
 538                 desc_offset += cpy_len;
 539         }
 540
 541         return 0;
 542 }
 543
 544 static inline uint32_t __attribute__((always_inline))
 545 virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 546         struct rte_mbuf **pkts, uint32_t count)
 547 {
 548         struct vhost_virtqueue *vq;
 549         uint32_t pkt_idx = 0;
 550         uint16_t num_buffers;
 551         struct buf_vector buf_vec[BUF_VECTOR_MAX];
 552         uint16_t avail_head;
 553
 554         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 555         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
 556                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 557                         dev->vid, __func__, queue_id);
 558                 return 0;
 559         }
 560
 561         vq = dev->virtqueue[queue_id];
 562         if (unlikely(vq->enabled == 0))
 563                 return 0;
 564
 565         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 566         if (count == 0)
 567                 return 0;
 568
 569         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
 570
 571         vq->shadow_used_idx = 0;
 572         avail_head = *((volatile uint16_t *)&vq->avail->idx);
 573         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 574                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 575
 576                 if (unlikely(reserve_avail_buf_mergeable(dev, vq,
 577                                                 pkt_len, buf_vec, &num_buffers,
 578                                                 avail_head) < 0)) {
 579                         LOG_DEBUG(VHOST_DATA,
 580                                 "(%d) failed to get enough desc from vring\n",
 581                                 dev->vid);
 582                         vq->shadow_used_idx -= num_buffers;
 583                         break;
 584                 }
 585
 586                 LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 587                         dev->vid, vq->last_avail_idx,
 588                         vq->last_avail_idx + num_buffers);
 589
 590                 if (copy_mbuf_to_desc_mergeable(dev, pkts[pkt_idx],
 591                                                 buf_vec, num_buffers) < 0) {
 592                         vq->shadow_used_idx -= num_buffers;
 593                         break;
 594                 }
 595
 596                 vq->last_avail_idx += num_buffers;
 597         }
 598
 599         if (likely(vq->shadow_used_idx)) {
 600                 flush_shadow_used_ring(dev, vq);
 601
 602                 /* flush used->idx update before we read avail->flags. */
 603                 rte_mb();
 604
 605                 /* Kick the guest if necessary. */
 606                 if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 607                                 && (vq->callfd >= 0))
 608                         eventfd_write(vq->callfd, (eventfd_t)1);
 609         }
 610
 611         return pkt_idx;
 612 }
 613
 614 uint16_t
 615 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 616         struct rte_mbuf **pkts, uint16_t count)
 617 {
 618         struct virtio_net *dev = get_device(vid);
 619
 620         if (!dev)
 621                 return 0;
 622
 623         if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
 624                 return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 625         else
 626                 return virtio_dev_rx(dev, queue_id, pkts, count);
 627 }
 628
 629 static inline bool
 630 virtio_net_with_host_offload(struct virtio_net *dev)
 631 {
 632         if (dev->features &
 633                         (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_ECN |
 634                          VIRTIO_NET_F_HOST_TSO4 | VIRTIO_NET_F_HOST_TSO6 |
 635                          VIRTIO_NET_F_HOST_UFO))
 636                 return true;
 637
 638         return false;
 639 }
 640
 641 static void
 642 parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
 643 {
 644         struct ipv4_hdr *ipv4_hdr;
 645         struct ipv6_hdr *ipv6_hdr;
 646         void *l3_hdr = NULL;
 647         struct ether_hdr *eth_hdr;
 648         uint16_t ethertype;
 649
 650         eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
 651
 652         m->l2_len = sizeof(struct ether_hdr);
 653         ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
 654
 655         if (ethertype == ETHER_TYPE_VLAN) {
 656                 struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
 657
 658                 m->l2_len += sizeof(struct vlan_hdr);
 659                 ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
 660         }
 661
 662         l3_hdr = (char *)eth_hdr + m->l2_len;
 663
 664         switch (ethertype) {
 665         case ETHER_TYPE_IPv4:
 666                 ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
 667                 *l4_proto = ipv4_hdr->next_proto_id;
 668                 m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
 669                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 670                 m->ol_flags |= PKT_TX_IPV4;
 671                 break;
 672         case ETHER_TYPE_IPv6:
 673                 ipv6_hdr = (struct ipv6_hdr *)l3_hdr;
 674                 *l4_proto = ipv6_hdr->proto;
 675                 m->l3_len = sizeof(struct ipv6_hdr);
 676                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 677                 m->ol_flags |= PKT_TX_IPV6;
 678                 break;
 679         default:
 680                 m->l3_len = 0;
 681                 *l4_proto = 0;
 682                 *l4_hdr = NULL;
 683                 break;
 684         }
 685 }
 686
 687 static inline void __attribute__((always_inline))
 688 vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 689 {
 690         uint16_t l4_proto = 0;
 691         void *l4_hdr = NULL;
 692         struct tcp_hdr *tcp_hdr = NULL;
 693
 694         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 695                 return;
 696
 697         parse_ethernet(m, &l4_proto, &l4_hdr);
 698         if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 699                 if (hdr->csum_start == (m->l2_len + m->l3_len)) {
 700                         switch (hdr->csum_offset) {
 701                         case (offsetof(struct tcp_hdr, cksum)):
 702                                 if (l4_proto == IPPROTO_TCP)
 703                                         m->ol_flags |= PKT_TX_TCP_CKSUM;
 704                                 break;
 705                         case (offsetof(struct udp_hdr, dgram_cksum)):
 706                                 if (l4_proto == IPPROTO_UDP)
 707                                         m->ol_flags |= PKT_TX_UDP_CKSUM;
 708                                 break;
 709                         case (offsetof(struct sctp_hdr, cksum)):
 710                                 if (l4_proto == IPPROTO_SCTP)
 711                                         m->ol_flags |= PKT_TX_SCTP_CKSUM;
 712                                 break;
 713                         default:
 714                                 break;
 715                         }
 716                 }
 717         }
 718
 719         if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 720                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 721                 case VIRTIO_NET_HDR_GSO_TCPV4:
 722                 case VIRTIO_NET_HDR_GSO_TCPV6:
 723                         tcp_hdr = (struct tcp_hdr *)l4_hdr;
 724                         m->ol_flags |= PKT_TX_TCP_SEG;
 725                         m->tso_segsz = hdr->gso_size;
 726                         m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 727                         break;
 728                 default:
 729                         RTE_LOG(WARNING, VHOST_DATA,
 730                                 "unsupported gso type %u.\n", hdr->gso_type);
 731                         break;
 732                 }
 733         }
 734 }
 735
 736 #define RARP_PKT_SIZE   64
 737
 738 static int
 739 make_rarp_packet(struct rte_mbuf *rarp_mbuf, const struct ether_addr *mac)
 740 {
 741         struct ether_hdr *eth_hdr;
 742         struct arp_hdr  *rarp;
 743
 744         if (rarp_mbuf->buf_len < 64) {
 745                 RTE_LOG(WARNING, VHOST_DATA,
 746                         "failed to make RARP; mbuf size too small %u (< %d)\n",
 747                         rarp_mbuf->buf_len, RARP_PKT_SIZE);
 748                 return -1;
 749         }
 750
 751         /* Ethernet header. */
 752         eth_hdr = rte_pktmbuf_mtod_offset(rarp_mbuf, struct ether_hdr *, 0);
 753         memset(eth_hdr->d_addr.addr_bytes, 0xff, ETHER_ADDR_LEN);
 754         ether_addr_copy(mac, &eth_hdr->s_addr);
 755         eth_hdr->ether_type = htons(ETHER_TYPE_RARP);
 756
 757         /* RARP header. */
 758         rarp = (struct arp_hdr *)(eth_hdr + 1);
 759         rarp->arp_hrd = htons(ARP_HRD_ETHER);
 760         rarp->arp_pro = htons(ETHER_TYPE_IPv4);
 761         rarp->arp_hln = ETHER_ADDR_LEN;
 762         rarp->arp_pln = 4;
 763         rarp->arp_op  = htons(ARP_OP_REVREQUEST);
 764
 765         ether_addr_copy(mac, &rarp->arp_data.arp_sha);
 766         ether_addr_copy(mac, &rarp->arp_data.arp_tha);
 767         memset(&rarp->arp_data.arp_sip, 0x00, 4);
 768         memset(&rarp->arp_data.arp_tip, 0x00, 4);
 769
 770         rarp_mbuf->pkt_len  = rarp_mbuf->data_len = RARP_PKT_SIZE;
 771
 772         return 0;
 773 }
 774
 775 static inline void __attribute__((always_inline))
 776 put_zmbuf(struct zcopy_mbuf *zmbuf)
 777 {
 778         zmbuf->in_use = 0;
 779 }
 780
 781 static inline int __attribute__((always_inline))
 782 copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs,
 783                   uint16_t max_desc, struct rte_mbuf *m, uint16_t desc_idx,
 784                   struct rte_mempool *mbuf_pool)
 785 {
 786         struct vring_desc *desc;
 787         uint64_t desc_addr;
 788         uint32_t desc_avail, desc_offset;
 789         uint32_t mbuf_avail, mbuf_offset;
 790         uint32_t cpy_len;
 791         struct rte_mbuf *cur = m, *prev = m;
 792         struct virtio_net_hdr *hdr = NULL;
 793         /* A counter to avoid desc dead loop chain */
 794         uint32_t nr_desc = 1;
 795
 796         desc = &descs[desc_idx];
 797         if (unlikely((desc->len < dev->vhost_hlen)) ||
 798                         (desc->flags & VRING_DESC_F_INDIRECT))
 799                 return -1;
 800
 801         desc_addr = gpa_to_vva(dev, desc->addr);
 802         if (unlikely(!desc_addr))
 803                 return -1;
 804
 805         if (virtio_net_with_host_offload(dev)) {
 806                 hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
 807                 rte_prefetch0(hdr);
 808         }
 809
 810         /*
 811          * A virtio driver normally uses at least 2 desc buffers
 812          * for Tx: the first for storing the header, and others
 813          * for storing the data.
 814          */
 815         if (likely((desc->len == dev->vhost_hlen) &&
 816                    (desc->flags & VRING_DESC_F_NEXT) != 0)) {
 817                 desc = &descs[desc->next];
 818                 if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 819                         return -1;
 820
 821                 desc_addr = gpa_to_vva(dev, desc->addr);
 822                 if (unlikely(!desc_addr))
 823                         return -1;
 824
 825                 desc_offset = 0;
 826                 desc_avail  = desc->len;
 827                 nr_desc    += 1;
 828         } else {
 829                 desc_avail  = desc->len - dev->vhost_hlen;
 830                 desc_offset = dev->vhost_hlen;
 831         }
 832
 833         rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
 834
 835         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
 836
 837         mbuf_offset = 0;
 838         mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 839         while (1) {
 840                 uint64_t hpa;
 841
 842                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 843
 844                 /*
 845                  * A desc buf might across two host physical pages that are
 846                  * not continuous. In such case (gpa_to_hpa returns 0), data
 847                  * will be copied even though zero copy is enabled.
 848                  */
 849                 if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
 850                                         desc->addr + desc_offset, cpy_len)))) {
 851                         cur->data_len = cpy_len;
 852                         cur->data_off = 0;
 853                         cur->buf_addr = (void *)(uintptr_t)desc_addr;
 854                         cur->buf_physaddr = hpa;
 855
 856                         /*
 857                          * In zero copy mode, one mbuf can only reference data
 858                          * for one or partial of one desc buff.
 859                          */
 860                         mbuf_avail = cpy_len;
 861                 } else {
 862                         rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 863                                                            mbuf_offset),
 864                                 (void *)((uintptr_t)(desc_addr + desc_offset)),
 865                                 cpy_len);
 866                 }
 867
 868                 mbuf_avail  -= cpy_len;
 869                 mbuf_offset += cpy_len;
 870                 desc_avail  -= cpy_len;
 871                 desc_offset += cpy_len;
 872
 873                 /* This desc reaches to its end, get the next one */
 874                 if (desc_avail == 0) {
 875                         if ((desc->flags & VRING_DESC_F_NEXT) == 0)
 876                                 break;
 877
 878                         if (unlikely(desc->next >= max_desc ||
 879                                      ++nr_desc > max_desc))
 880                                 return -1;
 881                         desc = &descs[desc->next];
 882                         if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 883                                 return -1;
 884
 885                         desc_addr = gpa_to_vva(dev, desc->addr);
 886                         if (unlikely(!desc_addr))
 887                                 return -1;
 888
 889                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 890
 891                         desc_offset = 0;
 892                         desc_avail  = desc->len;
 893
 894                         PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
 895                 }
 896
 897                 /*
 898                  * This mbuf reaches to its end, get a new one
 899                  * to hold more data.
 900                  */
 901                 if (mbuf_avail == 0) {
 902                         cur = rte_pktmbuf_alloc(mbuf_pool);
 903                         if (unlikely(cur == NULL)) {
 904                                 RTE_LOG(ERR, VHOST_DATA, "Failed to "
 905                                         "allocate memory for mbuf.\n");
 906                                 return -1;
 907                         }
 908                         if (unlikely(dev->dequeue_zero_copy))
 909                                 rte_mbuf_refcnt_update(cur, 1);
 910
 911                         prev->next = cur;
 912                         prev->data_len = mbuf_offset;
 913                         m->nb_segs += 1;
 914                         m->pkt_len += mbuf_offset;
 915                         prev = cur;
 916
 917                         mbuf_offset = 0;
 918                         mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 919                 }
 920         }
 921
 922         prev->data_len = mbuf_offset;
 923         m->pkt_len    += mbuf_offset;
 924
 925         if (hdr)
 926                 vhost_dequeue_offload(hdr, m);
 927
 928         return 0;
 929 }
 930
 931 static inline void __attribute__((always_inline))
 932 update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
 933                  uint32_t used_idx, uint32_t desc_idx)
 934 {
 935         vq->used->ring[used_idx].id  = desc_idx;
 936         vq->used->ring[used_idx].len = 0;
 937         vhost_log_used_vring(dev, vq,
 938                         offsetof(struct vring_used, ring[used_idx]),
 939                         sizeof(vq->used->ring[used_idx]));
 940 }
 941
 942 static inline void __attribute__((always_inline))
 943 update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 944                 uint32_t count)
 945 {
 946         if (unlikely(count == 0))
 947                 return;
 948
 949         rte_smp_wmb();
 950         rte_smp_rmb();
 951
 952         vq->used->idx += count;
 953         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 954                         sizeof(vq->used->idx));
 955
 956         /* Kick guest if required. */
 957         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 958                         && (vq->callfd >= 0))
 959                 eventfd_write(vq->callfd, (eventfd_t)1);
 960 }
 961
 962 static inline struct zcopy_mbuf *__attribute__((always_inline))
 963 get_zmbuf(struct vhost_virtqueue *vq)
 964 {
 965         uint16_t i;
 966         uint16_t last;
 967         int tries = 0;
 968
 969         /* search [last_zmbuf_idx, zmbuf_size) */
 970         i = vq->last_zmbuf_idx;
 971         last = vq->zmbuf_size;
 972
 973 again:
 974         for (; i < last; i++) {
 975                 if (vq->zmbufs[i].in_use == 0) {
 976                         vq->last_zmbuf_idx = i + 1;
 977                         vq->zmbufs[i].in_use = 1;
 978                         return &vq->zmbufs[i];
 979                 }
 980         }
 981
 982         tries++;
 983         if (tries == 1) {
 984                 /* search [0, last_zmbuf_idx) */
 985                 i = 0;
 986                 last = vq->last_zmbuf_idx;
 987                 goto again;
 988         }
 989
 990         return NULL;
 991 }
 992
 993 static inline bool __attribute__((always_inline))
 994 mbuf_is_consumed(struct rte_mbuf *m)
 995 {
 996         while (m) {
 997                 if (rte_mbuf_refcnt_read(m) > 1)
 998                         return false;
 999                 m = m->next;
1000         }
1001
1002         return true;
1003 }
1004
1005 uint16_t
1006 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
1007         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
1008 {
1009         struct virtio_net *dev;
1010         struct rte_mbuf *rarp_mbuf = NULL;
1011         struct vhost_virtqueue *vq;
1012         uint32_t desc_indexes[MAX_PKT_BURST];
1013         uint32_t used_idx;
1014         uint32_t i = 0;
1015         uint16_t free_entries;
1016         uint16_t avail_idx;
1017
1018         dev = get_device(vid);
1019         if (!dev)
1020                 return 0;
1021
1022         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->virt_qp_nb))) {
1023                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
1024                         dev->vid, __func__, queue_id);
1025                 return 0;
1026         }
1027
1028         vq = dev->virtqueue[queue_id];
1029         if (unlikely(vq->enabled == 0))
1030                 return 0;
1031
1032         if (unlikely(dev->dequeue_zero_copy)) {
1033                 struct zcopy_mbuf *zmbuf, *next;
1034                 int nr_updated = 0;
1035
1036                 for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
1037                      zmbuf != NULL; zmbuf = next) {
1038                         next = TAILQ_NEXT(zmbuf, next);
1039
1040                         if (mbuf_is_consumed(zmbuf->mbuf)) {
1041                                 used_idx = vq->last_used_idx++ & (vq->size - 1);
1042                                 update_used_ring(dev, vq, used_idx,
1043                                                  zmbuf->desc_idx);
1044                                 nr_updated += 1;
1045
1046                                 TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
1047                                 rte_pktmbuf_free(zmbuf->mbuf);
1048                                 put_zmbuf(zmbuf);
1049                                 vq->nr_zmbuf -= 1;
1050                         }
1051                 }
1052
1053                 update_used_idx(dev, vq, nr_updated);
1054         }
1055
1056         /*
1057          * Construct a RARP broadcast packet, and inject it to the "pkts"
1058          * array, to looks like that guest actually send such packet.
1059          *
1060          * Check user_send_rarp() for more information.
1061          *
1062          * broadcast_rarp shares a cacheline in the virtio_net structure
1063          * with some fields that are accessed during enqueue and
1064          * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
1065          * result in false sharing between enqueue and dequeue.
1066          *
1067          * Prevent unnecessary false sharing by reading broadcast_rarp first
1068          * and only performing cmpset if the read indicates it is likely to
1069          * be set.
1070          */
1071
1072         if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
1073                         rte_atomic16_cmpset((volatile uint16_t *)
1074                                 &dev->broadcast_rarp.cnt, 1, 0))) {
1075
1076                 rarp_mbuf = rte_pktmbuf_alloc(mbuf_pool);
1077                 if (rarp_mbuf == NULL) {
1078                         RTE_LOG(ERR, VHOST_DATA,
1079                                 "Failed to allocate memory for mbuf.\n");
1080                         return 0;
1081                 }
1082
1083                 if (make_rarp_packet(rarp_mbuf, &dev->mac)) {
1084                         rte_pktmbuf_free(rarp_mbuf);
1085                         rarp_mbuf = NULL;
1086                 } else {
1087                         count -= 1;
1088                 }
1089         }
1090
1091         free_entries = *((volatile uint16_t *)&vq->avail->idx) -
1092                         vq->last_avail_idx;
1093         if (free_entries == 0)
1094                 goto out;
1095
1096         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
1097
1098         /* Prefetch available and used ring */
1099         avail_idx = vq->last_avail_idx & (vq->size - 1);
1100         used_idx  = vq->last_used_idx  & (vq->size - 1);
1101         rte_prefetch0(&vq->avail->ring[avail_idx]);
1102         rte_prefetch0(&vq->used->ring[used_idx]);
1103
1104         count = RTE_MIN(count, MAX_PKT_BURST);
1105         count = RTE_MIN(count, free_entries);
1106         LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n",
1107                         dev->vid, count);
1108
1109         /* Retrieve all of the head indexes first to avoid caching issues. */
1110         for (i = 0; i < count; i++) {
1111                 avail_idx = (vq->last_avail_idx + i) & (vq->size - 1);
1112                 used_idx  = (vq->last_used_idx  + i) & (vq->size - 1);
1113                 desc_indexes[i] = vq->avail->ring[avail_idx];
1114
1115                 if (likely(dev->dequeue_zero_copy == 0))
1116                         update_used_ring(dev, vq, used_idx, desc_indexes[i]);
1117         }
1118
1119         /* Prefetch descriptor index. */
1120         rte_prefetch0(&vq->desc[desc_indexes[0]]);
1121         for (i = 0; i < count; i++) {
1122                 struct vring_desc *desc;
1123                 uint16_t sz, idx;
1124                 int err;
1125
1126                 if (likely(i + 1 < count))
1127                         rte_prefetch0(&vq->desc[desc_indexes[i + 1]]);
1128
1129                 if (vq->desc[desc_indexes[i]].flags & VRING_DESC_F_INDIRECT) {
1130                         desc = (struct vring_desc *)(uintptr_t)gpa_to_vva(dev,
1131                                         vq->desc[desc_indexes[i]].addr);
1132                         if (unlikely(!desc))
1133                                 break;
1134
1135                         rte_prefetch0(desc);
1136                         sz = vq->desc[desc_indexes[i]].len / sizeof(*desc);
1137                         idx = 0;
1138                 } else {
1139                         desc = vq->desc;
1140                         sz = vq->size;
1141                         idx = desc_indexes[i];
1142                 }
1143
1144                 pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
1145                 if (unlikely(pkts[i] == NULL)) {
1146                         RTE_LOG(ERR, VHOST_DATA,
1147                                 "Failed to allocate memory for mbuf.\n");
1148                         break;
1149                 }
1150
1151                 err = copy_desc_to_mbuf(dev, desc, sz, pkts[i], idx, mbuf_pool);
1152                 if (unlikely(err)) {
1153                         rte_pktmbuf_free(pkts[i]);
1154                         break;
1155                 }
1156
1157                 if (unlikely(dev->dequeue_zero_copy)) {
1158                         struct zcopy_mbuf *zmbuf;
1159
1160                         zmbuf = get_zmbuf(vq);
1161                         if (!zmbuf) {
1162                                 rte_pktmbuf_free(pkts[i]);
1163                                 break;
1164                         }
1165                         zmbuf->mbuf = pkts[i];
1166                         zmbuf->desc_idx = desc_indexes[i];
1167
1168                         /*
1169                          * Pin lock the mbuf; we will check later to see
1170                          * whether the mbuf is freed (when we are the last
1171                          * user) or not. If that's the case, we then could
1172                          * update the used ring safely.
1173                          */
1174                         rte_mbuf_refcnt_update(pkts[i], 1);
1175
1176                         vq->nr_zmbuf += 1;
1177                         TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
1178                 }
1179         }
1180         vq->last_avail_idx += i;
1181
1182         if (likely(dev->dequeue_zero_copy == 0)) {
1183                 vq->last_used_idx += i;
1184                 update_used_idx(dev, vq, i);
1185         }
1186
1187 out:
1188         if (unlikely(rarp_mbuf != NULL)) {
1189                 /*
1190                  * Inject it to the head of "pkts" array, so that switch's mac
1191                  * learning table will get updated first.
1192                  */
1193                 memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *));
1194                 pkts[0] = rarp_mbuf;
1195                 i += 1;
1196         }
1197
1198         return i;
1199 }