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 #define REALIZE_CONNECTION_RETRIES 3
  35
  36 static const int user_feature_bits[] = {
  37     VIRTIO_BLK_F_SIZE_MAX,
  38     VIRTIO_BLK_F_SEG_MAX,
  39     VIRTIO_BLK_F_GEOMETRY,
  40     VIRTIO_BLK_F_BLK_SIZE,
  41     VIRTIO_BLK_F_TOPOLOGY,
  42     VIRTIO_BLK_F_MQ,
  43     VIRTIO_BLK_F_RO,
  44     VIRTIO_BLK_F_FLUSH,
  45     VIRTIO_BLK_F_CONFIG_WCE,
  46     VIRTIO_BLK_F_DISCARD,
  47     VIRTIO_BLK_F_WRITE_ZEROES,
  48     VIRTIO_F_VERSION_1,
  49     VIRTIO_RING_F_INDIRECT_DESC,
  50     VIRTIO_RING_F_EVENT_IDX,
  51     VIRTIO_F_NOTIFY_ON_EMPTY,
  52     VIRTIO_F_RING_PACKED,
  53     VIRTIO_F_IOMMU_PLATFORM,
  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, sizeof(struct virtio_blk_config));
  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_MASTER);
  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     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
  96     Error *local_err = NULL;
  97
  98     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
  99                                sizeof(struct virtio_blk_config),
 100                                &local_err);
 101     if (ret < 0) {
 102         error_report_err(local_err);
 103         return ret;
 104     }
 105
 106     /* valid for resize only */
 107     if (blkcfg.capacity != s->blkcfg.capacity) {
 108         s->blkcfg.capacity = blkcfg.capacity;
 109         memcpy(dev->vdev->config, &s->blkcfg, sizeof(struct virtio_blk_config));
 110         virtio_notify_config(dev->vdev);
 111     }
 112
 113     return 0;
 114 }
 115
 116 const VhostDevConfigOps blk_ops = {
 117     .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
 118 };
 119
 120 static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
 121 {
 122     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 123     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 124     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 125     int i, ret;
 126
 127     if (!k->set_guest_notifiers) {
 128         error_setg(errp, "binding does not support guest notifiers");
 129         return -ENOSYS;
 130     }
 131
 132     ret = vhost_dev_enable_notifiers(&s->dev, vdev);
 133     if (ret < 0) {
 134         error_setg_errno(errp, -ret, "Error enabling host notifiers");
 135         return ret;
 136     }
 137
 138     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
 139     if (ret < 0) {
 140         error_setg_errno(errp, -ret, "Error binding guest notifier");
 141         goto err_host_notifiers;
 142     }
 143
 144     s->dev.acked_features = vdev->guest_features;
 145
 146     ret = vhost_dev_prepare_inflight(&s->dev, vdev);
 147     if (ret < 0) {
 148         error_setg_errno(errp, -ret, "Error setting inflight format");
 149         goto err_guest_notifiers;
 150     }
 151
 152     if (!s->inflight->addr) {
 153         ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
 154         if (ret < 0) {
 155             error_setg_errno(errp, -ret, "Error getting inflight");
 156             goto err_guest_notifiers;
 157         }
 158     }
 159
 160     ret = vhost_dev_set_inflight(&s->dev, s->inflight);
 161     if (ret < 0) {
 162         error_setg_errno(errp, -ret, "Error setting inflight");
 163         goto err_guest_notifiers;
 164     }
 165
 166     ret = vhost_dev_start(&s->dev, vdev);
 167     if (ret < 0) {
 168         error_setg_errno(errp, -ret, "Error starting vhost");
 169         goto err_guest_notifiers;
 170     }
 171     s->started_vu = true;
 172
 173     /* guest_notifier_mask/pending not used yet, so just unmask
 174      * everything here. virtio-pci will do the right thing by
 175      * enabling/disabling irqfd.
 176      */
 177     for (i = 0; i < s->dev.nvqs; i++) {
 178         vhost_virtqueue_mask(&s->dev, vdev, i, false);
 179     }
 180
 181     return ret;
 182
 183 err_guest_notifiers:
 184     k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 185 err_host_notifiers:
 186     vhost_dev_disable_notifiers(&s->dev, vdev);
 187     return ret;
 188 }
 189
 190 static void vhost_user_blk_stop(VirtIODevice *vdev)
 191 {
 192     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 193     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 194     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 195     int ret;
 196
 197     if (!s->started_vu) {
 198         return;
 199     }
 200     s->started_vu = false;
 201
 202     if (!k->set_guest_notifiers) {
 203         return;
 204     }
 205
 206     vhost_dev_stop(&s->dev, vdev);
 207
 208     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
 209     if (ret < 0) {
 210         error_report("vhost guest notifier cleanup failed: %d", ret);
 211         return;
 212     }
 213
 214     vhost_dev_disable_notifiers(&s->dev, vdev);
 215 }
 216
 217 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 218 {
 219     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 220     bool should_start = virtio_device_started(vdev, status);
 221     Error *local_err = NULL;
 222     int ret;
 223
 224     if (!vdev->vm_running) {
 225         should_start = false;
 226     }
 227
 228     if (!s->connected) {
 229         return;
 230     }
 231
 232     if (s->dev.started == should_start) {
 233         return;
 234     }
 235
 236     if (should_start) {
 237         ret = vhost_user_blk_start(vdev, &local_err);
 238         if (ret < 0) {
 239             error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
 240             qemu_chr_fe_disconnect(&s->chardev);
 241         }
 242     } else {
 243         vhost_user_blk_stop(vdev);
 244     }
 245
 246 }
 247
 248 static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
 249                                             uint64_t features,
 250                                             Error **errp)
 251 {
 252     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 253
 254     /* Turn on pre-defined features */
 255     virtio_add_feature(&features, VIRTIO_BLK_F_SIZE_MAX);
 256     virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
 257     virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
 258     virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
 259     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
 260     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
 261     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
 262     virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
 263     virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
 264
 265     if (s->config_wce) {
 266         virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
 267     }
 268     if (s->num_queues > 1) {
 269         virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
 270     }
 271
 272     return vhost_get_features(&s->dev, user_feature_bits, features);
 273 }
 274
 275 static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 276 {
 277     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 278     Error *local_err = NULL;
 279     int i, ret;
 280
 281     if (!vdev->start_on_kick) {
 282         return;
 283     }
 284
 285     if (!s->connected) {
 286         return;
 287     }
 288
 289     if (s->dev.started) {
 290         return;
 291     }
 292
 293     /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
 294      * vhost here instead of waiting for .set_status().
 295      */
 296     ret = vhost_user_blk_start(vdev, &local_err);
 297     if (ret < 0) {
 298         error_reportf_err(local_err, "vhost-user-blk: vhost start failed: ");
 299         qemu_chr_fe_disconnect(&s->chardev);
 300         return;
 301     }
 302
 303     /* Kick right away to begin processing requests already in vring */
 304     for (i = 0; i < s->dev.nvqs; i++) {
 305         VirtQueue *kick_vq = virtio_get_queue(vdev, i);
 306
 307         if (!virtio_queue_get_desc_addr(vdev, i)) {
 308             continue;
 309         }
 310         event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
 311     }
 312 }
 313
 314 static void vhost_user_blk_reset(VirtIODevice *vdev)
 315 {
 316     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 317
 318     vhost_dev_free_inflight(s->inflight);
 319 }
 320
 321 static int vhost_user_blk_connect(DeviceState *dev, Error **errp)
 322 {
 323     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 324     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 325     int ret = 0;
 326
 327     if (s->connected) {
 328         return 0;
 329     }
 330     s->connected = true;
 331
 332     s->dev.num_queues = s->num_queues;
 333     s->dev.nvqs = s->num_queues;
 334     s->dev.vqs = s->vhost_vqs;
 335     s->dev.vq_index = 0;
 336     s->dev.backend_features = 0;
 337
 338     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 339
 340     ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
 341                          errp);
 342     if (ret < 0) {
 343         return ret;
 344     }
 345
 346     /* restore vhost state */
 347     if (virtio_device_started(vdev, vdev->status)) {
 348         ret = vhost_user_blk_start(vdev, errp);
 349         if (ret < 0) {
 350             return ret;
 351         }
 352     }
 353
 354     return 0;
 355 }
 356
 357 static void vhost_user_blk_disconnect(DeviceState *dev)
 358 {
 359     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 360     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 361
 362     if (!s->connected) {
 363         return;
 364     }
 365     s->connected = false;
 366
 367     vhost_user_blk_stop(vdev);
 368
 369     vhost_dev_cleanup(&s->dev);
 370 }
 371
 372 static void vhost_user_blk_chr_closed_bh(void *opaque)
 373 {
 374     DeviceState *dev = opaque;
 375     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 376     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 377
 378     vhost_user_blk_disconnect(dev);
 379     qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
 380                              NULL, opaque, NULL, true);
 381 }
 382
 383 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
 384 {
 385     DeviceState *dev = opaque;
 386     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 387     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 388     Error *local_err = NULL;
 389
 390     switch (event) {
 391     case CHR_EVENT_OPENED:
 392         if (vhost_user_blk_connect(dev, &local_err) < 0) {
 393             error_report_err(local_err);
 394             qemu_chr_fe_disconnect(&s->chardev);
 395             return;
 396         }
 397         break;
 398     case CHR_EVENT_CLOSED:
 399         if (!runstate_check(RUN_STATE_SHUTDOWN)) {
 400             /*
 401              * A close event may happen during a read/write, but vhost
 402              * code assumes the vhost_dev remains setup, so delay the
 403              * stop & clear.
 404              */
 405             AioContext *ctx = qemu_get_current_aio_context();
 406
 407             qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL,
 408                     NULL, NULL, false);
 409             aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque);
 410
 411             /*
 412              * Move vhost device to the stopped state. The vhost-user device
 413              * will be clean up and disconnected in BH. This can be useful in
 414              * the vhost migration code. If disconnect was caught there is an
 415              * option for the general vhost code to get the dev state without
 416              * knowing its type (in this case vhost-user).
 417              */
 418             s->dev.started = false;
 419         }
 420         break;
 421     case CHR_EVENT_BREAK:
 422     case CHR_EVENT_MUX_IN:
 423     case CHR_EVENT_MUX_OUT:
 424         /* Ignore */
 425         break;
 426     }
 427 }
 428
 429 static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp)
 430 {
 431     DeviceState *dev = &s->parent_obj.parent_obj;
 432     int ret;
 433
 434     s->connected = false;
 435
 436     ret = qemu_chr_fe_wait_connected(&s->chardev, errp);
 437     if (ret < 0) {
 438         return ret;
 439     }
 440
 441     ret = vhost_user_blk_connect(dev, errp);
 442     if (ret < 0) {
 443         qemu_chr_fe_disconnect(&s->chardev);
 444         return ret;
 445     }
 446     assert(s->connected);
 447
 448     ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
 449                                sizeof(struct virtio_blk_config), errp);
 450     if (ret < 0) {
 451         qemu_chr_fe_disconnect(&s->chardev);
 452         vhost_dev_cleanup(&s->dev);
 453         return ret;
 454     }
 455
 456     return 0;
 457 }
 458
 459 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 460 {
 461     ERRP_GUARD();
 462     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 463     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 464     int retries;
 465     int i, ret;
 466
 467     if (!s->chardev.chr) {
 468         error_setg(errp, "chardev is mandatory");
 469         return;
 470     }
 471
 472     if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
 473         s->num_queues = 1;
 474     }
 475     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
 476         error_setg(errp, "invalid number of IO queues");
 477         return;
 478     }
 479
 480     if (!s->queue_size) {
 481         error_setg(errp, "queue size must be non-zero");
 482         return;
 483     }
 484     if (s->queue_size > VIRTQUEUE_MAX_SIZE) {
 485         error_setg(errp, "queue size must not exceed %d",
 486                    VIRTQUEUE_MAX_SIZE);
 487         return;
 488     }
 489
 490     if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
 491         return;
 492     }
 493
 494     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
 495                 sizeof(struct virtio_blk_config));
 496
 497     s->virtqs = g_new(VirtQueue *, s->num_queues);
 498     for (i = 0; i < s->num_queues; i++) {
 499         s->virtqs[i] = virtio_add_queue(vdev, s->queue_size,
 500                                         vhost_user_blk_handle_output);
 501     }
 502
 503     s->inflight = g_new0(struct vhost_inflight, 1);
 504     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
 505
 506     retries = REALIZE_CONNECTION_RETRIES;
 507     assert(!*errp);
 508     do {
 509         if (*errp) {
 510             error_prepend(errp, "Reconnecting after error: ");
 511             error_report_err(*errp);
 512             *errp = NULL;
 513         }
 514         ret = vhost_user_blk_realize_connect(s, errp);
 515     } while (ret < 0 && retries--);
 516
 517     if (ret < 0) {
 518         goto virtio_err;
 519     }
 520
 521     /* we're fully initialized, now we can operate, so add the handler */
 522     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL,
 523                              vhost_user_blk_event, NULL, (void *)dev,
 524                              NULL, true);
 525     return;
 526
 527 virtio_err:
 528     g_free(s->vhost_vqs);
 529     s->vhost_vqs = NULL;
 530     g_free(s->inflight);
 531     s->inflight = NULL;
 532     for (i = 0; i < s->num_queues; i++) {
 533         virtio_delete_queue(s->virtqs[i]);
 534     }
 535     g_free(s->virtqs);
 536     virtio_cleanup(vdev);
 537     vhost_user_cleanup(&s->vhost_user);
 538 }
 539
 540 static void vhost_user_blk_device_unrealize(DeviceState *dev)
 541 {
 542     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 543     VHostUserBlk *s = VHOST_USER_BLK(dev);
 544     int i;
 545
 546     virtio_set_status(vdev, 0);
 547     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, NULL,
 548                              NULL, NULL, NULL, false);
 549     vhost_dev_cleanup(&s->dev);
 550     vhost_dev_free_inflight(s->inflight);
 551     g_free(s->vhost_vqs);
 552     s->vhost_vqs = NULL;
 553     g_free(s->inflight);
 554     s->inflight = NULL;
 555
 556     for (i = 0; i < s->num_queues; i++) {
 557         virtio_delete_queue(s->virtqs[i]);
 558     }
 559     g_free(s->virtqs);
 560     virtio_cleanup(vdev);
 561     vhost_user_cleanup(&s->vhost_user);
 562 }
 563
 564 static void vhost_user_blk_instance_init(Object *obj)
 565 {
 566     VHostUserBlk *s = VHOST_USER_BLK(obj);
 567
 568     device_add_bootindex_property(obj, &s->bootindex, "bootindex",
 569                                   "/disk@0,0", DEVICE(obj));
 570 }
 571
 572 static const VMStateDescription vmstate_vhost_user_blk = {
 573     .name = "vhost-user-blk",
 574     .minimum_version_id = 1,
 575     .version_id = 1,
 576     .fields = (VMStateField[]) {
 577         VMSTATE_VIRTIO_DEVICE,
 578         VMSTATE_END_OF_LIST()
 579     },
 580 };
 581
 582 static Property vhost_user_blk_properties[] = {
 583     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
 584     DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
 585                        VHOST_USER_BLK_AUTO_NUM_QUEUES),
 586     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
 587     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
 588     DEFINE_PROP_END_OF_LIST(),
 589 };
 590
 591 static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
 592 {
 593     DeviceClass *dc = DEVICE_CLASS(klass);
 594     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 595
 596     device_class_set_props(dc, vhost_user_blk_properties);
 597     dc->vmsd = &vmstate_vhost_user_blk;
 598     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 599     vdc->realize = vhost_user_blk_device_realize;
 600     vdc->unrealize = vhost_user_blk_device_unrealize;
 601     vdc->get_config = vhost_user_blk_update_config;
 602     vdc->set_config = vhost_user_blk_set_config;
 603     vdc->get_features = vhost_user_blk_get_features;
 604     vdc->set_status = vhost_user_blk_set_status;
 605     vdc->reset = vhost_user_blk_reset;
 606 }
 607
 608 static const TypeInfo vhost_user_blk_info = {
 609     .name = TYPE_VHOST_USER_BLK,
 610     .parent = TYPE_VIRTIO_DEVICE,
 611     .instance_size = sizeof(VHostUserBlk),
 612     .instance_init = vhost_user_blk_instance_init,
 613     .class_init = vhost_user_blk_class_init,
 614 };
 615
 616 static void virtio_register_types(void)
 617 {
 618     type_register_static(&vhost_user_blk_info);
 619 }
 620
 621 type_init(virtio_register_types)