lib/librte_vhost/vhost_rxtx.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2014 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 <linux/virtio_net.h>
  36
  37 #include <rte_mbuf.h>
  38 #include <rte_memcpy.h>
  39 #include <rte_virtio_net.h>
  40
  41 #include "vhost-net.h"
  42
  43 #define MAX_PKT_BURST 32
  44
  45 /**
  46  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
  47  * be received from the physical port or from another virtio device. A packet
  48  * count is returned to indicate the number of packets that are succesfully
  49  * added to the RX queue. This function works when mergeable is disabled.
  50  */
  51 static inline uint32_t __attribute__((always_inline))
  52 virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
  53         struct rte_mbuf **pkts, uint32_t count)
  54 {
  55         struct vhost_virtqueue *vq;
  56         struct vring_desc *desc;
  57         struct rte_mbuf *buff;
  58         /* The virtio_hdr is initialised to 0. */
  59         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
  60         uint64_t buff_addr = 0;
  61         uint64_t buff_hdr_addr = 0;
  62         uint32_t head[MAX_PKT_BURST], packet_len = 0;
  63         uint32_t head_idx, packet_success = 0;
  64         uint16_t avail_idx, res_cur_idx;
  65         uint16_t res_base_idx, res_end_idx;
  66         uint16_t free_entries;
  67         uint8_t success = 0;
  68
  69         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_rx()\n", dev->device_fh);
  70         if (unlikely(queue_id != VIRTIO_RXQ)) {
  71                 LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
  72                 return 0;
  73         }
  74
  75         vq = dev->virtqueue[VIRTIO_RXQ];
  76         count = (count > MAX_PKT_BURST) ? MAX_PKT_BURST : count;
  77
  78         /*
  79          * As many data cores may want access to available buffers,
  80          * they need to be reserved.
  81          */
  82         do {
  83                 res_base_idx = vq->last_used_idx_res;
  84                 avail_idx = *((volatile uint16_t *)&vq->avail->idx);
  85
  86                 free_entries = (avail_idx - res_base_idx);
  87                 /*check that we have enough buffers*/
  88                 if (unlikely(count > free_entries))
  89                         count = free_entries;
  90
  91                 if (count == 0)
  92                         return 0;
  93
  94                 res_end_idx = res_base_idx + count;
  95                 /* vq->last_used_idx_res is atomically updated. */
  96                 /* TODO: Allow to disable cmpset if no concurrency in application. */
  97                 success = rte_atomic16_cmpset(&vq->last_used_idx_res,
  98                                 res_base_idx, res_end_idx);
  99         } while (unlikely(success == 0));
 100         res_cur_idx = res_base_idx;
 101         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| End Index %d\n",
 102                         dev->device_fh, res_cur_idx, res_end_idx);
 103
 104         /* Prefetch available ring to retrieve indexes. */
 105         rte_prefetch0(&vq->avail->ring[res_cur_idx & (vq->size - 1)]);
 106
 107         /* Retrieve all of the head indexes first to avoid caching issues. */
 108         for (head_idx = 0; head_idx < count; head_idx++)
 109                 head[head_idx] = vq->avail->ring[(res_cur_idx + head_idx) &
 110                                         (vq->size - 1)];
 111
 112         /*Prefetch descriptor index. */
 113         rte_prefetch0(&vq->desc[head[packet_success]]);
 114
 115         while (res_cur_idx != res_end_idx) {
 116                 /* Get descriptor from available ring */
 117                 desc = &vq->desc[head[packet_success]];
 118
 119                 buff = pkts[packet_success];
 120
 121                 /* Convert from gpa to vva (guest physical addr -> vhost virtual addr) */
 122                 buff_addr = gpa_to_vva(dev, desc->addr);
 123                 /* Prefetch buffer address. */
 124                 rte_prefetch0((void *)(uintptr_t)buff_addr);
 125
 126                 /* Copy virtio_hdr to packet and increment buffer address */
 127                 buff_hdr_addr = buff_addr;
 128                 packet_len = rte_pktmbuf_data_len(buff) + vq->vhost_hlen;
 129
 130                 /*
 131                  * If the descriptors are chained the header and data are
 132                  * placed in separate buffers.
 133                  */
 134                 if (desc->flags & VRING_DESC_F_NEXT) {
 135                         desc->len = vq->vhost_hlen;
 136                         desc = &vq->desc[desc->next];
 137                         /* Buffer address translation. */
 138                         buff_addr = gpa_to_vva(dev, desc->addr);
 139                         desc->len = rte_pktmbuf_data_len(buff);
 140                 } else {
 141                         buff_addr += vq->vhost_hlen;
 142                         desc->len = packet_len;
 143                 }
 144
 145                 /* Update used ring with desc information */
 146                 vq->used->ring[res_cur_idx & (vq->size - 1)].id =
 147                                                         head[packet_success];
 148                 vq->used->ring[res_cur_idx & (vq->size - 1)].len = packet_len;
 149
 150                 /* Copy mbuf data to buffer */
 151                 /* FIXME for sg mbuf and the case that desc couldn't hold the mbuf data */
 152                 rte_memcpy((void *)(uintptr_t)buff_addr,
 153                         rte_pktmbuf_mtod(buff, const void *),
 154                         rte_pktmbuf_data_len(buff));
 155                 PRINT_PACKET(dev, (uintptr_t)buff_addr,
 156                         rte_pktmbuf_data_len(buff), 0);
 157
 158                 res_cur_idx++;
 159                 packet_success++;
 160
 161                 rte_memcpy((void *)(uintptr_t)buff_hdr_addr,
 162                         (const void *)&virtio_hdr, vq->vhost_hlen);
 163
 164                 PRINT_PACKET(dev, (uintptr_t)buff_hdr_addr, vq->vhost_hlen, 1);
 165
 166                 if (res_cur_idx < res_end_idx) {
 167                         /* Prefetch descriptor index. */
 168                         rte_prefetch0(&vq->desc[head[packet_success]]);
 169                 }
 170         }
 171
 172         rte_compiler_barrier();
 173
 174         /* Wait until it's our turn to add our buffer to the used ring. */
 175         while (unlikely(vq->last_used_idx != res_base_idx))
 176                 rte_pause();
 177
 178         *(volatile uint16_t *)&vq->used->idx += count;
 179         vq->last_used_idx = res_end_idx;
 180
 181         /* Kick the guest if necessary. */
 182         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
 183                 eventfd_write((int)vq->kickfd, 1);
 184         return count;
 185 }
 186
 187 static inline uint32_t __attribute__((always_inline))
 188 copy_from_mbuf_to_vring(struct virtio_net *dev, uint16_t res_base_idx,
 189         uint16_t res_end_idx, struct rte_mbuf *pkt)
 190 {
 191         uint32_t vec_idx = 0;
 192         uint32_t entry_success = 0;
 193         struct vhost_virtqueue *vq;
 194         /* The virtio_hdr is initialised to 0. */
 195         struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {
 196                 {0, 0, 0, 0, 0, 0}, 0};
 197         uint16_t cur_idx = res_base_idx;
 198         uint64_t vb_addr = 0;
 199         uint64_t vb_hdr_addr = 0;
 200         uint32_t seg_offset = 0;
 201         uint32_t vb_offset = 0;
 202         uint32_t seg_avail;
 203         uint32_t vb_avail;
 204         uint32_t cpy_len, entry_len;
 205
 206         if (pkt == NULL)
 207                 return 0;
 208
 209         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| "
 210                 "End Index %d\n",
 211                 dev->device_fh, cur_idx, res_end_idx);
 212
 213         /*
 214          * Convert from gpa to vva
 215          * (guest physical addr -> vhost virtual addr)
 216          */
 217         vq = dev->virtqueue[VIRTIO_RXQ];
 218         vb_addr =
 219                 gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
 220         vb_hdr_addr = vb_addr;
 221
 222         /* Prefetch buffer address. */
 223         rte_prefetch0((void *)(uintptr_t)vb_addr);
 224
 225         virtio_hdr.num_buffers = res_end_idx - res_base_idx;
 226
 227         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") RX: Num merge buffers %d\n",
 228                 dev->device_fh, virtio_hdr.num_buffers);
 229
 230         rte_memcpy((void *)(uintptr_t)vb_hdr_addr,
 231                 (const void *)&virtio_hdr, vq->vhost_hlen);
 232
 233         PRINT_PACKET(dev, (uintptr_t)vb_hdr_addr, vq->vhost_hlen, 1);
 234
 235         seg_avail = rte_pktmbuf_data_len(pkt);
 236         vb_offset = vq->vhost_hlen;
 237         vb_avail =
 238                 vq->buf_vec[vec_idx].buf_len - vq->vhost_hlen;
 239
 240         entry_len = vq->vhost_hlen;
 241
 242         if (vb_avail == 0) {
 243                 uint32_t desc_idx =
 244                         vq->buf_vec[vec_idx].desc_idx;
 245                 vq->desc[desc_idx].len = vq->vhost_hlen;
 246
 247                 if ((vq->desc[desc_idx].flags
 248                         & VRING_DESC_F_NEXT) == 0) {
 249                         /* Update used ring with desc information */
 250                         vq->used->ring[cur_idx & (vq->size - 1)].id
 251                                 = vq->buf_vec[vec_idx].desc_idx;
 252                         vq->used->ring[cur_idx & (vq->size - 1)].len
 253                                 = entry_len;
 254
 255                         entry_len = 0;
 256                         cur_idx++;
 257                         entry_success++;
 258                 }
 259
 260                 vec_idx++;
 261                 vb_addr =
 262                         gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
 263
 264                 /* Prefetch buffer address. */
 265                 rte_prefetch0((void *)(uintptr_t)vb_addr);
 266                 vb_offset = 0;
 267                 vb_avail = vq->buf_vec[vec_idx].buf_len;
 268         }
 269
 270         cpy_len = RTE_MIN(vb_avail, seg_avail);
 271
 272         while (cpy_len > 0) {
 273                 /* Copy mbuf data to vring buffer */
 274                 rte_memcpy((void *)(uintptr_t)(vb_addr + vb_offset),
 275                         (const void *)(rte_pktmbuf_mtod(pkt, char*) + seg_offset),
 276                         cpy_len);
 277
 278                 PRINT_PACKET(dev,
 279                         (uintptr_t)(vb_addr + vb_offset),
 280                         cpy_len, 0);
 281
 282                 seg_offset += cpy_len;
 283                 vb_offset += cpy_len;
 284                 seg_avail -= cpy_len;
 285                 vb_avail -= cpy_len;
 286                 entry_len += cpy_len;
 287
 288                 if (seg_avail != 0) {
 289                         /*
 290                          * The virtio buffer in this vring
 291                          * entry reach to its end.
 292                          * But the segment doesn't complete.
 293                          */
 294                         if ((vq->desc[vq->buf_vec[vec_idx].desc_idx].flags &
 295                                 VRING_DESC_F_NEXT) == 0) {
 296                                 /* Update used ring with desc information */
 297                                 vq->used->ring[cur_idx & (vq->size - 1)].id
 298                                         = vq->buf_vec[vec_idx].desc_idx;
 299                                 vq->used->ring[cur_idx & (vq->size - 1)].len
 300                                         = entry_len;
 301                                 entry_len = 0;
 302                                 cur_idx++;
 303                                 entry_success++;
 304                         }
 305
 306                         vec_idx++;
 307                         vb_addr = gpa_to_vva(dev,
 308                                 vq->buf_vec[vec_idx].buf_addr);
 309                         vb_offset = 0;
 310                         vb_avail = vq->buf_vec[vec_idx].buf_len;
 311                         cpy_len = RTE_MIN(vb_avail, seg_avail);
 312                 } else {
 313                         /*
 314                          * This current segment complete, need continue to
 315                          * check if the whole packet complete or not.
 316                          */
 317                         pkt = pkt->next;
 318                         if (pkt != NULL) {
 319                                 /*
 320                                  * There are more segments.
 321                                  */
 322                                 if (vb_avail == 0) {
 323                                         /*
 324                                          * This current buffer from vring is
 325                                          * used up, need fetch next buffer
 326                                          * from buf_vec.
 327                                          */
 328                                         uint32_t desc_idx =
 329                                                 vq->buf_vec[vec_idx].desc_idx;
 330                                         vq->desc[desc_idx].len = vb_offset;
 331
 332                                         if ((vq->desc[desc_idx].flags &
 333                                                 VRING_DESC_F_NEXT) == 0) {
 334                                                 uint16_t wrapped_idx =
 335                                                         cur_idx & (vq->size - 1);
 336                                                 /*
 337                                                  * Update used ring with the
 338                                                  * descriptor information
 339                                                  */
 340                                                 vq->used->ring[wrapped_idx].id
 341                                                         = desc_idx;
 342                                                 vq->used->ring[wrapped_idx].len
 343                                                         = entry_len;
 344                                                 entry_success++;
 345                                                 entry_len = 0;
 346                                                 cur_idx++;
 347                                         }
 348
 349                                         /* Get next buffer from buf_vec. */
 350                                         vec_idx++;
 351                                         vb_addr = gpa_to_vva(dev,
 352                                                 vq->buf_vec[vec_idx].buf_addr);
 353                                         vb_avail =
 354                                                 vq->buf_vec[vec_idx].buf_len;
 355                                         vb_offset = 0;
 356                                 }
 357
 358                                 seg_offset = 0;
 359                                 seg_avail = rte_pktmbuf_data_len(pkt);
 360                                 cpy_len = RTE_MIN(vb_avail, seg_avail);
 361                         } else {
 362                                 /*
 363                                  * This whole packet completes.
 364                                  */
 365                                 uint32_t desc_idx =
 366                                         vq->buf_vec[vec_idx].desc_idx;
 367                                 vq->desc[desc_idx].len = vb_offset;
 368
 369                                 while (vq->desc[desc_idx].flags &
 370                                         VRING_DESC_F_NEXT) {
 371                                         desc_idx = vq->desc[desc_idx].next;
 372                                          vq->desc[desc_idx].len = 0;
 373                                 }
 374
 375                                 /* Update used ring with desc information */
 376                                 vq->used->ring[cur_idx & (vq->size - 1)].id
 377                                         = vq->buf_vec[vec_idx].desc_idx;
 378                                 vq->used->ring[cur_idx & (vq->size - 1)].len
 379                                         = entry_len;
 380                                 entry_len = 0;
 381                                 cur_idx++;
 382                                 entry_success++;
 383                                 seg_avail = 0;
 384                                 cpy_len = RTE_MIN(vb_avail, seg_avail);
 385                         }
 386                 }
 387         }
 388
 389         return entry_success;
 390 }
 391
 392 /*
 393  * This function works for mergeable RX.
 394  */
 395 static inline uint32_t __attribute__((always_inline))
 396 virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 397         struct rte_mbuf **pkts, uint32_t count)
 398 {
 399         struct vhost_virtqueue *vq;
 400         uint32_t pkt_idx = 0, entry_success = 0;
 401         uint16_t avail_idx, res_cur_idx;
 402         uint16_t res_base_idx, res_end_idx;
 403         uint8_t success = 0;
 404
 405         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_rx()\n",
 406                 dev->device_fh);
 407         if (unlikely(queue_id != VIRTIO_RXQ)) {
 408                 LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
 409         }
 410
 411         vq = dev->virtqueue[VIRTIO_RXQ];
 412         count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 413
 414         if (count == 0)
 415                 return 0;
 416
 417         for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
 418                 uint32_t secure_len = 0;
 419                 uint16_t need_cnt;
 420                 uint32_t vec_idx = 0;
 421                 uint32_t pkt_len = pkts[pkt_idx]->pkt_len + vq->vhost_hlen;
 422                 uint16_t i, id;
 423
 424                 do {
 425                         /*
 426                          * As many data cores may want access to available
 427                          * buffers, they need to be reserved.
 428                          */
 429                         res_base_idx = vq->last_used_idx_res;
 430                         res_cur_idx = res_base_idx;
 431
 432                         do {
 433                                 avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 434                                 if (unlikely(res_cur_idx == avail_idx)) {
 435                                         LOG_DEBUG(VHOST_DATA,
 436                                                 "(%"PRIu64") Failed "
 437                                                 "to get enough desc from "
 438                                                 "vring\n",
 439                                                 dev->device_fh);
 440                                         return pkt_idx;
 441                                 } else {
 442                                         uint16_t wrapped_idx =
 443                                                 (res_cur_idx) & (vq->size - 1);
 444                                         uint32_t idx =
 445                                                 vq->avail->ring[wrapped_idx];
 446                                         uint8_t next_desc;
 447
 448                                         do {
 449                                                 next_desc = 0;
 450                                                 secure_len += vq->desc[idx].len;
 451                                                 if (vq->desc[idx].flags &
 452                                                         VRING_DESC_F_NEXT) {
 453                                                         idx = vq->desc[idx].next;
 454                                                         next_desc = 1;
 455                                                 }
 456                                         } while (next_desc);
 457
 458                                         res_cur_idx++;
 459                                 }
 460                         } while (pkt_len > secure_len);
 461
 462                         /* vq->last_used_idx_res is atomically updated. */
 463                         success = rte_atomic16_cmpset(&vq->last_used_idx_res,
 464                                                         res_base_idx,
 465                                                         res_cur_idx);
 466                 } while (success == 0);
 467
 468                 id = res_base_idx;
 469                 need_cnt = res_cur_idx - res_base_idx;
 470
 471                 for (i = 0; i < need_cnt; i++, id++) {
 472                         uint16_t wrapped_idx = id & (vq->size - 1);
 473                         uint32_t idx = vq->avail->ring[wrapped_idx];
 474                         uint8_t next_desc;
 475                         do {
 476                                 next_desc = 0;
 477                                 vq->buf_vec[vec_idx].buf_addr =
 478                                         vq->desc[idx].addr;
 479                                 vq->buf_vec[vec_idx].buf_len =
 480                                         vq->desc[idx].len;
 481                                 vq->buf_vec[vec_idx].desc_idx = idx;
 482                                 vec_idx++;
 483
 484                                 if (vq->desc[idx].flags & VRING_DESC_F_NEXT) {
 485                                         idx = vq->desc[idx].next;
 486                                         next_desc = 1;
 487                                 }
 488                         } while (next_desc);
 489                 }
 490
 491                 res_end_idx = res_cur_idx;
 492
 493                 entry_success = copy_from_mbuf_to_vring(dev, res_base_idx,
 494                         res_end_idx, pkts[pkt_idx]);
 495
 496                 rte_compiler_barrier();
 497
 498                 /*
 499                  * Wait until it's our turn to add our buffer
 500                  * to the used ring.
 501                  */
 502                 while (unlikely(vq->last_used_idx != res_base_idx))
 503                         rte_pause();
 504
 505                 *(volatile uint16_t *)&vq->used->idx += entry_success;
 506                 vq->last_used_idx = res_end_idx;
 507
 508                 /* Kick the guest if necessary. */
 509                 if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
 510                         eventfd_write((int)vq->kickfd, 1);
 511         }
 512
 513         return count;
 514 }
 515
 516 uint16_t
 517 rte_vhost_enqueue_burst(struct virtio_net *dev, uint16_t queue_id,
 518         struct rte_mbuf **pkts, uint16_t count)
 519 {
 520         if (unlikely(dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)))
 521                 return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 522         else
 523                 return virtio_dev_rx(dev, queue_id, pkts, count);
 524 }
 525
 526 uint16_t
 527 rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
 528         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
 529 {
 530         struct rte_mbuf *m, *prev;
 531         struct vhost_virtqueue *vq;
 532         struct vring_desc *desc;
 533         uint64_t vb_addr = 0;
 534         uint32_t head[MAX_PKT_BURST];
 535         uint32_t used_idx;
 536         uint32_t i;
 537         uint16_t free_entries, entry_success = 0;
 538         uint16_t avail_idx;
 539
 540         if (unlikely(queue_id != VIRTIO_TXQ)) {
 541                 LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
 542                 return 0;
 543         }
 544
 545         vq = dev->virtqueue[VIRTIO_TXQ];
 546         avail_idx =  *((volatile uint16_t *)&vq->avail->idx);
 547
 548         /* If there are no available buffers then return. */
 549         if (vq->last_used_idx == avail_idx)
 550                 return 0;
 551
 552         LOG_DEBUG(VHOST_DATA, "%s (%"PRIu64")\n", __func__,
 553                 dev->device_fh);
 554
 555         /* Prefetch available ring to retrieve head indexes. */
 556         rte_prefetch0(&vq->avail->ring[vq->last_used_idx & (vq->size - 1)]);
 557
 558         /*get the number of free entries in the ring*/
 559         free_entries = (avail_idx - vq->last_used_idx);
 560
 561         free_entries = RTE_MIN(free_entries, count);
 562         /* Limit to MAX_PKT_BURST. */
 563         free_entries = RTE_MIN(free_entries, MAX_PKT_BURST);
 564
 565         LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Buffers available %d\n",
 566                         dev->device_fh, free_entries);
 567         /* Retrieve all of the head indexes first to avoid caching issues. */
 568         for (i = 0; i < free_entries; i++)
 569                 head[i] = vq->avail->ring[(vq->last_used_idx + i) & (vq->size - 1)];
 570
 571         /* Prefetch descriptor index. */
 572         rte_prefetch0(&vq->desc[head[entry_success]]);
 573         rte_prefetch0(&vq->used->ring[vq->last_used_idx & (vq->size - 1)]);
 574
 575         while (entry_success < free_entries) {
 576                 uint32_t vb_avail, vb_offset;
 577                 uint32_t seg_avail, seg_offset;
 578                 uint32_t cpy_len;
 579                 uint32_t seg_num = 0;
 580                 struct rte_mbuf *cur;
 581                 uint8_t alloc_err = 0;
 582
 583                 desc = &vq->desc[head[entry_success]];
 584
 585                 /* Discard first buffer as it is the virtio header */
 586                 desc = &vq->desc[desc->next];
 587
 588                 /* Buffer address translation. */
 589                 vb_addr = gpa_to_vva(dev, desc->addr);
 590                 /* Prefetch buffer address. */
 591                 rte_prefetch0((void *)(uintptr_t)vb_addr);
 592
 593                 used_idx = vq->last_used_idx & (vq->size - 1);
 594
 595                 if (entry_success < (free_entries - 1)) {
 596                         /* Prefetch descriptor index. */
 597                         rte_prefetch0(&vq->desc[head[entry_success+1]]);
 598                         rte_prefetch0(&vq->used->ring[(used_idx + 1) & (vq->size - 1)]);
 599                 }
 600
 601                 /* Update used index buffer information. */
 602                 vq->used->ring[used_idx].id = head[entry_success];
 603                 vq->used->ring[used_idx].len = 0;
 604
 605                 vb_offset = 0;
 606                 vb_avail = desc->len;
 607                 /* Allocate an mbuf and populate the structure. */
 608                 m = rte_pktmbuf_alloc(mbuf_pool);
 609                 if (unlikely(m == NULL)) {
 610                         RTE_LOG(ERR, VHOST_DATA,
 611                                 "Failed to allocate memory for mbuf.\n");
 612                         return entry_success;
 613                 }
 614                 seg_offset = 0;
 615                 seg_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
 616                 cpy_len = RTE_MIN(vb_avail, seg_avail);
 617
 618                 PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);
 619
 620                 seg_num++;
 621                 cur = m;
 622                 prev = m;
 623                 while (cpy_len != 0) {
 624                         rte_memcpy((void *)(rte_pktmbuf_mtod(cur, char *) + seg_offset),
 625                                 (void *)((uintptr_t)(vb_addr + vb_offset)),
 626                                 cpy_len);
 627
 628                         seg_offset += cpy_len;
 629                         vb_offset += cpy_len;
 630                         vb_avail -= cpy_len;
 631                         seg_avail -= cpy_len;
 632
 633                         if (vb_avail != 0) {
 634                                 /*
 635                                  * The segment reachs to its end,
 636                                  * while the virtio buffer in TX vring has
 637                                  * more data to be copied.
 638                                  */
 639                                 cur->data_len = seg_offset;
 640                                 m->pkt_len += seg_offset;
 641                                 /* Allocate mbuf and populate the structure. */
 642                                 cur = rte_pktmbuf_alloc(mbuf_pool);
 643                                 if (unlikely(cur == NULL)) {
 644                                         RTE_LOG(ERR, VHOST_DATA, "Failed to "
 645                                                 "allocate memory for mbuf.\n");
 646                                         rte_pktmbuf_free(m);
 647                                         alloc_err = 1;
 648                                         break;
 649                                 }
 650
 651                                 seg_num++;
 652                                 prev->next = cur;
 653                                 prev = cur;
 654                                 seg_offset = 0;
 655                                 seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 656                         } else {
 657                                 if (desc->flags & VRING_DESC_F_NEXT) {
 658                                         /*
 659                                          * There are more virtio buffers in
 660                                          * same vring entry need to be copied.
 661                                          */
 662                                         if (seg_avail == 0) {
 663                                                 /*
 664                                                  * The current segment hasn't
 665                                                  * room to accomodate more
 666                                                  * data.
 667                                                  */
 668                                                 cur->data_len = seg_offset;
 669                                                 m->pkt_len += seg_offset;
 670                                                 /*
 671                                                  * Allocate an mbuf and
 672                                                  * populate the structure.
 673                                                  */
 674                                                 cur = rte_pktmbuf_alloc(mbuf_pool);
 675                                                 if (unlikely(cur == NULL)) {
 676                                                         RTE_LOG(ERR,
 677                                                                 VHOST_DATA,
 678                                                                 "Failed to "
 679                                                                 "allocate memory "
 680                                                                 "for mbuf\n");
 681                                                         rte_pktmbuf_free(m);
 682                                                         alloc_err = 1;
 683                                                         break;
 684                                                 }
 685                                                 seg_num++;
 686                                                 prev->next = cur;
 687                                                 prev = cur;
 688                                                 seg_offset = 0;
 689                                                 seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
 690                                         }
 691
 692                                         desc = &vq->desc[desc->next];
 693
 694                                         /* Buffer address translation. */
 695                                         vb_addr = gpa_to_vva(dev, desc->addr);
 696                                         /* Prefetch buffer address. */
 697                                         rte_prefetch0((void *)(uintptr_t)vb_addr);
 698                                         vb_offset = 0;
 699                                         vb_avail = desc->len;
 700
 701                                         PRINT_PACKET(dev, (uintptr_t)vb_addr,
 702                                                 desc->len, 0);
 703                                 } else {
 704                                         /* The whole packet completes. */
 705                                         cur->data_len = seg_offset;
 706                                         m->pkt_len += seg_offset;
 707                                         vb_avail = 0;
 708                                 }
 709                         }
 710
 711                         cpy_len = RTE_MIN(vb_avail, seg_avail);
 712                 }
 713
 714                 if (unlikely(alloc_err == 1))
 715                         break;
 716
 717                 m->nb_segs = seg_num;
 718
 719                 pkts[entry_success] = m;
 720                 vq->last_used_idx++;
 721                 entry_success++;
 722         }
 723
 724         rte_compiler_barrier();
 725         vq->used->idx += entry_success;
 726         /* Kick guest if required. */
 727         if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
 728                 eventfd_write((int)vq->kickfd, 1);
 729         return entry_success;
 730 }