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 /*
  54  * Atomically set a bit in memory.
  55  */
  56 static inline void __attribute__((always_inline))
  57 vhost_set_bit(unsigned int nr, volatile uint8_t *addr)
  58 {
  59         __sync_fetch_and_or_8(addr, (1U << nr));
  60 }
  61
  62 static inline void __attribute__((always_inline))
  63 vhost_log_page(uint8_t *log_base, uint64_t page)
  64 {
  65         vhost_set_bit(page % 8, &log_base[page / 8]);
  66 }
  67
  68 static inline void __attribute__((always_inline))
  69 vhost_log_write(struct virtio_net *dev, uint64_t addr, uint64_t len)
  70 {
  71         uint64_t page;
  72
  73         if (likely(((dev->features & (1ULL << VHOST_F_LOG_ALL)) == 0) ||
  74                    !dev->log_base || !len))
  75                 return;
  76
  77         if (unlikely(dev->log_size <= ((addr + len - 1) / VHOST_LOG_PAGE / 8)))
  78                 return;
  79
  80         /* To make sure guest memory updates are committed before logging */
  81         rte_smp_wmb();
  82
  83         page = addr / VHOST_LOG_PAGE;
  84         while (page * VHOST_LOG_PAGE < addr + len) {
  85                 vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page);
  86                 page += 1;
  87         }
  88 }
  89
  90 static inline void __attribute__((always_inline))
  91 vhost_log_used_vring(struct virtio_net *dev, struct vhost_virtqueue *vq,
  92                      uint64_t offset, uint64_t len)
  93 {
  94         vhost_log_write(dev, vq->log_guest_addr + offset, len);
  95 }
  96
  97 static bool
  98 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
  99 {
 100         return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
 101 }
 102
 103 static inline void __attribute__((always_inline))
 104 do_flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
 105                           uint16_t to, uint16_t from, uint16_t size)
 106 {
 107         rte_memcpy(&vq->used->ring[to],
 108                         &vq->shadow_used_ring[from],
 109                         size * sizeof(struct vring_used_elem));
 110         vhost_log_used_vring(dev, vq,
 111                         offsetof(struct vring_used, ring[to]),
 112                         size * sizeof(struct vring_used_elem));
 113 }
 114
 115 static inline void __attribute__((always_inline))
 116 flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq)
 117 {
 118         uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
 119
 120         if (used_idx + vq->shadow_used_idx <= vq->size) {
 121                 do_flush_shadow_used_ring(dev, vq, used_idx, 0,
 122                                           vq->shadow_used_idx);
 123         } else {
 124                 uint16_t size;
 125
 126                 /* update used ring interval [used_idx, vq->size] */
 127                 size = vq->size - used_idx;
 128                 do_flush_shadow_used_ring(dev, vq, used_idx, 0, size);
 129
 130                 /* update the left half used ring interval [0, left_size] */
 131                 do_flush_shadow_used_ring(dev, vq, 0, size,
 132                                           vq->shadow_used_idx - size);
 133         }
 134         vq->last_used_idx += vq->shadow_used_idx;
 135
 136         rte_smp_wmb();
 137
 138         *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx;
 139         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 140                 sizeof(vq->used->idx));
 141 }
 142
 143 static inline void __attribute__((always_inline))
 144 update_shadow_used_ring(struct vhost_virtqueue *vq,
 145                          uint16_t desc_idx, uint16_t len)
 146 {
 147         uint16_t i = vq->shadow_used_idx++;
 148
 149         vq->shadow_used_ring[i].id  = desc_idx;
 150         vq->shadow_used_ring[i].len = len;
 151 }
 152
 153 static void
 154 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 155 {
 156         uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK;
 157
 158         if (m_buf->ol_flags & PKT_TX_TCP_SEG)
 159                 csum_l4 |= PKT_TX_TCP_CKSUM;
 160
 161         if (csum_l4) {
 162                 net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 163                 net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
 164
 165                 switch (csum_l4) {
 166                 case PKT_TX_TCP_CKSUM:
 167                         net_hdr->csum_offset = (offsetof(struct tcp_hdr,
 168                                                 cksum));
 169                         break;
 170                 case PKT_TX_UDP_CKSUM:
 171                         net_hdr->csum_offset = (offsetof(struct udp_hdr,
 172                                                 dgram_cksum));
 173                         break;
 174                 case PKT_TX_SCTP_CKSUM:
 175                         net_hdr->csum_offset = (offsetof(struct sctp_hdr,
 176                                                 cksum));
 177                         break;
 178                 }
 179         }
 180
 181         /* IP cksum verification cannot be bypassed, then calculate here */
 182         if (m_buf->ol_flags & PKT_TX_IP_CKSUM) {
 183                 struct ipv4_hdr *ipv4_hdr;
 184
 185                 ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct ipv4_hdr *,
 186                                                    m_buf->l2_len);
 187                 ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
 188         }
 189
 190         if (m_buf->ol_flags & PKT_TX_TCP_SEG) {
 191                 if (m_buf->ol_flags & PKT_TX_IPV4)
 192                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 193                 else
 194                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 195                 net_hdr->gso_size = m_buf->tso_segsz;
 196                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 197                                         + m_buf->l4_len;
 198         }
 199 }
 200
 201 static inline void
 202 copy_virtio_net_hdr(struct virtio_net *dev, uint64_t desc_addr,
 203                     struct virtio_net_hdr_mrg_rxbuf hdr)
 204 {
 205         if (dev->vhost_hlen == sizeof(struct virtio_net_hdr_mrg_rxbuf))
 206                 *(struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr = hdr;
 207         else
 208                 *(struct virtio_net_hdr *)(uintptr_t)desc_addr = hdr.hdr;
 209 }
 210
 211 static inline int __attribute__((always_inline))
 212 copy_mbuf_to_desc(struct virtio_net *dev, struct vring_desc *descs,
 213                   struct rte_mbuf *m, uint16_t desc_idx, uint32_t size)
 214 {
 215         uint32_t desc_avail, desc_offset;
 216         uint32_t mbuf_avail, mbuf_offset;
 217         uint32_t cpy_len;
 218         struct vring_desc *desc;
 219         uint64_t desc_addr;
 220         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 221         /* A counter to avoid desc dead loop chain */
 222         uint16_t nr_desc = 1;
 223
 224         desc = &descs[desc_idx];
 225         desc_addr = gpa_to_vva(dev, desc->addr);
 226         /*
 227          * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
 228          * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
 229          * otherwise stores offset on the stack instead of in a register.
 230          */
 231         if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
 232                 return -1;
 233
 234         rte_prefetch0((void *)(uintptr_t)desc_addr);
 235
 236         virtio_enqueue_offload(m, &virtio_hdr.hdr);
 237         copy_virtio_net_hdr(dev, desc_addr, virtio_hdr);
 238         vhost_log_write(dev, desc->addr, dev->vhost_hlen);
 239         PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
 240
 241         desc_offset = dev->vhost_hlen;
 242         desc_avail  = desc->len - dev->vhost_hlen;
 243
 244         mbuf_avail  = rte_pktmbuf_data_len(m);
 245         mbuf_offset = 0;
 246         while (mbuf_avail != 0 || m->next != NULL) {
 247                 /* done with current mbuf, fetch next */
 248                 if (mbuf_avail == 0) {
 249                         m = m->next;
 250
 251                         mbuf_offset = 0;
 252                         mbuf_avail  = rte_pktmbuf_data_len(m);
 253                 }
 254
 255                 /* done with current desc buf, fetch next */
 256                 if (desc_avail == 0) {
 257                         if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
 258                                 /* Room in vring buffer is not enough */
 259                                 return -1;
 260                         }
 261                         if (unlikely(desc->next >= size || ++nr_desc > size))
 262                                 return -1;
 263
 264                         desc = &descs[desc->next];
 265                         desc_addr = gpa_to_vva(dev, desc->addr);
 266                         if (unlikely(!desc_addr))
 267                                 return -1;
 268
 269                         desc_offset = 0;
 270                         desc_avail  = desc->len;
 271                 }
 272
 273                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 274                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 275                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 276                         cpy_len);
 277                 vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
 278                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 279                              cpy_len, 0);
 280
 281                 mbuf_avail  -= cpy_len;
 282                 mbuf_offset += cpy_len;
 283                 desc_avail  -= cpy_len;
 284                 desc_offset += cpy_len;
 285         }
 286
 287         return 0;
 288 }
 289
 290 /**
 291  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 292  * be received from the physical port or from another virtio device. A packet
 293  * count is returned to indicate the number of packets that are succesfully
 294  * added to the RX queue. This function works when the mbuf is scattered, but
 295  * it doesn't support the mergeable feature.
 296  */
 297 static inline uint32_t __attribute__((always_inline))
 298 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 299               struct rte_mbuf **pkts, uint32_t count)
 300 {
 301         struct vhost_virtqueue *vq;
 302         uint16_t avail_idx, free_entries, start_idx;
 303         uint16_t desc_indexes[MAX_PKT_BURST];
 304         struct vring_desc *descs;
 305         uint16_t used_idx;
 306         uint32_t i, sz;
 307
 308         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 309         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
 310                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 311                         dev->vid, __func__, queue_id);
 312                 return 0;
 313         }
 314
 315         vq = dev->virtqueue[queue_id];
 316         if (unlikely(vq->enabled == 0))
 317                 return 0;
 318
 319         avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 320         start_idx = vq->last_used_idx;
 321         free_entries = avail_idx - start_idx;
 322         count = RTE_MIN(count, free_entries);
 323         count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
 324         if (count == 0)
 325                 return 0;
 326
 327         LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
 328                 dev->vid, start_idx, start_idx + count);
 329
 330         /* Retrieve all of the desc indexes first to avoid caching issues. */
 331         rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
 332         for (i = 0; i < count; i++) {
 333                 used_idx = (start_idx + i) & (vq->size - 1);
 334                 desc_indexes[i] = vq->avail->ring[used_idx];
 335                 vq->used->ring[used_idx].id = desc_indexes[i];
 336                 vq->used->ring[used_idx].len = pkts[i]->pkt_len +
 337                                                dev->vhost_hlen;
 338                 vhost_log_used_vring(dev, vq,
 339                         offsetof(struct vring_used, ring[used_idx]),
 340                         sizeof(vq->used->ring[used_idx]));
 341         }
 342
 343         rte_prefetch0(&vq->desc[desc_indexes[0]]);
 344         for (i = 0; i < count; i++) {
 345                 uint16_t desc_idx = desc_indexes[i];
 346                 int err;
 347
 348                 if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
 349                         descs = (struct vring_desc *)(uintptr_t)gpa_to_vva(dev,
 350                                         vq->desc[desc_idx].addr);
 351                         if (unlikely(!descs)) {
 352                                 count = i;
 353                                 break;
 354                         }
 355
 356                         desc_idx = 0;
 357                         sz = vq->desc[desc_idx].len / sizeof(*descs);
 358                 } else {
 359                         descs = vq->desc;
 360                         sz = vq->size;
 361                 }
 362
 363                 err = copy_mbuf_to_desc(dev, descs, pkts[i], desc_idx, sz);
 364                 if (unlikely(err)) {
 365                         used_idx = (start_idx + i) & (vq->size - 1);
 366                         vq->used->ring[used_idx].len = dev->vhost_hlen;
 367                         vhost_log_used_vring(dev, vq,
 368                                 offsetof(struct vring_used, ring[used_idx]),
 369                                 sizeof(vq->used->ring[used_idx]));
 370                 }
 371
 372                 if (i + 1 < count)
 373                         rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
 374         }
 375
 376         rte_smp_wmb();
 377
 378         *(volatile uint16_t *)&vq->used->idx += count;
 379         vq->last_used_idx += count;
 380         vhost_log_used_vring(dev, vq,
 381                 offsetof(struct vring_used, idx),
 382                 sizeof(vq->used->idx));
 383
 384         /* flush used->idx update before we read avail->flags. */
 385         rte_mb();
 386
 387         /* Kick the guest if necessary. */
 388         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 389                         && (vq->callfd >= 0))
 390                 eventfd_write(vq->callfd, (eventfd_t)1);
 391         return count;
 392 }
 393
 394 static inline int __attribute__((always_inline))
 395 fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 396                          uint32_t avail_idx, uint32_t *vec_idx,
 397                          struct buf_vector *buf_vec, uint16_t *desc_chain_head,
 398                          uint16_t *desc_chain_len)
 399 {
 400         uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
 401         uint32_t vec_id = *vec_idx;
 402         uint32_t len    = 0;
 403         struct vring_desc *descs = vq->desc;
 404
 405         *desc_chain_head = idx;
 406
 407         if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
 408                 descs = (struct vring_desc *)(uintptr_t)
 409                                         gpa_to_vva(dev, vq->desc[idx].addr);
 410                 if (unlikely(!descs))
 411                         return -1;
 412
 413                 idx = 0;
 414         }
 415
 416         while (1) {
 417                 if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
 418                         return -1;
 419
 420                 len += descs[idx].len;
 421                 buf_vec[vec_id].buf_addr = descs[idx].addr;
 422                 buf_vec[vec_id].buf_len  = descs[idx].len;
 423                 buf_vec[vec_id].desc_idx = idx;
 424                 vec_id++;
 425
 426                 if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
 427                         break;
 428
 429                 idx = descs[idx].next;
 430         }
 431
 432         *desc_chain_len = len;
 433         *vec_idx = vec_id;
 434
 435         return 0;
 436 }
 437
 438 /*
 439  * Returns -1 on fail, 0 on success
 440  */
 441 static inline int
 442 reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 443                                 uint32_t size, struct buf_vector *buf_vec,
 444                                 uint16_t *num_buffers, uint16_t avail_head)
 445 {
 446         uint16_t cur_idx;
 447         uint32_t vec_idx = 0;
 448         uint16_t tries = 0;
 449
 450         uint16_t head_idx = 0;
 451         uint16_t len = 0;
 452
 453         *num_buffers = 0;
 454         cur_idx  = vq->last_avail_idx;
 455
 456         while (size > 0) {
 457                 if (unlikely(cur_idx == avail_head))
 458                         return -1;
 459
 460                 if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec,
 461                                                 &head_idx, &len) < 0))
 462                         return -1;
 463                 len = RTE_MIN(len, size);
 464                 update_shadow_used_ring(vq, head_idx, len);
 465                 size -= len;
 466
 467                 cur_idx++;
 468                 tries++;
 469                 *num_buffers += 1;
 470
 471                 /*
 472                  * if we tried all available ring items, and still
 473                  * can't get enough buf, it means something abnormal
 474                  * happened.
 475                  */
 476                 if (unlikely(tries >= vq->size))
 477                         return -1;
 478         }
 479
 480         return 0;
 481 }
 482
 483 static inline int __attribute__((always_inline))
 484 copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct rte_mbuf *m,
 485                             struct buf_vector *buf_vec, uint16_t num_buffers)
 486 {
 487         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 488         uint32_t vec_idx = 0;
 489         uint64_t desc_addr;
 490         uint32_t mbuf_offset, mbuf_avail;
 491         uint32_t desc_offset, desc_avail;
 492         uint32_t cpy_len;
 493         uint64_t hdr_addr, hdr_phys_addr;
 494         struct rte_mbuf *hdr_mbuf;
 495
 496         if (unlikely(m == NULL))
 497                 return -1;
 498
 499         desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
 500         if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr)
 501                 return -1;
 502
 503         hdr_mbuf = m;
 504         hdr_addr = desc_addr;
 505         hdr_phys_addr = buf_vec[vec_idx].buf_addr;
 506         rte_prefetch0((void *)(uintptr_t)hdr_addr);
 507
 508         virtio_hdr.num_buffers = num_buffers;
 509         LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
 510                 dev->vid, num_buffers);
 511
 512         desc_avail  = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
 513         desc_offset = dev->vhost_hlen;
 514
 515         mbuf_avail  = rte_pktmbuf_data_len(m);
 516         mbuf_offset = 0;
 517         while (mbuf_avail != 0 || m->next != NULL) {
 518                 /* done with current desc buf, get the next one */
 519                 if (desc_avail == 0) {
 520                         vec_idx++;
 521                         desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
 522                         if (unlikely(!desc_addr))
 523                                 return -1;
 524
 525                         /* Prefetch buffer address. */
 526                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 527                         desc_offset = 0;
 528                         desc_avail  = buf_vec[vec_idx].buf_len;
 529                 }
 530
 531                 /* done with current mbuf, get the next one */
 532                 if (mbuf_avail == 0) {
 533                         m = m->next;
 534
 535                         mbuf_offset = 0;
 536                         mbuf_avail  = rte_pktmbuf_data_len(m);
 537                 }
 538
 539                 if (hdr_addr) {
 540                         virtio_enqueue_offload(hdr_mbuf, &virtio_hdr.hdr);
 541                         copy_virtio_net_hdr(dev, hdr_addr, virtio_hdr);
 542                         vhost_log_write(dev, hdr_phys_addr, dev->vhost_hlen);
 543                         PRINT_PACKET(dev, (uintptr_t)hdr_addr,
 544                                      dev->vhost_hlen, 0);
 545
 546                         hdr_addr = 0;
 547                 }
 548
 549                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 550                 rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
 551                         rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 552                         cpy_len);
 553                 vhost_log_write(dev, buf_vec[vec_idx].buf_addr + desc_offset,
 554                         cpy_len);
 555                 PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 556                         cpy_len, 0);
 557
 558                 mbuf_avail  -= cpy_len;
 559                 mbuf_offset += cpy_len;
 560                 desc_avail  -= cpy_len;
 561                 desc_offset += cpy_len;
 562         }
 563
 564         return 0;
 565 }
 566
 567 static inline uint32_t __attribute__((always_inline))
 568 virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 569         struct rte_mbuf **pkts, uint32_t count)
 570 {
 571         struct vhost_virtqueue *vq;
 572         uint32_t pkt_idx = 0;
 573         uint16_t num_buffers;
 574         struct buf_vector buf_vec[BUF_VECTOR_MAX];
 575         uint16_t avail_head;
 576
 577         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 578         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
 579                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 580                         dev->vid, __func__, queue_id);
 581                 return 0;
 582         }
 583
 584         vq = dev->virtqueue[queue_id];
 585         if (unlikely(vq->enabled == 0))
 586                 return 0;
 587
 588         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 589         if (count == 0)
 590                 return 0;
 591
 592         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
 593
 594         vq->shadow_used_idx = 0;
 595         avail_head = *((volatile uint16_t *)&vq->avail->idx);
 596         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 597                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 598
 599                 if (unlikely(reserve_avail_buf_mergeable(dev, vq,
 600                                                 pkt_len, buf_vec, &num_buffers,
 601                                                 avail_head) < 0)) {
 602                         LOG_DEBUG(VHOST_DATA,
 603                                 "(%d) failed to get enough desc from vring\n",
 604                                 dev->vid);
 605                         vq->shadow_used_idx -= num_buffers;
 606                         break;
 607                 }
 608
 609                 LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 610                         dev->vid, vq->last_avail_idx,
 611                         vq->last_avail_idx + num_buffers);
 612
 613                 if (copy_mbuf_to_desc_mergeable(dev, pkts[pkt_idx],
 614                                                 buf_vec, num_buffers) < 0) {
 615                         vq->shadow_used_idx -= num_buffers;
 616                         break;
 617                 }
 618
 619                 vq->last_avail_idx += num_buffers;
 620         }
 621
 622         if (likely(vq->shadow_used_idx)) {
 623                 flush_shadow_used_ring(dev, vq);
 624
 625                 /* flush used->idx update before we read avail->flags. */
 626                 rte_mb();
 627
 628                 /* Kick the guest if necessary. */
 629                 if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 630                                 && (vq->callfd >= 0))
 631                         eventfd_write(vq->callfd, (eventfd_t)1);
 632         }
 633
 634         return pkt_idx;
 635 }
 636
 637 uint16_t
 638 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 639         struct rte_mbuf **pkts, uint16_t count)
 640 {
 641         struct virtio_net *dev = get_device(vid);
 642
 643         if (!dev)
 644                 return 0;
 645
 646         if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
 647                 return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 648         else
 649                 return virtio_dev_rx(dev, queue_id, pkts, count);
 650 }
 651
 652 static inline bool
 653 virtio_net_with_host_offload(struct virtio_net *dev)
 654 {
 655         if (dev->features &
 656                         ((1ULL << VIRTIO_NET_F_CSUM) |
 657                          (1ULL << VIRTIO_NET_F_HOST_ECN) |
 658                          (1ULL << VIRTIO_NET_F_HOST_TSO4) |
 659                          (1ULL << VIRTIO_NET_F_HOST_TSO6) |
 660                          (1ULL << VIRTIO_NET_F_HOST_UFO)))
 661                 return true;
 662
 663         return false;
 664 }
 665
 666 static void
 667 parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
 668 {
 669         struct ipv4_hdr *ipv4_hdr;
 670         struct ipv6_hdr *ipv6_hdr;
 671         void *l3_hdr = NULL;
 672         struct ether_hdr *eth_hdr;
 673         uint16_t ethertype;
 674
 675         eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
 676
 677         m->l2_len = sizeof(struct ether_hdr);
 678         ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
 679
 680         if (ethertype == ETHER_TYPE_VLAN) {
 681                 struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
 682
 683                 m->l2_len += sizeof(struct vlan_hdr);
 684                 ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
 685         }
 686
 687         l3_hdr = (char *)eth_hdr + m->l2_len;
 688
 689         switch (ethertype) {
 690         case ETHER_TYPE_IPv4:
 691                 ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
 692                 *l4_proto = ipv4_hdr->next_proto_id;
 693                 m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
 694                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 695                 m->ol_flags |= PKT_TX_IPV4;
 696                 break;
 697         case ETHER_TYPE_IPv6:
 698                 ipv6_hdr = (struct ipv6_hdr *)l3_hdr;
 699                 *l4_proto = ipv6_hdr->proto;
 700                 m->l3_len = sizeof(struct ipv6_hdr);
 701                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 702                 m->ol_flags |= PKT_TX_IPV6;
 703                 break;
 704         default:
 705                 m->l3_len = 0;
 706                 *l4_proto = 0;
 707                 *l4_hdr = NULL;
 708                 break;
 709         }
 710 }
 711
 712 static inline void __attribute__((always_inline))
 713 vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 714 {
 715         uint16_t l4_proto = 0;
 716         void *l4_hdr = NULL;
 717         struct tcp_hdr *tcp_hdr = NULL;
 718
 719         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 720                 return;
 721
 722         parse_ethernet(m, &l4_proto, &l4_hdr);
 723         if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 724                 if (hdr->csum_start == (m->l2_len + m->l3_len)) {
 725                         switch (hdr->csum_offset) {
 726                         case (offsetof(struct tcp_hdr, cksum)):
 727                                 if (l4_proto == IPPROTO_TCP)
 728                                         m->ol_flags |= PKT_TX_TCP_CKSUM;
 729                                 break;
 730                         case (offsetof(struct udp_hdr, dgram_cksum)):
 731                                 if (l4_proto == IPPROTO_UDP)
 732                                         m->ol_flags |= PKT_TX_UDP_CKSUM;
 733                                 break;
 734                         case (offsetof(struct sctp_hdr, cksum)):
 735                                 if (l4_proto == IPPROTO_SCTP)
 736                                         m->ol_flags |= PKT_TX_SCTP_CKSUM;
 737                                 break;
 738                         default:
 739                                 break;
 740                         }
 741                 }
 742         }
 743
 744         if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 745                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 746                 case VIRTIO_NET_HDR_GSO_TCPV4:
 747                 case VIRTIO_NET_HDR_GSO_TCPV6:
 748                         tcp_hdr = (struct tcp_hdr *)l4_hdr;
 749                         m->ol_flags |= PKT_TX_TCP_SEG;
 750                         m->tso_segsz = hdr->gso_size;
 751                         m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 752                         break;
 753                 default:
 754                         RTE_LOG(WARNING, VHOST_DATA,
 755                                 "unsupported gso type %u.\n", hdr->gso_type);
 756                         break;
 757                 }
 758         }
 759 }
 760
 761 #define RARP_PKT_SIZE   64
 762
 763 static int
 764 make_rarp_packet(struct rte_mbuf *rarp_mbuf, const struct ether_addr *mac)
 765 {
 766         struct ether_hdr *eth_hdr;
 767         struct arp_hdr  *rarp;
 768
 769         if (rarp_mbuf->buf_len < 64) {
 770                 RTE_LOG(WARNING, VHOST_DATA,
 771                         "failed to make RARP; mbuf size too small %u (< %d)\n",
 772                         rarp_mbuf->buf_len, RARP_PKT_SIZE);
 773                 return -1;
 774         }
 775
 776         /* Ethernet header. */
 777         eth_hdr = rte_pktmbuf_mtod_offset(rarp_mbuf, struct ether_hdr *, 0);
 778         memset(eth_hdr->d_addr.addr_bytes, 0xff, ETHER_ADDR_LEN);
 779         ether_addr_copy(mac, &eth_hdr->s_addr);
 780         eth_hdr->ether_type = htons(ETHER_TYPE_RARP);
 781
 782         /* RARP header. */
 783         rarp = (struct arp_hdr *)(eth_hdr + 1);
 784         rarp->arp_hrd = htons(ARP_HRD_ETHER);
 785         rarp->arp_pro = htons(ETHER_TYPE_IPv4);
 786         rarp->arp_hln = ETHER_ADDR_LEN;
 787         rarp->arp_pln = 4;
 788         rarp->arp_op  = htons(ARP_OP_REVREQUEST);
 789
 790         ether_addr_copy(mac, &rarp->arp_data.arp_sha);
 791         ether_addr_copy(mac, &rarp->arp_data.arp_tha);
 792         memset(&rarp->arp_data.arp_sip, 0x00, 4);
 793         memset(&rarp->arp_data.arp_tip, 0x00, 4);
 794
 795         rarp_mbuf->pkt_len  = rarp_mbuf->data_len = RARP_PKT_SIZE;
 796
 797         return 0;
 798 }
 799
 800 static inline void __attribute__((always_inline))
 801 put_zmbuf(struct zcopy_mbuf *zmbuf)
 802 {
 803         zmbuf->in_use = 0;
 804 }
 805
 806 static inline int __attribute__((always_inline))
 807 copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs,
 808                   uint16_t max_desc, struct rte_mbuf *m, uint16_t desc_idx,
 809                   struct rte_mempool *mbuf_pool)
 810 {
 811         struct vring_desc *desc;
 812         uint64_t desc_addr;
 813         uint32_t desc_avail, desc_offset;
 814         uint32_t mbuf_avail, mbuf_offset;
 815         uint32_t cpy_len;
 816         struct rte_mbuf *cur = m, *prev = m;
 817         struct virtio_net_hdr *hdr = NULL;
 818         /* A counter to avoid desc dead loop chain */
 819         uint32_t nr_desc = 1;
 820
 821         desc = &descs[desc_idx];
 822         if (unlikely((desc->len < dev->vhost_hlen)) ||
 823                         (desc->flags & VRING_DESC_F_INDIRECT))
 824                 return -1;
 825
 826         desc_addr = gpa_to_vva(dev, desc->addr);
 827         if (unlikely(!desc_addr))
 828                 return -1;
 829
 830         if (virtio_net_with_host_offload(dev)) {
 831                 hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
 832                 rte_prefetch0(hdr);
 833         }
 834
 835         /*
 836          * A virtio driver normally uses at least 2 desc buffers
 837          * for Tx: the first for storing the header, and others
 838          * for storing the data.
 839          */
 840         if (likely((desc->len == dev->vhost_hlen) &&
 841                    (desc->flags & VRING_DESC_F_NEXT) != 0)) {
 842                 desc = &descs[desc->next];
 843                 if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 844                         return -1;
 845
 846                 desc_addr = gpa_to_vva(dev, desc->addr);
 847                 if (unlikely(!desc_addr))
 848                         return -1;
 849
 850                 desc_offset = 0;
 851                 desc_avail  = desc->len;
 852                 nr_desc    += 1;
 853         } else {
 854                 desc_avail  = desc->len - dev->vhost_hlen;
 855                 desc_offset = dev->vhost_hlen;
 856         }
 857
 858         rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
 859
 860         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
 861
 862         mbuf_offset = 0;
 863         mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 864         while (1) {
 865                 uint64_t hpa;
 866
 867                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 868
 869                 /*
 870                  * A desc buf might across two host physical pages that are
 871                  * not continuous. In such case (gpa_to_hpa returns 0), data
 872                  * will be copied even though zero copy is enabled.
 873                  */
 874                 if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
 875                                         desc->addr + desc_offset, cpy_len)))) {
 876                         cur->data_len = cpy_len;
 877                         cur->data_off = 0;
 878                         cur->buf_addr = (void *)(uintptr_t)desc_addr;
 879                         cur->buf_physaddr = hpa;
 880
 881                         /*
 882                          * In zero copy mode, one mbuf can only reference data
 883                          * for one or partial of one desc buff.
 884                          */
 885                         mbuf_avail = cpy_len;
 886                 } else {
 887                         rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 888                                                            mbuf_offset),
 889                                 (void *)((uintptr_t)(desc_addr + desc_offset)),
 890                                 cpy_len);
 891                 }
 892
 893                 mbuf_avail  -= cpy_len;
 894                 mbuf_offset += cpy_len;
 895                 desc_avail  -= cpy_len;
 896                 desc_offset += cpy_len;
 897
 898                 /* This desc reaches to its end, get the next one */
 899                 if (desc_avail == 0) {
 900                         if ((desc->flags & VRING_DESC_F_NEXT) == 0)
 901                                 break;
 902
 903                         if (unlikely(desc->next >= max_desc ||
 904                                      ++nr_desc > max_desc))
 905                                 return -1;
 906                         desc = &descs[desc->next];
 907                         if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
 908                                 return -1;
 909
 910                         desc_addr = gpa_to_vva(dev, desc->addr);
 911                         if (unlikely(!desc_addr))
 912                                 return -1;
 913
 914                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 915
 916                         desc_offset = 0;
 917                         desc_avail  = desc->len;
 918
 919                         PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
 920                 }
 921
 922                 /*
 923                  * This mbuf reaches to its end, get a new one
 924                  * to hold more data.
 925                  */
 926                 if (mbuf_avail == 0) {
 927                         cur = rte_pktmbuf_alloc(mbuf_pool);
 928                         if (unlikely(cur == NULL)) {
 929                                 RTE_LOG(ERR, VHOST_DATA, "Failed to "
 930                                         "allocate memory for mbuf.\n");
 931                                 return -1;
 932                         }
 933                         if (unlikely(dev->dequeue_zero_copy))
 934                                 rte_mbuf_refcnt_update(cur, 1);
 935
 936                         prev->next = cur;
 937                         prev->data_len = mbuf_offset;
 938                         m->nb_segs += 1;
 939                         m->pkt_len += mbuf_offset;
 940                         prev = cur;
 941
 942                         mbuf_offset = 0;
 943                         mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 944                 }
 945         }
 946
 947         prev->data_len = mbuf_offset;
 948         m->pkt_len    += mbuf_offset;
 949
 950         if (hdr)
 951                 vhost_dequeue_offload(hdr, m);
 952
 953         return 0;
 954 }
 955
 956 static inline void __attribute__((always_inline))
 957 update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
 958                  uint32_t used_idx, uint32_t desc_idx)
 959 {
 960         vq->used->ring[used_idx].id  = desc_idx;
 961         vq->used->ring[used_idx].len = 0;
 962         vhost_log_used_vring(dev, vq,
 963                         offsetof(struct vring_used, ring[used_idx]),
 964                         sizeof(vq->used->ring[used_idx]));
 965 }
 966
 967 static inline void __attribute__((always_inline))
 968 update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 969                 uint32_t count)
 970 {
 971         if (unlikely(count == 0))
 972                 return;
 973
 974         rte_smp_wmb();
 975         rte_smp_rmb();
 976
 977         vq->used->idx += count;
 978         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 979                         sizeof(vq->used->idx));
 980
 981         /* Kick guest if required. */
 982         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
 983                         && (vq->callfd >= 0))
 984                 eventfd_write(vq->callfd, (eventfd_t)1);
 985 }
 986
 987 static inline struct zcopy_mbuf *__attribute__((always_inline))
 988 get_zmbuf(struct vhost_virtqueue *vq)
 989 {
 990         uint16_t i;
 991         uint16_t last;
 992         int tries = 0;
 993
 994         /* search [last_zmbuf_idx, zmbuf_size) */
 995         i = vq->last_zmbuf_idx;
 996         last = vq->zmbuf_size;
 997
 998 again:
 999         for (; i < last; i++) {
1000                 if (vq->zmbufs[i].in_use == 0) {
1001                         vq->last_zmbuf_idx = i + 1;
1002                         vq->zmbufs[i].in_use = 1;
1003                         return &vq->zmbufs[i];
1004                 }
1005         }
1006
1007         tries++;
1008         if (tries == 1) {
1009                 /* search [0, last_zmbuf_idx) */
1010                 i = 0;
1011                 last = vq->last_zmbuf_idx;
1012                 goto again;
1013         }
1014
1015         return NULL;
1016 }
1017
1018 static inline bool __attribute__((always_inline))
1019 mbuf_is_consumed(struct rte_mbuf *m)
1020 {
1021         while (m) {
1022                 if (rte_mbuf_refcnt_read(m) > 1)
1023                         return false;
1024                 m = m->next;
1025         }
1026
1027         return true;
1028 }
1029
1030 uint16_t
1031 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
1032         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
1033 {
1034         struct virtio_net *dev;
1035         struct rte_mbuf *rarp_mbuf = NULL;
1036         struct vhost_virtqueue *vq;
1037         uint32_t desc_indexes[MAX_PKT_BURST];
1038         uint32_t used_idx;
1039         uint32_t i = 0;
1040         uint16_t free_entries;
1041         uint16_t avail_idx;
1042
1043         dev = get_device(vid);
1044         if (!dev)
1045                 return 0;
1046
1047         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->virt_qp_nb))) {
1048                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
1049                         dev->vid, __func__, queue_id);
1050                 return 0;
1051         }
1052
1053         vq = dev->virtqueue[queue_id];
1054         if (unlikely(vq->enabled == 0))
1055                 return 0;
1056
1057         if (unlikely(dev->dequeue_zero_copy)) {
1058                 struct zcopy_mbuf *zmbuf, *next;
1059                 int nr_updated = 0;
1060
1061                 for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
1062                      zmbuf != NULL; zmbuf = next) {
1063                         next = TAILQ_NEXT(zmbuf, next);
1064
1065                         if (mbuf_is_consumed(zmbuf->mbuf)) {
1066                                 used_idx = vq->last_used_idx++ & (vq->size - 1);
1067                                 update_used_ring(dev, vq, used_idx,
1068                                                  zmbuf->desc_idx);
1069                                 nr_updated += 1;
1070
1071                                 TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
1072                                 rte_pktmbuf_free(zmbuf->mbuf);
1073                                 put_zmbuf(zmbuf);
1074                                 vq->nr_zmbuf -= 1;
1075                         }
1076                 }
1077
1078                 update_used_idx(dev, vq, nr_updated);
1079         }
1080
1081         /*
1082          * Construct a RARP broadcast packet, and inject it to the "pkts"
1083          * array, to looks like that guest actually send such packet.
1084          *
1085          * Check user_send_rarp() for more information.
1086          *
1087          * broadcast_rarp shares a cacheline in the virtio_net structure
1088          * with some fields that are accessed during enqueue and
1089          * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
1090          * result in false sharing between enqueue and dequeue.
1091          *
1092          * Prevent unnecessary false sharing by reading broadcast_rarp first
1093          * and only performing cmpset if the read indicates it is likely to
1094          * be set.
1095          */
1096
1097         if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
1098                         rte_atomic16_cmpset((volatile uint16_t *)
1099                                 &dev->broadcast_rarp.cnt, 1, 0))) {
1100
1101                 rarp_mbuf = rte_pktmbuf_alloc(mbuf_pool);
1102                 if (rarp_mbuf == NULL) {
1103                         RTE_LOG(ERR, VHOST_DATA,
1104                                 "Failed to allocate memory for mbuf.\n");
1105                         return 0;
1106                 }
1107
1108                 if (make_rarp_packet(rarp_mbuf, &dev->mac)) {
1109                         rte_pktmbuf_free(rarp_mbuf);
1110                         rarp_mbuf = NULL;
1111                 } else {
1112                         count -= 1;
1113                 }
1114         }
1115
1116         free_entries = *((volatile uint16_t *)&vq->avail->idx) -
1117                         vq->last_avail_idx;
1118         if (free_entries == 0)
1119                 goto out;
1120
1121         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
1122
1123         /* Prefetch available and used ring */
1124         avail_idx = vq->last_avail_idx & (vq->size - 1);
1125         used_idx  = vq->last_used_idx  & (vq->size - 1);
1126         rte_prefetch0(&vq->avail->ring[avail_idx]);
1127         rte_prefetch0(&vq->used->ring[used_idx]);
1128
1129         count = RTE_MIN(count, MAX_PKT_BURST);
1130         count = RTE_MIN(count, free_entries);
1131         LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n",
1132                         dev->vid, count);
1133
1134         /* Retrieve all of the head indexes first to avoid caching issues. */
1135         for (i = 0; i < count; i++) {
1136                 avail_idx = (vq->last_avail_idx + i) & (vq->size - 1);
1137                 used_idx  = (vq->last_used_idx  + i) & (vq->size - 1);
1138                 desc_indexes[i] = vq->avail->ring[avail_idx];
1139
1140                 if (likely(dev->dequeue_zero_copy == 0))
1141                         update_used_ring(dev, vq, used_idx, desc_indexes[i]);
1142         }
1143
1144         /* Prefetch descriptor index. */
1145         rte_prefetch0(&vq->desc[desc_indexes[0]]);
1146         for (i = 0; i < count; i++) {
1147                 struct vring_desc *desc;
1148                 uint16_t sz, idx;
1149                 int err;
1150
1151                 if (likely(i + 1 < count))
1152                         rte_prefetch0(&vq->desc[desc_indexes[i + 1]]);
1153
1154                 if (vq->desc[desc_indexes[i]].flags & VRING_DESC_F_INDIRECT) {
1155                         desc = (struct vring_desc *)(uintptr_t)gpa_to_vva(dev,
1156                                         vq->desc[desc_indexes[i]].addr);
1157                         if (unlikely(!desc))
1158                                 break;
1159
1160                         rte_prefetch0(desc);
1161                         sz = vq->desc[desc_indexes[i]].len / sizeof(*desc);
1162                         idx = 0;
1163                 } else {
1164                         desc = vq->desc;
1165                         sz = vq->size;
1166                         idx = desc_indexes[i];
1167                 }
1168
1169                 pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
1170                 if (unlikely(pkts[i] == NULL)) {
1171                         RTE_LOG(ERR, VHOST_DATA,
1172                                 "Failed to allocate memory for mbuf.\n");
1173                         break;
1174                 }
1175
1176                 err = copy_desc_to_mbuf(dev, desc, sz, pkts[i], idx, mbuf_pool);
1177                 if (unlikely(err)) {
1178                         rte_pktmbuf_free(pkts[i]);
1179                         break;
1180                 }
1181
1182                 if (unlikely(dev->dequeue_zero_copy)) {
1183                         struct zcopy_mbuf *zmbuf;
1184
1185                         zmbuf = get_zmbuf(vq);
1186                         if (!zmbuf) {
1187                                 rte_pktmbuf_free(pkts[i]);
1188                                 break;
1189                         }
1190                         zmbuf->mbuf = pkts[i];
1191                         zmbuf->desc_idx = desc_indexes[i];
1192
1193                         /*
1194                          * Pin lock the mbuf; we will check later to see
1195                          * whether the mbuf is freed (when we are the last
1196                          * user) or not. If that's the case, we then could
1197                          * update the used ring safely.
1198                          */
1199                         rte_mbuf_refcnt_update(pkts[i], 1);
1200
1201                         vq->nr_zmbuf += 1;
1202                         TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
1203                 }
1204         }
1205         vq->last_avail_idx += i;
1206
1207         if (likely(dev->dequeue_zero_copy == 0)) {
1208                 vq->last_used_idx += i;
1209                 update_used_idx(dev, vq, i);
1210         }
1211
1212 out:
1213         if (unlikely(rarp_mbuf != NULL)) {
1214                 /*
1215                  * Inject it to the head of "pkts" array, so that switch's mac
1216                  * learning table will get updated first.
1217                  */
1218                 memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *));
1219                 pkts[0] = rarp_mbuf;
1220                 i += 1;
1221         }
1222
1223         return i;
1224 }