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/main-loop.h"
  11 #include "qemu/module.h"
  12 #include "qemu/option.h"
  13 #include "qapi/error.h"
  14 #include "qapi/qapi-commands-block-core.h"
  15 #include "qapi/qapi-commands-qom.h"
  16 #include "qapi/qapi-visit-block-core.h"
  17 #include "qapi/qobject-input-visitor.h"
  18 #include "qapi/visitor.h"
  19 #include "qapi/qmp/qdict.h"
  20 #include "qapi/qmp/qstring.h"
  21 #include "qom/object_interfaces.h"
  22 #include "hw/xen/xen_common.h"
  23 #include "hw/block/xen_blkif.h"
  24 #include "hw/qdev-properties.h"
  25 #include "hw/xen/xen-block.h"
  26 #include "hw/xen/xen-backend.h"
  27 #include "sysemu/blockdev.h"
  28 #include "sysemu/block-backend.h"
  29 #include "sysemu/iothread.h"
  30 #include "dataplane/xen-block.h"
  31 #include "trace.h"
  32
  33 static char *xen_block_get_name(XenDevice *xendev, Error **errp)
  34 {
  35     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  36     XenBlockVdev *vdev = &blockdev->props.vdev;
  37
  38     return g_strdup_printf("%lu", vdev->number);
  39 }
  40
  41 static void xen_block_disconnect(XenDevice *xendev, Error **errp)
  42 {
  43     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  44     const char *type = object_get_typename(OBJECT(blockdev));
  45     XenBlockVdev *vdev = &blockdev->props.vdev;
  46
  47     trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
  48
  49     xen_block_dataplane_stop(blockdev->dataplane);
  50 }
  51
  52 static void xen_block_connect(XenDevice *xendev, Error **errp)
  53 {
  54     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
  55     const char *type = object_get_typename(OBJECT(blockdev));
  56     XenBlockVdev *vdev = &blockdev->props.vdev;
  57     BlockConf *conf = &blockdev->props.conf;
  58     unsigned int feature_large_sector_size;
  59     unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
  60     char *str;
  61
  62     trace_xen_block_connect(type, vdev->disk, vdev->partition);
  63
  64     if (xen_device_frontend_scanf(xendev, "feature-large-sector-size", "%u",
  65                                   &feature_large_sector_size) != 1) {
  66         feature_large_sector_size = 0;
  67     }
  68
  69     if (feature_large_sector_size != 1 &&
  70         conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
  71         error_setg(errp, "logical_block_size != %u not supported by frontend",
  72                    XEN_BLKIF_SECTOR_SIZE);
  73         return;
  74     }
  75
  76     if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
  77                                   &order) != 1) {
  78         nr_ring_ref = 1;
  79         ring_ref = g_new(unsigned int, nr_ring_ref);
  80
  81         if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
  82                                       &ring_ref[0]) != 1) {
  83             error_setg(errp, "failed to read ring-ref");
  84             g_free(ring_ref);
  85             return;
  86         }
  87     } else if (order <= blockdev->props.max_ring_page_order) {
  88         unsigned int i;
  89
  90         nr_ring_ref = 1 << order;
  91         ring_ref = g_new(unsigned int, nr_ring_ref);
  92
  93         for (i = 0; i < nr_ring_ref; i++) {
  94             const char *key = g_strdup_printf("ring-ref%u", i);
  95
  96             if (xen_device_frontend_scanf(xendev, key, "%u",
  97                                           &ring_ref[i]) != 1) {
  98                 error_setg(errp, "failed to read %s", key);
  99                 g_free((gpointer)key);
 100                 g_free(ring_ref);
 101                 return;
 102             }
 103
 104             g_free((gpointer)key);
 105         }
 106     } else {
 107         error_setg(errp, "invalid ring-page-order (%d)", order);
 108         return;
 109     }
 110
 111     if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
 112                                   &event_channel) != 1) {
 113         error_setg(errp, "failed to read event-channel");
 114         g_free(ring_ref);
 115         return;
 116     }
 117
 118     if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
 119                                   &str) != 1) {
 120         protocol = BLKIF_PROTOCOL_NATIVE;
 121     } else {
 122         if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
 123             protocol = BLKIF_PROTOCOL_X86_32;
 124         } else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
 125             protocol = BLKIF_PROTOCOL_X86_64;
 126         } else {
 127             protocol = BLKIF_PROTOCOL_NATIVE;
 128         }
 129
 130         free(str);
 131     }
 132
 133     xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
 134                               event_channel, protocol, errp);
 135
 136     g_free(ring_ref);
 137 }
 138
 139 static void xen_block_unrealize(XenDevice *xendev)
 140 {
 141     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 142     XenBlockDeviceClass *blockdev_class =
 143         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
 144     const char *type = object_get_typename(OBJECT(blockdev));
 145     XenBlockVdev *vdev = &blockdev->props.vdev;
 146
 147     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
 148         return;
 149     }
 150
 151     trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
 152
 153     /* Disconnect from the frontend in case this has not already happened */
 154     xen_block_disconnect(xendev, NULL);
 155
 156     xen_block_dataplane_destroy(blockdev->dataplane);
 157     blockdev->dataplane = NULL;
 158
 159     if (blockdev_class->unrealize) {
 160         blockdev_class->unrealize(blockdev);
 161     }
 162 }
 163
 164 static void xen_block_set_size(XenBlockDevice *blockdev)
 165 {
 166     const char *type = object_get_typename(OBJECT(blockdev));
 167     XenBlockVdev *vdev = &blockdev->props.vdev;
 168     BlockConf *conf = &blockdev->props.conf;
 169     int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
 170     XenDevice *xendev = XEN_DEVICE(blockdev);
 171
 172     trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
 173
 174     xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
 175 }
 176
 177 static void xen_block_resize_cb(void *opaque)
 178 {
 179     XenBlockDevice *blockdev = opaque;
 180     XenDevice *xendev = XEN_DEVICE(blockdev);
 181     enum xenbus_state state = xen_device_backend_get_state(xendev);
 182
 183     xen_block_set_size(blockdev);
 184
 185     /*
 186      * Mimic the behaviour of Linux xen-blkback and re-write the state
 187      * to trigger the frontend watch.
 188      */
 189     xen_device_backend_printf(xendev, "state", "%u", state);
 190 }
 191
 192 static const BlockDevOps xen_block_dev_ops = {
 193     .resize_cb = xen_block_resize_cb,
 194 };
 195
 196 static void xen_block_realize(XenDevice *xendev, Error **errp)
 197 {
 198     ERRP_GUARD();
 199     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 200     XenBlockDeviceClass *blockdev_class =
 201         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
 202     const char *type = object_get_typename(OBJECT(blockdev));
 203     XenBlockVdev *vdev = &blockdev->props.vdev;
 204     BlockConf *conf = &blockdev->props.conf;
 205     BlockBackend *blk = conf->blk;
 206
 207     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
 208         error_setg(errp, "vdev property not set");
 209         return;
 210     }
 211
 212     trace_xen_block_realize(type, vdev->disk, vdev->partition);
 213
 214     if (blockdev_class->realize) {
 215         blockdev_class->realize(blockdev, errp);
 216         if (*errp) {
 217             return;
 218         }
 219     }
 220
 221     /*
 222      * The blkif protocol does not deal with removable media, so it must
 223      * always be present, even for CDRom devices.
 224      */
 225     assert(blk);
 226     if (!blk_is_inserted(blk)) {
 227         error_setg(errp, "device needs media, but drive is empty");
 228         return;
 229     }
 230
 231     if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
 232                                        true, errp)) {
 233         return;
 234     }
 235
 236     if (!(blockdev->info & VDISK_CDROM) &&
 237         !blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
 238         return;
 239     }
 240
 241     if (!blkconf_blocksizes(conf, errp)) {
 242         return;
 243     }
 244
 245     blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
 246
 247     if (conf->discard_granularity == -1) {
 248         conf->discard_granularity = conf->physical_block_size;
 249     }
 250
 251     if (blk_get_flags(blk) & BDRV_O_UNMAP) {
 252         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
 253         xen_device_backend_printf(xendev, "discard-granularity", "%u",
 254                                   conf->discard_granularity);
 255         xen_device_backend_printf(xendev, "discard-alignment", "%u", 0);
 256     }
 257
 258     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
 259     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
 260                               blockdev->props.max_ring_page_order);
 261     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
 262
 263     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
 264                                vdev->number);
 265     xen_device_frontend_printf(xendev, "device-type", "%s",
 266                                blockdev->device_type);
 267
 268     xen_device_backend_printf(xendev, "sector-size", "%u",
 269                               conf->logical_block_size);
 270
 271     xen_block_set_size(blockdev);
 272
 273     blockdev->dataplane =
 274         xen_block_dataplane_create(xendev, blk, conf->logical_block_size,
 275                                    blockdev->props.iothread);
 276 }
 277
 278 static void xen_block_frontend_changed(XenDevice *xendev,
 279                                        enum xenbus_state frontend_state,
 280                                        Error **errp)
 281 {
 282     ERRP_GUARD();
 283     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
 284
 285     switch (frontend_state) {
 286     case XenbusStateInitialised:
 287     case XenbusStateConnected:
 288         if (backend_state == XenbusStateConnected) {
 289             break;
 290         }
 291
 292         xen_block_disconnect(xendev, errp);
 293         if (*errp) {
 294             break;
 295         }
 296
 297         xen_block_connect(xendev, errp);
 298         if (*errp) {
 299             break;
 300         }
 301
 302         xen_device_backend_set_state(xendev, XenbusStateConnected);
 303         break;
 304
 305     case XenbusStateClosing:
 306         xen_device_backend_set_state(xendev, XenbusStateClosing);
 307         break;
 308
 309     case XenbusStateClosed:
 310     case XenbusStateUnknown:
 311         xen_block_disconnect(xendev, errp);
 312         if (*errp) {
 313             break;
 314         }
 315
 316         xen_device_backend_set_state(xendev, XenbusStateClosed);
 317         break;
 318
 319     default:
 320         break;
 321     }
 322 }
 323
 324 static char *disk_to_vbd_name(unsigned int disk)
 325 {
 326     char *name, *prefix = (disk >= 26) ?
 327         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
 328
 329     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
 330     g_free(prefix);
 331
 332     return name;
 333 }
 334
 335 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
 336                                void *opaque, Error **errp)
 337 {
 338     Property *prop = opaque;
 339     XenBlockVdev *vdev = object_field_prop_ptr(obj, prop);
 340     char *str;
 341
 342     switch (vdev->type) {
 343     case XEN_BLOCK_VDEV_TYPE_DP:
 344         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
 345         break;
 346
 347     case XEN_BLOCK_VDEV_TYPE_XVD:
 348     case XEN_BLOCK_VDEV_TYPE_HD:
 349     case XEN_BLOCK_VDEV_TYPE_SD: {
 350         char *name = disk_to_vbd_name(vdev->disk);
 351
 352         str = g_strdup_printf("%s%s%lu",
 353                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
 354                               "xvd" :
 355                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
 356                               "hd" :
 357                               "sd",
 358                               name, vdev->partition);
 359         g_free(name);
 360         break;
 361     }
 362     default:
 363         error_setg(errp, "invalid vdev type");
 364         return;
 365     }
 366
 367     visit_type_str(v, name, &str, errp);
 368     g_free(str);
 369 }
 370
 371 static int vbd_name_to_disk(const char *name, const char **endp,
 372                             unsigned long *disk)
 373 {
 374     unsigned int n = 0;
 375
 376     while (*name != '\0') {
 377         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
 378             break;
 379         }
 380
 381         n *= 26;
 382         n += *name++ - 'a' + 1;
 383     }
 384     *endp = name;
 385
 386     if (!n) {
 387         return -1;
 388     }
 389
 390     *disk = n - 1;
 391
 392     return 0;
 393 }
 394
 395 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
 396                                void *opaque, Error **errp)
 397 {
 398     Property *prop = opaque;
 399     XenBlockVdev *vdev = object_field_prop_ptr(obj, prop);
 400     char *str, *p;
 401     const char *end;
 402
 403     if (!visit_type_str(v, name, &str, errp)) {
 404         return;
 405     }
 406
 407     p = strchr(str, 'd');
 408     if (!p) {
 409         goto invalid;
 410     }
 411
 412     *p++ = '\0';
 413     if (*str == '\0') {
 414         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
 415     } else if (strcmp(str, "xv") == 0) {
 416         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
 417     } else if (strcmp(str, "h") == 0) {
 418         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
 419     } else if (strcmp(str, "s") == 0) {
 420         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
 421     } else {
 422         goto invalid;
 423     }
 424
 425     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
 426         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
 427             goto invalid;
 428         }
 429
 430         if (*end == 'p') {
 431             if (*(++end) == '\0') {
 432                 goto invalid;
 433             }
 434         }
 435     } else {
 436         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
 437             goto invalid;
 438         }
 439     }
 440
 441     if (*end != '\0') {
 442         p = (char *)end;
 443
 444         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
 445             goto invalid;
 446         }
 447
 448         if (*end != '\0') {
 449             goto invalid;
 450         }
 451     } else {
 452         vdev->partition = 0;
 453     }
 454
 455     switch (vdev->type) {
 456     case XEN_BLOCK_VDEV_TYPE_DP:
 457     case XEN_BLOCK_VDEV_TYPE_XVD:
 458         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 459             vdev->number = (202 << 8) | (vdev->disk << 4) |
 460                 vdev->partition;
 461         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
 462             vdev->number = (1 << 28) | (vdev->disk << 8) |
 463                 vdev->partition;
 464         } else {
 465             goto invalid;
 466         }
 467         break;
 468
 469     case XEN_BLOCK_VDEV_TYPE_HD:
 470         if ((vdev->disk == 0 || vdev->disk == 1) &&
 471             vdev->partition < (1 << 6)) {
 472             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
 473         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
 474                    vdev->partition < (1 << 6)) {
 475             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
 476                 vdev->partition;
 477         } else {
 478             goto invalid;
 479         }
 480         break;
 481
 482     case XEN_BLOCK_VDEV_TYPE_SD:
 483         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
 484             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
 485         } else {
 486             goto invalid;
 487         }
 488         break;
 489
 490     default:
 491         goto invalid;
 492     }
 493
 494     g_free(str);
 495     return;
 496
 497 invalid:
 498     error_setg(errp, "invalid virtual disk specifier");
 499
 500     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
 501     g_free(str);
 502 }
 503
 504 /*
 505  * This property deals with 'vdev' names adhering to the Xen VBD naming
 506  * scheme described in:
 507  *
 508  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
 509  */
 510 const PropertyInfo xen_block_prop_vdev = {
 511     .name  = "str",
 512     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
 513     .get = xen_block_get_vdev,
 514     .set = xen_block_set_vdev,
 515 };
 516
 517 static Property xen_block_props[] = {
 518     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
 519                 xen_block_prop_vdev, XenBlockVdev),
 520     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
 521     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
 522                        props.max_ring_page_order, 4),
 523     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
 524                      TYPE_IOTHREAD, IOThread *),
 525     DEFINE_PROP_END_OF_LIST()
 526 };
 527
 528 static void xen_block_class_init(ObjectClass *class, void *data)
 529 {
 530     DeviceClass *dev_class = DEVICE_CLASS(class);
 531     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
 532
 533     xendev_class->backend = "qdisk";
 534     xendev_class->device = "vbd";
 535     xendev_class->get_name = xen_block_get_name;
 536     xendev_class->realize = xen_block_realize;
 537     xendev_class->frontend_changed = xen_block_frontend_changed;
 538     xendev_class->unrealize = xen_block_unrealize;
 539
 540     device_class_set_props(dev_class, xen_block_props);
 541 }
 542
 543 static const TypeInfo xen_block_type_info = {
 544     .name = TYPE_XEN_BLOCK_DEVICE,
 545     .parent = TYPE_XEN_DEVICE,
 546     .instance_size = sizeof(XenBlockDevice),
 547     .abstract = true,
 548     .class_size = sizeof(XenBlockDeviceClass),
 549     .class_init = xen_block_class_init,
 550 };
 551
 552 static void xen_disk_unrealize(XenBlockDevice *blockdev)
 553 {
 554     trace_xen_disk_unrealize();
 555 }
 556
 557 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
 558 {
 559     BlockConf *conf = &blockdev->props.conf;
 560
 561     trace_xen_disk_realize();
 562
 563     blockdev->device_type = "disk";
 564
 565     if (!conf->blk) {
 566         error_setg(errp, "drive property not set");
 567         return;
 568     }
 569
 570     blockdev->info = blk_supports_write_perm(conf->blk) ? 0 : VDISK_READONLY;
 571 }
 572
 573 static void xen_disk_class_init(ObjectClass *class, void *data)
 574 {
 575     DeviceClass *dev_class = DEVICE_CLASS(class);
 576     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 577
 578     blockdev_class->realize = xen_disk_realize;
 579     blockdev_class->unrealize = xen_disk_unrealize;
 580
 581     dev_class->desc = "Xen Disk Device";
 582 }
 583
 584 static const TypeInfo xen_disk_type_info = {
 585     .name = TYPE_XEN_DISK_DEVICE,
 586     .parent = TYPE_XEN_BLOCK_DEVICE,
 587     .instance_size = sizeof(XenDiskDevice),
 588     .class_init = xen_disk_class_init,
 589 };
 590
 591 static void xen_cdrom_unrealize(XenBlockDevice *blockdev)
 592 {
 593     trace_xen_cdrom_unrealize();
 594 }
 595
 596 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
 597 {
 598     BlockConf *conf = &blockdev->props.conf;
 599
 600     trace_xen_cdrom_realize();
 601
 602     blockdev->device_type = "cdrom";
 603
 604     if (!conf->blk) {
 605         int rc;
 606
 607         /* Set up an empty drive */
 608         conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
 609
 610         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
 611         if (!rc) {
 612             error_setg_errno(errp, -rc, "failed to create drive");
 613             return;
 614         }
 615     }
 616
 617     blockdev->info = VDISK_READONLY | VDISK_CDROM;
 618 }
 619
 620 static void xen_cdrom_class_init(ObjectClass *class, void *data)
 621 {
 622     DeviceClass *dev_class = DEVICE_CLASS(class);
 623     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
 624
 625     blockdev_class->realize = xen_cdrom_realize;
 626     blockdev_class->unrealize = xen_cdrom_unrealize;
 627
 628     dev_class->desc = "Xen CD-ROM Device";
 629 }
 630
 631 static const TypeInfo xen_cdrom_type_info = {
 632     .name = TYPE_XEN_CDROM_DEVICE,
 633     .parent = TYPE_XEN_BLOCK_DEVICE,
 634     .instance_size = sizeof(XenCDRomDevice),
 635     .class_init = xen_cdrom_class_init,
 636 };
 637
 638 static void xen_block_register_types(void)
 639 {
 640     type_register_static(&xen_block_type_info);
 641     type_register_static(&xen_disk_type_info);
 642     type_register_static(&xen_cdrom_type_info);
 643 }
 644
 645 type_init(xen_block_register_types)
 646
 647 static void xen_block_blockdev_del(const char *node_name, Error **errp)
 648 {
 649     trace_xen_block_blockdev_del(node_name);
 650
 651     qmp_blockdev_del(node_name, errp);
 652 }
 653
 654 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
 655                                     Error **errp)
 656 {
 657     ERRP_GUARD();
 658     const char *driver = qdict_get_try_str(qdict, "driver");
 659     BlockdevOptions *options = NULL;
 660     char *node_name;
 661     Visitor *v;
 662
 663     if (!driver) {
 664         error_setg(errp, "no 'driver' parameter");
 665         return NULL;
 666     }
 667
 668     node_name = g_strdup_printf("%s-%s", id, driver);
 669     qdict_put_str(qdict, "node-name", node_name);
 670
 671     trace_xen_block_blockdev_add(node_name);
 672
 673     v = qobject_input_visitor_new(QOBJECT(qdict));
 674     visit_type_BlockdevOptions(v, NULL, &options, errp);
 675     visit_free(v);
 676     if (!options) {
 677         goto fail;
 678     }
 679
 680     qmp_blockdev_add(options, errp);
 681
 682     if (*errp) {
 683         goto fail;
 684     }
 685
 686     qapi_free_BlockdevOptions(options);
 687
 688     return node_name;
 689
 690 fail:
 691     if (options) {
 692         qapi_free_BlockdevOptions(options);
 693     }
 694     g_free(node_name);
 695
 696     return NULL;
 697 }
 698
 699 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
 700 {
 701     ERRP_GUARD();
 702     char *node_name = drive->node_name;
 703
 704     if (node_name) {
 705         xen_block_blockdev_del(node_name, errp);
 706         if (*errp) {
 707             return;
 708         }
 709         g_free(node_name);
 710         drive->node_name = NULL;
 711     }
 712     g_free(drive->id);
 713     g_free(drive);
 714 }
 715
 716 static XenBlockDrive *xen_block_drive_create(const char *id,
 717                                              const char *device_type,
 718                                              QDict *opts, Error **errp)
 719 {
 720     ERRP_GUARD();
 721     const char *params = qdict_get_try_str(opts, "params");
 722     const char *mode = qdict_get_try_str(opts, "mode");
 723     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
 724     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
 725     char *driver = NULL;
 726     char *filename = NULL;
 727     XenBlockDrive *drive = NULL;
 728     QDict *file_layer;
 729     QDict *driver_layer;
 730     struct stat st;
 731     int rc;
 732
 733     if (params) {
 734         char **v = g_strsplit(params, ":", 2);
 735
 736         if (v[1] == NULL) {
 737             filename = g_strdup(v[0]);
 738             driver = g_strdup("raw");
 739         } else {
 740             if (strcmp(v[0], "aio") == 0) {
 741                 driver = g_strdup("raw");
 742             } else if (strcmp(v[0], "vhd") == 0) {
 743                 driver = g_strdup("vpc");
 744             } else {
 745                 driver = g_strdup(v[0]);
 746             }
 747             filename = g_strdup(v[1]);
 748         }
 749
 750         g_strfreev(v);
 751     } else {
 752         error_setg(errp, "no params");
 753         goto done;
 754     }
 755
 756     assert(filename);
 757     assert(driver);
 758
 759     drive = g_new0(XenBlockDrive, 1);
 760     drive->id = g_strdup(id);
 761
 762     file_layer = qdict_new();
 763     driver_layer = qdict_new();
 764
 765     rc = stat(filename, &st);
 766     if (rc) {
 767         error_setg_errno(errp, errno, "Could not stat file '%s'", filename);
 768         goto done;
 769     }
 770     if (S_ISBLK(st.st_mode)) {
 771         qdict_put_str(file_layer, "driver", "host_device");
 772     } else {
 773         qdict_put_str(file_layer, "driver", "file");
 774     }
 775
 776     qdict_put_str(file_layer, "filename", filename);
 777     g_free(filename);
 778
 779     if (mode && *mode != 'w') {
 780         qdict_put_bool(file_layer, "read-only", true);
 781     }
 782
 783     if (direct_io_safe) {
 784         unsigned long value;
 785
 786         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
 787             QDict *cache_qdict = qdict_new();
 788
 789             qdict_put_bool(cache_qdict, "direct", true);
 790             qdict_put(file_layer, "cache", cache_qdict);
 791
 792             qdict_put_str(file_layer, "aio", "native");
 793         }
 794     }
 795
 796     if (discard_enable) {
 797         unsigned long value;
 798
 799         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
 800             qdict_put_str(file_layer, "discard", "unmap");
 801             qdict_put_str(driver_layer, "discard", "unmap");
 802         }
 803     }
 804
 805     /*
 806      * It is necessary to turn file locking off as an emulated device
 807      * may have already opened the same image file.
 808      */
 809     qdict_put_str(file_layer, "locking", "off");
 810
 811     qdict_put_str(driver_layer, "driver", driver);
 812     g_free(driver);
 813
 814     qdict_put(driver_layer, "file", file_layer);
 815
 816     g_assert(!drive->node_name);
 817     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
 818                                               errp);
 819
 820     qobject_unref(driver_layer);
 821
 822 done:
 823     if (*errp) {
 824         xen_block_drive_destroy(drive, NULL);
 825         return NULL;
 826     }
 827
 828     return drive;
 829 }
 830
 831 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
 832 {
 833     return drive->node_name ? drive->node_name : "";
 834 }
 835
 836 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
 837                                        Error **errp)
 838 {
 839     qmp_object_del(iothread->id, errp);
 840
 841     g_free(iothread->id);
 842     g_free(iothread);
 843 }
 844
 845 static XenBlockIOThread *xen_block_iothread_create(const char *id,
 846                                                    Error **errp)
 847 {
 848     ERRP_GUARD();
 849     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
 850     ObjectOptions *opts;
 851
 852     iothread->id = g_strdup(id);
 853
 854     opts = g_new(ObjectOptions, 1);
 855     *opts = (ObjectOptions) {
 856         .qom_type = OBJECT_TYPE_IOTHREAD,
 857         .id = g_strdup(id),
 858     };
 859     qmp_object_add(opts, errp);
 860     qapi_free_ObjectOptions(opts);
 861
 862     if (*errp) {
 863         g_free(iothread->id);
 864         g_free(iothread);
 865         return NULL;
 866     }
 867
 868     return iothread;
 869 }
 870
 871 static void xen_block_device_create(XenBackendInstance *backend,
 872                                     QDict *opts, Error **errp)
 873 {
 874     ERRP_GUARD();
 875     XenBus *xenbus = xen_backend_get_bus(backend);
 876     const char *name = xen_backend_get_name(backend);
 877     unsigned long number;
 878     const char *vdev, *device_type;
 879     XenBlockDrive *drive = NULL;
 880     XenBlockIOThread *iothread = NULL;
 881     XenDevice *xendev = NULL;
 882     const char *type;
 883     XenBlockDevice *blockdev;
 884
 885     if (qemu_strtoul(name, NULL, 10, &number)) {
 886         error_setg(errp, "failed to parse name '%s'", name);
 887         goto fail;
 888     }
 889
 890     trace_xen_block_device_create(number);
 891
 892     vdev = qdict_get_try_str(opts, "dev");
 893     if (!vdev) {
 894         error_setg(errp, "no dev parameter");
 895         goto fail;
 896     }
 897
 898     device_type = qdict_get_try_str(opts, "device-type");
 899     if (!device_type) {
 900         error_setg(errp, "no device-type parameter");
 901         goto fail;
 902     }
 903
 904     if (!strcmp(device_type, "disk")) {
 905         type = TYPE_XEN_DISK_DEVICE;
 906     } else if (!strcmp(device_type, "cdrom")) {
 907         type = TYPE_XEN_CDROM_DEVICE;
 908     } else {
 909         error_setg(errp, "invalid device-type parameter '%s'", device_type);
 910         goto fail;
 911     }
 912
 913     drive = xen_block_drive_create(vdev, device_type, opts, errp);
 914     if (!drive) {
 915         error_prepend(errp, "failed to create drive: ");
 916         goto fail;
 917     }
 918
 919     iothread = xen_block_iothread_create(vdev, errp);
 920     if (*errp) {
 921         error_prepend(errp, "failed to create iothread: ");
 922         goto fail;
 923     }
 924
 925     xendev = XEN_DEVICE(qdev_new(type));
 926     blockdev = XEN_BLOCK_DEVICE(xendev);
 927
 928     if (!object_property_set_str(OBJECT(xendev), "vdev", vdev,
 929                                  errp)) {
 930         error_prepend(errp, "failed to set 'vdev': ");
 931         goto fail;
 932     }
 933
 934     if (!object_property_set_str(OBJECT(xendev), "drive",
 935                                  xen_block_drive_get_node_name(drive),
 936                                  errp)) {
 937         error_prepend(errp, "failed to set 'drive': ");
 938         goto fail;
 939     }
 940
 941     if (!object_property_set_str(OBJECT(xendev), "iothread", iothread->id,
 942                                  errp)) {
 943         error_prepend(errp, "failed to set 'iothread': ");
 944         goto fail;
 945     }
 946
 947     blockdev->iothread = iothread;
 948     blockdev->drive = drive;
 949
 950     if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) {
 951         error_prepend(errp, "realization of device %s failed: ", type);
 952         goto fail;
 953     }
 954
 955     xen_backend_set_device(backend, xendev);
 956     return;
 957
 958 fail:
 959     if (xendev) {
 960         object_unparent(OBJECT(xendev));
 961     }
 962
 963     if (iothread) {
 964         xen_block_iothread_destroy(iothread, NULL);
 965     }
 966
 967     if (drive) {
 968         xen_block_drive_destroy(drive, NULL);
 969     }
 970 }
 971
 972 static void xen_block_device_destroy(XenBackendInstance *backend,
 973                                      Error **errp)
 974 {
 975     ERRP_GUARD();
 976     XenDevice *xendev = xen_backend_get_device(backend);
 977     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
 978     XenBlockVdev *vdev = &blockdev->props.vdev;
 979     XenBlockDrive *drive = blockdev->drive;
 980     XenBlockIOThread *iothread = blockdev->iothread;
 981
 982     trace_xen_block_device_destroy(vdev->number);
 983
 984     object_unparent(OBJECT(xendev));
 985
 986     /*
 987      * Drain all pending RCU callbacks as object_unparent() frees `xendev'
 988      * in a RCU callback.
 989      * And due to the property "drive" still existing in `xendev', we
 990      * can't destroy the XenBlockDrive associated with `xendev' with
 991      * xen_block_drive_destroy() below.
 992      */
 993     drain_call_rcu();
 994
 995     if (iothread) {
 996         xen_block_iothread_destroy(iothread, errp);
 997         if (*errp) {
 998             error_prepend(errp, "failed to destroy iothread: ");
 999             return;
1000         }
1001     }
1002
1003     if (drive) {
1004         xen_block_drive_destroy(drive, errp);
1005         if (*errp) {
1006             error_prepend(errp, "failed to destroy drive: ");
1007             return;
1008         }
1009     }
1010 }
1011
1012 static const XenBackendInfo xen_block_backend_info = {
1013     .type = "qdisk",
1014     .create = xen_block_device_create,
1015     .destroy = xen_block_device_destroy,
1016 };
1017
1018 static void xen_block_register_backend(void)
1019 {
1020     xen_backend_register(&xen_block_backend_info);
1021 }
1022
1023 xen_backend_init(xen_block_register_backend);