hw/xen/xen-bus.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/main-loop.h"
  10 #include "qemu/module.h"
  11 #include "qemu/uuid.h"
  12 #include "hw/qdev-properties.h"
  13 #include "hw/sysbus.h"
  14 #include "hw/xen/xen.h"
  15 #include "hw/xen/xen-backend.h"
  16 #include "hw/xen/xen-bus.h"
  17 #include "hw/xen/xen-bus-helper.h"
  18 #include "monitor/monitor.h"
  19 #include "qapi/error.h"
  20 #include "qapi/qmp/qdict.h"
  21 #include "sysemu/sysemu.h"
  22 #include "trace.h"
  23
  24 static char *xen_device_get_backend_path(XenDevice *xendev)
  25 {
  26     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
  27     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
  28     const char *type = object_get_typename(OBJECT(xendev));
  29     const char *backend = xendev_class->backend;
  30
  31     if (!backend) {
  32         backend = type;
  33     }
  34
  35     return g_strdup_printf("/local/domain/%u/backend/%s/%u/%s",
  36                            xenbus->backend_id, backend, xendev->frontend_id,
  37                            xendev->name);
  38 }
  39
  40 static char *xen_device_get_frontend_path(XenDevice *xendev)
  41 {
  42     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
  43     const char *type = object_get_typename(OBJECT(xendev));
  44     const char *device = xendev_class->device;
  45
  46     if (!device) {
  47         device = type;
  48     }
  49
  50     return g_strdup_printf("/local/domain/%u/device/%s/%s",
  51                            xendev->frontend_id, device, xendev->name);
  52 }
  53
  54 static void xen_device_unplug(XenDevice *xendev, Error **errp)
  55 {
  56     ERRP_GUARD();
  57     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
  58     const char *type = object_get_typename(OBJECT(xendev));
  59     xs_transaction_t tid;
  60
  61     trace_xen_device_unplug(type, xendev->name);
  62
  63     /* Mimic the way the Xen toolstack does an unplug */
  64 again:
  65     tid = xs_transaction_start(xenbus->xsh);
  66     if (tid == XBT_NULL) {
  67         error_setg_errno(errp, errno, "failed xs_transaction_start");
  68         return;
  69     }
  70
  71     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "online",
  72                    errp, "%u", 0);
  73     if (*errp) {
  74         goto abort;
  75     }
  76
  77     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "state",
  78                    errp, "%u", XenbusStateClosing);
  79     if (*errp) {
  80         goto abort;
  81     }
  82
  83     if (!xs_transaction_end(xenbus->xsh, tid, false)) {
  84         if (errno == EAGAIN) {
  85             goto again;
  86         }
  87
  88         error_setg_errno(errp, errno, "failed xs_transaction_end");
  89     }
  90
  91     return;
  92
  93 abort:
  94     /*
  95      * We only abort if there is already a failure so ignore any error
  96      * from ending the transaction.
  97      */
  98     xs_transaction_end(xenbus->xsh, tid, true);
  99 }
 100
 101 static void xen_bus_print_dev(Monitor *mon, DeviceState *dev, int indent)
 102 {
 103     XenDevice *xendev = XEN_DEVICE(dev);
 104
 105     monitor_printf(mon, "%*sname = '%s' frontend_id = %u\n",
 106                    indent, "", xendev->name, xendev->frontend_id);
 107 }
 108
 109 static char *xen_bus_get_dev_path(DeviceState *dev)
 110 {
 111     return xen_device_get_backend_path(XEN_DEVICE(dev));
 112 }
 113
 114 struct XenWatch {
 115     char *node, *key;
 116     char *token;
 117     XenWatchHandler handler;
 118     void *opaque;
 119     Notifier notifier;
 120 };
 121
 122 static void watch_notify(Notifier *n, void *data)
 123 {
 124     XenWatch *watch = container_of(n, XenWatch, notifier);
 125     const char *token = data;
 126
 127     if (!strcmp(watch->token, token)) {
 128         watch->handler(watch->opaque);
 129     }
 130 }
 131
 132 static XenWatch *new_watch(const char *node, const char *key,
 133                            XenWatchHandler handler, void *opaque)
 134 {
 135     XenWatch *watch = g_new0(XenWatch, 1);
 136     QemuUUID uuid;
 137
 138     qemu_uuid_generate(&uuid);
 139
 140     watch->token = qemu_uuid_unparse_strdup(&uuid);
 141     watch->node = g_strdup(node);
 142     watch->key = g_strdup(key);
 143     watch->handler = handler;
 144     watch->opaque = opaque;
 145     watch->notifier.notify = watch_notify;
 146
 147     return watch;
 148 }
 149
 150 static void free_watch(XenWatch *watch)
 151 {
 152     g_free(watch->token);
 153     g_free(watch->key);
 154     g_free(watch->node);
 155
 156     g_free(watch);
 157 }
 158
 159 struct XenWatchList {
 160     struct xs_handle *xsh;
 161     NotifierList notifiers;
 162 };
 163
 164 static void watch_list_event(void *opaque)
 165 {
 166     XenWatchList *watch_list = opaque;
 167     char **v;
 168     const char *token;
 169
 170     v = xs_check_watch(watch_list->xsh);
 171     if (!v) {
 172         return;
 173     }
 174
 175     token = v[XS_WATCH_TOKEN];
 176
 177     notifier_list_notify(&watch_list->notifiers, (void *)token);
 178
 179     free(v);
 180 }
 181
 182 static XenWatchList *watch_list_create(struct xs_handle *xsh)
 183 {
 184     XenWatchList *watch_list = g_new0(XenWatchList, 1);
 185
 186     g_assert(xsh);
 187
 188     watch_list->xsh = xsh;
 189     notifier_list_init(&watch_list->notifiers);
 190     qemu_set_fd_handler(xs_fileno(watch_list->xsh), watch_list_event, NULL,
 191                         watch_list);
 192
 193     return watch_list;
 194 }
 195
 196 static void watch_list_destroy(XenWatchList *watch_list)
 197 {
 198     g_assert(notifier_list_empty(&watch_list->notifiers));
 199     qemu_set_fd_handler(xs_fileno(watch_list->xsh), NULL, NULL, NULL);
 200     g_free(watch_list);
 201 }
 202
 203 static XenWatch *watch_list_add(XenWatchList *watch_list, const char *node,
 204                                 const char *key, XenWatchHandler handler,
 205                                 void *opaque, Error **errp)
 206 {
 207     ERRP_GUARD();
 208     XenWatch *watch = new_watch(node, key, handler, opaque);
 209
 210     notifier_list_add(&watch_list->notifiers, &watch->notifier);
 211
 212     xs_node_watch(watch_list->xsh, node, key, watch->token, errp);
 213     if (*errp) {
 214         notifier_remove(&watch->notifier);
 215         free_watch(watch);
 216
 217         return NULL;
 218     }
 219
 220     return watch;
 221 }
 222
 223 static void watch_list_remove(XenWatchList *watch_list, XenWatch *watch,
 224                               Error **errp)
 225 {
 226     xs_node_unwatch(watch_list->xsh, watch->node, watch->key, watch->token,
 227                     errp);
 228
 229     notifier_remove(&watch->notifier);
 230     free_watch(watch);
 231 }
 232
 233 static XenWatch *xen_bus_add_watch(XenBus *xenbus, const char *node,
 234                                    const char *key, XenWatchHandler handler,
 235                                    Error **errp)
 236 {
 237     trace_xen_bus_add_watch(node, key);
 238
 239     return watch_list_add(xenbus->watch_list, node, key, handler, xenbus,
 240                           errp);
 241 }
 242
 243 static void xen_bus_remove_watch(XenBus *xenbus, XenWatch *watch,
 244                                  Error **errp)
 245 {
 246     trace_xen_bus_remove_watch(watch->node, watch->key);
 247
 248     watch_list_remove(xenbus->watch_list, watch, errp);
 249 }
 250
 251 static void xen_bus_backend_create(XenBus *xenbus, const char *type,
 252                                    const char *name, char *path,
 253                                    Error **errp)
 254 {
 255     ERRP_GUARD();
 256     xs_transaction_t tid;
 257     char **key;
 258     QDict *opts;
 259     unsigned int i, n;
 260
 261     trace_xen_bus_backend_create(type, path);
 262
 263 again:
 264     tid = xs_transaction_start(xenbus->xsh);
 265     if (tid == XBT_NULL) {
 266         error_setg(errp, "failed xs_transaction_start");
 267         return;
 268     }
 269
 270     key = xs_directory(xenbus->xsh, tid, path, &n);
 271     if (!key) {
 272         if (!xs_transaction_end(xenbus->xsh, tid, true)) {
 273             error_setg_errno(errp, errno, "failed xs_transaction_end");
 274         }
 275         return;
 276     }
 277
 278     opts = qdict_new();
 279     for (i = 0; i < n; i++) {
 280         char *val;
 281
 282         /*
 283          * Assume anything found in the xenstore backend area, other than
 284          * the keys created for a generic XenDevice, are parameters
 285          * to be used to configure the backend.
 286          */
 287         if (!strcmp(key[i], "state") ||
 288             !strcmp(key[i], "online") ||
 289             !strcmp(key[i], "frontend") ||
 290             !strcmp(key[i], "frontend-id") ||
 291             !strcmp(key[i], "hotplug-status"))
 292             continue;
 293
 294         if (xs_node_scanf(xenbus->xsh, tid, path, key[i], NULL, "%ms",
 295                           &val) == 1) {
 296             qdict_put_str(opts, key[i], val);
 297             free(val);
 298         }
 299     }
 300
 301     free(key);
 302
 303     if (!xs_transaction_end(xenbus->xsh, tid, false)) {
 304         qobject_unref(opts);
 305
 306         if (errno == EAGAIN) {
 307             goto again;
 308         }
 309
 310         error_setg_errno(errp, errno, "failed xs_transaction_end");
 311         return;
 312     }
 313
 314     xen_backend_device_create(xenbus, type, name, opts, errp);
 315     qobject_unref(opts);
 316
 317     if (*errp) {
 318         error_prepend(errp, "failed to create '%s' device '%s': ", type, name);
 319     }
 320 }
 321
 322 static void xen_bus_type_enumerate(XenBus *xenbus, const char *type)
 323 {
 324     char *domain_path = g_strdup_printf("backend/%s/%u", type, xen_domid);
 325     char **backend;
 326     unsigned int i, n;
 327
 328     trace_xen_bus_type_enumerate(type);
 329
 330     backend = xs_directory(xenbus->xsh, XBT_NULL, domain_path, &n);
 331     if (!backend) {
 332         goto out;
 333     }
 334
 335     for (i = 0; i < n; i++) {
 336         char *backend_path = g_strdup_printf("%s/%s", domain_path,
 337                                              backend[i]);
 338         enum xenbus_state state;
 339         unsigned int online;
 340
 341         if (xs_node_scanf(xenbus->xsh, XBT_NULL, backend_path, "state",
 342                           NULL, "%u", &state) != 1)
 343             state = XenbusStateUnknown;
 344
 345         if (xs_node_scanf(xenbus->xsh, XBT_NULL, backend_path, "online",
 346                           NULL, "%u", &online) != 1)
 347             online = 0;
 348
 349         if (online && state == XenbusStateInitialising) {
 350             Error *local_err = NULL;
 351
 352             xen_bus_backend_create(xenbus, type, backend[i], backend_path,
 353                                    &local_err);
 354             if (local_err) {
 355                 error_report_err(local_err);
 356             }
 357         }
 358
 359         g_free(backend_path);
 360     }
 361
 362     free(backend);
 363
 364 out:
 365     g_free(domain_path);
 366 }
 367
 368 static void xen_bus_enumerate(XenBus *xenbus)
 369 {
 370     char **type;
 371     unsigned int i, n;
 372
 373     trace_xen_bus_enumerate();
 374
 375     type = xs_directory(xenbus->xsh, XBT_NULL, "backend", &n);
 376     if (!type) {
 377         return;
 378     }
 379
 380     for (i = 0; i < n; i++) {
 381         xen_bus_type_enumerate(xenbus, type[i]);
 382     }
 383
 384     free(type);
 385 }
 386
 387 static void xen_bus_device_cleanup(XenDevice *xendev)
 388 {
 389     const char *type = object_get_typename(OBJECT(xendev));
 390     Error *local_err = NULL;
 391
 392     trace_xen_bus_device_cleanup(type, xendev->name);
 393
 394     g_assert(!xendev->backend_online);
 395
 396     if (!xen_backend_try_device_destroy(xendev, &local_err)) {
 397         object_unparent(OBJECT(xendev));
 398     }
 399
 400     if (local_err) {
 401         error_report_err(local_err);
 402     }
 403 }
 404
 405 static void xen_bus_cleanup(XenBus *xenbus)
 406 {
 407     XenDevice *xendev, *next;
 408
 409     trace_xen_bus_cleanup();
 410
 411     QLIST_FOREACH_SAFE(xendev, &xenbus->inactive_devices, list, next) {
 412         g_assert(xendev->inactive);
 413         QLIST_REMOVE(xendev, list);
 414         xen_bus_device_cleanup(xendev);
 415     }
 416 }
 417
 418 static void xen_bus_backend_changed(void *opaque)
 419 {
 420     XenBus *xenbus = opaque;
 421
 422     xen_bus_enumerate(xenbus);
 423     xen_bus_cleanup(xenbus);
 424 }
 425
 426 static void xen_bus_unrealize(BusState *bus)
 427 {
 428     XenBus *xenbus = XEN_BUS(bus);
 429
 430     trace_xen_bus_unrealize();
 431
 432     if (xenbus->backend_watch) {
 433         xen_bus_remove_watch(xenbus, xenbus->backend_watch, NULL);
 434         xenbus->backend_watch = NULL;
 435     }
 436
 437     if (xenbus->watch_list) {
 438         watch_list_destroy(xenbus->watch_list);
 439         xenbus->watch_list = NULL;
 440     }
 441
 442     if (xenbus->xsh) {
 443         xs_close(xenbus->xsh);
 444     }
 445 }
 446
 447 static void xen_bus_realize(BusState *bus, Error **errp)
 448 {
 449     XenBus *xenbus = XEN_BUS(bus);
 450     unsigned int domid;
 451     Error *local_err = NULL;
 452
 453     trace_xen_bus_realize();
 454
 455     xenbus->xsh = xs_open(0);
 456     if (!xenbus->xsh) {
 457         error_setg_errno(errp, errno, "failed xs_open");
 458         goto fail;
 459     }
 460
 461     if (xs_node_scanf(xenbus->xsh, XBT_NULL, "", /* domain root node */
 462                       "domid", NULL, "%u", &domid) == 1) {
 463         xenbus->backend_id = domid;
 464     } else {
 465         xenbus->backend_id = 0; /* Assume lack of node means dom0 */
 466     }
 467
 468     xenbus->watch_list = watch_list_create(xenbus->xsh);
 469
 470     module_call_init(MODULE_INIT_XEN_BACKEND);
 471
 472     xenbus->backend_watch =
 473         xen_bus_add_watch(xenbus, "", /* domain root node */
 474                           "backend", xen_bus_backend_changed, &local_err);
 475     if (local_err) {
 476         /* This need not be treated as a hard error so don't propagate */
 477         error_reportf_err(local_err,
 478                           "failed to set up enumeration watch: ");
 479     }
 480
 481     return;
 482
 483 fail:
 484     xen_bus_unrealize(bus);
 485 }
 486
 487 static void xen_bus_unplug_request(HotplugHandler *hotplug,
 488                                    DeviceState *dev,
 489                                    Error **errp)
 490 {
 491     XenDevice *xendev = XEN_DEVICE(dev);
 492
 493     xen_device_unplug(xendev, errp);
 494 }
 495
 496 static void xen_bus_class_init(ObjectClass *class, void *data)
 497 {
 498     BusClass *bus_class = BUS_CLASS(class);
 499     HotplugHandlerClass *hotplug_class = HOTPLUG_HANDLER_CLASS(class);
 500
 501     bus_class->print_dev = xen_bus_print_dev;
 502     bus_class->get_dev_path = xen_bus_get_dev_path;
 503     bus_class->realize = xen_bus_realize;
 504     bus_class->unrealize = xen_bus_unrealize;
 505
 506     hotplug_class->unplug_request = xen_bus_unplug_request;
 507 }
 508
 509 static const TypeInfo xen_bus_type_info = {
 510     .name = TYPE_XEN_BUS,
 511     .parent = TYPE_BUS,
 512     .instance_size = sizeof(XenBus),
 513     .class_size = sizeof(XenBusClass),
 514     .class_init = xen_bus_class_init,
 515     .interfaces = (InterfaceInfo[]) {
 516         { TYPE_HOTPLUG_HANDLER },
 517         { }
 518     },
 519 };
 520
 521 void xen_device_backend_printf(XenDevice *xendev, const char *key,
 522                                const char *fmt, ...)
 523 {
 524     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 525     Error *local_err = NULL;
 526     va_list ap;
 527
 528     g_assert(xenbus->xsh);
 529
 530     va_start(ap, fmt);
 531     xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
 532                     &local_err, fmt, ap);
 533     va_end(ap);
 534
 535     if (local_err) {
 536         error_report_err(local_err);
 537     }
 538 }
 539
 540 static int xen_device_backend_scanf(XenDevice *xendev, const char *key,
 541                                     const char *fmt, ...)
 542 {
 543     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 544     va_list ap;
 545     int rc;
 546
 547     g_assert(xenbus->xsh);
 548
 549     va_start(ap, fmt);
 550     rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
 551                         NULL, fmt, ap);
 552     va_end(ap);
 553
 554     return rc;
 555 }
 556
 557 void xen_device_backend_set_state(XenDevice *xendev,
 558                                   enum xenbus_state state)
 559 {
 560     const char *type = object_get_typename(OBJECT(xendev));
 561
 562     if (xendev->backend_state == state) {
 563         return;
 564     }
 565
 566     trace_xen_device_backend_state(type, xendev->name,
 567                                    xs_strstate(state));
 568
 569     xendev->backend_state = state;
 570     xen_device_backend_printf(xendev, "state", "%u", state);
 571 }
 572
 573 enum xenbus_state xen_device_backend_get_state(XenDevice *xendev)
 574 {
 575     return xendev->backend_state;
 576 }
 577
 578 static void xen_device_backend_set_online(XenDevice *xendev, bool online)
 579 {
 580     const char *type = object_get_typename(OBJECT(xendev));
 581
 582     if (xendev->backend_online == online) {
 583         return;
 584     }
 585
 586     trace_xen_device_backend_online(type, xendev->name, online);
 587
 588     xendev->backend_online = online;
 589     xen_device_backend_printf(xendev, "online", "%u", online);
 590 }
 591
 592 /*
 593  * Tell from the state whether the frontend is likely alive,
 594  * i.e. it will react to a change of state of the backend.
 595  */
 596 static bool xen_device_frontend_is_active(XenDevice *xendev)
 597 {
 598     switch (xendev->frontend_state) {
 599     case XenbusStateInitWait:
 600     case XenbusStateInitialised:
 601     case XenbusStateConnected:
 602     case XenbusStateClosing:
 603         return true;
 604     default:
 605         return false;
 606     }
 607 }
 608
 609 static void xen_device_backend_changed(void *opaque)
 610 {
 611     XenDevice *xendev = opaque;
 612     const char *type = object_get_typename(OBJECT(xendev));
 613     enum xenbus_state state;
 614     unsigned int online;
 615
 616     trace_xen_device_backend_changed(type, xendev->name);
 617
 618     if (xen_device_backend_scanf(xendev, "state", "%u", &state) != 1) {
 619         state = XenbusStateUnknown;
 620     }
 621
 622     xen_device_backend_set_state(xendev, state);
 623
 624     if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) {
 625         online = 0;
 626     }
 627
 628     xen_device_backend_set_online(xendev, !!online);
 629
 630     /*
 631      * If the toolstack (or unplug request callback) has set the backend
 632      * state to Closing, but there is no active frontend then set the
 633      * backend state to Closed.
 634      */
 635     if (state == XenbusStateClosing &&
 636         !xen_device_frontend_is_active(xendev)) {
 637         xen_device_backend_set_state(xendev, XenbusStateClosed);
 638     }
 639
 640     /*
 641      * If a backend is still 'online' then we should leave it alone but,
 642      * if a backend is not 'online', then the device is a candidate
 643      * for destruction. Hence add it to the 'inactive' list to be cleaned
 644      * by xen_bus_cleanup().
 645      */
 646     if (!online &&
 647         (state == XenbusStateClosed ||  state == XenbusStateInitialising ||
 648          state == XenbusStateInitWait || state == XenbusStateUnknown) &&
 649         !xendev->inactive) {
 650         XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 651
 652         xendev->inactive = true;
 653         QLIST_INSERT_HEAD(&xenbus->inactive_devices, xendev, list);
 654
 655         /*
 656          * Re-write the state to cause a XenBus backend_watch notification,
 657          * resulting in a call to xen_bus_cleanup().
 658          */
 659         xen_device_backend_printf(xendev, "state", "%u", state);
 660     }
 661 }
 662
 663 static XenWatch *xen_device_add_watch(XenDevice *xendev, const char *node,
 664                                       const char *key,
 665                                       XenWatchHandler handler,
 666                                       Error **errp)
 667 {
 668     const char *type = object_get_typename(OBJECT(xendev));
 669
 670     trace_xen_device_add_watch(type, xendev->name, node, key);
 671
 672     return watch_list_add(xendev->watch_list, node, key, handler, xendev,
 673                           errp);
 674 }
 675
 676 static void xen_device_remove_watch(XenDevice *xendev, XenWatch *watch,
 677                                     Error **errp)
 678 {
 679     const char *type = object_get_typename(OBJECT(xendev));
 680
 681     trace_xen_device_remove_watch(type, xendev->name, watch->node,
 682                                   watch->key);
 683
 684     watch_list_remove(xendev->watch_list, watch, errp);
 685 }
 686
 687
 688 static void xen_device_backend_create(XenDevice *xendev, Error **errp)
 689 {
 690     ERRP_GUARD();
 691     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 692     struct xs_permissions perms[2];
 693
 694     xendev->backend_path = xen_device_get_backend_path(xendev);
 695
 696     perms[0].id = xenbus->backend_id;
 697     perms[0].perms = XS_PERM_NONE;
 698     perms[1].id = xendev->frontend_id;
 699     perms[1].perms = XS_PERM_READ;
 700
 701     g_assert(xenbus->xsh);
 702
 703     xs_node_create(xenbus->xsh, XBT_NULL, xendev->backend_path, perms,
 704                    ARRAY_SIZE(perms), errp);
 705     if (*errp) {
 706         error_prepend(errp, "failed to create backend: ");
 707         return;
 708     }
 709
 710     xendev->backend_state_watch =
 711         xen_device_add_watch(xendev, xendev->backend_path,
 712                              "state", xen_device_backend_changed,
 713                              errp);
 714     if (*errp) {
 715         error_prepend(errp, "failed to watch backend state: ");
 716         return;
 717     }
 718
 719     xendev->backend_online_watch =
 720         xen_device_add_watch(xendev, xendev->backend_path,
 721                              "online", xen_device_backend_changed,
 722                              errp);
 723     if (*errp) {
 724         error_prepend(errp, "failed to watch backend online: ");
 725         return;
 726     }
 727 }
 728
 729 static void xen_device_backend_destroy(XenDevice *xendev)
 730 {
 731     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 732     Error *local_err = NULL;
 733
 734     if (xendev->backend_online_watch) {
 735         xen_device_remove_watch(xendev, xendev->backend_online_watch, NULL);
 736         xendev->backend_online_watch = NULL;
 737     }
 738
 739     if (xendev->backend_state_watch) {
 740         xen_device_remove_watch(xendev, xendev->backend_state_watch, NULL);
 741         xendev->backend_state_watch = NULL;
 742     }
 743
 744     if (!xendev->backend_path) {
 745         return;
 746     }
 747
 748     g_assert(xenbus->xsh);
 749
 750     xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->backend_path,
 751                     &local_err);
 752     g_free(xendev->backend_path);
 753     xendev->backend_path = NULL;
 754
 755     if (local_err) {
 756         error_report_err(local_err);
 757     }
 758 }
 759
 760 void xen_device_frontend_printf(XenDevice *xendev, const char *key,
 761                                 const char *fmt, ...)
 762 {
 763     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 764     Error *local_err = NULL;
 765     va_list ap;
 766
 767     g_assert(xenbus->xsh);
 768
 769     va_start(ap, fmt);
 770     xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
 771                     &local_err, fmt, ap);
 772     va_end(ap);
 773
 774     if (local_err) {
 775         error_report_err(local_err);
 776     }
 777 }
 778
 779 int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
 780                               const char *fmt, ...)
 781 {
 782     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 783     va_list ap;
 784     int rc;
 785
 786     g_assert(xenbus->xsh);
 787
 788     va_start(ap, fmt);
 789     rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
 790                         NULL, fmt, ap);
 791     va_end(ap);
 792
 793     return rc;
 794 }
 795
 796 static void xen_device_frontend_set_state(XenDevice *xendev,
 797                                           enum xenbus_state state,
 798                                           bool publish)
 799 {
 800     const char *type = object_get_typename(OBJECT(xendev));
 801
 802     if (xendev->frontend_state == state) {
 803         return;
 804     }
 805
 806     trace_xen_device_frontend_state(type, xendev->name,
 807                                     xs_strstate(state));
 808
 809     xendev->frontend_state = state;
 810     if (publish) {
 811         xen_device_frontend_printf(xendev, "state", "%u", state);
 812     }
 813 }
 814
 815 static void xen_device_frontend_changed(void *opaque)
 816 {
 817     XenDevice *xendev = opaque;
 818     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
 819     const char *type = object_get_typename(OBJECT(xendev));
 820     enum xenbus_state state;
 821
 822     trace_xen_device_frontend_changed(type, xendev->name);
 823
 824     if (xen_device_frontend_scanf(xendev, "state", "%u", &state) != 1) {
 825         state = XenbusStateUnknown;
 826     }
 827
 828     xen_device_frontend_set_state(xendev, state, false);
 829
 830     if (state == XenbusStateInitialising &&
 831         xendev->backend_state == XenbusStateClosed &&
 832         xendev->backend_online) {
 833         /*
 834          * The frontend is re-initializing so switch back to
 835          * InitWait.
 836          */
 837         xen_device_backend_set_state(xendev, XenbusStateInitWait);
 838         return;
 839     }
 840
 841     if (xendev_class->frontend_changed) {
 842         Error *local_err = NULL;
 843
 844         xendev_class->frontend_changed(xendev, state, &local_err);
 845
 846         if (local_err) {
 847             error_reportf_err(local_err, "frontend change error: ");
 848         }
 849     }
 850 }
 851
 852 static bool xen_device_frontend_exists(XenDevice *xendev)
 853 {
 854     enum xenbus_state state;
 855
 856     return (xen_device_frontend_scanf(xendev, "state", "%u", &state) == 1);
 857 }
 858
 859 static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
 860 {
 861     ERRP_GUARD();
 862     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 863     struct xs_permissions perms[2];
 864
 865     xendev->frontend_path = xen_device_get_frontend_path(xendev);
 866
 867     /*
 868      * The frontend area may have already been created by a legacy
 869      * toolstack.
 870      */
 871     if (!xen_device_frontend_exists(xendev)) {
 872         perms[0].id = xendev->frontend_id;
 873         perms[0].perms = XS_PERM_NONE;
 874         perms[1].id = xenbus->backend_id;
 875         perms[1].perms = XS_PERM_READ | XS_PERM_WRITE;
 876
 877         g_assert(xenbus->xsh);
 878
 879         xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms,
 880                        ARRAY_SIZE(perms), errp);
 881         if (*errp) {
 882             error_prepend(errp, "failed to create frontend: ");
 883             return;
 884         }
 885     }
 886
 887     xendev->frontend_state_watch =
 888         xen_device_add_watch(xendev, xendev->frontend_path, "state",
 889                              xen_device_frontend_changed, errp);
 890     if (*errp) {
 891         error_prepend(errp, "failed to watch frontend state: ");
 892     }
 893 }
 894
 895 static void xen_device_frontend_destroy(XenDevice *xendev)
 896 {
 897     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 898     Error *local_err = NULL;
 899
 900     if (xendev->frontend_state_watch) {
 901         xen_device_remove_watch(xendev, xendev->frontend_state_watch,
 902                                 NULL);
 903         xendev->frontend_state_watch = NULL;
 904     }
 905
 906     if (!xendev->frontend_path) {
 907         return;
 908     }
 909
 910     g_assert(xenbus->xsh);
 911
 912     xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->frontend_path,
 913                     &local_err);
 914     g_free(xendev->frontend_path);
 915     xendev->frontend_path = NULL;
 916
 917     if (local_err) {
 918         error_report_err(local_err);
 919     }
 920 }
 921
 922 void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
 923                                    Error **errp)
 924 {
 925     if (xengnttab_set_max_grants(xendev->xgth, nr_refs)) {
 926         error_setg_errno(errp, errno, "xengnttab_set_max_grants failed");
 927     }
 928 }
 929
 930 void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
 931                                 unsigned int nr_refs, int prot,
 932                                 Error **errp)
 933 {
 934     void *map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_refs,
 935                                                 xendev->frontend_id, refs,
 936                                                 prot);
 937
 938     if (!map) {
 939         error_setg_errno(errp, errno,
 940                          "xengnttab_map_domain_grant_refs failed");
 941     }
 942
 943     return map;
 944 }
 945
 946 void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
 947                                  unsigned int nr_refs, Error **errp)
 948 {
 949     if (xengnttab_unmap(xendev->xgth, map, nr_refs)) {
 950         error_setg_errno(errp, errno, "xengnttab_unmap failed");
 951     }
 952 }
 953
 954 static void compat_copy_grant_refs(XenDevice *xendev, bool to_domain,
 955                                    XenDeviceGrantCopySegment segs[],
 956                                    unsigned int nr_segs, Error **errp)
 957 {
 958     uint32_t *refs = g_new(uint32_t, nr_segs);
 959     int prot = to_domain ? PROT_WRITE : PROT_READ;
 960     void *map;
 961     unsigned int i;
 962
 963     for (i = 0; i < nr_segs; i++) {
 964         XenDeviceGrantCopySegment *seg = &segs[i];
 965
 966         refs[i] = to_domain ? seg->dest.foreign.ref :
 967             seg->source.foreign.ref;
 968     }
 969
 970     map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_segs,
 971                                           xendev->frontend_id, refs,
 972                                           prot);
 973     if (!map) {
 974         error_setg_errno(errp, errno,
 975                          "xengnttab_map_domain_grant_refs failed");
 976         goto done;
 977     }
 978
 979     for (i = 0; i < nr_segs; i++) {
 980         XenDeviceGrantCopySegment *seg = &segs[i];
 981         void *page = map + (i * XC_PAGE_SIZE);
 982
 983         if (to_domain) {
 984             memcpy(page + seg->dest.foreign.offset, seg->source.virt,
 985                    seg->len);
 986         } else {
 987             memcpy(seg->dest.virt, page + seg->source.foreign.offset,
 988                    seg->len);
 989         }
 990     }
 991
 992     if (xengnttab_unmap(xendev->xgth, map, nr_segs)) {
 993         error_setg_errno(errp, errno, "xengnttab_unmap failed");
 994     }
 995
 996 done:
 997     g_free(refs);
 998 }
 999
1000 void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
1001                                 XenDeviceGrantCopySegment segs[],
1002                                 unsigned int nr_segs, Error **errp)
1003 {
1004     xengnttab_grant_copy_segment_t *xengnttab_segs;
1005     unsigned int i;
1006
1007     if (!xendev->feature_grant_copy) {
1008         compat_copy_grant_refs(xendev, to_domain, segs, nr_segs, errp);
1009         return;
1010     }
1011
1012     xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs);
1013
1014     for (i = 0; i < nr_segs; i++) {
1015         XenDeviceGrantCopySegment *seg = &segs[i];
1016         xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
1017
1018         if (to_domain) {
1019             xengnttab_seg->flags = GNTCOPY_dest_gref;
1020             xengnttab_seg->dest.foreign.domid = xendev->frontend_id;
1021             xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref;
1022             xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset;
1023             xengnttab_seg->source.virt = seg->source.virt;
1024         } else {
1025             xengnttab_seg->flags = GNTCOPY_source_gref;
1026             xengnttab_seg->source.foreign.domid = xendev->frontend_id;
1027             xengnttab_seg->source.foreign.ref = seg->source.foreign.ref;
1028             xengnttab_seg->source.foreign.offset =
1029                 seg->source.foreign.offset;
1030             xengnttab_seg->dest.virt = seg->dest.virt;
1031         }
1032
1033         xengnttab_seg->len = seg->len;
1034     }
1035
1036     if (xengnttab_grant_copy(xendev->xgth, nr_segs, xengnttab_segs)) {
1037         error_setg_errno(errp, errno, "xengnttab_grant_copy failed");
1038         goto done;
1039     }
1040
1041     for (i = 0; i < nr_segs; i++) {
1042         xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
1043
1044         if (xengnttab_seg->status != GNTST_okay) {
1045             error_setg(errp, "xengnttab_grant_copy seg[%u] failed", i);
1046             break;
1047         }
1048     }
1049
1050 done:
1051     g_free(xengnttab_segs);
1052 }
1053
1054 struct XenEventChannel {
1055     QLIST_ENTRY(XenEventChannel) list;
1056     AioContext *ctx;
1057     xenevtchn_handle *xeh;
1058     evtchn_port_t local_port;
1059     XenEventHandler handler;
1060     void *opaque;
1061 };
1062
1063 static bool xen_device_poll(void *opaque)
1064 {
1065     XenEventChannel *channel = opaque;
1066
1067     return channel->handler(channel->opaque);
1068 }
1069
1070 static void xen_device_event(void *opaque)
1071 {
1072     XenEventChannel *channel = opaque;
1073     unsigned long port = xenevtchn_pending(channel->xeh);
1074
1075     if (port == channel->local_port) {
1076         xen_device_poll(channel);
1077
1078         xenevtchn_unmask(channel->xeh, port);
1079     }
1080 }
1081
1082 void xen_device_set_event_channel_context(XenDevice *xendev,
1083                                           XenEventChannel *channel,
1084                                           AioContext *ctx,
1085                                           Error **errp)
1086 {
1087     if (!channel) {
1088         error_setg(errp, "bad channel");
1089         return;
1090     }
1091
1092     if (channel->ctx)
1093         aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1094                            NULL, NULL, NULL, NULL);
1095
1096     channel->ctx = ctx;
1097     aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1098                        xen_device_event, NULL, xen_device_poll, channel);
1099 }
1100
1101 XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
1102                                                unsigned int port,
1103                                                XenEventHandler handler,
1104                                                void *opaque, Error **errp)
1105 {
1106     XenEventChannel *channel = g_new0(XenEventChannel, 1);
1107     xenevtchn_port_or_error_t local_port;
1108
1109     channel->xeh = xenevtchn_open(NULL, 0);
1110     if (!channel->xeh) {
1111         error_setg_errno(errp, errno, "failed xenevtchn_open");
1112         goto fail;
1113     }
1114
1115     local_port = xenevtchn_bind_interdomain(channel->xeh,
1116                                             xendev->frontend_id,
1117                                             port);
1118     if (local_port < 0) {
1119         error_setg_errno(errp, errno, "xenevtchn_bind_interdomain failed");
1120         goto fail;
1121     }
1122
1123     channel->local_port = local_port;
1124     channel->handler = handler;
1125     channel->opaque = opaque;
1126
1127     /* Only reason for failure is a NULL channel */
1128     xen_device_set_event_channel_context(xendev, channel,
1129                                          qemu_get_aio_context(),
1130                                          &error_abort);
1131
1132     QLIST_INSERT_HEAD(&xendev->event_channels, channel, list);
1133
1134     return channel;
1135
1136 fail:
1137     if (channel->xeh) {
1138         xenevtchn_close(channel->xeh);
1139     }
1140
1141     g_free(channel);
1142
1143     return NULL;
1144 }
1145
1146 void xen_device_notify_event_channel(XenDevice *xendev,
1147                                      XenEventChannel *channel,
1148                                      Error **errp)
1149 {
1150     if (!channel) {
1151         error_setg(errp, "bad channel");
1152         return;
1153     }
1154
1155     if (xenevtchn_notify(channel->xeh, channel->local_port) < 0) {
1156         error_setg_errno(errp, errno, "xenevtchn_notify failed");
1157     }
1158 }
1159
1160 void xen_device_unbind_event_channel(XenDevice *xendev,
1161                                      XenEventChannel *channel,
1162                                      Error **errp)
1163 {
1164     if (!channel) {
1165         error_setg(errp, "bad channel");
1166         return;
1167     }
1168
1169     QLIST_REMOVE(channel, list);
1170
1171     aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1172                        NULL, NULL, NULL, NULL);
1173
1174     if (xenevtchn_unbind(channel->xeh, channel->local_port) < 0) {
1175         error_setg_errno(errp, errno, "xenevtchn_unbind failed");
1176     }
1177
1178     xenevtchn_close(channel->xeh);
1179     g_free(channel);
1180 }
1181
1182 static void xen_device_unrealize(DeviceState *dev)
1183 {
1184     XenDevice *xendev = XEN_DEVICE(dev);
1185     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
1186     const char *type = object_get_typename(OBJECT(xendev));
1187     XenEventChannel *channel, *next;
1188
1189     if (!xendev->name) {
1190         return;
1191     }
1192
1193     trace_xen_device_unrealize(type, xendev->name);
1194
1195     if (xendev->exit.notify) {
1196         qemu_remove_exit_notifier(&xendev->exit);
1197         xendev->exit.notify = NULL;
1198     }
1199
1200     if (xendev_class->unrealize) {
1201         xendev_class->unrealize(xendev);
1202     }
1203
1204     /* Make sure all event channels are cleaned up */
1205     QLIST_FOREACH_SAFE(channel, &xendev->event_channels, list, next) {
1206         xen_device_unbind_event_channel(xendev, channel, NULL);
1207     }
1208
1209     xen_device_frontend_destroy(xendev);
1210     xen_device_backend_destroy(xendev);
1211
1212     if (xendev->xgth) {
1213         xengnttab_close(xendev->xgth);
1214         xendev->xgth = NULL;
1215     }
1216
1217     if (xendev->watch_list) {
1218         watch_list_destroy(xendev->watch_list);
1219         xendev->watch_list = NULL;
1220     }
1221
1222     if (xendev->xsh) {
1223         xs_close(xendev->xsh);
1224         xendev->xsh = NULL;
1225     }
1226
1227     g_free(xendev->name);
1228     xendev->name = NULL;
1229 }
1230
1231 static void xen_device_exit(Notifier *n, void *data)
1232 {
1233     XenDevice *xendev = container_of(n, XenDevice, exit);
1234
1235     xen_device_unrealize(DEVICE(xendev));
1236 }
1237
1238 static void xen_device_realize(DeviceState *dev, Error **errp)
1239 {
1240     ERRP_GUARD();
1241     XenDevice *xendev = XEN_DEVICE(dev);
1242     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
1243     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
1244     const char *type = object_get_typename(OBJECT(xendev));
1245
1246     if (xendev->frontend_id == DOMID_INVALID) {
1247         xendev->frontend_id = xen_domid;
1248     }
1249
1250     if (xendev->frontend_id >= DOMID_FIRST_RESERVED) {
1251         error_setg(errp, "invalid frontend-id");
1252         goto unrealize;
1253     }
1254
1255     if (!xendev_class->get_name) {
1256         error_setg(errp, "get_name method not implemented");
1257         goto unrealize;
1258     }
1259
1260     xendev->name = xendev_class->get_name(xendev, errp);
1261     if (*errp) {
1262         error_prepend(errp, "failed to get device name: ");
1263         goto unrealize;
1264     }
1265
1266     trace_xen_device_realize(type, xendev->name);
1267
1268     xendev->xsh = xs_open(0);
1269     if (!xendev->xsh) {
1270         error_setg_errno(errp, errno, "failed xs_open");
1271         goto unrealize;
1272     }
1273
1274     xendev->watch_list = watch_list_create(xendev->xsh);
1275
1276     xendev->xgth = xengnttab_open(NULL, 0);
1277     if (!xendev->xgth) {
1278         error_setg_errno(errp, errno, "failed xengnttab_open");
1279         goto unrealize;
1280     }
1281
1282     xendev->feature_grant_copy =
1283         (xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
1284
1285     xen_device_backend_create(xendev, errp);
1286     if (*errp) {
1287         goto unrealize;
1288     }
1289
1290     xen_device_frontend_create(xendev, errp);
1291     if (*errp) {
1292         goto unrealize;
1293     }
1294
1295     if (xendev_class->realize) {
1296         xendev_class->realize(xendev, errp);
1297         if (*errp) {
1298             goto unrealize;
1299         }
1300     }
1301
1302     xen_device_backend_printf(xendev, "frontend", "%s",
1303                               xendev->frontend_path);
1304     xen_device_backend_printf(xendev, "frontend-id", "%u",
1305                               xendev->frontend_id);
1306     xen_device_backend_printf(xendev, "hotplug-status", "connected");
1307
1308     xen_device_backend_set_online(xendev, true);
1309     xen_device_backend_set_state(xendev, XenbusStateInitWait);
1310
1311     if (!xen_device_frontend_exists(xendev)) {
1312         xen_device_frontend_printf(xendev, "backend", "%s",
1313                                    xendev->backend_path);
1314         xen_device_frontend_printf(xendev, "backend-id", "%u",
1315                                    xenbus->backend_id);
1316
1317         xen_device_frontend_set_state(xendev, XenbusStateInitialising, true);
1318     }
1319
1320     xendev->exit.notify = xen_device_exit;
1321     qemu_add_exit_notifier(&xendev->exit);
1322     return;
1323
1324 unrealize:
1325     xen_device_unrealize(dev);
1326 }
1327
1328 static Property xen_device_props[] = {
1329     DEFINE_PROP_UINT16("frontend-id", XenDevice, frontend_id,
1330                        DOMID_INVALID),
1331     DEFINE_PROP_END_OF_LIST()
1332 };
1333
1334 static void xen_device_class_init(ObjectClass *class, void *data)
1335 {
1336     DeviceClass *dev_class = DEVICE_CLASS(class);
1337
1338     dev_class->realize = xen_device_realize;
1339     dev_class->unrealize = xen_device_unrealize;
1340     device_class_set_props(dev_class, xen_device_props);
1341     dev_class->bus_type = TYPE_XEN_BUS;
1342 }
1343
1344 static const TypeInfo xen_device_type_info = {
1345     .name = TYPE_XEN_DEVICE,
1346     .parent = TYPE_DEVICE,
1347     .instance_size = sizeof(XenDevice),
1348     .abstract = true,
1349     .class_size = sizeof(XenDeviceClass),
1350     .class_init = xen_device_class_init,
1351 };
1352
1353 typedef struct XenBridge {
1354     SysBusDevice busdev;
1355 } XenBridge;
1356
1357 #define TYPE_XEN_BRIDGE "xen-bridge"
1358
1359 static const TypeInfo xen_bridge_type_info = {
1360     .name = TYPE_XEN_BRIDGE,
1361     .parent = TYPE_SYS_BUS_DEVICE,
1362     .instance_size = sizeof(XenBridge),
1363 };
1364
1365 static void xen_register_types(void)
1366 {
1367     type_register_static(&xen_bridge_type_info);
1368     type_register_static(&xen_bus_type_info);
1369     type_register_static(&xen_device_type_info);
1370 }
1371
1372 type_init(xen_register_types)
1373
1374 void xen_bus_init(void)
1375 {
1376     DeviceState *dev = qdev_new(TYPE_XEN_BRIDGE);
1377     BusState *bus = qbus_create(TYPE_XEN_BUS, dev, NULL);
1378
1379     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
1380     qbus_set_bus_hotplug_handler(bus);
1381 }