hw/block/vhost-user-blk.c

   1 /*
   2  * vhost-user-blk host device
   3  *
   4  * Copyright(C) 2017 Intel Corporation.
   5  *
   6  * Authors:
   7  *  Changpeng Liu <changpeng.liu@intel.com>
   8  *
   9  * Largely based on the "vhost-user-scsi.c" and "vhost-scsi.c" implemented by:
  10  * Felipe Franciosi <felipe@nutanix.com>
  11  * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
  12  * Nicholas Bellinger <nab@risingtidesystems.com>
  13  *
  14  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  15  * See the COPYING.LIB file in the top-level directory.
  16  *
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "qapi/error.h"
  21 #include "qemu/error-report.h"
  22 #include "qemu/cutils.h"
  23 #include "hw/qdev-core.h"
  24 #include "hw/qdev-properties.h"
  25 #include "hw/qdev-properties-system.h"
  26 #include "hw/virtio/vhost.h"
  27 #include "hw/virtio/vhost-user-blk.h"
  28 #include "hw/virtio/virtio.h"
  29 #include "hw/virtio/virtio-bus.h"
  30 #include "hw/virtio/virtio-access.h"
  31 #include "sysemu/sysemu.h"
  32 #include "sysemu/runstate.h"
  33
  34 static const int user_feature_bits[] = {
  35     VIRTIO_BLK_F_SIZE_MAX,
  36     VIRTIO_BLK_F_SEG_MAX,
  37     VIRTIO_BLK_F_GEOMETRY,
  38     VIRTIO_BLK_F_BLK_SIZE,
  39     VIRTIO_BLK_F_TOPOLOGY,
  40     VIRTIO_BLK_F_MQ,
  41     VIRTIO_BLK_F_RO,
  42     VIRTIO_BLK_F_FLUSH,
  43     VIRTIO_BLK_F_CONFIG_WCE,
  44     VIRTIO_BLK_F_DISCARD,
  45     VIRTIO_BLK_F_WRITE_ZEROES,
  46     VIRTIO_F_VERSION_1,
  47     VIRTIO_RING_F_INDIRECT_DESC,
  48     VIRTIO_RING_F_EVENT_IDX,
  49     VIRTIO_F_NOTIFY_ON_EMPTY,
  50     VHOST_INVALID_FEATURE_BIT
  51 };
  52
  53 static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t *config)
  54 {
  55     VHostUserBlk *s = VHOST_USER_BLK(vdev);
  56
  57     /* Our num_queues overrides the device backend */
  58     virtio_stw_p(vdev, &s->blkcfg.num_queues, s->num_queues);
  59
  60     memcpy(config, &s->blkcfg, sizeof(struct virtio_blk_config));
  61 }
  62
  63 static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
  64 {
  65     VHostUserBlk *s = VHOST_USER_BLK(vdev);
  66     struct virtio_blk_config *blkcfg = (struct virtio_blk_config *)config;
  67     int ret;
  68
  69     if (blkcfg->wce == s->blkcfg.wce) {
  70         return;
  71     }
  72
  73     ret = vhost_dev_set_config(&s->dev, &blkcfg->wce,
  74                                offsetof(struct virtio_blk_config, wce),
  75                                sizeof(blkcfg->wce),
  76                                VHOST_SET_CONFIG_TYPE_MASTER);
  77     if (ret) {
  78         error_report("set device config space failed");
  79         return;
  80     }
  81
  82     s->blkcfg.wce = blkcfg->wce;
  83 }
  84
  85 static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
  86 {
  87     int ret;
  88     struct virtio_blk_config blkcfg;
  89     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
  90
  91     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
  92                                sizeof(struct virtio_blk_config));
  93     if (ret < 0) {
  94         error_report("get config space failed");
  95         return -1;
  96     }
  97
  98     /* valid for resize only */
  99     if (blkcfg.capacity != s->blkcfg.capacity) {
 100         s->blkcfg.capacity = blkcfg.capacity;
 101         memcpy(dev->vdev->config, &s->blkcfg, sizeof(struct virtio_blk_config));
 102         virtio_notify_config(dev->vdev);
 103     }
 104
 105     return 0;
 106 }
 107
 108 const VhostDevConfigOps blk_ops = {
 109     .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
 110 };
 111
 112 static int vhost_user_blk_start(VirtIODevice *vdev)
 113 {
 114     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 115     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 116     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 117     int i, ret;
 118
 119     if (!k->set_guest_notifiers) {
 120         error_report("binding does not support guest notifiers");
 121         return -ENOSYS;
 122     }
 123
 124     ret = vhost_dev_enable_notifiers(&s->dev, vdev);
 125     if (ret < 0) {
 126         error_report("Error enabling host notifiers: %d", -ret);
 127         return ret;
 128     }
 129
 130     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
 131     if (ret < 0) {
 132         error_report("Error binding guest notifier: %d", -ret);
 133         goto err_host_notifiers;
 134     }
 135
 136     s->dev.acked_features = vdev->guest_features;
 137
 138     ret = vhost_dev_prepare_inflight(&s->dev, vdev);
 139     if (ret < 0) {
 140         error_report("Error set inflight format: %d", -ret);
 141         goto err_guest_notifiers;
 142     }
 143
 144     if (!s->inflight->addr) {
 145         ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
 146         if (ret < 0) {
 147             error_report("Error get inflight: %d", -ret);
 148             goto err_guest_notifiers;
 149         }
 150     }
 151
 152     ret = vhost_dev_set_inflight(&s->dev, s->inflight);
 153     if (ret < 0) {
 154         error_report("Error set inflight: %d", -ret);
 155         goto err_guest_notifiers;
 156     }
 157
 158     ret = vhost_dev_start(&s->dev, vdev);
 159     if (ret < 0) {
 160         error_report("Error starting vhost: %d", -ret);
 161         goto err_guest_notifiers;
 162     }
 163     s->started_vu = true;
 164
 165     /* guest_notifier_mask/pending not used yet, so just unmask
 166      * everything here. virtio-pci will do the right thing by
 167      * enabling/disabling irqfd.
 168      */
 169     for (i = 0; i < s->dev.nvqs; i++) {
 170         vhost_virtqueue_mask(&s->dev, vdev, i, false);
 171     }
 172
 173     return ret;
 174
 175 err_guest_notifiers:
 176     k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 177 err_host_notifiers:
 178     vhost_dev_disable_notifiers(&s->dev, vdev);
 179     return ret;
 180 }
 181
 182 static void vhost_user_blk_stop(VirtIODevice *vdev)
 183 {
 184     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 185     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 186     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 187     int ret;
 188
 189     if (!s->started_vu) {
 190         return;
 191     }
 192     s->started_vu = false;
 193
 194     if (!k->set_guest_notifiers) {
 195         return;
 196     }
 197
 198     vhost_dev_stop(&s->dev, vdev);
 199
 200     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 201     if (ret < 0) {
 202         error_report("vhost guest notifier cleanup failed: %d", ret);
 203         return;
 204     }
 205
 206     vhost_dev_disable_notifiers(&s->dev, vdev);
 207 }
 208
 209 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 210 {
 211     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 212     bool should_start = virtio_device_started(vdev, status);
 213     int ret;
 214
 215     if (!vdev->vm_running) {
 216         should_start = false;
 217     }
 218
 219     if (!s->connected) {
 220         return;
 221     }
 222
 223     if (s->dev.started == should_start) {
 224         return;
 225     }
 226
 227     if (should_start) {
 228         ret = vhost_user_blk_start(vdev);
 229         if (ret < 0) {
 230             error_report("vhost-user-blk: vhost start failed: %s",
 231                          strerror(-ret));
 232             qemu_chr_fe_disconnect(&s->chardev);
 233         }
 234     } else {
 235         vhost_user_blk_stop(vdev);
 236     }
 237
 238 }
 239
 240 static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
 241                                             uint64_t features,
 242                                             Error **errp)
 243 {
 244     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 245
 246     /* Turn on pre-defined features */
 247     virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
 248     virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
 249     virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
 250     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
 251     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
 252     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
 253     virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
 254     virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
 255
 256     if (s->config_wce) {
 257         virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
 258     }
 259     if (s->num_queues > 1) {
 260         virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
 261     }
 262
 263     return vhost_get_features(&s->dev, user_feature_bits, features);
 264 }
 265
 266 static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 267 {
 268     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 269     int i, ret;
 270
 271     if (!vdev->start_on_kick) {
 272         return;
 273     }
 274
 275     if (!s->connected) {
 276         return;
 277     }
 278
 279     if (s->dev.started) {
 280         return;
 281     }
 282
 283     /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
 284      * vhost here instead of waiting for .set_status().
 285      */
 286     ret = vhost_user_blk_start(vdev);
 287     if (ret < 0) {
 288         error_report("vhost-user-blk: vhost start failed: %s",
 289                      strerror(-ret));
 290         qemu_chr_fe_disconnect(&s->chardev);
 291         return;
 292     }
 293
 294     /* Kick right away to begin processing requests already in vring */
 295     for (i = 0; i < s->dev.nvqs; i++) {
 296         VirtQueue *kick_vq = virtio_get_queue(vdev, i);
 297
 298         if (!virtio_queue_get_desc_addr(vdev, i)) {
 299             continue;
 300         }
 301         event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
 302     }
 303 }
 304
 305 static void vhost_user_blk_reset(VirtIODevice *vdev)
 306 {
 307     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 308
 309     vhost_dev_free_inflight(s->inflight);
 310 }
 311
 312 static int vhost_user_blk_connect(DeviceState *dev)
 313 {
 314     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 315     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 316     int ret = 0;
 317
 318     if (s->connected) {
 319         return 0;
 320     }
 321     s->connected = true;
 322
 323     s->dev.nvqs = s->num_queues;
 324     s->dev.vqs = s->vhost_vqs;
 325     s->dev.vq_index = 0;
 326     s->dev.backend_features = 0;
 327
 328     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 329
 330     ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
 331     if (ret < 0) {
 332         error_report("vhost-user-blk: vhost initialization failed: %s",
 333                      strerror(-ret));
 334         return ret;
 335     }
 336
 337     /* restore vhost state */
 338     if (virtio_device_started(vdev, vdev->status)) {
 339         ret = vhost_user_blk_start(vdev);
 340         if (ret < 0) {
 341             error_report("vhost-user-blk: vhost start failed: %s",
 342                          strerror(-ret));
 343             return ret;
 344         }
 345     }
 346
 347     return 0;
 348 }
 349
 350 static void vhost_user_blk_disconnect(DeviceState *dev)
 351 {
 352     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 353     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 354
 355     if (!s->connected) {
 356         return;
 357     }
 358     s->connected = false;
 359
 360     vhost_user_blk_stop(vdev);
 361
 362     vhost_dev_cleanup(&s->dev);
 363 }
 364
 365 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event);
 366
 367 static void vhost_user_blk_chr_closed_bh(void *opaque)
 368 {
 369     DeviceState *dev = opaque;
 370     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 371     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 372
 373     vhost_user_blk_disconnect(dev);
 374     qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
 375             NULL, opaque, NULL, true);
 376 }
 377
 378 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
 379 {
 380     DeviceState *dev = opaque;
 381     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 382     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 383
 384     switch (event) {
 385     case CHR_EVENT_OPENED:
 386         if (vhost_user_blk_connect(dev) < 0) {
 387             qemu_chr_fe_disconnect(&s->chardev);
 388             return;
 389         }
 390         break;
 391     case CHR_EVENT_CLOSED:
 392         /*
 393          * A close event may happen during a read/write, but vhost
 394          * code assumes the vhost_dev remains setup, so delay the
 395          * stop & clear. There are two possible paths to hit this
 396          * disconnect event:
 397          * 1. When VM is in the RUN_STATE_PRELAUNCH state. The
 398          * vhost_user_blk_device_realize() is a caller.
 399          * 2. In tha main loop phase after VM start.
 400          *
 401          * For p2 the disconnect event will be delayed. We can't
 402          * do the same for p1, because we are not running the loop
 403          * at this moment. So just skip this step and perform
 404          * disconnect in the caller function.
 405          *
 406          * TODO: maybe it is a good idea to make the same fix
 407          * for other vhost-user devices.
 408          */
 409         if (runstate_is_running()) {
 410             AioContext *ctx = qemu_get_current_aio_context();
 411
 412             qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL,
 413                     NULL, NULL, false);
 414             aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque);
 415         }
 416
 417         /*
 418          * Move vhost device to the stopped state. The vhost-user device
 419          * will be clean up and disconnected in BH. This can be useful in
 420          * the vhost migration code. If disconnect was caught there is an
 421          * option for the general vhost code to get the dev state without
 422          * knowing its type (in this case vhost-user).
 423          */
 424         s->dev.started = false;
 425         break;
 426     case CHR_EVENT_BREAK:
 427     case CHR_EVENT_MUX_IN:
 428     case CHR_EVENT_MUX_OUT:
 429         /* Ignore */
 430         break;
 431     }
 432 }
 433
 434 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 435 {
 436     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 437     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 438     Error *err = NULL;
 439     int i, ret;
 440
 441     if (!s->chardev.chr) {
 442         error_setg(errp, "vhost-user-blk: chardev is mandatory");
 443         return;
 444     }
 445
 446     if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
 447         s->num_queues = 1;
 448     }
 449     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
 450         error_setg(errp, "vhost-user-blk: invalid number of IO queues");
 451         return;
 452     }
 453
 454     if (!s->queue_size) {
 455         error_setg(errp, "vhost-user-blk: queue size must be non-zero");
 456         return;
 457     }
 458
 459     if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
 460         return;
 461     }
 462
 463     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
 464                 sizeof(struct virtio_blk_config));
 465
 466     s->virtqs = g_new(VirtQueue *, s->num_queues);
 467     for (i = 0; i < s->num_queues; i++) {
 468         s->virtqs[i] = virtio_add_queue(vdev, s->queue_size,
 469                                         vhost_user_blk_handle_output);
 470     }
 471
 472     s->inflight = g_new0(struct vhost_inflight, 1);
 473     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
 474     s->connected = false;
 475
 476     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, vhost_user_blk_event,
 477                              NULL, (void *)dev, NULL, true);
 478
 479 reconnect:
 480     if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) {
 481         error_report_err(err);
 482         goto virtio_err;
 483     }
 484
 485     /* check whether vhost_user_blk_connect() failed or not */
 486     if (!s->connected) {
 487         goto reconnect;
 488     }
 489
 490     ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
 491                                sizeof(struct virtio_blk_config));
 492     if (ret < 0) {
 493         error_report("vhost-user-blk: get block config failed");
 494         goto reconnect;
 495     }
 496
 497     return;
 498
 499 virtio_err:
 500     g_free(s->vhost_vqs);
 501     s->vhost_vqs = NULL;
 502     g_free(s->inflight);
 503     s->inflight = NULL;
 504     for (i = 0; i < s->num_queues; i++) {
 505         virtio_delete_queue(s->virtqs[i]);
 506     }
 507     g_free(s->virtqs);
 508     virtio_cleanup(vdev);
 509     vhost_user_cleanup(&s->vhost_user);
 510 }
 511
 512 static void vhost_user_blk_device_unrealize(DeviceState *dev)
 513 {
 514     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 515     VHostUserBlk *s = VHOST_USER_BLK(dev);
 516     int i;
 517
 518     virtio_set_status(vdev, 0);
 519     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, NULL,
 520                              NULL, NULL, NULL, false);
 521     vhost_dev_cleanup(&s->dev);
 522     vhost_dev_free_inflight(s->inflight);
 523     g_free(s->vhost_vqs);
 524     s->vhost_vqs = NULL;
 525     g_free(s->inflight);
 526     s->inflight = NULL;
 527
 528     for (i = 0; i < s->num_queues; i++) {
 529         virtio_delete_queue(s->virtqs[i]);
 530     }
 531     g_free(s->virtqs);
 532     virtio_cleanup(vdev);
 533     vhost_user_cleanup(&s->vhost_user);
 534 }
 535
 536 static void vhost_user_blk_instance_init(Object *obj)
 537 {
 538     VHostUserBlk *s = VHOST_USER_BLK(obj);
 539
 540     device_add_bootindex_property(obj, &s->bootindex, "bootindex",
 541                                   "/disk@0,0", DEVICE(obj));
 542 }
 543
 544 static const VMStateDescription vmstate_vhost_user_blk = {
 545     .name = "vhost-user-blk",
 546     .minimum_version_id = 1,
 547     .version_id = 1,
 548     .fields = (VMStateField[]) {
 549         VMSTATE_VIRTIO_DEVICE,
 550         VMSTATE_END_OF_LIST()
 551     },
 552 };
 553
 554 static Property vhost_user_blk_properties[] = {
 555     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
 556     DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
 557                        VHOST_USER_BLK_AUTO_NUM_QUEUES),
 558     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
 559     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
 560     DEFINE_PROP_END_OF_LIST(),
 561 };
 562
 563 static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
 564 {
 565     DeviceClass *dc = DEVICE_CLASS(klass);
 566     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 567
 568     device_class_set_props(dc, vhost_user_blk_properties);
 569     dc->vmsd = &vmstate_vhost_user_blk;
 570     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 571     vdc->realize = vhost_user_blk_device_realize;
 572     vdc->unrealize = vhost_user_blk_device_unrealize;
 573     vdc->get_config = vhost_user_blk_update_config;
 574     vdc->set_config = vhost_user_blk_set_config;
 575     vdc->get_features = vhost_user_blk_get_features;
 576     vdc->set_status = vhost_user_blk_set_status;
 577     vdc->reset = vhost_user_blk_reset;
 578 }
 579
 580 static const TypeInfo vhost_user_blk_info = {
 581     .name = TYPE_VHOST_USER_BLK,
 582     .parent = TYPE_VIRTIO_DEVICE,
 583     .instance_size = sizeof(VHostUserBlk),
 584     .instance_init = vhost_user_blk_instance_init,
 585     .class_init = vhost_user_blk_class_init,
 586 };
 587
 588 static void virtio_register_types(void)
 589 {
 590     type_register_static(&vhost_user_blk_info);
 591 }
 592
 593 type_init(virtio_register_types)