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         unsigned int i;
 434
 435         for (i = 0; i < xenbus->backend_types; i++) {
 436             if (xenbus->backend_watch[i]) {
 437                 xen_bus_remove_watch(xenbus, xenbus->backend_watch[i], NULL);
 438             }
 439         }
 440
 441         g_free(xenbus->backend_watch);
 442         xenbus->backend_watch = NULL;
 443     }
 444
 445     if (xenbus->watch_list) {
 446         watch_list_destroy(xenbus->watch_list);
 447         xenbus->watch_list = NULL;
 448     }
 449
 450     if (xenbus->xsh) {
 451         xs_close(xenbus->xsh);
 452     }
 453 }
 454
 455 static void xen_bus_realize(BusState *bus, Error **errp)
 456 {
 457     char *key = g_strdup_printf("%u", xen_domid);
 458     XenBus *xenbus = XEN_BUS(bus);
 459     unsigned int domid;
 460     const char **type;
 461     unsigned int i;
 462     Error *local_err = NULL;
 463
 464     trace_xen_bus_realize();
 465
 466     xenbus->xsh = xs_open(0);
 467     if (!xenbus->xsh) {
 468         error_setg_errno(errp, errno, "failed xs_open");
 469         goto fail;
 470     }
 471
 472     if (xs_node_scanf(xenbus->xsh, XBT_NULL, "", /* domain root node */
 473                       "domid", NULL, "%u", &domid) == 1) {
 474         xenbus->backend_id = domid;
 475     } else {
 476         xenbus->backend_id = 0; /* Assume lack of node means dom0 */
 477     }
 478
 479     xenbus->watch_list = watch_list_create(xenbus->xsh);
 480
 481     module_call_init(MODULE_INIT_XEN_BACKEND);
 482
 483     type = xen_backend_get_types(&xenbus->backend_types);
 484     xenbus->backend_watch = g_new(XenWatch *, xenbus->backend_types);
 485
 486     for (i = 0; i < xenbus->backend_types; i++) {
 487         char *node = g_strdup_printf("backend/%s", type[i]);
 488
 489         xenbus->backend_watch[i] =
 490             xen_bus_add_watch(xenbus, node, key, xen_bus_backend_changed,
 491                               &local_err);
 492         if (local_err) {
 493             /* This need not be treated as a hard error so don't propagate */
 494             error_reportf_err(local_err,
 495                               "failed to set up '%s' enumeration watch: ",
 496                               type[i]);
 497         }
 498
 499         g_free(node);
 500     }
 501
 502     g_free(type);
 503     g_free(key);
 504     return;
 505
 506 fail:
 507     xen_bus_unrealize(bus);
 508     g_free(key);
 509 }
 510
 511 static void xen_bus_unplug_request(HotplugHandler *hotplug,
 512                                    DeviceState *dev,
 513                                    Error **errp)
 514 {
 515     XenDevice *xendev = XEN_DEVICE(dev);
 516
 517     xen_device_unplug(xendev, errp);
 518 }
 519
 520 static void xen_bus_class_init(ObjectClass *class, void *data)
 521 {
 522     BusClass *bus_class = BUS_CLASS(class);
 523     HotplugHandlerClass *hotplug_class = HOTPLUG_HANDLER_CLASS(class);
 524
 525     bus_class->print_dev = xen_bus_print_dev;
 526     bus_class->get_dev_path = xen_bus_get_dev_path;
 527     bus_class->realize = xen_bus_realize;
 528     bus_class->unrealize = xen_bus_unrealize;
 529
 530     hotplug_class->unplug_request = xen_bus_unplug_request;
 531 }
 532
 533 static const TypeInfo xen_bus_type_info = {
 534     .name = TYPE_XEN_BUS,
 535     .parent = TYPE_BUS,
 536     .instance_size = sizeof(XenBus),
 537     .class_size = sizeof(XenBusClass),
 538     .class_init = xen_bus_class_init,
 539     .interfaces = (InterfaceInfo[]) {
 540         { TYPE_HOTPLUG_HANDLER },
 541         { }
 542     },
 543 };
 544
 545 void xen_device_backend_printf(XenDevice *xendev, const char *key,
 546                                const char *fmt, ...)
 547 {
 548     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 549     Error *local_err = NULL;
 550     va_list ap;
 551
 552     g_assert(xenbus->xsh);
 553
 554     va_start(ap, fmt);
 555     xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
 556                     &local_err, fmt, ap);
 557     va_end(ap);
 558
 559     if (local_err) {
 560         error_report_err(local_err);
 561     }
 562 }
 563
 564 static int xen_device_backend_scanf(XenDevice *xendev, const char *key,
 565                                     const char *fmt, ...)
 566 {
 567     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 568     va_list ap;
 569     int rc;
 570
 571     g_assert(xenbus->xsh);
 572
 573     va_start(ap, fmt);
 574     rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->backend_path, key,
 575                         NULL, fmt, ap);
 576     va_end(ap);
 577
 578     return rc;
 579 }
 580
 581 void xen_device_backend_set_state(XenDevice *xendev,
 582                                   enum xenbus_state state)
 583 {
 584     const char *type = object_get_typename(OBJECT(xendev));
 585
 586     if (xendev->backend_state == state) {
 587         return;
 588     }
 589
 590     trace_xen_device_backend_state(type, xendev->name,
 591                                    xs_strstate(state));
 592
 593     xendev->backend_state = state;
 594     xen_device_backend_printf(xendev, "state", "%u", state);
 595 }
 596
 597 enum xenbus_state xen_device_backend_get_state(XenDevice *xendev)
 598 {
 599     return xendev->backend_state;
 600 }
 601
 602 static void xen_device_backend_set_online(XenDevice *xendev, bool online)
 603 {
 604     const char *type = object_get_typename(OBJECT(xendev));
 605
 606     if (xendev->backend_online == online) {
 607         return;
 608     }
 609
 610     trace_xen_device_backend_online(type, xendev->name, online);
 611
 612     xendev->backend_online = online;
 613     xen_device_backend_printf(xendev, "online", "%u", online);
 614 }
 615
 616 /*
 617  * Tell from the state whether the frontend is likely alive,
 618  * i.e. it will react to a change of state of the backend.
 619  */
 620 static bool xen_device_frontend_is_active(XenDevice *xendev)
 621 {
 622     switch (xendev->frontend_state) {
 623     case XenbusStateInitWait:
 624     case XenbusStateInitialised:
 625     case XenbusStateConnected:
 626     case XenbusStateClosing:
 627         return true;
 628     default:
 629         return false;
 630     }
 631 }
 632
 633 static void xen_device_backend_changed(void *opaque)
 634 {
 635     XenDevice *xendev = opaque;
 636     const char *type = object_get_typename(OBJECT(xendev));
 637     enum xenbus_state state;
 638     unsigned int online;
 639
 640     trace_xen_device_backend_changed(type, xendev->name);
 641
 642     if (xen_device_backend_scanf(xendev, "state", "%u", &state) != 1) {
 643         state = XenbusStateUnknown;
 644     }
 645
 646     xen_device_backend_set_state(xendev, state);
 647
 648     if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) {
 649         online = 0;
 650     }
 651
 652     xen_device_backend_set_online(xendev, !!online);
 653
 654     /*
 655      * If the toolstack (or unplug request callback) has set the backend
 656      * state to Closing, but there is no active frontend then set the
 657      * backend state to Closed.
 658      */
 659     if (state == XenbusStateClosing &&
 660         !xen_device_frontend_is_active(xendev)) {
 661         xen_device_backend_set_state(xendev, XenbusStateClosed);
 662     }
 663
 664     /*
 665      * If a backend is still 'online' then we should leave it alone but,
 666      * if a backend is not 'online', then the device is a candidate
 667      * for destruction. Hence add it to the 'inactive' list to be cleaned
 668      * by xen_bus_cleanup().
 669      */
 670     if (!online &&
 671         (state == XenbusStateClosed ||  state == XenbusStateInitialising ||
 672          state == XenbusStateInitWait || state == XenbusStateUnknown) &&
 673         !xendev->inactive) {
 674         XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 675
 676         xendev->inactive = true;
 677         QLIST_INSERT_HEAD(&xenbus->inactive_devices, xendev, list);
 678
 679         /*
 680          * Re-write the state to cause a XenBus backend_watch notification,
 681          * resulting in a call to xen_bus_cleanup().
 682          */
 683         xen_device_backend_printf(xendev, "state", "%u", state);
 684     }
 685 }
 686
 687 static XenWatch *xen_device_add_watch(XenDevice *xendev, const char *node,
 688                                       const char *key,
 689                                       XenWatchHandler handler,
 690                                       Error **errp)
 691 {
 692     const char *type = object_get_typename(OBJECT(xendev));
 693
 694     trace_xen_device_add_watch(type, xendev->name, node, key);
 695
 696     return watch_list_add(xendev->watch_list, node, key, handler, xendev,
 697                           errp);
 698 }
 699
 700 static void xen_device_remove_watch(XenDevice *xendev, XenWatch *watch,
 701                                     Error **errp)
 702 {
 703     const char *type = object_get_typename(OBJECT(xendev));
 704
 705     trace_xen_device_remove_watch(type, xendev->name, watch->node,
 706                                   watch->key);
 707
 708     watch_list_remove(xendev->watch_list, watch, errp);
 709 }
 710
 711
 712 static void xen_device_backend_create(XenDevice *xendev, Error **errp)
 713 {
 714     ERRP_GUARD();
 715     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 716     struct xs_permissions perms[2];
 717
 718     xendev->backend_path = xen_device_get_backend_path(xendev);
 719
 720     perms[0].id = xenbus->backend_id;
 721     perms[0].perms = XS_PERM_NONE;
 722     perms[1].id = xendev->frontend_id;
 723     perms[1].perms = XS_PERM_READ;
 724
 725     g_assert(xenbus->xsh);
 726
 727     xs_node_create(xenbus->xsh, XBT_NULL, xendev->backend_path, perms,
 728                    ARRAY_SIZE(perms), errp);
 729     if (*errp) {
 730         error_prepend(errp, "failed to create backend: ");
 731         return;
 732     }
 733
 734     xendev->backend_state_watch =
 735         xen_device_add_watch(xendev, xendev->backend_path,
 736                              "state", xen_device_backend_changed,
 737                              errp);
 738     if (*errp) {
 739         error_prepend(errp, "failed to watch backend state: ");
 740         return;
 741     }
 742
 743     xendev->backend_online_watch =
 744         xen_device_add_watch(xendev, xendev->backend_path,
 745                              "online", xen_device_backend_changed,
 746                              errp);
 747     if (*errp) {
 748         error_prepend(errp, "failed to watch backend online: ");
 749         return;
 750     }
 751 }
 752
 753 static void xen_device_backend_destroy(XenDevice *xendev)
 754 {
 755     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 756     Error *local_err = NULL;
 757
 758     if (xendev->backend_online_watch) {
 759         xen_device_remove_watch(xendev, xendev->backend_online_watch, NULL);
 760         xendev->backend_online_watch = NULL;
 761     }
 762
 763     if (xendev->backend_state_watch) {
 764         xen_device_remove_watch(xendev, xendev->backend_state_watch, NULL);
 765         xendev->backend_state_watch = NULL;
 766     }
 767
 768     if (!xendev->backend_path) {
 769         return;
 770     }
 771
 772     g_assert(xenbus->xsh);
 773
 774     xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->backend_path,
 775                     &local_err);
 776     g_free(xendev->backend_path);
 777     xendev->backend_path = NULL;
 778
 779     if (local_err) {
 780         error_report_err(local_err);
 781     }
 782 }
 783
 784 void xen_device_frontend_printf(XenDevice *xendev, const char *key,
 785                                 const char *fmt, ...)
 786 {
 787     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 788     Error *local_err = NULL;
 789     va_list ap;
 790
 791     g_assert(xenbus->xsh);
 792
 793     va_start(ap, fmt);
 794     xs_node_vprintf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
 795                     &local_err, fmt, ap);
 796     va_end(ap);
 797
 798     if (local_err) {
 799         error_report_err(local_err);
 800     }
 801 }
 802
 803 int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
 804                               const char *fmt, ...)
 805 {
 806     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 807     va_list ap;
 808     int rc;
 809
 810     g_assert(xenbus->xsh);
 811
 812     va_start(ap, fmt);
 813     rc = xs_node_vscanf(xenbus->xsh, XBT_NULL, xendev->frontend_path, key,
 814                         NULL, fmt, ap);
 815     va_end(ap);
 816
 817     return rc;
 818 }
 819
 820 static void xen_device_frontend_set_state(XenDevice *xendev,
 821                                           enum xenbus_state state,
 822                                           bool publish)
 823 {
 824     const char *type = object_get_typename(OBJECT(xendev));
 825
 826     if (xendev->frontend_state == state) {
 827         return;
 828     }
 829
 830     trace_xen_device_frontend_state(type, xendev->name,
 831                                     xs_strstate(state));
 832
 833     xendev->frontend_state = state;
 834     if (publish) {
 835         xen_device_frontend_printf(xendev, "state", "%u", state);
 836     }
 837 }
 838
 839 static void xen_device_frontend_changed(void *opaque)
 840 {
 841     XenDevice *xendev = opaque;
 842     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
 843     const char *type = object_get_typename(OBJECT(xendev));
 844     enum xenbus_state state;
 845
 846     trace_xen_device_frontend_changed(type, xendev->name);
 847
 848     if (xen_device_frontend_scanf(xendev, "state", "%u", &state) != 1) {
 849         state = XenbusStateUnknown;
 850     }
 851
 852     xen_device_frontend_set_state(xendev, state, false);
 853
 854     if (state == XenbusStateInitialising &&
 855         xendev->backend_state == XenbusStateClosed &&
 856         xendev->backend_online) {
 857         /*
 858          * The frontend is re-initializing so switch back to
 859          * InitWait.
 860          */
 861         xen_device_backend_set_state(xendev, XenbusStateInitWait);
 862         return;
 863     }
 864
 865     if (xendev_class->frontend_changed) {
 866         Error *local_err = NULL;
 867
 868         xendev_class->frontend_changed(xendev, state, &local_err);
 869
 870         if (local_err) {
 871             error_reportf_err(local_err, "frontend change error: ");
 872         }
 873     }
 874 }
 875
 876 static bool xen_device_frontend_exists(XenDevice *xendev)
 877 {
 878     enum xenbus_state state;
 879
 880     return (xen_device_frontend_scanf(xendev, "state", "%u", &state) == 1);
 881 }
 882
 883 static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
 884 {
 885     ERRP_GUARD();
 886     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 887     struct xs_permissions perms[2];
 888
 889     xendev->frontend_path = xen_device_get_frontend_path(xendev);
 890
 891     /*
 892      * The frontend area may have already been created by a legacy
 893      * toolstack.
 894      */
 895     if (!xen_device_frontend_exists(xendev)) {
 896         perms[0].id = xendev->frontend_id;
 897         perms[0].perms = XS_PERM_NONE;
 898         perms[1].id = xenbus->backend_id;
 899         perms[1].perms = XS_PERM_READ | XS_PERM_WRITE;
 900
 901         g_assert(xenbus->xsh);
 902
 903         xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms,
 904                        ARRAY_SIZE(perms), errp);
 905         if (*errp) {
 906             error_prepend(errp, "failed to create frontend: ");
 907             return;
 908         }
 909     }
 910
 911     xendev->frontend_state_watch =
 912         xen_device_add_watch(xendev, xendev->frontend_path, "state",
 913                              xen_device_frontend_changed, errp);
 914     if (*errp) {
 915         error_prepend(errp, "failed to watch frontend state: ");
 916     }
 917 }
 918
 919 static void xen_device_frontend_destroy(XenDevice *xendev)
 920 {
 921     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
 922     Error *local_err = NULL;
 923
 924     if (xendev->frontend_state_watch) {
 925         xen_device_remove_watch(xendev, xendev->frontend_state_watch,
 926                                 NULL);
 927         xendev->frontend_state_watch = NULL;
 928     }
 929
 930     if (!xendev->frontend_path) {
 931         return;
 932     }
 933
 934     g_assert(xenbus->xsh);
 935
 936     xs_node_destroy(xenbus->xsh, XBT_NULL, xendev->frontend_path,
 937                     &local_err);
 938     g_free(xendev->frontend_path);
 939     xendev->frontend_path = NULL;
 940
 941     if (local_err) {
 942         error_report_err(local_err);
 943     }
 944 }
 945
 946 void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
 947                                    Error **errp)
 948 {
 949     if (xengnttab_set_max_grants(xendev->xgth, nr_refs)) {
 950         error_setg_errno(errp, errno, "xengnttab_set_max_grants failed");
 951     }
 952 }
 953
 954 void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
 955                                 unsigned int nr_refs, int prot,
 956                                 Error **errp)
 957 {
 958     void *map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_refs,
 959                                                 xendev->frontend_id, refs,
 960                                                 prot);
 961
 962     if (!map) {
 963         error_setg_errno(errp, errno,
 964                          "xengnttab_map_domain_grant_refs failed");
 965     }
 966
 967     return map;
 968 }
 969
 970 void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
 971                                  unsigned int nr_refs, Error **errp)
 972 {
 973     if (xengnttab_unmap(xendev->xgth, map, nr_refs)) {
 974         error_setg_errno(errp, errno, "xengnttab_unmap failed");
 975     }
 976 }
 977
 978 static void compat_copy_grant_refs(XenDevice *xendev, bool to_domain,
 979                                    XenDeviceGrantCopySegment segs[],
 980                                    unsigned int nr_segs, Error **errp)
 981 {
 982     uint32_t *refs = g_new(uint32_t, nr_segs);
 983     int prot = to_domain ? PROT_WRITE : PROT_READ;
 984     void *map;
 985     unsigned int i;
 986
 987     for (i = 0; i < nr_segs; i++) {
 988         XenDeviceGrantCopySegment *seg = &segs[i];
 989
 990         refs[i] = to_domain ? seg->dest.foreign.ref :
 991             seg->source.foreign.ref;
 992     }
 993
 994     map = xengnttab_map_domain_grant_refs(xendev->xgth, nr_segs,
 995                                           xendev->frontend_id, refs,
 996                                           prot);
 997     if (!map) {
 998         error_setg_errno(errp, errno,
 999                          "xengnttab_map_domain_grant_refs failed");
1000         goto done;
1001     }
1002
1003     for (i = 0; i < nr_segs; i++) {
1004         XenDeviceGrantCopySegment *seg = &segs[i];
1005         void *page = map + (i * XC_PAGE_SIZE);
1006
1007         if (to_domain) {
1008             memcpy(page + seg->dest.foreign.offset, seg->source.virt,
1009                    seg->len);
1010         } else {
1011             memcpy(seg->dest.virt, page + seg->source.foreign.offset,
1012                    seg->len);
1013         }
1014     }
1015
1016     if (xengnttab_unmap(xendev->xgth, map, nr_segs)) {
1017         error_setg_errno(errp, errno, "xengnttab_unmap failed");
1018     }
1019
1020 done:
1021     g_free(refs);
1022 }
1023
1024 void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
1025                                 XenDeviceGrantCopySegment segs[],
1026                                 unsigned int nr_segs, Error **errp)
1027 {
1028     xengnttab_grant_copy_segment_t *xengnttab_segs;
1029     unsigned int i;
1030
1031     if (!xendev->feature_grant_copy) {
1032         compat_copy_grant_refs(xendev, to_domain, segs, nr_segs, errp);
1033         return;
1034     }
1035
1036     xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs);
1037
1038     for (i = 0; i < nr_segs; i++) {
1039         XenDeviceGrantCopySegment *seg = &segs[i];
1040         xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
1041
1042         if (to_domain) {
1043             xengnttab_seg->flags = GNTCOPY_dest_gref;
1044             xengnttab_seg->dest.foreign.domid = xendev->frontend_id;
1045             xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref;
1046             xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset;
1047             xengnttab_seg->source.virt = seg->source.virt;
1048         } else {
1049             xengnttab_seg->flags = GNTCOPY_source_gref;
1050             xengnttab_seg->source.foreign.domid = xendev->frontend_id;
1051             xengnttab_seg->source.foreign.ref = seg->source.foreign.ref;
1052             xengnttab_seg->source.foreign.offset =
1053                 seg->source.foreign.offset;
1054             xengnttab_seg->dest.virt = seg->dest.virt;
1055         }
1056
1057         xengnttab_seg->len = seg->len;
1058     }
1059
1060     if (xengnttab_grant_copy(xendev->xgth, nr_segs, xengnttab_segs)) {
1061         error_setg_errno(errp, errno, "xengnttab_grant_copy failed");
1062         goto done;
1063     }
1064
1065     for (i = 0; i < nr_segs; i++) {
1066         xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
1067
1068         if (xengnttab_seg->status != GNTST_okay) {
1069             error_setg(errp, "xengnttab_grant_copy seg[%u] failed", i);
1070             break;
1071         }
1072     }
1073
1074 done:
1075     g_free(xengnttab_segs);
1076 }
1077
1078 struct XenEventChannel {
1079     QLIST_ENTRY(XenEventChannel) list;
1080     AioContext *ctx;
1081     xenevtchn_handle *xeh;
1082     evtchn_port_t local_port;
1083     XenEventHandler handler;
1084     void *opaque;
1085 };
1086
1087 static bool xen_device_poll(void *opaque)
1088 {
1089     XenEventChannel *channel = opaque;
1090
1091     return channel->handler(channel->opaque);
1092 }
1093
1094 static void xen_device_event(void *opaque)
1095 {
1096     XenEventChannel *channel = opaque;
1097     unsigned long port = xenevtchn_pending(channel->xeh);
1098
1099     if (port == channel->local_port) {
1100         xen_device_poll(channel);
1101
1102         xenevtchn_unmask(channel->xeh, port);
1103     }
1104 }
1105
1106 void xen_device_set_event_channel_context(XenDevice *xendev,
1107                                           XenEventChannel *channel,
1108                                           AioContext *ctx,
1109                                           Error **errp)
1110 {
1111     if (!channel) {
1112         error_setg(errp, "bad channel");
1113         return;
1114     }
1115
1116     if (channel->ctx)
1117         aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1118                            NULL, NULL, NULL, NULL);
1119
1120     channel->ctx = ctx;
1121     aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1122                        xen_device_event, NULL, xen_device_poll, channel);
1123 }
1124
1125 XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
1126                                                unsigned int port,
1127                                                XenEventHandler handler,
1128                                                void *opaque, Error **errp)
1129 {
1130     XenEventChannel *channel = g_new0(XenEventChannel, 1);
1131     xenevtchn_port_or_error_t local_port;
1132
1133     channel->xeh = xenevtchn_open(NULL, 0);
1134     if (!channel->xeh) {
1135         error_setg_errno(errp, errno, "failed xenevtchn_open");
1136         goto fail;
1137     }
1138
1139     local_port = xenevtchn_bind_interdomain(channel->xeh,
1140                                             xendev->frontend_id,
1141                                             port);
1142     if (local_port < 0) {
1143         error_setg_errno(errp, errno, "xenevtchn_bind_interdomain failed");
1144         goto fail;
1145     }
1146
1147     channel->local_port = local_port;
1148     channel->handler = handler;
1149     channel->opaque = opaque;
1150
1151     /* Only reason for failure is a NULL channel */
1152     xen_device_set_event_channel_context(xendev, channel,
1153                                          qemu_get_aio_context(),
1154                                          &error_abort);
1155
1156     QLIST_INSERT_HEAD(&xendev->event_channels, channel, list);
1157
1158     return channel;
1159
1160 fail:
1161     if (channel->xeh) {
1162         xenevtchn_close(channel->xeh);
1163     }
1164
1165     g_free(channel);
1166
1167     return NULL;
1168 }
1169
1170 void xen_device_notify_event_channel(XenDevice *xendev,
1171                                      XenEventChannel *channel,
1172                                      Error **errp)
1173 {
1174     if (!channel) {
1175         error_setg(errp, "bad channel");
1176         return;
1177     }
1178
1179     if (xenevtchn_notify(channel->xeh, channel->local_port) < 0) {
1180         error_setg_errno(errp, errno, "xenevtchn_notify failed");
1181     }
1182 }
1183
1184 void xen_device_unbind_event_channel(XenDevice *xendev,
1185                                      XenEventChannel *channel,
1186                                      Error **errp)
1187 {
1188     if (!channel) {
1189         error_setg(errp, "bad channel");
1190         return;
1191     }
1192
1193     QLIST_REMOVE(channel, list);
1194
1195     aio_set_fd_handler(channel->ctx, xenevtchn_fd(channel->xeh), true,
1196                        NULL, NULL, NULL, NULL);
1197
1198     if (xenevtchn_unbind(channel->xeh, channel->local_port) < 0) {
1199         error_setg_errno(errp, errno, "xenevtchn_unbind failed");
1200     }
1201
1202     xenevtchn_close(channel->xeh);
1203     g_free(channel);
1204 }
1205
1206 static void xen_device_unrealize(DeviceState *dev)
1207 {
1208     XenDevice *xendev = XEN_DEVICE(dev);
1209     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
1210     const char *type = object_get_typename(OBJECT(xendev));
1211     XenEventChannel *channel, *next;
1212
1213     if (!xendev->name) {
1214         return;
1215     }
1216
1217     trace_xen_device_unrealize(type, xendev->name);
1218
1219     if (xendev->exit.notify) {
1220         qemu_remove_exit_notifier(&xendev->exit);
1221         xendev->exit.notify = NULL;
1222     }
1223
1224     if (xendev_class->unrealize) {
1225         xendev_class->unrealize(xendev);
1226     }
1227
1228     /* Make sure all event channels are cleaned up */
1229     QLIST_FOREACH_SAFE(channel, &xendev->event_channels, list, next) {
1230         xen_device_unbind_event_channel(xendev, channel, NULL);
1231     }
1232
1233     xen_device_frontend_destroy(xendev);
1234     xen_device_backend_destroy(xendev);
1235
1236     if (xendev->xgth) {
1237         xengnttab_close(xendev->xgth);
1238         xendev->xgth = NULL;
1239     }
1240
1241     if (xendev->watch_list) {
1242         watch_list_destroy(xendev->watch_list);
1243         xendev->watch_list = NULL;
1244     }
1245
1246     if (xendev->xsh) {
1247         xs_close(xendev->xsh);
1248         xendev->xsh = NULL;
1249     }
1250
1251     g_free(xendev->name);
1252     xendev->name = NULL;
1253 }
1254
1255 static void xen_device_exit(Notifier *n, void *data)
1256 {
1257     XenDevice *xendev = container_of(n, XenDevice, exit);
1258
1259     xen_device_unrealize(DEVICE(xendev));
1260 }
1261
1262 static void xen_device_realize(DeviceState *dev, Error **errp)
1263 {
1264     ERRP_GUARD();
1265     XenDevice *xendev = XEN_DEVICE(dev);
1266     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
1267     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
1268     const char *type = object_get_typename(OBJECT(xendev));
1269
1270     if (xendev->frontend_id == DOMID_INVALID) {
1271         xendev->frontend_id = xen_domid;
1272     }
1273
1274     if (xendev->frontend_id >= DOMID_FIRST_RESERVED) {
1275         error_setg(errp, "invalid frontend-id");
1276         goto unrealize;
1277     }
1278
1279     if (!xendev_class->get_name) {
1280         error_setg(errp, "get_name method not implemented");
1281         goto unrealize;
1282     }
1283
1284     xendev->name = xendev_class->get_name(xendev, errp);
1285     if (*errp) {
1286         error_prepend(errp, "failed to get device name: ");
1287         goto unrealize;
1288     }
1289
1290     trace_xen_device_realize(type, xendev->name);
1291
1292     xendev->xsh = xs_open(0);
1293     if (!xendev->xsh) {
1294         error_setg_errno(errp, errno, "failed xs_open");
1295         goto unrealize;
1296     }
1297
1298     xendev->watch_list = watch_list_create(xendev->xsh);
1299
1300     xendev->xgth = xengnttab_open(NULL, 0);
1301     if (!xendev->xgth) {
1302         error_setg_errno(errp, errno, "failed xengnttab_open");
1303         goto unrealize;
1304     }
1305
1306     xendev->feature_grant_copy =
1307         (xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
1308
1309     xen_device_backend_create(xendev, errp);
1310     if (*errp) {
1311         goto unrealize;
1312     }
1313
1314     xen_device_frontend_create(xendev, errp);
1315     if (*errp) {
1316         goto unrealize;
1317     }
1318
1319     if (xendev_class->realize) {
1320         xendev_class->realize(xendev, errp);
1321         if (*errp) {
1322             goto unrealize;
1323         }
1324     }
1325
1326     xen_device_backend_printf(xendev, "frontend", "%s",
1327                               xendev->frontend_path);
1328     xen_device_backend_printf(xendev, "frontend-id", "%u",
1329                               xendev->frontend_id);
1330     xen_device_backend_printf(xendev, "hotplug-status", "connected");
1331
1332     xen_device_backend_set_online(xendev, true);
1333     xen_device_backend_set_state(xendev, XenbusStateInitWait);
1334
1335     if (!xen_device_frontend_exists(xendev)) {
1336         xen_device_frontend_printf(xendev, "backend", "%s",
1337                                    xendev->backend_path);
1338         xen_device_frontend_printf(xendev, "backend-id", "%u",
1339                                    xenbus->backend_id);
1340
1341         xen_device_frontend_set_state(xendev, XenbusStateInitialising, true);
1342     }
1343
1344     xendev->exit.notify = xen_device_exit;
1345     qemu_add_exit_notifier(&xendev->exit);
1346     return;
1347
1348 unrealize:
1349     xen_device_unrealize(dev);
1350 }
1351
1352 static Property xen_device_props[] = {
1353     DEFINE_PROP_UINT16("frontend-id", XenDevice, frontend_id,
1354                        DOMID_INVALID),
1355     DEFINE_PROP_END_OF_LIST()
1356 };
1357
1358 static void xen_device_class_init(ObjectClass *class, void *data)
1359 {
1360     DeviceClass *dev_class = DEVICE_CLASS(class);
1361
1362     dev_class->realize = xen_device_realize;
1363     dev_class->unrealize = xen_device_unrealize;
1364     device_class_set_props(dev_class, xen_device_props);
1365     dev_class->bus_type = TYPE_XEN_BUS;
1366 }
1367
1368 static const TypeInfo xen_device_type_info = {
1369     .name = TYPE_XEN_DEVICE,
1370     .parent = TYPE_DEVICE,
1371     .instance_size = sizeof(XenDevice),
1372     .abstract = true,
1373     .class_size = sizeof(XenDeviceClass),
1374     .class_init = xen_device_class_init,
1375 };
1376
1377 typedef struct XenBridge {
1378     SysBusDevice busdev;
1379 } XenBridge;
1380
1381 #define TYPE_XEN_BRIDGE "xen-bridge"
1382
1383 static const TypeInfo xen_bridge_type_info = {
1384     .name = TYPE_XEN_BRIDGE,
1385     .parent = TYPE_SYS_BUS_DEVICE,
1386     .instance_size = sizeof(XenBridge),
1387 };
1388
1389 static void xen_register_types(void)
1390 {
1391     type_register_static(&xen_bridge_type_info);
1392     type_register_static(&xen_bus_type_info);
1393     type_register_static(&xen_device_type_info);
1394 }
1395
1396 type_init(xen_register_types)
1397
1398 void xen_bus_init(void)
1399 {
1400     DeviceState *dev = qdev_new(TYPE_XEN_BRIDGE);
1401     BusState *bus = qbus_create(TYPE_XEN_BUS, dev, NULL);
1402
1403     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
1404     qbus_set_bus_hotplug_handler(bus);
1405 }