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 -1;
 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_SEG_MAX);
 256     virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
 257     virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
 258     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
 259     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
 260     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
 261     virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
 262     virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
 263
 264     if (s->config_wce) {
 265         virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
 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 (s->dev.started) {
 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     s->connected = true;
 330
 331     s->dev.num_queues = s->num_queues;
 332     s->dev.nvqs = s->num_queues;
 333     s->dev.vqs = s->vhost_vqs;
 334     s->dev.vq_index = 0;
 335     s->dev.backend_features = 0;
 336
 337     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
 338
 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     /* restore vhost state */
 346     if (virtio_device_started(vdev, vdev->status)) {
 347         ret = vhost_user_blk_start(vdev, errp);
 348         if (ret < 0) {
 349             return ret;
 350         }
 351     }
 352
 353     return 0;
 354 }
 355
 356 static void vhost_user_blk_disconnect(DeviceState *dev)
 357 {
 358     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 359     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 360
 361     if (!s->connected) {
 362         return;
 363     }
 364     s->connected = false;
 365
 366     vhost_user_blk_stop(vdev);
 367
 368     vhost_dev_cleanup(&s->dev);
 369 }
 370
 371 static void vhost_user_blk_chr_closed_bh(void *opaque)
 372 {
 373     DeviceState *dev = opaque;
 374     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 375     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 376
 377     vhost_user_blk_disconnect(dev);
 378     qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
 379                              NULL, opaque, NULL, true);
 380 }
 381
 382 static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
 383 {
 384     DeviceState *dev = opaque;
 385     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 386     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 387     Error *local_err = NULL;
 388
 389     switch (event) {
 390     case CHR_EVENT_OPENED:
 391         if (vhost_user_blk_connect(dev, &local_err) < 0) {
 392             error_report_err(local_err);
 393             qemu_chr_fe_disconnect(&s->chardev);
 394             return;
 395         }
 396         break;
 397     case CHR_EVENT_CLOSED:
 398         if (!runstate_check(RUN_STATE_SHUTDOWN)) {
 399             /*
 400              * A close event may happen during a read/write, but vhost
 401              * code assumes the vhost_dev remains setup, so delay the
 402              * stop & clear.
 403              */
 404             AioContext *ctx = qemu_get_current_aio_context();
 405
 406             qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL,
 407                     NULL, NULL, false);
 408             aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque);
 409
 410             /*
 411              * Move vhost device to the stopped state. The vhost-user device
 412              * will be clean up and disconnected in BH. This can be useful in
 413              * the vhost migration code. If disconnect was caught there is an
 414              * option for the general vhost code to get the dev state without
 415              * knowing its type (in this case vhost-user).
 416              */
 417             s->dev.started = false;
 418         }
 419         break;
 420     case CHR_EVENT_BREAK:
 421     case CHR_EVENT_MUX_IN:
 422     case CHR_EVENT_MUX_OUT:
 423         /* Ignore */
 424         break;
 425     }
 426 }
 427
 428 static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp)
 429 {
 430     DeviceState *dev = &s->parent_obj.parent_obj;
 431     int ret;
 432
 433     s->connected = false;
 434
 435     ret = qemu_chr_fe_wait_connected(&s->chardev, errp);
 436     if (ret < 0) {
 437         return ret;
 438     }
 439
 440     ret = vhost_user_blk_connect(dev, errp);
 441     if (ret < 0) {
 442         qemu_chr_fe_disconnect(&s->chardev);
 443         return ret;
 444     }
 445     assert(s->connected);
 446
 447     ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
 448                                sizeof(struct virtio_blk_config), errp);
 449     if (ret < 0) {
 450         qemu_chr_fe_disconnect(&s->chardev);
 451         vhost_dev_cleanup(&s->dev);
 452         return ret;
 453     }
 454
 455     return 0;
 456 }
 457
 458 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 459 {
 460     ERRP_GUARD();
 461     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 462     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 463     int retries;
 464     int i, ret;
 465
 466     if (!s->chardev.chr) {
 467         error_setg(errp, "chardev is mandatory");
 468         return;
 469     }
 470
 471     if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
 472         s->num_queues = 1;
 473     }
 474     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
 475         error_setg(errp, "invalid number of IO queues");
 476         return;
 477     }
 478
 479     if (!s->queue_size) {
 480         error_setg(errp, "queue size must be non-zero");
 481         return;
 482     }
 483     if (s->queue_size > VIRTQUEUE_MAX_SIZE) {
 484         error_setg(errp, "queue size must not exceed %d",
 485                    VIRTQUEUE_MAX_SIZE);
 486         return;
 487     }
 488
 489     if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
 490         return;
 491     }
 492
 493     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
 494                 sizeof(struct virtio_blk_config));
 495
 496     s->virtqs = g_new(VirtQueue *, s->num_queues);
 497     for (i = 0; i < s->num_queues; i++) {
 498         s->virtqs[i] = virtio_add_queue(vdev, s->queue_size,
 499                                         vhost_user_blk_handle_output);
 500     }
 501
 502     s->inflight = g_new0(struct vhost_inflight, 1);
 503     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
 504
 505     retries = REALIZE_CONNECTION_RETRIES;
 506     assert(!*errp);
 507     do {
 508         if (*errp) {
 509             error_prepend(errp, "Reconnecting after error: ");
 510             error_report_err(*errp);
 511             *errp = NULL;
 512         }
 513         ret = vhost_user_blk_realize_connect(s, errp);
 514     } while (ret == -EPROTO && retries--);
 515
 516     if (ret < 0) {
 517         goto virtio_err;
 518     }
 519
 520     /* we're fully initialized, now we can operate, so add the handler */
 521     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL,
 522                              vhost_user_blk_event, NULL, (void *)dev,
 523                              NULL, true);
 524     return;
 525
 526 virtio_err:
 527     g_free(s->vhost_vqs);
 528     s->vhost_vqs = NULL;
 529     g_free(s->inflight);
 530     s->inflight = NULL;
 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_device_unrealize(DeviceState *dev)
 540 {
 541     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 542     VHostUserBlk *s = VHOST_USER_BLK(dev);
 543     int i;
 544
 545     virtio_set_status(vdev, 0);
 546     qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, NULL,
 547                              NULL, NULL, NULL, false);
 548     vhost_dev_cleanup(&s->dev);
 549     vhost_dev_free_inflight(s->inflight);
 550     g_free(s->vhost_vqs);
 551     s->vhost_vqs = NULL;
 552     g_free(s->inflight);
 553     s->inflight = NULL;
 554
 555     for (i = 0; i < s->num_queues; i++) {
 556         virtio_delete_queue(s->virtqs[i]);
 557     }
 558     g_free(s->virtqs);
 559     virtio_cleanup(vdev);
 560     vhost_user_cleanup(&s->vhost_user);
 561 }
 562
 563 static void vhost_user_blk_instance_init(Object *obj)
 564 {
 565     VHostUserBlk *s = VHOST_USER_BLK(obj);
 566
 567     device_add_bootindex_property(obj, &s->bootindex, "bootindex",
 568                                   "/disk@0,0", DEVICE(obj));
 569 }
 570
 571 static const VMStateDescription vmstate_vhost_user_blk = {
 572     .name = "vhost-user-blk",
 573     .minimum_version_id = 1,
 574     .version_id = 1,
 575     .fields = (VMStateField[]) {
 576         VMSTATE_VIRTIO_DEVICE,
 577         VMSTATE_END_OF_LIST()
 578     },
 579 };
 580
 581 static Property vhost_user_blk_properties[] = {
 582     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
 583     DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
 584                        VHOST_USER_BLK_AUTO_NUM_QUEUES),
 585     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
 586     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
 587     DEFINE_PROP_END_OF_LIST(),
 588 };
 589
 590 static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
 591 {
 592     DeviceClass *dc = DEVICE_CLASS(klass);
 593     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 594
 595     device_class_set_props(dc, vhost_user_blk_properties);
 596     dc->vmsd = &vmstate_vhost_user_blk;
 597     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 598     vdc->realize = vhost_user_blk_device_realize;
 599     vdc->unrealize = vhost_user_blk_device_unrealize;
 600     vdc->get_config = vhost_user_blk_update_config;
 601     vdc->set_config = vhost_user_blk_set_config;
 602     vdc->get_features = vhost_user_blk_get_features;
 603     vdc->set_status = vhost_user_blk_set_status;
 604     vdc->reset = vhost_user_blk_reset;
 605 }
 606
 607 static const TypeInfo vhost_user_blk_info = {
 608     .name = TYPE_VHOST_USER_BLK,
 609     .parent = TYPE_VIRTIO_DEVICE,
 610     .instance_size = sizeof(VHostUserBlk),
 611     .instance_init = vhost_user_blk_instance_init,
 612     .class_init = vhost_user_blk_class_init,
 613 };
 614
 615 static void virtio_register_types(void)
 616 {
 617     type_register_static(&vhost_user_blk_info);
 618 }
 619
 620 type_init(virtio_register_types)