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/virtio-blk-common.h"
  27 #include "hw/virtio/vhost.h"
  28 #include "hw/virtio/vhost-user-blk.h"
  29 #include "hw/virtio/virtio.h"
  30 #include "hw/virtio/virtio-bus.h"
  31 #include "hw/virtio/virtio-access.h"
  32 #include "sysemu/sysemu.h"
  33 #include "sysemu/runstate.h"
  34
  35 static const int user_feature_bits[] = {
  36     VIRTIO_BLK_F_SIZE_MAX,
  37     VIRTIO_BLK_F_SEG_MAX,
  38     VIRTIO_BLK_F_GEOMETRY,
  39     VIRTIO_BLK_F_BLK_SIZE,
  40     VIRTIO_BLK_F_TOPOLOGY,
  41     VIRTIO_BLK_F_MQ,
  42     VIRTIO_BLK_F_RO,
  43     VIRTIO_BLK_F_FLUSH,
  44     VIRTIO_BLK_F_CONFIG_WCE,
  45     VIRTIO_BLK_F_DISCARD,
  46     VIRTIO_BLK_F_WRITE_ZEROES,
  47     VIRTIO_F_VERSION_1,
  48     VIRTIO_RING_F_INDIRECT_DESC,
  49     VIRTIO_RING_F_EVENT_IDX,
  50     VIRTIO_F_NOTIFY_ON_EMPTY,
  51     VIRTIO_F_RING_PACKED,
  52     VIRTIO_F_IOMMU_PLATFORM,
  53     VIRTIO_F_RING_RESET,
  54     VHOST_INVALID_FEATURE_BIT
  55 };
  56
  57 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event);
  58
  59 static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t *config)
  60 {
  61     VHostUserBlk *s = VHOST_USER_BLK(vdev);
  62
  63     /* Our num_queues overrides the device backend */
  64     virtio_stw_p(vdev, &s->blkcfg.num_queues, s->num_queues);
  65
  66     memcpy(config, &s->blkcfg, vdev->config_len);
  67 }
  68
  69 static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
  70 {
  71     VHostUserBlk *s = VHOST_USER_BLK(vdev);
  72     struct virtio_blk_config *blkcfg = (struct virtio_blk_config *)config;
  73     int ret;
  74
  75     if (blkcfg->wce == s->blkcfg.wce) {
  76         return;
  77     }
  78
  79     ret = vhost_dev_set_config(&s->dev, &blkcfg->wce,
  80                                offsetof(struct virtio_blk_config, wce),
  81                                sizeof(blkcfg->wce),
  82                                VHOST_SET_CONFIG_TYPE_FRONTEND);
  83     if (ret) {
  84         error_report("set device config space failed");
  85         return;
  86     }
  87
  88     s->blkcfg.wce = blkcfg->wce;
  89 }
  90
  91 static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
  92 {
  93     int ret;
  94     struct virtio_blk_config blkcfg;
  95     VirtIODevice *vdev = dev->vdev;
  96     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
  97     Error *local_err = NULL;
  98
  99     if (!dev->started) {
 100         return 0;
 101     }
 102
 103     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
 104                                vdev->config_len, &local_err);
 105     if (ret < 0) {
 106         error_report_err(local_err);
 107         return ret;
 108     }
 109
 110     /* valid for resize only */
 111     if (blkcfg.capacity != s->blkcfg.capacity) {
 112         s->blkcfg.capacity = blkcfg.capacity;
 113         memcpy(dev->vdev->config, &s->blkcfg, vdev->config_len);
 114         virtio_notify_config(dev->vdev);
 115     }
 116
 117     return 0;
 118 }
 119
 120 const VhostDevConfigOps blk_ops = {
 121     .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
 122 };
 123
 124 static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
 125 {
 126     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 127     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 128     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 129     int i, ret;
 130
 131     if (!k->set_guest_notifiers) {
 132         error_setg(errp, "binding does not support guest notifiers");
 133         return -ENOSYS;
 134     }
 135
 136     ret = vhost_dev_enable_notifiers(&s->dev, vdev);
 137     if (ret < 0) {
 138         error_setg_errno(errp, -ret, "Error enabling host notifiers");
 139         return ret;
 140     }
 141
 142     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
 143     if (ret < 0) {
 144         error_setg_errno(errp, -ret, "Error binding guest notifier");
 145         goto err_host_notifiers;
 146     }
 147
 148     s->dev.acked_features = vdev->guest_features;
 149
 150     ret = vhost_dev_prepare_inflight(&s->dev, vdev);
 151     if (ret < 0) {
 152         error_setg_errno(errp, -ret, "Error setting inflight format");
 153         goto err_guest_notifiers;
 154     }
 155
 156     if (!s->inflight->addr) {
 157         ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
 158         if (ret < 0) {
 159             error_setg_errno(errp, -ret, "Error getting inflight");
 160             goto err_guest_notifiers;
 161         }
 162     }
 163
 164     ret = vhost_dev_set_inflight(&s->dev, s->inflight);
 165     if (ret < 0) {
 166         error_setg_errno(errp, -ret, "Error setting inflight");
 167         goto err_guest_notifiers;
 168     }
 169
 170     /* guest_notifier_mask/pending not used yet, so just unmask
 171      * everything here. virtio-pci will do the right thing by
 172      * enabling/disabling irqfd.
 173      */
 174     for (i = 0; i < s->dev.nvqs; i++) {
 175         vhost_virtqueue_mask(&s->dev, vdev, i, false);
 176     }
 177
 178     s->dev.vq_index_end = s->dev.nvqs;
 179     ret = vhost_dev_start(&s->dev, vdev, true);
 180     if (ret < 0) {
 181         error_setg_errno(errp, -ret, "Error starting vhost");
 182         goto err_guest_notifiers;
 183     }
 184     s->started_vu = true;
 185
 186     return ret;
 187
 188 err_guest_notifiers:
 189     for (i = 0; i < s->dev.nvqs; i++) {
 190         vhost_virtqueue_mask(&s->dev, vdev, i, true);
 191     }
 192     k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 193 err_host_notifiers:
 194     vhost_dev_disable_notifiers(&s->dev, vdev);
 195     return ret;
 196 }
 197
 198 static void vhost_user_blk_stop(VirtIODevice *vdev)
 199 {
 200     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 201     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 202     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 203     int ret;
 204
 205     if (!s->started_vu) {
 206         return;
 207     }
 208     s->started_vu = false;
 209
 210     if (!k->set_guest_notifiers) {
 211         return;
 212     }
 213
 214     vhost_dev_stop(&s->dev, vdev, true);
 215
 216     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 217     if (ret < 0) {
 218         error_report("vhost guest notifier cleanup failed: %d", ret);
 219         return;
 220     }
 221
 222     vhost_dev_disable_notifiers(&s->dev, vdev);
 223 }
 224
 225 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 226 {
 227     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 228     bool should_start = virtio_device_should_start(vdev, status);
 229     Error *local_err = NULL;
 230     int ret;
 231
 232     if (!s->connected) {
 233         return;
 234     }
 235
 236     if (vhost_dev_is_started(&s->dev) == should_start) {
 237         return;
 238     }
 239
 240     if (should_start) {
 241         ret = vhost_user_blk_start(vdev, &local_err);
 242         if (ret < 0) {
 243             error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
 244             qemu_chr_fe_disconnect(&s->chardev);
 245         }
 246     } else {
 247         vhost_user_blk_stop(vdev);
 248     }
 249
 250 }
 251
 252 static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
 253                                             uint64_t features,
 254                                             Error **errp)
 255 {
 256     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 257
 258     /* Turn on pre-defined features */
 259     virtio_add_feature(&features, VIRTIO_BLK_F_SIZE_MAX);
 260     virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
 261     virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
 262     virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
 263     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
 264     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
 265     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
 266
 267     if (s->num_queues > 1) {
 268         virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
 269     }
 270
 271     return vhost_get_features(&s->dev, user_feature_bits, features);
 272 }
 273
 274 static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 275 {
 276     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 277     Error *local_err = NULL;
 278     int i, ret;
 279
 280     if (!vdev->start_on_kick) {
 281         return;
 282     }
 283
 284     if (!s->connected) {
 285         return;
 286     }
 287
 288     if (vhost_dev_is_started(&s->dev)) {
 289         return;
 290     }
 291
 292     /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
 293      * vhost here instead of waiting for .set_status().
 294      */
 295     ret = vhost_user_blk_start(vdev, &local_err);
 296     if (ret < 0) {
 297         error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
 298         qemu_chr_fe_disconnect(&s->chardev);
 299         return;
 300     }
 301
 302     /* Kick right away to begin processing requests already in vring */
 303     for (i = 0; i < s->dev.nvqs; i++) {
 304         VirtQueue *kick_vq = virtio_get_queue(vdev, i);
 305
 306         if (!virtio_queue_get_desc_addr(vdev, i)) {
 307             continue;
 308         }
 309         event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
 310     }
 311 }
 312
 313 static void vhost_user_blk_reset(VirtIODevice *vdev)
 314 {
 315     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 316
 317     vhost_dev_free_inflight(s->inflight);
 318 }
 319
 320 static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
 321 {
 322     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 323     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 324     int ret = 0;
 325
 326     if (s->connected) {
 327         return 0;
 328     }
 329
 330     s->dev.num_queues = s->num_queues;
 331     s->dev.nvqs = s->num_queues;
 332     s->dev.vqs = s->vhost_vqs;
 333     s->dev.vq_index = 0;
 334     s->dev.backend_features = 0;
 335
 336     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 337
 338     s->vhost_user.supports_config = true;
 339     ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
 340                          errp);
 341     if (ret < 0) {
 342         return ret;
 343     }
 344
 345     s->connected = true;
 346
 347     /* restore vhost state */
 348     if (virtio_device_started(vdev, vdev->status)) {
 349         ret = vhost_user_blk_start(vdev, errp);
 350     }
 351
 352     return ret;
 353 }
 354
 355 static void vhost_user_blk_disconnect(DeviceState *dev)
 356 {
 357     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 358     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 359
 360     if (!s->connected) {
 361         return;
 362     }
 363     s->connected = false;
 364
 365     vhost_user_blk_stop(vdev);
 366
 367     vhost_dev_cleanup(&s->dev);
 368
 369     /* Re-instate the event handler for new connections */
 370     qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
 371                              NULL, dev, NULL, true);
 372 }
 373
 374 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
 375 {
 376     DeviceState *dev = opaque;
 377     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 378     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 379     Error *local_err = NULL;
 380
 381     switch (event) {
 382     case CHR_EVENT_OPENED:
 383         if (vhost_user_blk_connect(dev, &local_err) < 0) {
 384             error_report_err(local_err);
 385             qemu_chr_fe_disconnect(&s->chardev);
 386             return;
 387         }
 388         break;
 389     case CHR_EVENT_CLOSED:
 390         /* defer close until later to avoid circular close */
 391         vhost_user_async_close(dev, &s->chardev, &s->dev,
 392                                vhost_user_blk_disconnect, vhost_user_blk_event);
 393         break;
 394     case CHR_EVENT_BREAK:
 395     case CHR_EVENT_MUX_IN:
 396     case CHR_EVENT_MUX_OUT:
 397         /* Ignore */
 398         break;
 399     }
 400 }
 401
 402 static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp)
 403 {
 404     DeviceState *dev = DEVICE(s);
 405     int ret;
 406
 407     s->connected = false;
 408
 409     ret = qemu_chr_fe_wait_connected(&s->chardev, errp);
 410     if (ret < 0) {
 411         return ret;
 412     }
 413
 414     ret = vhost_user_blk_connect(dev, errp);
 415     if (ret < 0) {
 416         qemu_chr_fe_disconnect(&s->chardev);
 417         return ret;
 418     }
 419     assert(s->connected);
 420
 421     ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
 422                                VIRTIO_DEVICE(s)->config_len, errp);
 423     if (ret < 0) {
 424         qemu_chr_fe_disconnect(&s->chardev);
 425         vhost_dev_cleanup(&s->dev);
 426         return ret;
 427     }
 428
 429     return 0;
 430 }
 431
 432 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 433 {
 434     ERRP_GUARD();
 435     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 436     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 437     size_t config_size;
 438     int retries;
 439     int i, ret;
 440
 441     if (!s->chardev.chr) {
 442         error_setg(errp, "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, "invalid number of IO queues");
 451         return;
 452     }
 453
 454     if (!s->queue_size) {
 455         error_setg(errp, "queue size must be non-zero");
 456         return;
 457     }
 458     if (s->queue_size > VIRTQUEUE_MAX_SIZE) {
 459         error_setg(errp, "queue size must not exceed %d",
 460                    VIRTQUEUE_MAX_SIZE);
 461         return;
 462     }
 463
 464     if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
 465         return;
 466     }
 467
 468     config_size = virtio_get_config_size(&virtio_blk_cfg_size_params,
 469                                          vdev->host_features);
 470     virtio_init(vdev, VIRTIO_ID_BLOCK, config_size);
 471
 472     s->virtqs = g_new(VirtQueue *, s->num_queues);
 473     for (i = 0; i < s->num_queues; i++) {
 474         s->virtqs[i] = virtio_add_queue(vdev, s->queue_size,
 475                                         vhost_user_blk_handle_output);
 476     }
 477
 478     s->inflight = g_new0(struct vhost_inflight, 1);
 479     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
 480
 481     retries = VU_REALIZE_CONN_RETRIES;
 482     assert(!*errp);
 483     do {
 484         if (*errp) {
 485             error_prepend(errp, "Reconnecting after error: ");
 486             error_report_err(*errp);
 487             *errp = NULL;
 488         }
 489         ret = vhost_user_blk_realize_connect(s, errp);
 490     } while (ret < 0 && retries--);
 491
 492     if (ret < 0) {
 493         goto virtio_err;
 494     }
 495
 496     /* we're fully initialized, now we can operate, so add the handler */
 497     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL,
 498                              vhost_user_blk_event, NULL, (void *)dev,
 499                              NULL, true);
 500     return;
 501
 502 virtio_err:
 503     g_free(s->vhost_vqs);
 504     s->vhost_vqs = NULL;
 505     g_free(s->inflight);
 506     s->inflight = NULL;
 507     for (i = 0; i < s->num_queues; i++) {
 508         virtio_delete_queue(s->virtqs[i]);
 509     }
 510     g_free(s->virtqs);
 511     virtio_cleanup(vdev);
 512     vhost_user_cleanup(&s->vhost_user);
 513 }
 514
 515 static void vhost_user_blk_device_unrealize(DeviceState *dev)
 516 {
 517     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 518     VHostUserBlk *s = VHOST_USER_BLK(dev);
 519     int i;
 520
 521     virtio_set_status(vdev, 0);
 522     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, NULL,
 523                              NULL, NULL, NULL, false);
 524     vhost_dev_cleanup(&s->dev);
 525     vhost_dev_free_inflight(s->inflight);
 526     g_free(s->vhost_vqs);
 527     s->vhost_vqs = NULL;
 528     g_free(s->inflight);
 529     s->inflight = NULL;
 530
 531     for (i = 0; i < s->num_queues; i++) {
 532         virtio_delete_queue(s->virtqs[i]);
 533     }
 534     g_free(s->virtqs);
 535     virtio_cleanup(vdev);
 536     vhost_user_cleanup(&s->vhost_user);
 537 }
 538
 539 static void vhost_user_blk_instance_init(Object *obj)
 540 {
 541     VHostUserBlk *s = VHOST_USER_BLK(obj);
 542
 543     device_add_bootindex_property(obj, &s->bootindex, "bootindex",
 544                                   "/disk@0,0", DEVICE(obj));
 545 }
 546
 547 static struct vhost_dev *vhost_user_blk_get_vhost(VirtIODevice *vdev)
 548 {
 549     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 550     return &s->dev;
 551 }
 552
 553 static const VMStateDescription vmstate_vhost_user_blk = {
 554     .name = "vhost-user-blk",
 555     .minimum_version_id = 1,
 556     .version_id = 1,
 557     .fields = (const VMStateField[]) {
 558         VMSTATE_VIRTIO_DEVICE,
 559         VMSTATE_END_OF_LIST()
 560     },
 561 };
 562
 563 static Property vhost_user_blk_properties[] = {
 564     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
 565     DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
 566                        VHOST_USER_BLK_AUTO_NUM_QUEUES),
 567     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
 568     DEFINE_PROP_BIT64("config-wce", VHostUserBlk, parent_obj.host_features,
 569                       VIRTIO_BLK_F_CONFIG_WCE, true),
 570     DEFINE_PROP_BIT64("discard", VHostUserBlk, parent_obj.host_features,
 571                       VIRTIO_BLK_F_DISCARD, true),
 572     DEFINE_PROP_BIT64("write-zeroes", VHostUserBlk, parent_obj.host_features,
 573                       VIRTIO_BLK_F_WRITE_ZEROES, true),
 574     DEFINE_PROP_END_OF_LIST(),
 575 };
 576
 577 static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
 578 {
 579     DeviceClass *dc = DEVICE_CLASS(klass);
 580     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 581
 582     device_class_set_props(dc, vhost_user_blk_properties);
 583     dc->vmsd = &vmstate_vhost_user_blk;
 584     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 585     vdc->realize = vhost_user_blk_device_realize;
 586     vdc->unrealize = vhost_user_blk_device_unrealize;
 587     vdc->get_config = vhost_user_blk_update_config;
 588     vdc->set_config = vhost_user_blk_set_config;
 589     vdc->get_features = vhost_user_blk_get_features;
 590     vdc->set_status = vhost_user_blk_set_status;
 591     vdc->reset = vhost_user_blk_reset;
 592     vdc->get_vhost = vhost_user_blk_get_vhost;
 593 }
 594
 595 static const TypeInfo vhost_user_blk_info = {
 596     .name = TYPE_VHOST_USER_BLK,
 597     .parent = TYPE_VIRTIO_DEVICE,
 598     .instance_size = sizeof(VHostUserBlk),
 599     .instance_init = vhost_user_blk_instance_init,
 600     .class_init = vhost_user_blk_class_init,
 601 };
 602
 603 static void virtio_register_types(void)
 604 {
 605     type_register_static(&vhost_user_blk_info);
 606 }
 607
 608 type_init(virtio_register_types)