lib/librte_vhost/virtio_net.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2016 Intel Corporation
   3  */
   4
   5 #include <stdint.h>
   6 #include <stdbool.h>
   7 #include <linux/virtio_net.h>
   8
   9 #include <rte_mbuf.h>
  10 #include <rte_memcpy.h>
  11 #include <rte_ether.h>
  12 #include <rte_ip.h>
  13 #include <rte_vhost.h>
  14 #include <rte_tcp.h>
  15 #include <rte_udp.h>
  16 #include <rte_sctp.h>
  17 #include <rte_arp.h>
  18 #include <rte_spinlock.h>
  19
  20 #include "iotlb.h"
  21 #include "vhost.h"
  22
  23 #define MAX_PKT_BURST 32
  24
  25 #define MAX_BATCH_LEN 256
  26
  27 static bool
  28 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
  29 {
  30         return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring;
  31 }
  32
  33 static __rte_always_inline void
  34 do_flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
  35                           uint16_t to, uint16_t from, uint16_t size)
  36 {
  37         rte_memcpy(&vq->used->ring[to],
  38                         &vq->shadow_used_ring[from],
  39                         size * sizeof(struct vring_used_elem));
  40         vhost_log_used_vring(dev, vq,
  41                         offsetof(struct vring_used, ring[to]),
  42                         size * sizeof(struct vring_used_elem));
  43 }
  44
  45 static __rte_always_inline void
  46 flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq)
  47 {
  48         uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
  49
  50         if (used_idx + vq->shadow_used_idx <= vq->size) {
  51                 do_flush_shadow_used_ring(dev, vq, used_idx, 0,
  52                                           vq->shadow_used_idx);
  53         } else {
  54                 uint16_t size;
  55
  56                 /* update used ring interval [used_idx, vq->size] */
  57                 size = vq->size - used_idx;
  58                 do_flush_shadow_used_ring(dev, vq, used_idx, 0, size);
  59
  60                 /* update the left half used ring interval [0, left_size] */
  61                 do_flush_shadow_used_ring(dev, vq, 0, size,
  62                                           vq->shadow_used_idx - size);
  63         }
  64         vq->last_used_idx += vq->shadow_used_idx;
  65
  66         rte_smp_wmb();
  67
  68         *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx;
  69         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
  70                 sizeof(vq->used->idx));
  71 }
  72
  73 static __rte_always_inline void
  74 update_shadow_used_ring(struct vhost_virtqueue *vq,
  75                          uint16_t desc_idx, uint16_t len)
  76 {
  77         uint16_t i = vq->shadow_used_idx++;
  78
  79         vq->shadow_used_ring[i].id  = desc_idx;
  80         vq->shadow_used_ring[i].len = len;
  81 }
  82
  83 static inline void
  84 do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq)
  85 {
  86         struct batch_copy_elem *elem = vq->batch_copy_elems;
  87         uint16_t count = vq->batch_copy_nb_elems;
  88         int i;
  89
  90         for (i = 0; i < count; i++) {
  91                 rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
  92                 vhost_log_write(dev, elem[i].log_addr, elem[i].len);
  93                 PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0);
  94         }
  95 }
  96
  97 static inline void
  98 do_data_copy_dequeue(struct vhost_virtqueue *vq)
  99 {
 100         struct batch_copy_elem *elem = vq->batch_copy_elems;
 101         uint16_t count = vq->batch_copy_nb_elems;
 102         int i;
 103
 104         for (i = 0; i < count; i++)
 105                 rte_memcpy(elem[i].dst, elem[i].src, elem[i].len);
 106 }
 107
 108 /* avoid write operation when necessary, to lessen cache issues */
 109 #define ASSIGN_UNLESS_EQUAL(var, val) do {      \
 110         if ((var) != (val))                     \
 111                 (var) = (val);                  \
 112 } while (0)
 113
 114 static void
 115 virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 116 {
 117         uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK;
 118
 119         if (m_buf->ol_flags & PKT_TX_TCP_SEG)
 120                 csum_l4 |= PKT_TX_TCP_CKSUM;
 121
 122         if (csum_l4) {
 123                 net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 124                 net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len;
 125
 126                 switch (csum_l4) {
 127                 case PKT_TX_TCP_CKSUM:
 128                         net_hdr->csum_offset = (offsetof(struct tcp_hdr,
 129                                                 cksum));
 130                         break;
 131                 case PKT_TX_UDP_CKSUM:
 132                         net_hdr->csum_offset = (offsetof(struct udp_hdr,
 133                                                 dgram_cksum));
 134                         break;
 135                 case PKT_TX_SCTP_CKSUM:
 136                         net_hdr->csum_offset = (offsetof(struct sctp_hdr,
 137                                                 cksum));
 138                         break;
 139                 }
 140         } else {
 141                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_start, 0);
 142                 ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0);
 143                 ASSIGN_UNLESS_EQUAL(net_hdr->flags, 0);
 144         }
 145
 146         /* IP cksum verification cannot be bypassed, then calculate here */
 147         if (m_buf->ol_flags & PKT_TX_IP_CKSUM) {
 148                 struct ipv4_hdr *ipv4_hdr;
 149
 150                 ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct ipv4_hdr *,
 151                                                    m_buf->l2_len);
 152                 ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
 153         }
 154
 155         if (m_buf->ol_flags & PKT_TX_TCP_SEG) {
 156                 if (m_buf->ol_flags & PKT_TX_IPV4)
 157                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 158                 else
 159                         net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 160                 net_hdr->gso_size = m_buf->tso_segsz;
 161                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 162                                         + m_buf->l4_len;
 163         } else if (m_buf->ol_flags & PKT_TX_UDP_SEG) {
 164                 net_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 165                 net_hdr->gso_size = m_buf->tso_segsz;
 166                 net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len +
 167                         m_buf->l4_len;
 168         } else {
 169                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0);
 170                 ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0);
 171                 ASSIGN_UNLESS_EQUAL(net_hdr->hdr_len, 0);
 172         }
 173 }
 174
 175 static __rte_always_inline int
 176 copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
 177                   struct vring_desc *descs, struct rte_mbuf *m,
 178                   uint16_t desc_idx, uint32_t size)
 179 {
 180         uint32_t desc_avail, desc_offset;
 181         uint32_t mbuf_avail, mbuf_offset;
 182         uint32_t cpy_len;
 183         struct vring_desc *desc;
 184         uint64_t desc_addr;
 185         /* A counter to avoid desc dead loop chain */
 186         uint16_t nr_desc = 1;
 187         struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
 188         uint16_t copy_nb = vq->batch_copy_nb_elems;
 189         int error = 0;
 190
 191         desc = &descs[desc_idx];
 192         desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
 193                                         desc->len, VHOST_ACCESS_RW);
 194         /*
 195          * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
 196          * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
 197          * otherwise stores offset on the stack instead of in a register.
 198          */
 199         if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr) {
 200                 error = -1;
 201                 goto out;
 202         }
 203
 204         rte_prefetch0((void *)(uintptr_t)desc_addr);
 205
 206         virtio_enqueue_offload(m, (struct virtio_net_hdr *)(uintptr_t)desc_addr);
 207         vhost_log_write(dev, desc->addr, dev->vhost_hlen);
 208         PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
 209
 210         desc_offset = dev->vhost_hlen;
 211         desc_avail  = desc->len - dev->vhost_hlen;
 212
 213         mbuf_avail  = rte_pktmbuf_data_len(m);
 214         mbuf_offset = 0;
 215         while (mbuf_avail != 0 || m->next != NULL) {
 216                 /* done with current mbuf, fetch next */
 217                 if (mbuf_avail == 0) {
 218                         m = m->next;
 219
 220                         mbuf_offset = 0;
 221                         mbuf_avail  = rte_pktmbuf_data_len(m);
 222                 }
 223
 224                 /* done with current desc buf, fetch next */
 225                 if (desc_avail == 0) {
 226                         if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
 227                                 /* Room in vring buffer is not enough */
 228                                 error = -1;
 229                                 goto out;
 230                         }
 231                         if (unlikely(desc->next >= size || ++nr_desc > size)) {
 232                                 error = -1;
 233                                 goto out;
 234                         }
 235
 236                         desc = &descs[desc->next];
 237                         desc_addr = vhost_iova_to_vva(dev, vq, desc->addr,
 238                                                         desc->len,
 239                                                         VHOST_ACCESS_RW);
 240                         if (unlikely(!desc_addr)) {
 241                                 error = -1;
 242                                 goto out;
 243                         }
 244
 245                         desc_offset = 0;
 246                         desc_avail  = desc->len;
 247                 }
 248
 249                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 250                 if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) {
 251                         rte_memcpy((void *)((uintptr_t)(desc_addr +
 252                                                         desc_offset)),
 253                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 254                                 cpy_len);
 255                         vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
 256                         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 257                                      cpy_len, 0);
 258                 } else {
 259                         batch_copy[copy_nb].dst =
 260                                 (void *)((uintptr_t)(desc_addr + desc_offset));
 261                         batch_copy[copy_nb].src =
 262                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
 263                         batch_copy[copy_nb].log_addr = desc->addr + desc_offset;
 264                         batch_copy[copy_nb].len = cpy_len;
 265                         copy_nb++;
 266                 }
 267
 268                 mbuf_avail  -= cpy_len;
 269                 mbuf_offset += cpy_len;
 270                 desc_avail  -= cpy_len;
 271                 desc_offset += cpy_len;
 272         }
 273
 274 out:
 275         vq->batch_copy_nb_elems = copy_nb;
 276
 277         return error;
 278 }
 279
 280 /**
 281  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 282  * be received from the physical port or from another virtio device. A packet
 283  * count is returned to indicate the number of packets that are successfully
 284  * added to the RX queue. This function works when the mbuf is scattered, but
 285  * it doesn't support the mergeable feature.
 286  */
 287 static __rte_always_inline uint32_t
 288 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 289               struct rte_mbuf **pkts, uint32_t count)
 290 {
 291         struct vhost_virtqueue *vq;
 292         uint16_t avail_idx, free_entries, start_idx;
 293         uint16_t desc_indexes[MAX_PKT_BURST];
 294         struct vring_desc *descs;
 295         uint16_t used_idx;
 296         uint32_t i, sz;
 297
 298         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 299         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
 300                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 301                         dev->vid, __func__, queue_id);
 302                 return 0;
 303         }
 304
 305         vq = dev->virtqueue[queue_id];
 306
 307         rte_spinlock_lock(&vq->access_lock);
 308
 309         if (unlikely(vq->enabled == 0))
 310                 goto out_access_unlock;
 311
 312         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 313                 vhost_user_iotlb_rd_lock(vq);
 314
 315         if (unlikely(vq->access_ok == 0)) {
 316                 if (unlikely(vring_translate(dev, vq) < 0)) {
 317                         count = 0;
 318                         goto out;
 319                 }
 320         }
 321
 322         avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 323         start_idx = vq->last_used_idx;
 324         free_entries = avail_idx - start_idx;
 325         count = RTE_MIN(count, free_entries);
 326         count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
 327         if (count == 0)
 328                 goto out;
 329
 330         LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
 331                 dev->vid, start_idx, start_idx + count);
 332
 333         vq->batch_copy_nb_elems = 0;
 334
 335         /* Retrieve all of the desc indexes first to avoid caching issues. */
 336         rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
 337         for (i = 0; i < count; i++) {
 338                 used_idx = (start_idx + i) & (vq->size - 1);
 339                 desc_indexes[i] = vq->avail->ring[used_idx];
 340                 vq->used->ring[used_idx].id = desc_indexes[i];
 341                 vq->used->ring[used_idx].len = pkts[i]->pkt_len +
 342                                                dev->vhost_hlen;
 343                 vhost_log_used_vring(dev, vq,
 344                         offsetof(struct vring_used, ring[used_idx]),
 345                         sizeof(vq->used->ring[used_idx]));
 346         }
 347
 348         rte_prefetch0(&vq->desc[desc_indexes[0]]);
 349         for (i = 0; i < count; i++) {
 350                 uint16_t desc_idx = desc_indexes[i];
 351                 int err;
 352
 353                 if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
 354                         descs = (struct vring_desc *)(uintptr_t)
 355                                 vhost_iova_to_vva(dev,
 356                                                 vq, vq->desc[desc_idx].addr,
 357                                                 vq->desc[desc_idx].len,
 358                                                 VHOST_ACCESS_RO);
 359                         if (unlikely(!descs)) {
 360                                 count = i;
 361                                 break;
 362                         }
 363
 364                         desc_idx = 0;
 365                         sz = vq->desc[desc_idx].len / sizeof(*descs);
 366                 } else {
 367                         descs = vq->desc;
 368                         sz = vq->size;
 369                 }
 370
 371                 err = copy_mbuf_to_desc(dev, vq, descs, pkts[i], desc_idx, sz);
 372                 if (unlikely(err)) {
 373                         count = i;
 374                         break;
 375                 }
 376
 377                 if (i + 1 < count)
 378                         rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
 379         }
 380
 381         do_data_copy_enqueue(dev, vq);
 382
 383         rte_smp_wmb();
 384
 385         *(volatile uint16_t *)&vq->used->idx += count;
 386         vq->last_used_idx += count;
 387         vhost_log_used_vring(dev, vq,
 388                 offsetof(struct vring_used, idx),
 389                 sizeof(vq->used->idx));
 390
 391         vhost_vring_call(dev, vq);
 392 out:
 393         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 394                 vhost_user_iotlb_rd_unlock(vq);
 395
 396 out_access_unlock:
 397         rte_spinlock_unlock(&vq->access_lock);
 398
 399         return count;
 400 }
 401
 402 static __rte_always_inline int
 403 fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 404                          uint32_t avail_idx, uint32_t *vec_idx,
 405                          struct buf_vector *buf_vec, uint16_t *desc_chain_head,
 406                          uint16_t *desc_chain_len)
 407 {
 408         uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
 409         uint32_t vec_id = *vec_idx;
 410         uint32_t len    = 0;
 411         struct vring_desc *descs = vq->desc;
 412
 413         *desc_chain_head = idx;
 414
 415         if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
 416                 descs = (struct vring_desc *)(uintptr_t)
 417                         vhost_iova_to_vva(dev, vq, vq->desc[idx].addr,
 418                                                 vq->desc[idx].len,
 419                                                 VHOST_ACCESS_RO);
 420                 if (unlikely(!descs))
 421                         return -1;
 422
 423                 idx = 0;
 424         }
 425
 426         while (1) {
 427                 if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
 428                         return -1;
 429
 430                 len += descs[idx].len;
 431                 buf_vec[vec_id].buf_addr = descs[idx].addr;
 432                 buf_vec[vec_id].buf_len  = descs[idx].len;
 433                 buf_vec[vec_id].desc_idx = idx;
 434                 vec_id++;
 435
 436                 if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
 437                         break;
 438
 439                 idx = descs[idx].next;
 440         }
 441
 442         *desc_chain_len = len;
 443         *vec_idx = vec_id;
 444
 445         return 0;
 446 }
 447
 448 /*
 449  * Returns -1 on fail, 0 on success
 450  */
 451 static inline int
 452 reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 453                                 uint32_t size, struct buf_vector *buf_vec,
 454                                 uint16_t *num_buffers, uint16_t avail_head)
 455 {
 456         uint16_t cur_idx;
 457         uint32_t vec_idx = 0;
 458         uint16_t tries = 0;
 459
 460         uint16_t head_idx = 0;
 461         uint16_t len = 0;
 462
 463         *num_buffers = 0;
 464         cur_idx  = vq->last_avail_idx;
 465
 466         while (size > 0) {
 467                 if (unlikely(cur_idx == avail_head))
 468                         return -1;
 469
 470                 if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec,
 471                                                 &head_idx, &len) < 0))
 472                         return -1;
 473                 len = RTE_MIN(len, size);
 474                 update_shadow_used_ring(vq, head_idx, len);
 475                 size -= len;
 476
 477                 cur_idx++;
 478                 tries++;
 479                 *num_buffers += 1;
 480
 481                 /*
 482                  * if we tried all available ring items, and still
 483                  * can't get enough buf, it means something abnormal
 484                  * happened.
 485                  */
 486                 if (unlikely(tries >= vq->size))
 487                         return -1;
 488         }
 489
 490         return 0;
 491 }
 492
 493 static __rte_always_inline int
 494 copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
 495                             struct rte_mbuf *m, struct buf_vector *buf_vec,
 496                             uint16_t num_buffers)
 497 {
 498         uint32_t vec_idx = 0;
 499         uint64_t desc_addr;
 500         uint32_t mbuf_offset, mbuf_avail;
 501         uint32_t desc_offset, desc_avail;
 502         uint32_t cpy_len;
 503         uint64_t hdr_addr, hdr_phys_addr;
 504         struct rte_mbuf *hdr_mbuf;
 505         struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
 506         uint16_t copy_nb = vq->batch_copy_nb_elems;
 507         int error = 0;
 508
 509         if (unlikely(m == NULL)) {
 510                 error = -1;
 511                 goto out;
 512         }
 513
 514         desc_addr = vhost_iova_to_vva(dev, vq, buf_vec[vec_idx].buf_addr,
 515                                                 buf_vec[vec_idx].buf_len,
 516                                                 VHOST_ACCESS_RW);
 517         if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr) {
 518                 error = -1;
 519                 goto out;
 520         }
 521
 522         hdr_mbuf = m;
 523         hdr_addr = desc_addr;
 524         hdr_phys_addr = buf_vec[vec_idx].buf_addr;
 525         rte_prefetch0((void *)(uintptr_t)hdr_addr);
 526
 527         LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
 528                 dev->vid, num_buffers);
 529
 530         desc_avail  = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
 531         desc_offset = dev->vhost_hlen;
 532
 533         mbuf_avail  = rte_pktmbuf_data_len(m);
 534         mbuf_offset = 0;
 535         while (mbuf_avail != 0 || m->next != NULL) {
 536                 /* done with current desc buf, get the next one */
 537                 if (desc_avail == 0) {
 538                         vec_idx++;
 539                         desc_addr =
 540                                 vhost_iova_to_vva(dev, vq,
 541                                         buf_vec[vec_idx].buf_addr,
 542                                         buf_vec[vec_idx].buf_len,
 543                                         VHOST_ACCESS_RW);
 544                         if (unlikely(!desc_addr)) {
 545                                 error = -1;
 546                                 goto out;
 547                         }
 548
 549                         /* Prefetch buffer address. */
 550                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 551                         desc_offset = 0;
 552                         desc_avail  = buf_vec[vec_idx].buf_len;
 553                 }
 554
 555                 /* done with current mbuf, get the next one */
 556                 if (mbuf_avail == 0) {
 557                         m = m->next;
 558
 559                         mbuf_offset = 0;
 560                         mbuf_avail  = rte_pktmbuf_data_len(m);
 561                 }
 562
 563                 if (hdr_addr) {
 564                         struct virtio_net_hdr_mrg_rxbuf *hdr;
 565
 566                         hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)
 567                                 hdr_addr;
 568                         virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
 569                         ASSIGN_UNLESS_EQUAL(hdr->num_buffers, num_buffers);
 570
 571                         vhost_log_write(dev, hdr_phys_addr, dev->vhost_hlen);
 572                         PRINT_PACKET(dev, (uintptr_t)hdr_addr,
 573                                      dev->vhost_hlen, 0);
 574
 575                         hdr_addr = 0;
 576                 }
 577
 578                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 579
 580                 if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) {
 581                         rte_memcpy((void *)((uintptr_t)(desc_addr +
 582                                                         desc_offset)),
 583                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
 584                                 cpy_len);
 585                         vhost_log_write(dev,
 586                                 buf_vec[vec_idx].buf_addr + desc_offset,
 587                                 cpy_len);
 588                         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
 589                                 cpy_len, 0);
 590                 } else {
 591                         batch_copy[copy_nb].dst =
 592                                 (void *)((uintptr_t)(desc_addr + desc_offset));
 593                         batch_copy[copy_nb].src =
 594                                 rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
 595                         batch_copy[copy_nb].log_addr =
 596                                 buf_vec[vec_idx].buf_addr + desc_offset;
 597                         batch_copy[copy_nb].len = cpy_len;
 598                         copy_nb++;
 599                 }
 600
 601                 mbuf_avail  -= cpy_len;
 602                 mbuf_offset += cpy_len;
 603                 desc_avail  -= cpy_len;
 604                 desc_offset += cpy_len;
 605         }
 606
 607 out:
 608         vq->batch_copy_nb_elems = copy_nb;
 609
 610         return error;
 611 }
 612
 613 static __rte_always_inline uint32_t
 614 virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 615         struct rte_mbuf **pkts, uint32_t count)
 616 {
 617         struct vhost_virtqueue *vq;
 618         uint32_t pkt_idx = 0;
 619         uint16_t num_buffers;
 620         struct buf_vector buf_vec[BUF_VECTOR_MAX];
 621         uint16_t avail_head;
 622
 623         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
 624         if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
 625                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 626                         dev->vid, __func__, queue_id);
 627                 return 0;
 628         }
 629
 630         vq = dev->virtqueue[queue_id];
 631
 632         rte_spinlock_lock(&vq->access_lock);
 633
 634         if (unlikely(vq->enabled == 0))
 635                 goto out_access_unlock;
 636
 637         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 638                 vhost_user_iotlb_rd_lock(vq);
 639
 640         if (unlikely(vq->access_ok == 0))
 641                 if (unlikely(vring_translate(dev, vq) < 0))
 642                         goto out;
 643
 644         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 645         if (count == 0)
 646                 goto out;
 647
 648         vq->batch_copy_nb_elems = 0;
 649
 650         rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
 651
 652         vq->shadow_used_idx = 0;
 653         avail_head = *((volatile uint16_t *)&vq->avail->idx);
 654         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 655                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 656
 657                 if (unlikely(reserve_avail_buf_mergeable(dev, vq,
 658                                                 pkt_len, buf_vec, &num_buffers,
 659                                                 avail_head) < 0)) {
 660                         LOG_DEBUG(VHOST_DATA,
 661                                 "(%d) failed to get enough desc from vring\n",
 662                                 dev->vid);
 663                         vq->shadow_used_idx -= num_buffers;
 664                         break;
 665                 }
 666
 667                 LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
 668                         dev->vid, vq->last_avail_idx,
 669                         vq->last_avail_idx + num_buffers);
 670
 671                 if (copy_mbuf_to_desc_mergeable(dev, vq, pkts[pkt_idx],
 672                                                 buf_vec, num_buffers) < 0) {
 673                         vq->shadow_used_idx -= num_buffers;
 674                         break;
 675                 }
 676
 677                 vq->last_avail_idx += num_buffers;
 678         }
 679
 680         do_data_copy_enqueue(dev, vq);
 681
 682         if (likely(vq->shadow_used_idx)) {
 683                 flush_shadow_used_ring(dev, vq);
 684                 vhost_vring_call(dev, vq);
 685         }
 686
 687 out:
 688         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 689                 vhost_user_iotlb_rd_unlock(vq);
 690
 691 out_access_unlock:
 692         rte_spinlock_unlock(&vq->access_lock);
 693
 694         return pkt_idx;
 695 }
 696
 697 uint16_t
 698 rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 699         struct rte_mbuf **pkts, uint16_t count)
 700 {
 701         struct virtio_net *dev = get_device(vid);
 702
 703         if (!dev)
 704                 return 0;
 705
 706         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 707                 RTE_LOG(ERR, VHOST_DATA,
 708                         "(%d) %s: built-in vhost net backend is disabled.\n",
 709                         dev->vid, __func__);
 710                 return 0;
 711         }
 712
 713         if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
 714                 return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 715         else
 716                 return virtio_dev_rx(dev, queue_id, pkts, count);
 717 }
 718
 719 static inline bool
 720 virtio_net_with_host_offload(struct virtio_net *dev)
 721 {
 722         if (dev->features &
 723                         ((1ULL << VIRTIO_NET_F_CSUM) |
 724                          (1ULL << VIRTIO_NET_F_HOST_ECN) |
 725                          (1ULL << VIRTIO_NET_F_HOST_TSO4) |
 726                          (1ULL << VIRTIO_NET_F_HOST_TSO6) |
 727                          (1ULL << VIRTIO_NET_F_HOST_UFO)))
 728                 return true;
 729
 730         return false;
 731 }
 732
 733 static void
 734 parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
 735 {
 736         struct ipv4_hdr *ipv4_hdr;
 737         struct ipv6_hdr *ipv6_hdr;
 738         void *l3_hdr = NULL;
 739         struct ether_hdr *eth_hdr;
 740         uint16_t ethertype;
 741
 742         eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
 743
 744         m->l2_len = sizeof(struct ether_hdr);
 745         ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
 746
 747         if (ethertype == ETHER_TYPE_VLAN) {
 748                 struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
 749
 750                 m->l2_len += sizeof(struct vlan_hdr);
 751                 ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
 752         }
 753
 754         l3_hdr = (char *)eth_hdr + m->l2_len;
 755
 756         switch (ethertype) {
 757         case ETHER_TYPE_IPv4:
 758                 ipv4_hdr = l3_hdr;
 759                 *l4_proto = ipv4_hdr->next_proto_id;
 760                 m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
 761                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 762                 m->ol_flags |= PKT_TX_IPV4;
 763                 break;
 764         case ETHER_TYPE_IPv6:
 765                 ipv6_hdr = l3_hdr;
 766                 *l4_proto = ipv6_hdr->proto;
 767                 m->l3_len = sizeof(struct ipv6_hdr);
 768                 *l4_hdr = (char *)l3_hdr + m->l3_len;
 769                 m->ol_flags |= PKT_TX_IPV6;
 770                 break;
 771         default:
 772                 m->l3_len = 0;
 773                 *l4_proto = 0;
 774                 *l4_hdr = NULL;
 775                 break;
 776         }
 777 }
 778
 779 static __rte_always_inline void
 780 vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 781 {
 782         uint16_t l4_proto = 0;
 783         void *l4_hdr = NULL;
 784         struct tcp_hdr *tcp_hdr = NULL;
 785
 786         if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
 787                 return;
 788
 789         parse_ethernet(m, &l4_proto, &l4_hdr);
 790         if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 791                 if (hdr->csum_start == (m->l2_len + m->l3_len)) {
 792                         switch (hdr->csum_offset) {
 793                         case (offsetof(struct tcp_hdr, cksum)):
 794                                 if (l4_proto == IPPROTO_TCP)
 795                                         m->ol_flags |= PKT_TX_TCP_CKSUM;
 796                                 break;
 797                         case (offsetof(struct udp_hdr, dgram_cksum)):
 798                                 if (l4_proto == IPPROTO_UDP)
 799                                         m->ol_flags |= PKT_TX_UDP_CKSUM;
 800                                 break;
 801                         case (offsetof(struct sctp_hdr, cksum)):
 802                                 if (l4_proto == IPPROTO_SCTP)
 803                                         m->ol_flags |= PKT_TX_SCTP_CKSUM;
 804                                 break;
 805                         default:
 806                                 break;
 807                         }
 808                 }
 809         }
 810
 811         if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 812                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 813                 case VIRTIO_NET_HDR_GSO_TCPV4:
 814                 case VIRTIO_NET_HDR_GSO_TCPV6:
 815                         tcp_hdr = l4_hdr;
 816                         m->ol_flags |= PKT_TX_TCP_SEG;
 817                         m->tso_segsz = hdr->gso_size;
 818                         m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 819                         break;
 820                 case VIRTIO_NET_HDR_GSO_UDP:
 821                         m->ol_flags |= PKT_TX_UDP_SEG;
 822                         m->tso_segsz = hdr->gso_size;
 823                         m->l4_len = sizeof(struct udp_hdr);
 824                         break;
 825                 default:
 826                         RTE_LOG(WARNING, VHOST_DATA,
 827                                 "unsupported gso type %u.\n", hdr->gso_type);
 828                         break;
 829                 }
 830         }
 831 }
 832
 833 static __rte_always_inline void
 834 put_zmbuf(struct zcopy_mbuf *zmbuf)
 835 {
 836         zmbuf->in_use = 0;
 837 }
 838
 839 static __rte_always_inline int
 840 copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 841                   struct vring_desc *descs, uint16_t max_desc,
 842                   struct rte_mbuf *m, uint16_t desc_idx,
 843                   struct rte_mempool *mbuf_pool)
 844 {
 845         struct vring_desc *desc;
 846         uint64_t desc_addr;
 847         uint32_t desc_avail, desc_offset;
 848         uint32_t mbuf_avail, mbuf_offset;
 849         uint32_t cpy_len;
 850         struct rte_mbuf *cur = m, *prev = m;
 851         struct virtio_net_hdr *hdr = NULL;
 852         /* A counter to avoid desc dead loop chain */
 853         uint32_t nr_desc = 1;
 854         struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
 855         uint16_t copy_nb = vq->batch_copy_nb_elems;
 856         int error = 0;
 857
 858         desc = &descs[desc_idx];
 859         if (unlikely((desc->len < dev->vhost_hlen)) ||
 860                         (desc->flags & VRING_DESC_F_INDIRECT)) {
 861                 error = -1;
 862                 goto out;
 863         }
 864
 865         desc_addr = vhost_iova_to_vva(dev,
 866                                         vq, desc->addr,
 867                                         desc->len,
 868                                         VHOST_ACCESS_RO);
 869         if (unlikely(!desc_addr)) {
 870                 error = -1;
 871                 goto out;
 872         }
 873
 874         if (virtio_net_with_host_offload(dev)) {
 875                 hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
 876                 rte_prefetch0(hdr);
 877         }
 878
 879         /*
 880          * A virtio driver normally uses at least 2 desc buffers
 881          * for Tx: the first for storing the header, and others
 882          * for storing the data.
 883          */
 884         if (likely((desc->len == dev->vhost_hlen) &&
 885                    (desc->flags & VRING_DESC_F_NEXT) != 0)) {
 886                 desc = &descs[desc->next];
 887                 if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) {
 888                         error = -1;
 889                         goto out;
 890                 }
 891
 892                 desc_addr = vhost_iova_to_vva(dev,
 893                                                         vq, desc->addr,
 894                                                         desc->len,
 895                                                         VHOST_ACCESS_RO);
 896                 if (unlikely(!desc_addr)) {
 897                         error = -1;
 898                         goto out;
 899                 }
 900
 901                 desc_offset = 0;
 902                 desc_avail  = desc->len;
 903                 nr_desc    += 1;
 904         } else {
 905                 desc_avail  = desc->len - dev->vhost_hlen;
 906                 desc_offset = dev->vhost_hlen;
 907         }
 908
 909         rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
 910
 911         PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
 912
 913         mbuf_offset = 0;
 914         mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
 915         while (1) {
 916                 uint64_t hpa;
 917
 918                 cpy_len = RTE_MIN(desc_avail, mbuf_avail);
 919
 920                 /*
 921                  * A desc buf might across two host physical pages that are
 922                  * not continuous. In such case (gpa_to_hpa returns 0), data
 923                  * will be copied even though zero copy is enabled.
 924                  */
 925                 if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
 926                                         desc->addr + desc_offset, cpy_len)))) {
 927                         cur->data_len = cpy_len;
 928                         cur->data_off = 0;
 929                         cur->buf_addr = (void *)(uintptr_t)(desc_addr
 930                                 + desc_offset);
 931                         cur->buf_iova = hpa;
 932
 933                         /*
 934                          * In zero copy mode, one mbuf can only reference data
 935                          * for one or partial of one desc buff.
 936                          */
 937                         mbuf_avail = cpy_len;
 938                 } else {
 939                         if (likely(cpy_len > MAX_BATCH_LEN ||
 940                                    copy_nb >= vq->size ||
 941                                    (hdr && cur == m))) {
 942                                 rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
 943                                                                    mbuf_offset),
 944                                            (void *)((uintptr_t)(desc_addr +
 945                                                                 desc_offset)),
 946                                            cpy_len);
 947                         } else {
 948                                 batch_copy[copy_nb].dst =
 949                                         rte_pktmbuf_mtod_offset(cur, void *,
 950                                                                 mbuf_offset);
 951                                 batch_copy[copy_nb].src =
 952                                         (void *)((uintptr_t)(desc_addr +
 953                                                              desc_offset));
 954                                 batch_copy[copy_nb].len = cpy_len;
 955                                 copy_nb++;
 956                         }
 957                 }
 958
 959                 mbuf_avail  -= cpy_len;
 960                 mbuf_offset += cpy_len;
 961                 desc_avail  -= cpy_len;
 962                 desc_offset += cpy_len;
 963
 964                 /* This desc reaches to its end, get the next one */
 965                 if (desc_avail == 0) {
 966                         if ((desc->flags & VRING_DESC_F_NEXT) == 0)
 967                                 break;
 968
 969                         if (unlikely(desc->next >= max_desc ||
 970                                      ++nr_desc > max_desc)) {
 971                                 error = -1;
 972                                 goto out;
 973                         }
 974                         desc = &descs[desc->next];
 975                         if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) {
 976                                 error = -1;
 977                                 goto out;
 978                         }
 979
 980                         desc_addr = vhost_iova_to_vva(dev,
 981                                                         vq, desc->addr,
 982                                                         desc->len,
 983                                                         VHOST_ACCESS_RO);
 984                         if (unlikely(!desc_addr)) {
 985                                 error = -1;
 986                                 goto out;
 987                         }
 988
 989                         rte_prefetch0((void *)(uintptr_t)desc_addr);
 990
 991                         desc_offset = 0;
 992                         desc_avail  = desc->len;
 993
 994                         PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
 995                 }
 996
 997                 /*
 998                  * This mbuf reaches to its end, get a new one
 999                  * to hold more data.
1000                  */
1001                 if (mbuf_avail == 0) {
1002                         cur = rte_pktmbuf_alloc(mbuf_pool);
1003                         if (unlikely(cur == NULL)) {
1004                                 RTE_LOG(ERR, VHOST_DATA, "Failed to "
1005                                         "allocate memory for mbuf.\n");
1006                                 error = -1;
1007                                 goto out;
1008                         }
1009                         if (unlikely(dev->dequeue_zero_copy))
1010                                 rte_mbuf_refcnt_update(cur, 1);
1011
1012                         prev->next = cur;
1013                         prev->data_len = mbuf_offset;
1014                         m->nb_segs += 1;
1015                         m->pkt_len += mbuf_offset;
1016                         prev = cur;
1017
1018                         mbuf_offset = 0;
1019                         mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
1020                 }
1021         }
1022
1023         prev->data_len = mbuf_offset;
1024         m->pkt_len    += mbuf_offset;
1025
1026         if (hdr)
1027                 vhost_dequeue_offload(hdr, m);
1028
1029 out:
1030         vq->batch_copy_nb_elems = copy_nb;
1031
1032         return error;
1033 }
1034
1035 static __rte_always_inline void
1036 update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
1037                  uint32_t used_idx, uint32_t desc_idx)
1038 {
1039         vq->used->ring[used_idx].id  = desc_idx;
1040         vq->used->ring[used_idx].len = 0;
1041         vhost_log_used_vring(dev, vq,
1042                         offsetof(struct vring_used, ring[used_idx]),
1043                         sizeof(vq->used->ring[used_idx]));
1044 }
1045
1046 static __rte_always_inline void
1047 update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
1048                 uint32_t count)
1049 {
1050         if (unlikely(count == 0))
1051                 return;
1052
1053         rte_smp_wmb();
1054         rte_smp_rmb();
1055
1056         vq->used->idx += count;
1057         vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
1058                         sizeof(vq->used->idx));
1059         vhost_vring_call(dev, vq);
1060 }
1061
1062 static __rte_always_inline struct zcopy_mbuf *
1063 get_zmbuf(struct vhost_virtqueue *vq)
1064 {
1065         uint16_t i;
1066         uint16_t last;
1067         int tries = 0;
1068
1069         /* search [last_zmbuf_idx, zmbuf_size) */
1070         i = vq->last_zmbuf_idx;
1071         last = vq->zmbuf_size;
1072
1073 again:
1074         for (; i < last; i++) {
1075                 if (vq->zmbufs[i].in_use == 0) {
1076                         vq->last_zmbuf_idx = i + 1;
1077                         vq->zmbufs[i].in_use = 1;
1078                         return &vq->zmbufs[i];
1079                 }
1080         }
1081
1082         tries++;
1083         if (tries == 1) {
1084                 /* search [0, last_zmbuf_idx) */
1085                 i = 0;
1086                 last = vq->last_zmbuf_idx;
1087                 goto again;
1088         }
1089
1090         return NULL;
1091 }
1092
1093 static __rte_always_inline bool
1094 mbuf_is_consumed(struct rte_mbuf *m)
1095 {
1096         while (m) {
1097                 if (rte_mbuf_refcnt_read(m) > 1)
1098                         return false;
1099                 m = m->next;
1100         }
1101
1102         return true;
1103 }
1104
1105 static __rte_always_inline void
1106 restore_mbuf(struct rte_mbuf *m)
1107 {
1108         uint32_t mbuf_size, priv_size;
1109
1110         while (m) {
1111                 priv_size = rte_pktmbuf_priv_size(m->pool);
1112                 mbuf_size = sizeof(struct rte_mbuf) + priv_size;
1113                 /* start of buffer is after mbuf structure and priv data */
1114
1115                 m->buf_addr = (char *)m + mbuf_size;
1116                 m->buf_iova = rte_mempool_virt2iova(m) + mbuf_size;
1117                 m = m->next;
1118         }
1119 }
1120
1121 uint16_t
1122 rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
1123         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
1124 {
1125         struct virtio_net *dev;
1126         struct rte_mbuf *rarp_mbuf = NULL;
1127         struct vhost_virtqueue *vq;
1128         uint32_t desc_indexes[MAX_PKT_BURST];
1129         uint32_t used_idx;
1130         uint32_t i = 0;
1131         uint16_t free_entries;
1132         uint16_t avail_idx;
1133
1134         dev = get_device(vid);
1135         if (!dev)
1136                 return 0;
1137
1138         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
1139                 RTE_LOG(ERR, VHOST_DATA,
1140                         "(%d) %s: built-in vhost net backend is disabled.\n",
1141                         dev->vid, __func__);
1142                 return 0;
1143         }
1144
1145         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {
1146                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
1147                         dev->vid, __func__, queue_id);
1148                 return 0;
1149         }
1150
1151         vq = dev->virtqueue[queue_id];
1152
1153         if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0))
1154                 return 0;
1155
1156         if (unlikely(vq->enabled == 0))
1157                 goto out_access_unlock;
1158
1159         vq->batch_copy_nb_elems = 0;
1160
1161         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1162                 vhost_user_iotlb_rd_lock(vq);
1163
1164         if (unlikely(vq->access_ok == 0))
1165                 if (unlikely(vring_translate(dev, vq) < 0))
1166                         goto out;
1167
1168         if (unlikely(dev->dequeue_zero_copy)) {
1169                 struct zcopy_mbuf *zmbuf, *next;
1170                 int nr_updated = 0;
1171
1172                 for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
1173                      zmbuf != NULL; zmbuf = next) {
1174                         next = TAILQ_NEXT(zmbuf, next);
1175
1176                         if (mbuf_is_consumed(zmbuf->mbuf)) {
1177                                 used_idx = vq->last_used_idx++ & (vq->size - 1);
1178                                 update_used_ring(dev, vq, used_idx,
1179                                                  zmbuf->desc_idx);
1180                                 nr_updated += 1;
1181
1182                                 TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
1183                                 restore_mbuf(zmbuf->mbuf);
1184                                 rte_pktmbuf_free(zmbuf->mbuf);
1185                                 put_zmbuf(zmbuf);
1186                                 vq->nr_zmbuf -= 1;
1187                         }
1188                 }
1189
1190                 update_used_idx(dev, vq, nr_updated);
1191         }
1192
1193         /*
1194          * Construct a RARP broadcast packet, and inject it to the "pkts"
1195          * array, to looks like that guest actually send such packet.
1196          *
1197          * Check user_send_rarp() for more information.
1198          *
1199          * broadcast_rarp shares a cacheline in the virtio_net structure
1200          * with some fields that are accessed during enqueue and
1201          * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
1202          * result in false sharing between enqueue and dequeue.
1203          *
1204          * Prevent unnecessary false sharing by reading broadcast_rarp first
1205          * and only performing cmpset if the read indicates it is likely to
1206          * be set.
1207          */
1208
1209         if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
1210                         rte_atomic16_cmpset((volatile uint16_t *)
1211                                 &dev->broadcast_rarp.cnt, 1, 0))) {
1212
1213                 rarp_mbuf = rte_net_make_rarp_packet(mbuf_pool, &dev->mac);
1214                 if (rarp_mbuf == NULL) {
1215                         RTE_LOG(ERR, VHOST_DATA,
1216                                 "Failed to make RARP packet.\n");
1217                         return 0;
1218                 }
1219                 count -= 1;
1220         }
1221
1222         free_entries = *((volatile uint16_t *)&vq->avail->idx) -
1223                         vq->last_avail_idx;
1224         if (free_entries == 0)
1225                 goto out;
1226
1227         LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
1228
1229         /* Prefetch available and used ring */
1230         avail_idx = vq->last_avail_idx & (vq->size - 1);
1231         used_idx  = vq->last_used_idx  & (vq->size - 1);
1232         rte_prefetch0(&vq->avail->ring[avail_idx]);
1233         rte_prefetch0(&vq->used->ring[used_idx]);
1234
1235         count = RTE_MIN(count, MAX_PKT_BURST);
1236         count = RTE_MIN(count, free_entries);
1237         LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n",
1238                         dev->vid, count);
1239
1240         /* Retrieve all of the head indexes first to avoid caching issues. */
1241         for (i = 0; i < count; i++) {
1242                 avail_idx = (vq->last_avail_idx + i) & (vq->size - 1);
1243                 used_idx  = (vq->last_used_idx  + i) & (vq->size - 1);
1244                 desc_indexes[i] = vq->avail->ring[avail_idx];
1245
1246                 if (likely(dev->dequeue_zero_copy == 0))
1247                         update_used_ring(dev, vq, used_idx, desc_indexes[i]);
1248         }
1249
1250         /* Prefetch descriptor index. */
1251         rte_prefetch0(&vq->desc[desc_indexes[0]]);
1252         for (i = 0; i < count; i++) {
1253                 struct vring_desc *desc;
1254                 uint16_t sz, idx;
1255                 int err;
1256
1257                 if (likely(i + 1 < count))
1258                         rte_prefetch0(&vq->desc[desc_indexes[i + 1]]);
1259
1260                 if (vq->desc[desc_indexes[i]].flags & VRING_DESC_F_INDIRECT) {
1261                         desc = (struct vring_desc *)(uintptr_t)
1262                                 vhost_iova_to_vva(dev, vq,
1263                                                 vq->desc[desc_indexes[i]].addr,
1264                                                 sizeof(*desc),
1265                                                 VHOST_ACCESS_RO);
1266                         if (unlikely(!desc))
1267                                 break;
1268
1269                         rte_prefetch0(desc);
1270                         sz = vq->desc[desc_indexes[i]].len / sizeof(*desc);
1271                         idx = 0;
1272                 } else {
1273                         desc = vq->desc;
1274                         sz = vq->size;
1275                         idx = desc_indexes[i];
1276                 }
1277
1278                 pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
1279                 if (unlikely(pkts[i] == NULL)) {
1280                         RTE_LOG(ERR, VHOST_DATA,
1281                                 "Failed to allocate memory for mbuf.\n");
1282                         break;
1283                 }
1284
1285                 err = copy_desc_to_mbuf(dev, vq, desc, sz, pkts[i], idx,
1286                                         mbuf_pool);
1287                 if (unlikely(err)) {
1288                         rte_pktmbuf_free(pkts[i]);
1289                         break;
1290                 }
1291
1292                 if (unlikely(dev->dequeue_zero_copy)) {
1293                         struct zcopy_mbuf *zmbuf;
1294
1295                         zmbuf = get_zmbuf(vq);
1296                         if (!zmbuf) {
1297                                 rte_pktmbuf_free(pkts[i]);
1298                                 break;
1299                         }
1300                         zmbuf->mbuf = pkts[i];
1301                         zmbuf->desc_idx = desc_indexes[i];
1302
1303                         /*
1304                          * Pin lock the mbuf; we will check later to see
1305                          * whether the mbuf is freed (when we are the last
1306                          * user) or not. If that's the case, we then could
1307                          * update the used ring safely.
1308                          */
1309                         rte_mbuf_refcnt_update(pkts[i], 1);
1310
1311                         vq->nr_zmbuf += 1;
1312                         TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
1313                 }
1314         }
1315         vq->last_avail_idx += i;
1316
1317         if (likely(dev->dequeue_zero_copy == 0)) {
1318                 do_data_copy_dequeue(vq);
1319                 vq->last_used_idx += i;
1320                 update_used_idx(dev, vq, i);
1321         }
1322
1323 out:
1324         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
1325                 vhost_user_iotlb_rd_unlock(vq);
1326
1327 out_access_unlock:
1328         rte_spinlock_unlock(&vq->access_lock);
1329
1330         if (unlikely(rarp_mbuf != NULL)) {
1331                 /*
1332                  * Inject it to the head of "pkts" array, so that switch's mac
1333                  * learning table will get updated first.
1334                  */
1335                 memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *));
1336                 pkts[0] = rarp_mbuf;
1337                 i += 1;
1338         }
1339
1340         return i;
1341 }