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