hw/block/xen-block.c

   1 /*
   2  * Copyright (c) 2018  Citrix Systems Inc.
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  */
   7
   8 #include "qemu/osdep.h"
   9 #include "qemu/cutils.h"
  10 #include "qemu/option.h"
  11 #include "qapi/error.h"
  12 #include "qapi/qapi-commands-block-core.h"
  13 #include "qapi/qapi-commands-misc.h"
  14 #include "qapi/qapi-visit-block-core.h"
  15 #include "qapi/qobject-input-visitor.h"
  16 #include "qapi/visitor.h"
  17 #include "qapi/qmp/qdict.h"
  18 #include "qapi/qmp/qstring.h"
  19 #include "hw/hw.h"
  20 #include "hw/xen/xen_common.h"
  21 #include "hw/block/xen_blkif.h"
  22 #include "hw/xen/xen-block.h"
  23 #include "hw/xen/xen-backend.h"
  24 #include "sysemu/blockdev.h"
  25 #include "sysemu/block-backend.h"
  26 #include "sysemu/iothread.h"
  27 #include "dataplane/xen-block.h"
  28 #include "trace.h"
  29
  30 static char *xen_block_get_name(XenDevice *xendev, Error **errp)
  31 {
  32     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  33     XenBlockVdev *vdev = &blockdev->props.vdev;
  34
  35     return g_strdup_printf("%lu", vdev->number);
  36 }
  37
  38 static void xen_block_disconnect(XenDevice *xendev, Error **errp)
  39 {
  40     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  41     const char *type = object_get_typename(OBJECT(blockdev));
  42     XenBlockVdev *vdev = &blockdev->props.vdev;
  43
  44     trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
  45
  46     xen_block_dataplane_stop(blockdev->dataplane);
  47 }
  48
  49 static void xen_block_connect(XenDevice *xendev, Error **errp)
  50 {
  51     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  52     const char *type = object_get_typename(OBJECT(blockdev));
  53     XenBlockVdev *vdev = &blockdev->props.vdev;
  54     unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
  55     char *str;
  56
  57     trace_xen_block_connect(type, vdev->disk, vdev->partition);
  58
  59     if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
  60                                   &order) != 1) {
  61         nr_ring_ref = 1;
  62         ring_ref = g_new(unsigned int, nr_ring_ref);
  63
  64         if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
  65                                       &ring_ref[0]) != 1) {
  66             error_setg(errp, "failed to read ring-ref");
  67             g_free(ring_ref);
  68             return;
  69         }
  70     } else if (order <= blockdev->props.max_ring_page_order) {
  71         unsigned int i;
  72
  73         nr_ring_ref = 1 << order;
  74         ring_ref = g_new(unsigned int, nr_ring_ref);
  75
  76         for (i = 0; i < nr_ring_ref; i++) {
  77             const char *key = g_strdup_printf("ring-ref%u", i);
  78
  79             if (xen_device_frontend_scanf(xendev, key, "%u",
  80                                           &ring_ref[i]) != 1) {
  81                 error_setg(errp, "failed to read %s", key);
  82                 g_free((gpointer)key);
  83                 g_free(ring_ref);
  84                 return;
  85             }
  86
  87             g_free((gpointer)key);
  88         }
  89     } else {
  90         error_setg(errp, "invalid ring-page-order (%d)", order);
  91         return;
  92     }
  93
  94     if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
  95                                   &event_channel) != 1) {
  96         error_setg(errp, "failed to read event-channel");
  97         g_free(ring_ref);
  98         return;
  99     }
 100
 101     if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
 102                                   &str) != 1) {
 103         protocol = BLKIF_PROTOCOL_NATIVE;
 104     } else {
 105         if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
 106             protocol = BLKIF_PROTOCOL_X86_32;
 107         } else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
 108             protocol = BLKIF_PROTOCOL_X86_64;
 109         } else {
 110             protocol = BLKIF_PROTOCOL_NATIVE;
 111         }
 112
 113         free(str);
 114     }
 115
 116     xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
 117                               event_channel, protocol, errp);
 118
 119     g_free(ring_ref);
 120 }
 121
 122 static void xen_block_unrealize(XenDevice *xendev, Error **errp)
 123 {
 124     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 125     XenBlockDeviceClass *blockdev_class =
 126         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
 127     const char *type = object_get_typename(OBJECT(blockdev));
 128     XenBlockVdev *vdev = &blockdev->props.vdev;
 129
 130     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
 131         return;
 132     }
 133
 134     trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
 135
 136     /* Disconnect from the frontend in case this has not already happened */
 137     xen_block_disconnect(xendev, NULL);
 138
 139     xen_block_dataplane_destroy(blockdev->dataplane);
 140     blockdev->dataplane = NULL;
 141
 142     if (blockdev_class->unrealize) {
 143         blockdev_class->unrealize(blockdev, errp);
 144     }
 145 }
 146
 147 static void xen_block_set_size(XenBlockDevice *blockdev)
 148 {
 149     const char *type = object_get_typename(OBJECT(blockdev));
 150     XenBlockVdev *vdev = &blockdev->props.vdev;
 151     BlockConf *conf = &blockdev->props.conf;
 152     int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
 153     XenDevice *xendev = XEN_DEVICE(blockdev);
 154
 155     trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
 156
 157     xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
 158 }
 159
 160 static void xen_block_resize_cb(void *opaque)
 161 {
 162     XenBlockDevice *blockdev = opaque;
 163     XenDevice *xendev = XEN_DEVICE(blockdev);
 164     enum xenbus_state state = xen_device_backend_get_state(xendev);
 165
 166     xen_block_set_size(blockdev);
 167
 168     /*
 169      * Mimic the behaviour of Linux xen-blkback and re-write the state
 170      * to trigger the frontend watch.
 171      */
 172     xen_device_backend_printf(xendev, "state", "%u", state);
 173 }
 174
 175 static const BlockDevOps xen_block_dev_ops = {
 176     .resize_cb = xen_block_resize_cb,
 177 };
 178
 179 static void xen_block_realize(XenDevice *xendev, Error **errp)
 180 {
 181     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 182     XenBlockDeviceClass *blockdev_class =
 183         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
 184     const char *type = object_get_typename(OBJECT(blockdev));
 185     XenBlockVdev *vdev = &blockdev->props.vdev;
 186     BlockConf *conf = &blockdev->props.conf;
 187     Error *local_err = NULL;
 188
 189     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
 190         error_setg(errp, "vdev property not set");
 191         return;
 192     }
 193
 194     trace_xen_block_realize(type, vdev->disk, vdev->partition);
 195
 196     if (blockdev_class->realize) {
 197         blockdev_class->realize(blockdev, &local_err);
 198         if (local_err) {
 199             error_propagate(errp, local_err);
 200             return;
 201         }
 202     }
 203
 204     /*
 205      * The blkif protocol does not deal with removable media, so it must
 206      * always be present, even for CDRom devices.
 207      */
 208     assert(conf->blk);
 209     if (!blk_is_inserted(conf->blk)) {
 210         error_setg(errp, "device needs media, but drive is empty");
 211         return;
 212     }
 213
 214     if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
 215                                        true, errp)) {
 216         return;
 217     }
 218
 219     if (!(blockdev->info & VDISK_CDROM) &&
 220         !blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
 221         return;
 222     }
 223
 224     blkconf_blocksizes(conf);
 225
 226     if (conf->logical_block_size > conf->physical_block_size) {
 227         error_setg(
 228             errp, "logical_block_size > physical_block_size not supported");
 229         return;
 230     }
 231
 232     blk_set_dev_ops(conf->blk, &xen_block_dev_ops, blockdev);
 233     blk_set_guest_block_size(conf->blk, conf->logical_block_size);
 234
 235     if (conf->discard_granularity > 0) {
 236         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
 237     }
 238
 239     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
 240     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
 241                               blockdev->props.max_ring_page_order);
 242     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
 243
 244     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
 245                                vdev->number);
 246     xen_device_frontend_printf(xendev, "device-type", "%s",
 247                                blockdev->device_type);
 248
 249     xen_device_backend_printf(xendev, "sector-size", "%u",
 250                               conf->logical_block_size);
 251
 252     xen_block_set_size(blockdev);
 253
 254     blockdev->dataplane =
 255         xen_block_dataplane_create(xendev, conf, blockdev->props.iothread);
 256 }
 257
 258 static void xen_block_frontend_changed(XenDevice *xendev,
 259                                        enum xenbus_state frontend_state,
 260                                        Error **errp)
 261 {
 262     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
 263     Error *local_err = NULL;
 264
 265     switch (frontend_state) {
 266     case XenbusStateInitialised:
 267     case XenbusStateConnected:
 268         if (backend_state == XenbusStateConnected) {
 269             break;
 270         }
 271
 272         xen_block_disconnect(xendev, &local_err);
 273         if (local_err) {
 274             error_propagate(errp, local_err);
 275             break;
 276         }
 277
 278         xen_block_connect(xendev, &local_err);
 279         if (local_err) {
 280             error_propagate(errp, local_err);
 281             break;
 282         }
 283
 284         xen_device_backend_set_state(xendev, XenbusStateConnected);
 285         break;
 286
 287     case XenbusStateClosing:
 288         xen_device_backend_set_state(xendev, XenbusStateClosing);
 289         break;
 290
 291     case XenbusStateClosed:
 292         xen_block_disconnect(xendev, &local_err);
 293         if (local_err) {
 294             error_propagate(errp, local_err);
 295             break;
 296         }
 297
 298         xen_device_backend_set_state(xendev, XenbusStateClosed);
 299         break;
 300
 301     default:
 302         break;
 303     }
 304 }
 305
 306 static char *disk_to_vbd_name(unsigned int disk)
 307 {
 308     char *name, *prefix = (disk >= 26) ?
 309         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
 310
 311     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
 312     g_free(prefix);
 313
 314     return name;
 315 }
 316
 317 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
 318                                void *opaque, Error **errp)
 319 {
 320     DeviceState *dev = DEVICE(obj);
 321     Property *prop = opaque;
 322     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
 323     char *str;
 324
 325     switch (vdev->type) {
 326     case XEN_BLOCK_VDEV_TYPE_DP:
 327         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
 328         break;
 329
 330     case XEN_BLOCK_VDEV_TYPE_XVD:
 331     case XEN_BLOCK_VDEV_TYPE_HD:
 332     case XEN_BLOCK_VDEV_TYPE_SD: {
 333         char *name = disk_to_vbd_name(vdev->disk);
 334
 335         str = g_strdup_printf("%s%s%lu",
 336                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
 337                               "xvd" :
 338                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
 339                               "hd" :
 340                               "sd",
 341                               name, vdev->partition);
 342         g_free(name);
 343         break;
 344     }
 345     default:
 346         error_setg(errp, "invalid vdev type");
 347         return;
 348     }
 349
 350     visit_type_str(v, name, &str, errp);
 351     g_free(str);
 352 }
 353
 354 static int vbd_name_to_disk(const char *name, const char **endp,
 355                             unsigned long *disk)
 356 {
 357     unsigned int n = 0;
 358
 359     while (*name != '\0') {
 360         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
 361             break;
 362         }
 363
 364         n *= 26;
 365         n += *name++ - 'a' + 1;
 366     }
 367     *endp = name;
 368
 369     if (!n) {
 370         return -1;
 371     }
 372
 373     *disk = n - 1;
 374
 375     return 0;
 376 }
 377
 378 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
 379                                void *opaque, Error **errp)
 380 {
 381     DeviceState *dev = DEVICE(obj);
 382     Property *prop = opaque;
 383     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
 384     Error *local_err = NULL;
 385     char *str, *p;
 386     const char *end;
 387
 388     if (dev->realized) {
 389         qdev_prop_set_after_realize(dev, name, errp);
 390         return;
 391     }
 392
 393     visit_type_str(v, name, &str, &local_err);
 394     if (local_err) {
 395         error_propagate(errp, local_err);
 396         return;
 397     }
 398
 399     p = strchr(str, 'd');
 400     if (!p) {
 401         goto invalid;
 402     }
 403
 404     *p++ = '\0';
 405     if (*str == '\0') {
 406         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
 407     } else if (strcmp(str, "xv") == 0) {
 408         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
 409     } else if (strcmp(str, "h") == 0) {
 410         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
 411     } else if (strcmp(str, "s") == 0) {
 412         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
 413     } else {
 414         goto invalid;
 415     }
 416
 417     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
 418         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
 419             goto invalid;
 420         }
 421
 422         if (*end == 'p') {
 423             if (*(++end) == '\0') {
 424                 goto invalid;
 425             }
 426         }
 427     } else {
 428         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
 429             goto invalid;
 430         }
 431     }
 432
 433     if (*end != '\0') {
 434         p = (char *)end;
 435
 436         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
 437             goto invalid;
 438         }
 439
 440         if (*end != '\0') {
 441             goto invalid;
 442         }
 443     } else {
 444         vdev->partition = 0;
 445     }
 446
 447     switch (vdev->type) {
 448     case XEN_BLOCK_VDEV_TYPE_DP:
 449     case XEN_BLOCK_VDEV_TYPE_XVD:
 450         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 451             vdev->number = (202 << 8) | (vdev->disk << 4) |
 452                 vdev->partition;
 453         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
 454             vdev->number = (1 << 28) | (vdev->disk << 8) |
 455                 vdev->partition;
 456         } else {
 457             goto invalid;
 458         }
 459         break;
 460
 461     case XEN_BLOCK_VDEV_TYPE_HD:
 462         if ((vdev->disk == 0 || vdev->disk == 1) &&
 463             vdev->partition < (1 << 6)) {
 464             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
 465         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
 466                    vdev->partition < (1 << 6)) {
 467             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
 468                 vdev->partition;
 469         } else {
 470             goto invalid;
 471         }
 472         break;
 473
 474     case XEN_BLOCK_VDEV_TYPE_SD:
 475         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 476             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
 477         } else {
 478             goto invalid;
 479         }
 480         break;
 481
 482     default:
 483         goto invalid;
 484     }
 485
 486     g_free(str);
 487     return;
 488
 489 invalid:
 490     error_setg(errp, "invalid virtual disk specifier");
 491
 492     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
 493     g_free(str);
 494 }
 495
 496 /*
 497  * This property deals with 'vdev' names adhering to the Xen VBD naming
 498  * scheme described in:
 499  *
 500  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
 501  */
 502 const PropertyInfo xen_block_prop_vdev = {
 503     .name  = "str",
 504     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
 505     .get = xen_block_get_vdev,
 506     .set = xen_block_set_vdev,
 507 };
 508
 509 static Property xen_block_props[] = {
 510     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
 511                 xen_block_prop_vdev, XenBlockVdev),
 512     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
 513     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
 514                        props.max_ring_page_order, 4),
 515     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
 516                      TYPE_IOTHREAD, IOThread *),
 517     DEFINE_PROP_END_OF_LIST()
 518 };
 519
 520 static void xen_block_class_init(ObjectClass *class, void *data)
 521 {
 522     DeviceClass *dev_class = DEVICE_CLASS(class);
 523     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
 524
 525     xendev_class->backend = "qdisk";
 526     xendev_class->device = "vbd";
 527     xendev_class->get_name = xen_block_get_name;
 528     xendev_class->realize = xen_block_realize;
 529     xendev_class->frontend_changed = xen_block_frontend_changed;
 530     xendev_class->unrealize = xen_block_unrealize;
 531
 532     dev_class->props = xen_block_props;
 533 }
 534
 535 static const TypeInfo xen_block_type_info = {
 536     .name = TYPE_XEN_BLOCK_DEVICE,
 537     .parent = TYPE_XEN_DEVICE,
 538     .instance_size = sizeof(XenBlockDevice),
 539     .abstract = true,
 540     .class_size = sizeof(XenBlockDeviceClass),
 541     .class_init = xen_block_class_init,
 542 };
 543
 544 static void xen_disk_unrealize(XenBlockDevice *blockdev, Error **errp)
 545 {
 546     trace_xen_disk_unrealize();
 547 }
 548
 549 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
 550 {
 551     BlockConf *conf = &blockdev->props.conf;
 552
 553     trace_xen_disk_realize();
 554
 555     blockdev->device_type = "disk";
 556
 557     if (!conf->blk) {
 558         error_setg(errp, "drive property not set");
 559         return;
 560     }
 561
 562     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
 563 }
 564
 565 static void xen_disk_class_init(ObjectClass *class, void *data)
 566 {
 567     DeviceClass *dev_class = DEVICE_CLASS(class);
 568     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 569
 570     blockdev_class->realize = xen_disk_realize;
 571     blockdev_class->unrealize = xen_disk_unrealize;
 572
 573     dev_class->desc = "Xen Disk Device";
 574 }
 575
 576 static const TypeInfo xen_disk_type_info = {
 577     .name = TYPE_XEN_DISK_DEVICE,
 578     .parent = TYPE_XEN_BLOCK_DEVICE,
 579     .instance_size = sizeof(XenDiskDevice),
 580     .class_init = xen_disk_class_init,
 581 };
 582
 583 static void xen_cdrom_unrealize(XenBlockDevice *blockdev, Error **errp)
 584 {
 585     trace_xen_cdrom_unrealize();
 586 }
 587
 588 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
 589 {
 590     BlockConf *conf = &blockdev->props.conf;
 591
 592     trace_xen_cdrom_realize();
 593
 594     blockdev->device_type = "cdrom";
 595
 596     if (!conf->blk) {
 597         int rc;
 598
 599         /* Set up an empty drive */
 600         conf->blk = blk_new(0, BLK_PERM_ALL);
 601
 602         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
 603         if (!rc) {
 604             error_setg_errno(errp, -rc, "failed to create drive");
 605             return;
 606         }
 607     }
 608
 609     blockdev->info = VDISK_READONLY | VDISK_CDROM;
 610 }
 611
 612 static void xen_cdrom_class_init(ObjectClass *class, void *data)
 613 {
 614     DeviceClass *dev_class = DEVICE_CLASS(class);
 615     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 616
 617     blockdev_class->realize = xen_cdrom_realize;
 618     blockdev_class->unrealize = xen_cdrom_unrealize;
 619
 620     dev_class->desc = "Xen CD-ROM Device";
 621 }
 622
 623 static const TypeInfo xen_cdrom_type_info = {
 624     .name = TYPE_XEN_CDROM_DEVICE,
 625     .parent = TYPE_XEN_BLOCK_DEVICE,
 626     .instance_size = sizeof(XenCDRomDevice),
 627     .class_init = xen_cdrom_class_init,
 628 };
 629
 630 static void xen_block_register_types(void)
 631 {
 632     type_register_static(&xen_block_type_info);
 633     type_register_static(&xen_disk_type_info);
 634     type_register_static(&xen_cdrom_type_info);
 635 }
 636
 637 type_init(xen_block_register_types)
 638
 639 static void xen_block_blockdev_del(const char *node_name, Error **errp)
 640 {
 641     trace_xen_block_blockdev_del(node_name);
 642
 643     qmp_blockdev_del(node_name, errp);
 644 }
 645
 646 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
 647                                     Error **errp)
 648 {
 649     const char *driver = qdict_get_try_str(qdict, "driver");
 650     BlockdevOptions *options = NULL;
 651     Error *local_err = NULL;
 652     char *node_name;
 653     Visitor *v;
 654
 655     if (!driver) {
 656         error_setg(errp, "no 'driver' parameter");
 657         return NULL;
 658     }
 659
 660     node_name = g_strdup_printf("%s-%s", id, driver);
 661     qdict_put_str(qdict, "node-name", node_name);
 662
 663     trace_xen_block_blockdev_add(node_name);
 664
 665     v = qobject_input_visitor_new(QOBJECT(qdict));
 666     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
 667     visit_free(v);
 668
 669     if (local_err) {
 670         error_propagate(errp, local_err);
 671         goto fail;
 672     }
 673
 674     qmp_blockdev_add(options, &local_err);
 675
 676     if (local_err) {
 677         error_propagate(errp, local_err);
 678         goto fail;
 679     }
 680
 681     qapi_free_BlockdevOptions(options);
 682
 683     return node_name;
 684
 685 fail:
 686     if (options) {
 687         qapi_free_BlockdevOptions(options);
 688     }
 689     g_free(node_name);
 690
 691     return NULL;
 692 }
 693
 694 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
 695 {
 696     char *node_name = drive->node_name;
 697
 698     if (node_name) {
 699         Error *local_err = NULL;
 700
 701         xen_block_blockdev_del(node_name, &local_err);
 702         if (local_err) {
 703             error_propagate(errp, local_err);
 704             return;
 705         }
 706         g_free(node_name);
 707         drive->node_name = NULL;
 708     }
 709     g_free(drive->id);
 710     g_free(drive);
 711 }
 712
 713 static XenBlockDrive *xen_block_drive_create(const char *id,
 714                                              const char *device_type,
 715                                              QDict *opts, Error **errp)
 716 {
 717     const char *params = qdict_get_try_str(opts, "params");
 718     const char *mode = qdict_get_try_str(opts, "mode");
 719     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
 720     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
 721     char *driver = NULL;
 722     char *filename = NULL;
 723     XenBlockDrive *drive = NULL;
 724     Error *local_err = NULL;
 725     QDict *file_layer;
 726     QDict *driver_layer;
 727
 728     if (params) {
 729         char **v = g_strsplit(params, ":", 2);
 730
 731         if (v[1] == NULL) {
 732             filename = g_strdup(v[0]);
 733             driver = g_strdup("raw");
 734         } else {
 735             if (strcmp(v[0], "aio") == 0) {
 736                 driver = g_strdup("raw");
 737             } else if (strcmp(v[0], "vhd") == 0) {
 738                 driver = g_strdup("vpc");
 739             } else {
 740                 driver = g_strdup(v[0]);
 741             }
 742             filename = g_strdup(v[1]);
 743         }
 744
 745         g_strfreev(v);
 746     } else {
 747         error_setg(errp, "no params");
 748         goto done;
 749     }
 750
 751     assert(filename);
 752     assert(driver);
 753
 754     drive = g_new0(XenBlockDrive, 1);
 755     drive->id = g_strdup(id);
 756
 757     file_layer = qdict_new();
 758
 759     qdict_put_str(file_layer, "driver", "file");
 760     qdict_put_str(file_layer, "filename", filename);
 761     g_free(filename);
 762
 763     if (mode && *mode != 'w') {
 764         qdict_put_bool(file_layer, "read-only", true);
 765     }
 766
 767     if (direct_io_safe) {
 768         unsigned long value;
 769
 770         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
 771             QDict *cache_qdict = qdict_new();
 772
 773             qdict_put_bool(cache_qdict, "direct", true);
 774             qdict_put(file_layer, "cache", cache_qdict);
 775
 776             qdict_put_str(file_layer, "aio", "native");
 777         }
 778     }
 779
 780     if (discard_enable) {
 781         unsigned long value;
 782
 783         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
 784             qdict_put_str(file_layer, "discard", "unmap");
 785         }
 786     }
 787
 788     /*
 789      * It is necessary to turn file locking off as an emulated device
 790      * may have already opened the same image file.
 791      */
 792     qdict_put_str(file_layer, "locking", "off");
 793
 794     driver_layer = qdict_new();
 795
 796     qdict_put_str(driver_layer, "driver", driver);
 797     g_free(driver);
 798
 799     qdict_put(driver_layer, "file", file_layer);
 800
 801     g_assert(!drive->node_name);
 802     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
 803                                               &local_err);
 804
 805     qobject_unref(driver_layer);
 806
 807 done:
 808     if (local_err) {
 809         error_propagate(errp, local_err);
 810         xen_block_drive_destroy(drive, NULL);
 811         return NULL;
 812     }
 813
 814     return drive;
 815 }
 816
 817 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
 818 {
 819     return drive->node_name ? drive->node_name : "";
 820 }
 821
 822 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
 823                                        Error **errp)
 824 {
 825     qmp_object_del(iothread->id, errp);
 826
 827     g_free(iothread->id);
 828     g_free(iothread);
 829 }
 830
 831 static XenBlockIOThread *xen_block_iothread_create(const char *id,
 832                                                    Error **errp)
 833 {
 834     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
 835     Error *local_err = NULL;
 836
 837     iothread->id = g_strdup(id);
 838
 839     qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
 840     if (local_err) {
 841         error_propagate(errp, local_err);
 842
 843         g_free(iothread->id);
 844         g_free(iothread);
 845         return NULL;
 846     }
 847
 848     return iothread;
 849 }
 850
 851 static void xen_block_device_create(XenBackendInstance *backend,
 852                                     QDict *opts, Error **errp)
 853 {
 854     XenBus *xenbus = xen_backend_get_bus(backend);
 855     const char *name = xen_backend_get_name(backend);
 856     unsigned long number;
 857     const char *vdev, *device_type;
 858     XenBlockDrive *drive = NULL;
 859     XenBlockIOThread *iothread = NULL;
 860     XenDevice *xendev = NULL;
 861     Error *local_err = NULL;
 862     const char *type;
 863     XenBlockDevice *blockdev;
 864
 865     if (qemu_strtoul(name, NULL, 10, &number)) {
 866         error_setg(errp, "failed to parse name '%s'", name);
 867         goto fail;
 868     }
 869
 870     trace_xen_block_device_create(number);
 871
 872     vdev = qdict_get_try_str(opts, "dev");
 873     if (!vdev) {
 874         error_setg(errp, "no dev parameter");
 875         goto fail;
 876     }
 877
 878     device_type = qdict_get_try_str(opts, "device-type");
 879     if (!device_type) {
 880         error_setg(errp, "no device-type parameter");
 881         goto fail;
 882     }
 883
 884     if (!strcmp(device_type, "disk")) {
 885         type = TYPE_XEN_DISK_DEVICE;
 886     } else if (!strcmp(device_type, "cdrom")) {
 887         type = TYPE_XEN_CDROM_DEVICE;
 888     } else {
 889         error_setg(errp, "invalid device-type parameter '%s'", device_type);
 890         goto fail;
 891     }
 892
 893     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
 894     if (!drive) {
 895         error_propagate_prepend(errp, local_err, "failed to create drive: ");
 896         goto fail;
 897     }
 898
 899     iothread = xen_block_iothread_create(vdev, &local_err);
 900     if (local_err) {
 901         error_propagate_prepend(errp, local_err,
 902                                 "failed to create iothread: ");
 903         goto fail;
 904     }
 905
 906     xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
 907     blockdev = XEN_BLOCK_DEVICE(xendev);
 908
 909     object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
 910     if (local_err) {
 911         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
 912         goto fail;
 913     }
 914
 915     object_property_set_str(OBJECT(xendev),
 916                             xen_block_drive_get_node_name(drive), "drive",
 917                             &local_err);
 918     if (local_err) {
 919         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
 920         goto fail;
 921     }
 922
 923     object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
 924                             &local_err);
 925     if (local_err) {
 926         error_propagate_prepend(errp, local_err,
 927                                 "failed to set 'iothread': ");
 928         goto fail;
 929     }
 930
 931     blockdev->iothread = iothread;
 932     blockdev->drive = drive;
 933
 934     object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
 935     if (local_err) {
 936         error_propagate_prepend(errp, local_err,
 937                                 "realization of device %s failed: ",
 938                                 type);
 939         goto fail;
 940     }
 941
 942     xen_backend_set_device(backend, xendev);
 943     return;
 944
 945 fail:
 946     if (xendev) {
 947         object_unparent(OBJECT(xendev));
 948     }
 949
 950     if (iothread) {
 951         xen_block_iothread_destroy(iothread, NULL);
 952     }
 953
 954     if (drive) {
 955         xen_block_drive_destroy(drive, NULL);
 956     }
 957 }
 958
 959 static void xen_block_device_destroy(XenBackendInstance *backend,
 960                                      Error **errp)
 961 {
 962     XenDevice *xendev = xen_backend_get_device(backend);
 963     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 964     XenBlockVdev *vdev = &blockdev->props.vdev;
 965     XenBlockDrive *drive = blockdev->drive;
 966     XenBlockIOThread *iothread = blockdev->iothread;
 967
 968     trace_xen_block_device_destroy(vdev->number);
 969
 970     object_unparent(OBJECT(xendev));
 971
 972     if (iothread) {
 973         Error *local_err = NULL;
 974
 975         xen_block_iothread_destroy(iothread, &local_err);
 976         if (local_err) {
 977             error_propagate_prepend(errp, local_err,
 978                                 "failed to destroy iothread: ");
 979             return;
 980         }
 981     }
 982
 983     if (drive) {
 984         Error *local_err = NULL;
 985
 986         xen_block_drive_destroy(drive, &local_err);
 987         if (local_err) {
 988             error_propagate_prepend(errp, local_err,
 989                                 "failed to destroy drive: ");
 990         }
 991     }
 992 }
 993
 994 static const XenBackendInfo xen_block_backend_info = {
 995     .type = "qdisk",
 996     .create = xen_block_device_create,
 997     .destroy = xen_block_device_destroy,
 998 };
 999
1000 static void xen_block_register_backend(void)
1001 {
1002     xen_backend_register(&xen_block_backend_info);
1003 }
1004
1005 xen_backend_init(xen_block_register_backend);