drivers/net/virtio/virtio_user/virtio_user_dev.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2016 Intel Corporation
   3  */
   4
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <fcntl.h>
   8 #include <string.h>
   9 #include <errno.h>
  10 #include <sys/mman.h>
  11 #include <unistd.h>
  12 #include <sys/eventfd.h>
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15
  16 #include <rte_string_fns.h>
  17 #include <rte_eal_memconfig.h>
  18
  19 #include "vhost.h"
  20 #include "virtio_user_dev.h"
  21 #include "../virtio_ethdev.h"
  22
  23 #define VIRTIO_USER_MEM_EVENT_CLB_NAME "virtio_user_mem_event_clb"
  24
  25 static int
  26 virtio_user_create_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
  27 {
  28         /* Of all per virtqueue MSGs, make sure VHOST_SET_VRING_CALL come
  29          * firstly because vhost depends on this msg to allocate virtqueue
  30          * pair.
  31          */
  32         struct vhost_vring_file file;
  33
  34         file.index = queue_sel;
  35         file.fd = dev->callfds[queue_sel];
  36         dev->ops->send_request(dev, VHOST_USER_SET_VRING_CALL, &file);
  37
  38         return 0;
  39 }
  40
  41 static int
  42 virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
  43 {
  44         struct vhost_vring_file file;
  45         struct vhost_vring_state state;
  46         struct vring *vring = &dev->vrings[queue_sel];
  47         struct vring_packed *pq_vring = &dev->packed_vrings[queue_sel];
  48         struct vhost_vring_addr addr = {
  49                 .index = queue_sel,
  50                 .log_guest_addr = 0,
  51                 .flags = 0, /* disable log */
  52         };
  53
  54         if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) {
  55                 addr.desc_user_addr =
  56                         (uint64_t)(uintptr_t)pq_vring->desc;
  57                 addr.avail_user_addr =
  58                         (uint64_t)(uintptr_t)pq_vring->driver;
  59                 addr.used_user_addr =
  60                         (uint64_t)(uintptr_t)pq_vring->device;
  61         } else {
  62                 addr.desc_user_addr = (uint64_t)(uintptr_t)vring->desc;
  63                 addr.avail_user_addr = (uint64_t)(uintptr_t)vring->avail;
  64                 addr.used_user_addr = (uint64_t)(uintptr_t)vring->used;
  65         }
  66
  67         state.index = queue_sel;
  68         state.num = vring->num;
  69         dev->ops->send_request(dev, VHOST_USER_SET_VRING_NUM, &state);
  70
  71         state.index = queue_sel;
  72         state.num = 0; /* no reservation */
  73         if (dev->features & (1ULL << VIRTIO_F_RING_PACKED))
  74                 state.num |= (1 << 15);
  75         dev->ops->send_request(dev, VHOST_USER_SET_VRING_BASE, &state);
  76
  77         dev->ops->send_request(dev, VHOST_USER_SET_VRING_ADDR, &addr);
  78
  79         /* Of all per virtqueue MSGs, make sure VHOST_USER_SET_VRING_KICK comes
  80          * lastly because vhost depends on this msg to judge if
  81          * virtio is ready.
  82          */
  83         file.index = queue_sel;
  84         file.fd = dev->kickfds[queue_sel];
  85         dev->ops->send_request(dev, VHOST_USER_SET_VRING_KICK, &file);
  86
  87         return 0;
  88 }
  89
  90 static int
  91 virtio_user_queue_setup(struct virtio_user_dev *dev,
  92                         int (*fn)(struct virtio_user_dev *, uint32_t))
  93 {
  94         uint32_t i, queue_sel;
  95
  96         for (i = 0; i < dev->max_queue_pairs; ++i) {
  97                 queue_sel = 2 * i + VTNET_SQ_RQ_QUEUE_IDX;
  98                 if (fn(dev, queue_sel) < 0) {
  99                         PMD_DRV_LOG(INFO, "setup rx vq fails: %u", i);
 100                         return -1;
 101                 }
 102         }
 103         for (i = 0; i < dev->max_queue_pairs; ++i) {
 104                 queue_sel = 2 * i + VTNET_SQ_TQ_QUEUE_IDX;
 105                 if (fn(dev, queue_sel) < 0) {
 106                         PMD_DRV_LOG(INFO, "setup tx vq fails: %u", i);
 107                         return -1;
 108                 }
 109         }
 110
 111         return 0;
 112 }
 113
 114 int
 115 is_vhost_user_by_type(const char *path)
 116 {
 117         struct stat sb;
 118
 119         if (stat(path, &sb) == -1)
 120                 return 0;
 121
 122         return S_ISSOCK(sb.st_mode);
 123 }
 124
 125 int
 126 virtio_user_start_device(struct virtio_user_dev *dev)
 127 {
 128         uint64_t features;
 129         int ret;
 130
 131         /*
 132          * XXX workaround!
 133          *
 134          * We need to make sure that the locks will be
 135          * taken in the correct order to avoid deadlocks.
 136          *
 137          * Before releasing this lock, this thread should
 138          * not trigger any memory hotplug events.
 139          *
 140          * This is a temporary workaround, and should be
 141          * replaced when we get proper supports from the
 142          * memory subsystem in the future.
 143          */
 144         rte_mcfg_mem_read_lock();
 145         pthread_mutex_lock(&dev->mutex);
 146
 147         if (is_vhost_user_by_type(dev->path) && dev->vhostfd < 0)
 148                 goto error;
 149
 150         /* Step 0: tell vhost to create queues */
 151         if (virtio_user_queue_setup(dev, virtio_user_create_queue) < 0)
 152                 goto error;
 153
 154         /* Step 1: set features */
 155         features = dev->features;
 156         /* Strip VIRTIO_NET_F_MAC, as MAC address is handled in vdev init */
 157         features &= ~(1ull << VIRTIO_NET_F_MAC);
 158         /* Strip VIRTIO_NET_F_CTRL_VQ, as devices do not really need to know */
 159         features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
 160         features &= ~(1ull << VIRTIO_NET_F_STATUS);
 161         ret = dev->ops->send_request(dev, VHOST_USER_SET_FEATURES, &features);
 162         if (ret < 0)
 163                 goto error;
 164         PMD_DRV_LOG(INFO, "set features: %" PRIx64, features);
 165
 166         /* Step 2: share memory regions */
 167         ret = dev->ops->send_request(dev, VHOST_USER_SET_MEM_TABLE, NULL);
 168         if (ret < 0)
 169                 goto error;
 170
 171         /* Step 3: kick queues */
 172         if (virtio_user_queue_setup(dev, virtio_user_kick_queue) < 0)
 173                 goto error;
 174
 175         /* Step 4: enable queues
 176          * we enable the 1st queue pair by default.
 177          */
 178         dev->ops->enable_qp(dev, 0, 1);
 179
 180         dev->started = true;
 181         pthread_mutex_unlock(&dev->mutex);
 182         rte_mcfg_mem_read_unlock();
 183
 184         return 0;
 185 error:
 186         pthread_mutex_unlock(&dev->mutex);
 187         rte_mcfg_mem_read_unlock();
 188         /* TODO: free resource here or caller to check */
 189         return -1;
 190 }
 191
 192 int virtio_user_stop_device(struct virtio_user_dev *dev)
 193 {
 194         struct vhost_vring_state state;
 195         uint32_t i;
 196         int error = 0;
 197
 198         pthread_mutex_lock(&dev->mutex);
 199         if (!dev->started)
 200                 goto out;
 201
 202         for (i = 0; i < dev->max_queue_pairs; ++i)
 203                 dev->ops->enable_qp(dev, i, 0);
 204
 205         /* Stop the backend. */
 206         for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
 207                 state.index = i;
 208                 if (dev->ops->send_request(dev, VHOST_USER_GET_VRING_BASE,
 209                                            &state) < 0) {
 210                         PMD_DRV_LOG(ERR, "get_vring_base failed, index=%u\n",
 211                                     i);
 212                         error = -1;
 213                         goto out;
 214                 }
 215         }
 216
 217         dev->started = false;
 218 out:
 219         pthread_mutex_unlock(&dev->mutex);
 220
 221         return error;
 222 }
 223
 224 static inline void
 225 parse_mac(struct virtio_user_dev *dev, const char *mac)
 226 {
 227         struct rte_ether_addr tmp;
 228
 229         if (!mac)
 230                 return;
 231
 232         if (rte_ether_unformat_addr(mac, &tmp) == 0) {
 233                 memcpy(dev->mac_addr, &tmp, RTE_ETHER_ADDR_LEN);
 234                 dev->mac_specified = 1;
 235         } else {
 236                 /* ignore the wrong mac, use random mac */
 237                 PMD_DRV_LOG(ERR, "wrong format of mac: %s", mac);
 238         }
 239 }
 240
 241 static int
 242 virtio_user_dev_init_notify(struct virtio_user_dev *dev)
 243 {
 244         uint32_t i, j;
 245         int callfd;
 246         int kickfd;
 247
 248         for (i = 0; i < VIRTIO_MAX_VIRTQUEUES; ++i) {
 249                 if (i >= dev->max_queue_pairs * 2) {
 250                         dev->kickfds[i] = -1;
 251                         dev->callfds[i] = -1;
 252                         continue;
 253                 }
 254
 255                 /* May use invalid flag, but some backend uses kickfd and
 256                  * callfd as criteria to judge if dev is alive. so finally we
 257                  * use real event_fd.
 258                  */
 259                 callfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
 260                 if (callfd < 0) {
 261                         PMD_DRV_LOG(ERR, "callfd error, %s", strerror(errno));
 262                         break;
 263                 }
 264                 kickfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
 265                 if (kickfd < 0) {
 266                         PMD_DRV_LOG(ERR, "kickfd error, %s", strerror(errno));
 267                         break;
 268                 }
 269                 dev->callfds[i] = callfd;
 270                 dev->kickfds[i] = kickfd;
 271         }
 272
 273         if (i < VIRTIO_MAX_VIRTQUEUES) {
 274                 for (j = 0; j <= i; ++j) {
 275                         close(dev->callfds[j]);
 276                         close(dev->kickfds[j]);
 277                 }
 278
 279                 return -1;
 280         }
 281
 282         return 0;
 283 }
 284
 285 static int
 286 virtio_user_fill_intr_handle(struct virtio_user_dev *dev)
 287 {
 288         uint32_t i;
 289         struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->port_id];
 290
 291         if (!eth_dev->intr_handle) {
 292                 eth_dev->intr_handle = malloc(sizeof(*eth_dev->intr_handle));
 293                 if (!eth_dev->intr_handle) {
 294                         PMD_DRV_LOG(ERR, "fail to allocate intr_handle");
 295                         return -1;
 296                 }
 297                 memset(eth_dev->intr_handle, 0, sizeof(*eth_dev->intr_handle));
 298         }
 299
 300         for (i = 0; i < dev->max_queue_pairs; ++i)
 301                 eth_dev->intr_handle->efds[i] = dev->callfds[i];
 302         eth_dev->intr_handle->nb_efd = dev->max_queue_pairs;
 303         eth_dev->intr_handle->max_intr = dev->max_queue_pairs + 1;
 304         eth_dev->intr_handle->type = RTE_INTR_HANDLE_VDEV;
 305         /* For virtio vdev, no need to read counter for clean */
 306         eth_dev->intr_handle->efd_counter_size = 0;
 307         eth_dev->intr_handle->fd = -1;
 308         if (dev->vhostfd >= 0)
 309                 eth_dev->intr_handle->fd = dev->vhostfd;
 310         else if (dev->is_server)
 311                 eth_dev->intr_handle->fd = dev->listenfd;
 312
 313         return 0;
 314 }
 315
 316 static void
 317 virtio_user_mem_event_cb(enum rte_mem_event type __rte_unused,
 318                                                  const void *addr __rte_unused,
 319                                                  size_t len __rte_unused,
 320                                                  void *arg)
 321 {
 322         struct virtio_user_dev *dev = arg;
 323         struct rte_memseg_list *msl;
 324         uint16_t i;
 325
 326         /* ignore externally allocated memory */
 327         msl = rte_mem_virt2memseg_list(addr);
 328         if (msl->external)
 329                 return;
 330
 331         pthread_mutex_lock(&dev->mutex);
 332
 333         if (dev->started == false)
 334                 goto exit;
 335
 336         /* Step 1: pause the active queues */
 337         for (i = 0; i < dev->queue_pairs; i++)
 338                 dev->ops->enable_qp(dev, i, 0);
 339
 340         /* Step 2: update memory regions */
 341         dev->ops->send_request(dev, VHOST_USER_SET_MEM_TABLE, NULL);
 342
 343         /* Step 3: resume the active queues */
 344         for (i = 0; i < dev->queue_pairs; i++)
 345                 dev->ops->enable_qp(dev, i, 1);
 346
 347 exit:
 348         pthread_mutex_unlock(&dev->mutex);
 349 }
 350
 351 static int
 352 virtio_user_dev_setup(struct virtio_user_dev *dev)
 353 {
 354         uint32_t q;
 355
 356         dev->vhostfd = -1;
 357         dev->vhostfds = NULL;
 358         dev->tapfds = NULL;
 359
 360         if (dev->is_server) {
 361                 if (access(dev->path, F_OK) == 0 &&
 362                     !is_vhost_user_by_type(dev->path)) {
 363                         PMD_DRV_LOG(ERR, "Server mode doesn't support vhost-kernel!");
 364                         return -1;
 365                 }
 366                 dev->ops = &virtio_ops_user;
 367         } else {
 368                 if (is_vhost_user_by_type(dev->path)) {
 369                         dev->ops = &virtio_ops_user;
 370                 } else {
 371                         dev->ops = &virtio_ops_kernel;
 372
 373                         dev->vhostfds = malloc(dev->max_queue_pairs *
 374                                                sizeof(int));
 375                         dev->tapfds = malloc(dev->max_queue_pairs *
 376                                              sizeof(int));
 377                         if (!dev->vhostfds || !dev->tapfds) {
 378                                 PMD_INIT_LOG(ERR, "Failed to malloc");
 379                                 return -1;
 380                         }
 381
 382                         for (q = 0; q < dev->max_queue_pairs; ++q) {
 383                                 dev->vhostfds[q] = -1;
 384                                 dev->tapfds[q] = -1;
 385                         }
 386                 }
 387         }
 388
 389         if (dev->ops->setup(dev) < 0)
 390                 return -1;
 391
 392         if (virtio_user_dev_init_notify(dev) < 0)
 393                 return -1;
 394
 395         if (virtio_user_fill_intr_handle(dev) < 0)
 396                 return -1;
 397
 398         return 0;
 399 }
 400
 401 /* Use below macro to filter features from vhost backend */
 402 #define VIRTIO_USER_SUPPORTED_FEATURES                  \
 403         (1ULL << VIRTIO_NET_F_MAC               |       \
 404          1ULL << VIRTIO_NET_F_STATUS            |       \
 405          1ULL << VIRTIO_NET_F_MQ                |       \
 406          1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR     |       \
 407          1ULL << VIRTIO_NET_F_CTRL_VQ           |       \
 408          1ULL << VIRTIO_NET_F_CTRL_RX           |       \
 409          1ULL << VIRTIO_NET_F_CTRL_VLAN         |       \
 410          1ULL << VIRTIO_NET_F_CSUM              |       \
 411          1ULL << VIRTIO_NET_F_HOST_TSO4         |       \
 412          1ULL << VIRTIO_NET_F_HOST_TSO6         |       \
 413          1ULL << VIRTIO_NET_F_MRG_RXBUF         |       \
 414          1ULL << VIRTIO_RING_F_INDIRECT_DESC    |       \
 415          1ULL << VIRTIO_NET_F_GUEST_CSUM        |       \
 416          1ULL << VIRTIO_NET_F_GUEST_TSO4        |       \
 417          1ULL << VIRTIO_NET_F_GUEST_TSO6        |       \
 418          1ULL << VIRTIO_F_IN_ORDER              |       \
 419          1ULL << VIRTIO_F_VERSION_1             |       \
 420          1ULL << VIRTIO_F_RING_PACKED)
 421
 422 int
 423 virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 424                      int cq, int queue_size, const char *mac, char **ifname,
 425                      int server, int mrg_rxbuf, int in_order, int packed_vq)
 426 {
 427         pthread_mutex_init(&dev->mutex, NULL);
 428         strlcpy(dev->path, path, PATH_MAX);
 429         dev->started = 0;
 430         dev->max_queue_pairs = queues;
 431         dev->queue_pairs = 1; /* mq disabled by default */
 432         dev->queue_size = queue_size;
 433         dev->is_server = server;
 434         dev->mac_specified = 0;
 435         dev->frontend_features = 0;
 436         dev->unsupported_features = ~VIRTIO_USER_SUPPORTED_FEATURES;
 437         parse_mac(dev, mac);
 438
 439         if (*ifname) {
 440                 dev->ifname = *ifname;
 441                 *ifname = NULL;
 442         }
 443
 444         if (virtio_user_dev_setup(dev) < 0) {
 445                 PMD_INIT_LOG(ERR, "backend set up fails");
 446                 return -1;
 447         }
 448
 449         if (!dev->is_server) {
 450                 if (dev->ops->send_request(dev, VHOST_USER_SET_OWNER,
 451                                            NULL) < 0) {
 452                         PMD_INIT_LOG(ERR, "set_owner fails: %s",
 453                                      strerror(errno));
 454                         return -1;
 455                 }
 456
 457                 if (dev->ops->send_request(dev, VHOST_USER_GET_FEATURES,
 458                                            &dev->device_features) < 0) {
 459                         PMD_INIT_LOG(ERR, "get_features failed: %s",
 460                                      strerror(errno));
 461                         return -1;
 462                 }
 463         } else {
 464                 /* We just pretend vhost-user can support all these features.
 465                  * Note that this could be problematic that if some feature is
 466                  * negotiated but not supported by the vhost-user which comes
 467                  * later.
 468                  */
 469                 dev->device_features = VIRTIO_USER_SUPPORTED_FEATURES;
 470         }
 471
 472         if (!mrg_rxbuf)
 473                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_MRG_RXBUF);
 474
 475         if (!in_order)
 476                 dev->unsupported_features |= (1ull << VIRTIO_F_IN_ORDER);
 477
 478         if (!packed_vq)
 479                 dev->unsupported_features |= (1ull << VIRTIO_F_RING_PACKED);
 480
 481         if (dev->mac_specified)
 482                 dev->frontend_features |= (1ull << VIRTIO_NET_F_MAC);
 483         else
 484                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_MAC);
 485
 486         if (cq) {
 487                 /* device does not really need to know anything about CQ,
 488                  * so if necessary, we just claim to support CQ
 489                  */
 490                 dev->frontend_features |= (1ull << VIRTIO_NET_F_CTRL_VQ);
 491         } else {
 492                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_CTRL_VQ);
 493                 /* Also disable features that depend on VIRTIO_NET_F_CTRL_VQ */
 494                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_CTRL_RX);
 495                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_CTRL_VLAN);
 496                 dev->unsupported_features |=
 497                         (1ull << VIRTIO_NET_F_GUEST_ANNOUNCE);
 498                 dev->unsupported_features |= (1ull << VIRTIO_NET_F_MQ);
 499                 dev->unsupported_features |=
 500                         (1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
 501         }
 502
 503         /* The backend will not report this feature, we add it explicitly */
 504         if (is_vhost_user_by_type(dev->path))
 505                 dev->frontend_features |= (1ull << VIRTIO_NET_F_STATUS);
 506
 507         /*
 508          * Device features =
 509          *     (frontend_features | backend_features) & ~unsupported_features;
 510          */
 511         dev->device_features |= dev->frontend_features;
 512         dev->device_features &= ~dev->unsupported_features;
 513
 514         if (rte_mem_event_callback_register(VIRTIO_USER_MEM_EVENT_CLB_NAME,
 515                                 virtio_user_mem_event_cb, dev)) {
 516                 if (rte_errno != ENOTSUP) {
 517                         PMD_INIT_LOG(ERR, "Failed to register mem event"
 518                                         " callback\n");
 519                         return -1;
 520                 }
 521         }
 522
 523         return 0;
 524 }
 525
 526 void
 527 virtio_user_dev_uninit(struct virtio_user_dev *dev)
 528 {
 529         uint32_t i;
 530
 531         virtio_user_stop_device(dev);
 532
 533         rte_mem_event_callback_unregister(VIRTIO_USER_MEM_EVENT_CLB_NAME, dev);
 534
 535         for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
 536                 close(dev->callfds[i]);
 537                 close(dev->kickfds[i]);
 538         }
 539
 540         close(dev->vhostfd);
 541
 542         if (dev->is_server && dev->listenfd >= 0) {
 543                 close(dev->listenfd);
 544                 dev->listenfd = -1;
 545         }
 546
 547         if (dev->vhostfds) {
 548                 for (i = 0; i < dev->max_queue_pairs; ++i)
 549                         close(dev->vhostfds[i]);
 550                 free(dev->vhostfds);
 551                 free(dev->tapfds);
 552         }
 553
 554         free(dev->ifname);
 555
 556         if (dev->is_server)
 557                 unlink(dev->path);
 558 }
 559
 560 uint8_t
 561 virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs)
 562 {
 563         uint16_t i;
 564         uint8_t ret = 0;
 565
 566         if (q_pairs > dev->max_queue_pairs) {
 567                 PMD_INIT_LOG(ERR, "multi-q config %u, but only %u supported",
 568                              q_pairs, dev->max_queue_pairs);
 569                 return -1;
 570         }
 571
 572         /* Server mode can't enable queue pairs if vhostfd is invalid,
 573          * always return 0 in this case.
 574          */
 575         if (!dev->is_server || dev->vhostfd >= 0) {
 576                 for (i = 0; i < q_pairs; ++i)
 577                         ret |= dev->ops->enable_qp(dev, i, 1);
 578                 for (i = q_pairs; i < dev->max_queue_pairs; ++i)
 579                         ret |= dev->ops->enable_qp(dev, i, 0);
 580         }
 581         dev->queue_pairs = q_pairs;
 582
 583         return ret;
 584 }
 585
 586 static uint32_t
 587 virtio_user_handle_ctrl_msg(struct virtio_user_dev *dev, struct vring *vring,
 588                             uint16_t idx_hdr)
 589 {
 590         struct virtio_net_ctrl_hdr *hdr;
 591         virtio_net_ctrl_ack status = ~0;
 592         uint16_t i, idx_data, idx_status;
 593         uint32_t n_descs = 0;
 594
 595         /* locate desc for header, data, and status */
 596         idx_data = vring->desc[idx_hdr].next;
 597         n_descs++;
 598
 599         i = idx_data;
 600         while (vring->desc[i].flags == VRING_DESC_F_NEXT) {
 601                 i = vring->desc[i].next;
 602                 n_descs++;
 603         }
 604
 605         /* locate desc for status */
 606         idx_status = i;
 607         n_descs++;
 608
 609         hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
 610         if (hdr->class == VIRTIO_NET_CTRL_MQ &&
 611             hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
 612                 uint16_t queues;
 613
 614                 queues = *(uint16_t *)(uintptr_t)vring->desc[idx_data].addr;
 615                 status = virtio_user_handle_mq(dev, queues);
 616         }
 617
 618         /* Update status */
 619         *(virtio_net_ctrl_ack *)(uintptr_t)vring->desc[idx_status].addr = status;
 620
 621         return n_descs;
 622 }
 623
 624 static inline int
 625 desc_is_avail(struct vring_packed_desc *desc, bool wrap_counter)
 626 {
 627         uint16_t flags = __atomic_load_n(&desc->flags, __ATOMIC_ACQUIRE);
 628
 629         return wrap_counter == !!(flags & VRING_PACKED_DESC_F_AVAIL) &&
 630                 wrap_counter != !!(flags & VRING_PACKED_DESC_F_USED);
 631 }
 632
 633 static uint32_t
 634 virtio_user_handle_ctrl_msg_packed(struct virtio_user_dev *dev,
 635                                    struct vring_packed *vring,
 636                                    uint16_t idx_hdr)
 637 {
 638         struct virtio_net_ctrl_hdr *hdr;
 639         virtio_net_ctrl_ack status = ~0;
 640         uint16_t idx_data, idx_status;
 641         /* initialize to one, header is first */
 642         uint32_t n_descs = 1;
 643
 644         /* locate desc for header, data, and status */
 645         idx_data = idx_hdr + 1;
 646         if (idx_data >= dev->queue_size)
 647                 idx_data -= dev->queue_size;
 648
 649         n_descs++;
 650
 651         idx_status = idx_data;
 652         while (vring->desc[idx_status].flags & VRING_DESC_F_NEXT) {
 653                 idx_status++;
 654                 if (idx_status >= dev->queue_size)
 655                         idx_status -= dev->queue_size;
 656                 n_descs++;
 657         }
 658
 659         hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
 660         if (hdr->class == VIRTIO_NET_CTRL_MQ &&
 661             hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
 662                 uint16_t queues;
 663
 664                 queues = *(uint16_t *)(uintptr_t)
 665                                 vring->desc[idx_data].addr;
 666                 status = virtio_user_handle_mq(dev, queues);
 667         }
 668
 669         /* Update status */
 670         *(virtio_net_ctrl_ack *)(uintptr_t)
 671                 vring->desc[idx_status].addr = status;
 672
 673         /* Update used descriptor */
 674         vring->desc[idx_hdr].id = vring->desc[idx_status].id;
 675         vring->desc[idx_hdr].len = sizeof(status);
 676
 677         return n_descs;
 678 }
 679
 680 void
 681 virtio_user_handle_cq_packed(struct virtio_user_dev *dev, uint16_t queue_idx)
 682 {
 683         struct virtio_user_queue *vq = &dev->packed_queues[queue_idx];
 684         struct vring_packed *vring = &dev->packed_vrings[queue_idx];
 685         uint16_t n_descs, flags;
 686
 687         /* Perform a load-acquire barrier in desc_is_avail to
 688          * enforce the ordering between desc flags and desc
 689          * content.
 690          */
 691         while (desc_is_avail(&vring->desc[vq->used_idx],
 692                              vq->used_wrap_counter)) {
 693
 694                 n_descs = virtio_user_handle_ctrl_msg_packed(dev, vring,
 695                                 vq->used_idx);
 696
 697                 flags = VRING_DESC_F_WRITE;
 698                 if (vq->used_wrap_counter)
 699                         flags |= VRING_PACKED_DESC_F_AVAIL_USED;
 700
 701                 __atomic_store_n(&vring->desc[vq->used_idx].flags, flags,
 702                                  __ATOMIC_RELEASE);
 703
 704                 vq->used_idx += n_descs;
 705                 if (vq->used_idx >= dev->queue_size) {
 706                         vq->used_idx -= dev->queue_size;
 707                         vq->used_wrap_counter ^= 1;
 708                 }
 709         }
 710 }
 711
 712 void
 713 virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
 714 {
 715         uint16_t avail_idx, desc_idx;
 716         struct vring_used_elem *uep;
 717         uint32_t n_descs;
 718         struct vring *vring = &dev->vrings[queue_idx];
 719
 720         /* Consume avail ring, using used ring idx as first one */
 721         while (vring->used->idx != vring->avail->idx) {
 722                 avail_idx = (vring->used->idx) & (vring->num - 1);
 723                 desc_idx = vring->avail->ring[avail_idx];
 724
 725                 n_descs = virtio_user_handle_ctrl_msg(dev, vring, desc_idx);
 726
 727                 /* Update used ring */
 728                 uep = &vring->used->ring[avail_idx];
 729                 uep->id = desc_idx;
 730                 uep->len = n_descs;
 731
 732                 vring->used->idx++;
 733         }
 734 }