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) / XEN_BLKIF_SECTOR_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 != XEN_BLKIF_SECTOR_SIZE) {
 227         error_setg(errp, "logical_block_size != %u not supported",
 228                    XEN_BLKIF_SECTOR_SIZE);
 229         return;
 230     }
 231
 232     if (conf->logical_block_size > conf->physical_block_size) {
 233         error_setg(
 234             errp, "logical_block_size > physical_block_size not supported");
 235         return;
 236     }
 237
 238     blk_set_dev_ops(conf->blk, &xen_block_dev_ops, blockdev);
 239     blk_set_guest_block_size(conf->blk, conf->logical_block_size);
 240
 241     if (conf->discard_granularity == -1) {
 242         conf->discard_granularity = conf->physical_block_size;
 243     }
 244
 245     if (blk_get_flags(conf->blk) & BDRV_O_UNMAP) {
 246         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
 247         xen_device_backend_printf(xendev, "discard-granularity", "%u",
 248                                   conf->discard_granularity);
 249     }
 250
 251     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
 252     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
 253                               blockdev->props.max_ring_page_order);
 254     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
 255
 256     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
 257                                vdev->number);
 258     xen_device_frontend_printf(xendev, "device-type", "%s",
 259                                blockdev->device_type);
 260
 261     xen_device_backend_printf(xendev, "sector-size", "%u",
 262                               XEN_BLKIF_SECTOR_SIZE);
 263
 264     xen_block_set_size(blockdev);
 265
 266     blockdev->dataplane =
 267         xen_block_dataplane_create(xendev, conf, blockdev->props.iothread);
 268 }
 269
 270 static void xen_block_frontend_changed(XenDevice *xendev,
 271                                        enum xenbus_state frontend_state,
 272                                        Error **errp)
 273 {
 274     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
 275     Error *local_err = NULL;
 276
 277     switch (frontend_state) {
 278     case XenbusStateInitialised:
 279     case XenbusStateConnected:
 280         if (backend_state == XenbusStateConnected) {
 281             break;
 282         }
 283
 284         xen_block_disconnect(xendev, &local_err);
 285         if (local_err) {
 286             error_propagate(errp, local_err);
 287             break;
 288         }
 289
 290         xen_block_connect(xendev, &local_err);
 291         if (local_err) {
 292             error_propagate(errp, local_err);
 293             break;
 294         }
 295
 296         xen_device_backend_set_state(xendev, XenbusStateConnected);
 297         break;
 298
 299     case XenbusStateClosing:
 300         xen_device_backend_set_state(xendev, XenbusStateClosing);
 301         break;
 302
 303     case XenbusStateClosed:
 304         xen_block_disconnect(xendev, &local_err);
 305         if (local_err) {
 306             error_propagate(errp, local_err);
 307             break;
 308         }
 309
 310         xen_device_backend_set_state(xendev, XenbusStateClosed);
 311         break;
 312
 313     default:
 314         break;
 315     }
 316 }
 317
 318 static char *disk_to_vbd_name(unsigned int disk)
 319 {
 320     char *name, *prefix = (disk >= 26) ?
 321         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
 322
 323     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
 324     g_free(prefix);
 325
 326     return name;
 327 }
 328
 329 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
 330                                void *opaque, Error **errp)
 331 {
 332     DeviceState *dev = DEVICE(obj);
 333     Property *prop = opaque;
 334     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
 335     char *str;
 336
 337     switch (vdev->type) {
 338     case XEN_BLOCK_VDEV_TYPE_DP:
 339         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
 340         break;
 341
 342     case XEN_BLOCK_VDEV_TYPE_XVD:
 343     case XEN_BLOCK_VDEV_TYPE_HD:
 344     case XEN_BLOCK_VDEV_TYPE_SD: {
 345         char *name = disk_to_vbd_name(vdev->disk);
 346
 347         str = g_strdup_printf("%s%s%lu",
 348                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
 349                               "xvd" :
 350                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
 351                               "hd" :
 352                               "sd",
 353                               name, vdev->partition);
 354         g_free(name);
 355         break;
 356     }
 357     default:
 358         error_setg(errp, "invalid vdev type");
 359         return;
 360     }
 361
 362     visit_type_str(v, name, &str, errp);
 363     g_free(str);
 364 }
 365
 366 static int vbd_name_to_disk(const char *name, const char **endp,
 367                             unsigned long *disk)
 368 {
 369     unsigned int n = 0;
 370
 371     while (*name != '\0') {
 372         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
 373             break;
 374         }
 375
 376         n *= 26;
 377         n += *name++ - 'a' + 1;
 378     }
 379     *endp = name;
 380
 381     if (!n) {
 382         return -1;
 383     }
 384
 385     *disk = n - 1;
 386
 387     return 0;
 388 }
 389
 390 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
 391                                void *opaque, Error **errp)
 392 {
 393     DeviceState *dev = DEVICE(obj);
 394     Property *prop = opaque;
 395     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
 396     Error *local_err = NULL;
 397     char *str, *p;
 398     const char *end;
 399
 400     if (dev->realized) {
 401         qdev_prop_set_after_realize(dev, name, errp);
 402         return;
 403     }
 404
 405     visit_type_str(v, name, &str, &local_err);
 406     if (local_err) {
 407         error_propagate(errp, local_err);
 408         return;
 409     }
 410
 411     p = strchr(str, 'd');
 412     if (!p) {
 413         goto invalid;
 414     }
 415
 416     *p++ = '\0';
 417     if (*str == '\0') {
 418         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
 419     } else if (strcmp(str, "xv") == 0) {
 420         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
 421     } else if (strcmp(str, "h") == 0) {
 422         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
 423     } else if (strcmp(str, "s") == 0) {
 424         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
 425     } else {
 426         goto invalid;
 427     }
 428
 429     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
 430         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
 431             goto invalid;
 432         }
 433
 434         if (*end == 'p') {
 435             if (*(++end) == '\0') {
 436                 goto invalid;
 437             }
 438         }
 439     } else {
 440         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
 441             goto invalid;
 442         }
 443     }
 444
 445     if (*end != '\0') {
 446         p = (char *)end;
 447
 448         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
 449             goto invalid;
 450         }
 451
 452         if (*end != '\0') {
 453             goto invalid;
 454         }
 455     } else {
 456         vdev->partition = 0;
 457     }
 458
 459     switch (vdev->type) {
 460     case XEN_BLOCK_VDEV_TYPE_DP:
 461     case XEN_BLOCK_VDEV_TYPE_XVD:
 462         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 463             vdev->number = (202 << 8) | (vdev->disk << 4) |
 464                 vdev->partition;
 465         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
 466             vdev->number = (1 << 28) | (vdev->disk << 8) |
 467                 vdev->partition;
 468         } else {
 469             goto invalid;
 470         }
 471         break;
 472
 473     case XEN_BLOCK_VDEV_TYPE_HD:
 474         if ((vdev->disk == 0 || vdev->disk == 1) &&
 475             vdev->partition < (1 << 6)) {
 476             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
 477         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
 478                    vdev->partition < (1 << 6)) {
 479             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
 480                 vdev->partition;
 481         } else {
 482             goto invalid;
 483         }
 484         break;
 485
 486     case XEN_BLOCK_VDEV_TYPE_SD:
 487         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 488             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
 489         } else {
 490             goto invalid;
 491         }
 492         break;
 493
 494     default:
 495         goto invalid;
 496     }
 497
 498     g_free(str);
 499     return;
 500
 501 invalid:
 502     error_setg(errp, "invalid virtual disk specifier");
 503
 504     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
 505     g_free(str);
 506 }
 507
 508 /*
 509  * This property deals with 'vdev' names adhering to the Xen VBD naming
 510  * scheme described in:
 511  *
 512  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
 513  */
 514 const PropertyInfo xen_block_prop_vdev = {
 515     .name  = "str",
 516     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
 517     .get = xen_block_get_vdev,
 518     .set = xen_block_set_vdev,
 519 };
 520
 521 static Property xen_block_props[] = {
 522     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
 523                 xen_block_prop_vdev, XenBlockVdev),
 524     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
 525     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
 526                        props.max_ring_page_order, 4),
 527     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
 528                      TYPE_IOTHREAD, IOThread *),
 529     DEFINE_PROP_END_OF_LIST()
 530 };
 531
 532 static void xen_block_class_init(ObjectClass *class, void *data)
 533 {
 534     DeviceClass *dev_class = DEVICE_CLASS(class);
 535     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
 536
 537     xendev_class->backend = "qdisk";
 538     xendev_class->device = "vbd";
 539     xendev_class->get_name = xen_block_get_name;
 540     xendev_class->realize = xen_block_realize;
 541     xendev_class->frontend_changed = xen_block_frontend_changed;
 542     xendev_class->unrealize = xen_block_unrealize;
 543
 544     dev_class->props = xen_block_props;
 545 }
 546
 547 static const TypeInfo xen_block_type_info = {
 548     .name = TYPE_XEN_BLOCK_DEVICE,
 549     .parent = TYPE_XEN_DEVICE,
 550     .instance_size = sizeof(XenBlockDevice),
 551     .abstract = true,
 552     .class_size = sizeof(XenBlockDeviceClass),
 553     .class_init = xen_block_class_init,
 554 };
 555
 556 static void xen_disk_unrealize(XenBlockDevice *blockdev, Error **errp)
 557 {
 558     trace_xen_disk_unrealize();
 559 }
 560
 561 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
 562 {
 563     BlockConf *conf = &blockdev->props.conf;
 564
 565     trace_xen_disk_realize();
 566
 567     blockdev->device_type = "disk";
 568
 569     if (!conf->blk) {
 570         error_setg(errp, "drive property not set");
 571         return;
 572     }
 573
 574     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
 575 }
 576
 577 static void xen_disk_class_init(ObjectClass *class, void *data)
 578 {
 579     DeviceClass *dev_class = DEVICE_CLASS(class);
 580     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 581
 582     blockdev_class->realize = xen_disk_realize;
 583     blockdev_class->unrealize = xen_disk_unrealize;
 584
 585     dev_class->desc = "Xen Disk Device";
 586 }
 587
 588 static const TypeInfo xen_disk_type_info = {
 589     .name = TYPE_XEN_DISK_DEVICE,
 590     .parent = TYPE_XEN_BLOCK_DEVICE,
 591     .instance_size = sizeof(XenDiskDevice),
 592     .class_init = xen_disk_class_init,
 593 };
 594
 595 static void xen_cdrom_unrealize(XenBlockDevice *blockdev, Error **errp)
 596 {
 597     trace_xen_cdrom_unrealize();
 598 }
 599
 600 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
 601 {
 602     BlockConf *conf = &blockdev->props.conf;
 603
 604     trace_xen_cdrom_realize();
 605
 606     blockdev->device_type = "cdrom";
 607
 608     if (!conf->blk) {
 609         int rc;
 610
 611         /* Set up an empty drive */
 612         conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
 613
 614         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
 615         if (!rc) {
 616             error_setg_errno(errp, -rc, "failed to create drive");
 617             return;
 618         }
 619     }
 620
 621     blockdev->info = VDISK_READONLY | VDISK_CDROM;
 622 }
 623
 624 static void xen_cdrom_class_init(ObjectClass *class, void *data)
 625 {
 626     DeviceClass *dev_class = DEVICE_CLASS(class);
 627     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 628
 629     blockdev_class->realize = xen_cdrom_realize;
 630     blockdev_class->unrealize = xen_cdrom_unrealize;
 631
 632     dev_class->desc = "Xen CD-ROM Device";
 633 }
 634
 635 static const TypeInfo xen_cdrom_type_info = {
 636     .name = TYPE_XEN_CDROM_DEVICE,
 637     .parent = TYPE_XEN_BLOCK_DEVICE,
 638     .instance_size = sizeof(XenCDRomDevice),
 639     .class_init = xen_cdrom_class_init,
 640 };
 641
 642 static void xen_block_register_types(void)
 643 {
 644     type_register_static(&xen_block_type_info);
 645     type_register_static(&xen_disk_type_info);
 646     type_register_static(&xen_cdrom_type_info);
 647 }
 648
 649 type_init(xen_block_register_types)
 650
 651 static void xen_block_blockdev_del(const char *node_name, Error **errp)
 652 {
 653     trace_xen_block_blockdev_del(node_name);
 654
 655     qmp_blockdev_del(node_name, errp);
 656 }
 657
 658 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
 659                                     Error **errp)
 660 {
 661     const char *driver = qdict_get_try_str(qdict, "driver");
 662     BlockdevOptions *options = NULL;
 663     Error *local_err = NULL;
 664     char *node_name;
 665     Visitor *v;
 666
 667     if (!driver) {
 668         error_setg(errp, "no 'driver' parameter");
 669         return NULL;
 670     }
 671
 672     node_name = g_strdup_printf("%s-%s", id, driver);
 673     qdict_put_str(qdict, "node-name", node_name);
 674
 675     trace_xen_block_blockdev_add(node_name);
 676
 677     v = qobject_input_visitor_new(QOBJECT(qdict));
 678     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
 679     visit_free(v);
 680
 681     if (local_err) {
 682         error_propagate(errp, local_err);
 683         goto fail;
 684     }
 685
 686     qmp_blockdev_add(options, &local_err);
 687
 688     if (local_err) {
 689         error_propagate(errp, local_err);
 690         goto fail;
 691     }
 692
 693     qapi_free_BlockdevOptions(options);
 694
 695     return node_name;
 696
 697 fail:
 698     if (options) {
 699         qapi_free_BlockdevOptions(options);
 700     }
 701     g_free(node_name);
 702
 703     return NULL;
 704 }
 705
 706 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
 707 {
 708     char *node_name = drive->node_name;
 709
 710     if (node_name) {
 711         Error *local_err = NULL;
 712
 713         xen_block_blockdev_del(node_name, &local_err);
 714         if (local_err) {
 715             error_propagate(errp, local_err);
 716             return;
 717         }
 718         g_free(node_name);
 719         drive->node_name = NULL;
 720     }
 721     g_free(drive->id);
 722     g_free(drive);
 723 }
 724
 725 static XenBlockDrive *xen_block_drive_create(const char *id,
 726                                              const char *device_type,
 727                                              QDict *opts, Error **errp)
 728 {
 729     const char *params = qdict_get_try_str(opts, "params");
 730     const char *mode = qdict_get_try_str(opts, "mode");
 731     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
 732     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
 733     char *driver = NULL;
 734     char *filename = NULL;
 735     XenBlockDrive *drive = NULL;
 736     Error *local_err = NULL;
 737     QDict *file_layer;
 738     QDict *driver_layer;
 739
 740     if (params) {
 741         char **v = g_strsplit(params, ":", 2);
 742
 743         if (v[1] == NULL) {
 744             filename = g_strdup(v[0]);
 745             driver = g_strdup("raw");
 746         } else {
 747             if (strcmp(v[0], "aio") == 0) {
 748                 driver = g_strdup("raw");
 749             } else if (strcmp(v[0], "vhd") == 0) {
 750                 driver = g_strdup("vpc");
 751             } else {
 752                 driver = g_strdup(v[0]);
 753             }
 754             filename = g_strdup(v[1]);
 755         }
 756
 757         g_strfreev(v);
 758     } else {
 759         error_setg(errp, "no params");
 760         goto done;
 761     }
 762
 763     assert(filename);
 764     assert(driver);
 765
 766     drive = g_new0(XenBlockDrive, 1);
 767     drive->id = g_strdup(id);
 768
 769     file_layer = qdict_new();
 770     driver_layer = qdict_new();
 771
 772     qdict_put_str(file_layer, "driver", "file");
 773     qdict_put_str(file_layer, "filename", filename);
 774     g_free(filename);
 775
 776     if (mode && *mode != 'w') {
 777         qdict_put_bool(file_layer, "read-only", true);
 778     }
 779
 780     if (direct_io_safe) {
 781         unsigned long value;
 782
 783         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
 784             QDict *cache_qdict = qdict_new();
 785
 786             qdict_put_bool(cache_qdict, "direct", true);
 787             qdict_put(file_layer, "cache", cache_qdict);
 788
 789             qdict_put_str(file_layer, "aio", "native");
 790         }
 791     }
 792
 793     if (discard_enable) {
 794         unsigned long value;
 795
 796         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
 797             qdict_put_str(file_layer, "discard", "unmap");
 798             qdict_put_str(driver_layer, "discard", "unmap");
 799         }
 800     }
 801
 802     /*
 803      * It is necessary to turn file locking off as an emulated device
 804      * may have already opened the same image file.
 805      */
 806     qdict_put_str(file_layer, "locking", "off");
 807
 808     qdict_put_str(driver_layer, "driver", driver);
 809     g_free(driver);
 810
 811     qdict_put(driver_layer, "file", file_layer);
 812
 813     g_assert(!drive->node_name);
 814     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
 815                                               &local_err);
 816
 817     qobject_unref(driver_layer);
 818
 819 done:
 820     if (local_err) {
 821         error_propagate(errp, local_err);
 822         xen_block_drive_destroy(drive, NULL);
 823         return NULL;
 824     }
 825
 826     return drive;
 827 }
 828
 829 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
 830 {
 831     return drive->node_name ? drive->node_name : "";
 832 }
 833
 834 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
 835                                        Error **errp)
 836 {
 837     qmp_object_del(iothread->id, errp);
 838
 839     g_free(iothread->id);
 840     g_free(iothread);
 841 }
 842
 843 static XenBlockIOThread *xen_block_iothread_create(const char *id,
 844                                                    Error **errp)
 845 {
 846     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
 847     Error *local_err = NULL;
 848
 849     iothread->id = g_strdup(id);
 850
 851     qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
 852     if (local_err) {
 853         error_propagate(errp, local_err);
 854
 855         g_free(iothread->id);
 856         g_free(iothread);
 857         return NULL;
 858     }
 859
 860     return iothread;
 861 }
 862
 863 static void xen_block_device_create(XenBackendInstance *backend,
 864                                     QDict *opts, Error **errp)
 865 {
 866     XenBus *xenbus = xen_backend_get_bus(backend);
 867     const char *name = xen_backend_get_name(backend);
 868     unsigned long number;
 869     const char *vdev, *device_type;
 870     XenBlockDrive *drive = NULL;
 871     XenBlockIOThread *iothread = NULL;
 872     XenDevice *xendev = NULL;
 873     Error *local_err = NULL;
 874     const char *type;
 875     XenBlockDevice *blockdev;
 876
 877     if (qemu_strtoul(name, NULL, 10, &number)) {
 878         error_setg(errp, "failed to parse name '%s'", name);
 879         goto fail;
 880     }
 881
 882     trace_xen_block_device_create(number);
 883
 884     vdev = qdict_get_try_str(opts, "dev");
 885     if (!vdev) {
 886         error_setg(errp, "no dev parameter");
 887         goto fail;
 888     }
 889
 890     device_type = qdict_get_try_str(opts, "device-type");
 891     if (!device_type) {
 892         error_setg(errp, "no device-type parameter");
 893         goto fail;
 894     }
 895
 896     if (!strcmp(device_type, "disk")) {
 897         type = TYPE_XEN_DISK_DEVICE;
 898     } else if (!strcmp(device_type, "cdrom")) {
 899         type = TYPE_XEN_CDROM_DEVICE;
 900     } else {
 901         error_setg(errp, "invalid device-type parameter '%s'", device_type);
 902         goto fail;
 903     }
 904
 905     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
 906     if (!drive) {
 907         error_propagate_prepend(errp, local_err, "failed to create drive: ");
 908         goto fail;
 909     }
 910
 911     iothread = xen_block_iothread_create(vdev, &local_err);
 912     if (local_err) {
 913         error_propagate_prepend(errp, local_err,
 914                                 "failed to create iothread: ");
 915         goto fail;
 916     }
 917
 918     xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
 919     blockdev = XEN_BLOCK_DEVICE(xendev);
 920
 921     object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
 922     if (local_err) {
 923         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
 924         goto fail;
 925     }
 926
 927     object_property_set_str(OBJECT(xendev),
 928                             xen_block_drive_get_node_name(drive), "drive",
 929                             &local_err);
 930     if (local_err) {
 931         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
 932         goto fail;
 933     }
 934
 935     object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
 936                             &local_err);
 937     if (local_err) {
 938         error_propagate_prepend(errp, local_err,
 939                                 "failed to set 'iothread': ");
 940         goto fail;
 941     }
 942
 943     blockdev->iothread = iothread;
 944     blockdev->drive = drive;
 945
 946     object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
 947     if (local_err) {
 948         error_propagate_prepend(errp, local_err,
 949                                 "realization of device %s failed: ",
 950                                 type);
 951         goto fail;
 952     }
 953
 954     xen_backend_set_device(backend, xendev);
 955     return;
 956
 957 fail:
 958     if (xendev) {
 959         object_unparent(OBJECT(xendev));
 960     }
 961
 962     if (iothread) {
 963         xen_block_iothread_destroy(iothread, NULL);
 964     }
 965
 966     if (drive) {
 967         xen_block_drive_destroy(drive, NULL);
 968     }
 969 }
 970
 971 static void xen_block_device_destroy(XenBackendInstance *backend,
 972                                      Error **errp)
 973 {
 974     XenDevice *xendev = xen_backend_get_device(backend);
 975     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 976     XenBlockVdev *vdev = &blockdev->props.vdev;
 977     XenBlockDrive *drive = blockdev->drive;
 978     XenBlockIOThread *iothread = blockdev->iothread;
 979
 980     trace_xen_block_device_destroy(vdev->number);
 981
 982     object_unparent(OBJECT(xendev));
 983
 984     if (iothread) {
 985         Error *local_err = NULL;
 986
 987         xen_block_iothread_destroy(iothread, &local_err);
 988         if (local_err) {
 989             error_propagate_prepend(errp, local_err,
 990                                 "failed to destroy iothread: ");
 991             return;
 992         }
 993     }
 994
 995     if (drive) {
 996         Error *local_err = NULL;
 997
 998         xen_block_drive_destroy(drive, &local_err);
 999         if (local_err) {
1000             error_propagate_prepend(errp, local_err,
1001                                 "failed to destroy drive: ");
1002         }
1003     }
1004 }
1005
1006 static const XenBackendInfo xen_block_backend_info = {
1007     .type = "qdisk",
1008     .create = xen_block_device_create,
1009     .destroy = xen_block_device_destroy,
1010 };
1011
1012 static void xen_block_register_backend(void)
1013 {
1014     xen_backend_register(&xen_block_backend_info);
1015 }
1016
1017 xen_backend_init(xen_block_register_backend);