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