drivers/xen/xen-pciback/xenbus.c

   1 /*
   2  * PCI Backend Xenbus Setup - handles setup with frontend and xend
   3  *
   4  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   5  */
   6 #include <linux/module.h>
   7 #include <linux/init.h>
   8 #include <linux/list.h>
   9 #include <linux/vmalloc.h>
  10 #include <linux/workqueue.h>
  11 #include <xen/xenbus.h>
  12 #include <xen/events.h>
  13 #include <asm/xen/pci.h>
  14 #include "pciback.h"
  15
  16 #define DRV_NAME        "xen-pciback"
  17 #define INVALID_EVTCHN_IRQ  (-1)
  18 struct workqueue_struct *xen_pcibk_wq;
  19
  20 static int __read_mostly passthrough;
  21 module_param(passthrough, bool, S_IRUGO);
  22 MODULE_PARM_DESC(passthrough,
  23         "Option to specify how to export PCI topology to guest:\n"\
  24         " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
  25         "   there is a single PCI bus with only the exported devices on it.\n"\
  26         "   For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
  27         "   while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
  28         " 1 - Passthrough provides a real view of the PCI topology to the\n"\
  29         "   frontend (for example, a device at 06:01.b will still appear at\n"\
  30         "   06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
  31         "   exposed PCI devices to its driver domains. This may be required\n"\
  32         "   for drivers which depend on finding their hardward in certain\n"\
  33         "   bus/slot locations.");
  34
  35 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
  36 {
  37         struct xen_pcibk_device *pdev;
  38
  39         pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
  40         if (pdev == NULL)
  41                 goto out;
  42         dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
  43
  44         pdev->xdev = xdev;
  45         dev_set_drvdata(&xdev->dev, pdev);
  46
  47         spin_lock_init(&pdev->dev_lock);
  48
  49         pdev->sh_info = NULL;
  50         pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
  51         pdev->be_watching = 0;
  52
  53         INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
  54
  55         if (xen_pcibk_init_devices(pdev)) {
  56                 kfree(pdev);
  57                 pdev = NULL;
  58         }
  59 out:
  60         return pdev;
  61 }
  62
  63 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
  64 {
  65         spin_lock(&pdev->dev_lock);
  66
  67         /* Ensure the guest can't trigger our handler before removing devices */
  68         if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
  69                 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
  70                 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
  71         }
  72         spin_unlock(&pdev->dev_lock);
  73
  74         /* If the driver domain started an op, make sure we complete it
  75          * before releasing the shared memory */
  76
  77         /* Note, the workqueue does not use spinlocks at all.*/
  78         flush_workqueue(xen_pcibk_wq);
  79
  80         spin_lock(&pdev->dev_lock);
  81         if (pdev->sh_info != NULL) {
  82                 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
  83                 pdev->sh_info = NULL;
  84         }
  85         spin_unlock(&pdev->dev_lock);
  86
  87 }
  88
  89 static void free_pdev(struct xen_pcibk_device *pdev)
  90 {
  91         if (pdev->be_watching) {
  92                 unregister_xenbus_watch(&pdev->be_watch);
  93                 pdev->be_watching = 0;
  94         }
  95
  96         xen_pcibk_disconnect(pdev);
  97
  98         xen_pcibk_release_devices(pdev);
  99
 100         dev_set_drvdata(&pdev->xdev->dev, NULL);
 101         pdev->xdev = NULL;
 102
 103         kfree(pdev);
 104 }
 105
 106 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
 107                              int remote_evtchn)
 108 {
 109         int err = 0;
 110         void *vaddr;
 111
 112         dev_dbg(&pdev->xdev->dev,
 113                 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
 114                 gnt_ref, remote_evtchn);
 115
 116         err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
 117         if (err < 0) {
 118                 xenbus_dev_fatal(pdev->xdev, err,
 119                                 "Error mapping other domain page in ours.");
 120                 goto out;
 121         }
 122
 123         spin_lock(&pdev->dev_lock);
 124         pdev->sh_info = vaddr;
 125         spin_unlock(&pdev->dev_lock);
 126
 127         err = bind_interdomain_evtchn_to_irqhandler(
 128                 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
 129                 0, DRV_NAME, pdev);
 130         if (err < 0) {
 131                 xenbus_dev_fatal(pdev->xdev, err,
 132                                  "Error binding event channel to IRQ");
 133                 goto out;
 134         }
 135
 136         spin_lock(&pdev->dev_lock);
 137         pdev->evtchn_irq = err;
 138         spin_unlock(&pdev->dev_lock);
 139         err = 0;
 140
 141         dev_dbg(&pdev->xdev->dev, "Attached!\n");
 142 out:
 143         return err;
 144 }
 145
 146 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
 147 {
 148         int err = 0;
 149         int gnt_ref, remote_evtchn;
 150         char *magic = NULL;
 151
 152
 153         /* Make sure we only do this setup once */
 154         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 155             XenbusStateInitialised)
 156                 goto out;
 157
 158         /* Wait for frontend to state that it has published the configuration */
 159         if (xenbus_read_driver_state(pdev->xdev->otherend) !=
 160             XenbusStateInitialised)
 161                 goto out;
 162
 163         dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
 164
 165         err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
 166                             "pci-op-ref", "%u", &gnt_ref,
 167                             "event-channel", "%u", &remote_evtchn,
 168                             "magic", NULL, &magic, NULL);
 169         if (err) {
 170                 /* If configuration didn't get read correctly, wait longer */
 171                 xenbus_dev_fatal(pdev->xdev, err,
 172                                  "Error reading configuration from frontend");
 173                 goto out;
 174         }
 175
 176         if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
 177                 xenbus_dev_fatal(pdev->xdev, -EFAULT,
 178                                  "version mismatch (%s/%s) with pcifront - "
 179                                  "halting xen_pcibk",
 180                                  magic, XEN_PCI_MAGIC);
 181                 goto out;
 182         }
 183
 184         err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
 185         if (err)
 186                 goto out;
 187
 188         dev_dbg(&pdev->xdev->dev, "Connecting...\n");
 189
 190         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 191         if (err)
 192                 xenbus_dev_fatal(pdev->xdev, err,
 193                                  "Error switching to connected state!");
 194
 195         dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
 196 out:
 197
 198         kfree(magic);
 199
 200         return err;
 201 }
 202
 203 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
 204                                    unsigned int domain, unsigned int bus,
 205                                    unsigned int devfn, unsigned int devid)
 206 {
 207         int err;
 208         int len;
 209         char str[64];
 210
 211         len = snprintf(str, sizeof(str), "vdev-%d", devid);
 212         if (unlikely(len >= (sizeof(str) - 1))) {
 213                 err = -ENOMEM;
 214                 goto out;
 215         }
 216
 217         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 218                             "%04x:%02x:%02x.%02x", domain, bus,
 219                             PCI_SLOT(devfn), PCI_FUNC(devfn));
 220
 221 out:
 222         return err;
 223 }
 224
 225 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
 226                                  int domain, int bus, int slot, int func,
 227                                  int devid)
 228 {
 229         struct pci_dev *dev;
 230         int err = 0;
 231
 232         dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
 233                 domain, bus, slot, func);
 234
 235         dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
 236         if (!dev) {
 237                 err = -EINVAL;
 238                 xenbus_dev_fatal(pdev->xdev, err,
 239                                  "Couldn't locate PCI device "
 240                                  "(%04x:%02x:%02x.%01x)! "
 241                                  "perhaps already in-use?",
 242                                  domain, bus, slot, func);
 243                 goto out;
 244         }
 245
 246         err = xen_pcibk_add_pci_dev(pdev, dev, devid,
 247                                     xen_pcibk_publish_pci_dev);
 248         if (err)
 249                 goto out;
 250
 251         dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
 252         dev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
 253         if (xen_register_device_domain_owner(dev,
 254                                              pdev->xdev->otherend_id) != 0) {
 255                 dev_err(&dev->dev, "device has been assigned to another " \
 256                         "domain! Over-writting the ownership, but beware.\n");
 257                 xen_unregister_device_domain_owner(dev);
 258                 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
 259         }
 260
 261         /* TODO: It'd be nice to export a bridge and have all of its children
 262          * get exported with it. This may be best done in xend (which will
 263          * have to calculate resource usage anyway) but we probably want to
 264          * put something in here to ensure that if a bridge gets given to a
 265          * driver domain, that all devices under that bridge are not given
 266          * to other driver domains (as he who controls the bridge can disable
 267          * it and stop the other devices from working).
 268          */
 269 out:
 270         return err;
 271 }
 272
 273 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
 274                                  int domain, int bus, int slot, int func)
 275 {
 276         int err = 0;
 277         struct pci_dev *dev;
 278
 279         dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
 280                 domain, bus, slot, func);
 281
 282         dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
 283         if (!dev) {
 284                 err = -EINVAL;
 285                 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
 286                         "(%04x:%02x:%02x.%01x)! not owned by this domain\n",
 287                         domain, bus, slot, func);
 288                 goto out;
 289         }
 290
 291         dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
 292         dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
 293         xen_unregister_device_domain_owner(dev);
 294
 295         xen_pcibk_release_pci_dev(pdev, dev);
 296
 297 out:
 298         return err;
 299 }
 300
 301 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
 302                                     unsigned int domain, unsigned int bus)
 303 {
 304         unsigned int d, b;
 305         int i, root_num, len, err;
 306         char str[64];
 307
 308         dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
 309
 310         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 311                            "root_num", "%d", &root_num);
 312         if (err == 0 || err == -ENOENT)
 313                 root_num = 0;
 314         else if (err < 0)
 315                 goto out;
 316
 317         /* Verify that we haven't already published this pci root */
 318         for (i = 0; i < root_num; i++) {
 319                 len = snprintf(str, sizeof(str), "root-%d", i);
 320                 if (unlikely(len >= (sizeof(str) - 1))) {
 321                         err = -ENOMEM;
 322                         goto out;
 323                 }
 324
 325                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 326                                    str, "%x:%x", &d, &b);
 327                 if (err < 0)
 328                         goto out;
 329                 if (err != 2) {
 330                         err = -EINVAL;
 331                         goto out;
 332                 }
 333
 334                 if (d == domain && b == bus) {
 335                         err = 0;
 336                         goto out;
 337                 }
 338         }
 339
 340         len = snprintf(str, sizeof(str), "root-%d", root_num);
 341         if (unlikely(len >= (sizeof(str) - 1))) {
 342                 err = -ENOMEM;
 343                 goto out;
 344         }
 345
 346         dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
 347                 root_num, domain, bus);
 348
 349         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 350                             "%04x:%02x", domain, bus);
 351         if (err)
 352                 goto out;
 353
 354         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 355                             "root_num", "%d", (root_num + 1));
 356
 357 out:
 358         return err;
 359 }
 360
 361 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 362 {
 363         int err = 0;
 364         int num_devs;
 365         int domain, bus, slot, func;
 366         int substate;
 367         int i, len;
 368         char state_str[64];
 369         char dev_str[64];
 370
 371
 372         dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
 373
 374         /* Make sure we only reconfigure once */
 375         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 376             XenbusStateReconfiguring)
 377                 goto out;
 378
 379         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 380                            &num_devs);
 381         if (err != 1) {
 382                 if (err >= 0)
 383                         err = -EINVAL;
 384                 xenbus_dev_fatal(pdev->xdev, err,
 385                                  "Error reading number of devices");
 386                 goto out;
 387         }
 388
 389         for (i = 0; i < num_devs; i++) {
 390                 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
 391                 if (unlikely(len >= (sizeof(state_str) - 1))) {
 392                         err = -ENOMEM;
 393                         xenbus_dev_fatal(pdev->xdev, err,
 394                                          "String overflow while reading "
 395                                          "configuration");
 396                         goto out;
 397                 }
 398                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
 399                                    "%d", &substate);
 400                 if (err != 1)
 401                         substate = XenbusStateUnknown;
 402
 403                 switch (substate) {
 404                 case XenbusStateInitialising:
 405                         dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
 406
 407                         len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 408                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 409                                 err = -ENOMEM;
 410                                 xenbus_dev_fatal(pdev->xdev, err,
 411                                                  "String overflow while "
 412                                                  "reading configuration");
 413                                 goto out;
 414                         }
 415                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 416                                            dev_str, "%x:%x:%x.%x",
 417                                            &domain, &bus, &slot, &func);
 418                         if (err < 0) {
 419                                 xenbus_dev_fatal(pdev->xdev, err,
 420                                                  "Error reading device "
 421                                                  "configuration");
 422                                 goto out;
 423                         }
 424                         if (err != 4) {
 425                                 err = -EINVAL;
 426                                 xenbus_dev_fatal(pdev->xdev, err,
 427                                                  "Error parsing pci device "
 428                                                  "configuration");
 429                                 goto out;
 430                         }
 431
 432                         err = xen_pcibk_export_device(pdev, domain, bus, slot,
 433                                                     func, i);
 434                         if (err)
 435                                 goto out;
 436
 437                         /* Publish pci roots. */
 438                         err = xen_pcibk_publish_pci_roots(pdev,
 439                                                 xen_pcibk_publish_pci_root);
 440                         if (err) {
 441                                 xenbus_dev_fatal(pdev->xdev, err,
 442                                                  "Error while publish PCI root"
 443                                                  "buses for frontend");
 444                                 goto out;
 445                         }
 446
 447                         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 448                                             state_str, "%d",
 449                                             XenbusStateInitialised);
 450                         if (err) {
 451                                 xenbus_dev_fatal(pdev->xdev, err,
 452                                                  "Error switching substate of "
 453                                                  "dev-%d\n", i);
 454                                 goto out;
 455                         }
 456                         break;
 457
 458                 case XenbusStateClosing:
 459                         dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
 460
 461                         len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
 462                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 463                                 err = -ENOMEM;
 464                                 xenbus_dev_fatal(pdev->xdev, err,
 465                                                  "String overflow while "
 466                                                  "reading configuration");
 467                                 goto out;
 468                         }
 469                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 470                                            dev_str, "%x:%x:%x.%x",
 471                                            &domain, &bus, &slot, &func);
 472                         if (err < 0) {
 473                                 xenbus_dev_fatal(pdev->xdev, err,
 474                                                  "Error reading device "
 475                                                  "configuration");
 476                                 goto out;
 477                         }
 478                         if (err != 4) {
 479                                 err = -EINVAL;
 480                                 xenbus_dev_fatal(pdev->xdev, err,
 481                                                  "Error parsing pci device "
 482                                                  "configuration");
 483                                 goto out;
 484                         }
 485
 486                         err = xen_pcibk_remove_device(pdev, domain, bus, slot,
 487                                                     func);
 488                         if (err)
 489                                 goto out;
 490
 491                         /* TODO: If at some point we implement support for pci
 492                          * root hot-remove on pcifront side, we'll need to
 493                          * remove unnecessary xenstore nodes of pci roots here.
 494                          */
 495
 496                         break;
 497
 498                 default:
 499                         break;
 500                 }
 501         }
 502
 503         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
 504         if (err) {
 505                 xenbus_dev_fatal(pdev->xdev, err,
 506                                  "Error switching to reconfigured state!");
 507                 goto out;
 508         }
 509
 510 out:
 511         return 0;
 512 }
 513
 514 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
 515                                      enum xenbus_state fe_state)
 516 {
 517         struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
 518
 519         dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
 520
 521         switch (fe_state) {
 522         case XenbusStateInitialised:
 523                 xen_pcibk_attach(pdev);
 524                 break;
 525
 526         case XenbusStateReconfiguring:
 527                 xen_pcibk_reconfigure(pdev);
 528                 break;
 529
 530         case XenbusStateConnected:
 531                 /* pcifront switched its state from reconfiguring to connected.
 532                  * Then switch to connected state.
 533                  */
 534                 xenbus_switch_state(xdev, XenbusStateConnected);
 535                 break;
 536
 537         case XenbusStateClosing:
 538                 xen_pcibk_disconnect(pdev);
 539                 xenbus_switch_state(xdev, XenbusStateClosing);
 540                 break;
 541
 542         case XenbusStateClosed:
 543                 xen_pcibk_disconnect(pdev);
 544                 xenbus_switch_state(xdev, XenbusStateClosed);
 545                 if (xenbus_dev_is_online(xdev))
 546                         break;
 547                 /* fall through if not online */
 548         case XenbusStateUnknown:
 549                 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
 550                 device_unregister(&xdev->dev);
 551                 break;
 552
 553         default:
 554                 break;
 555         }
 556 }
 557
 558 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
 559 {
 560         /* Get configuration from xend (if available now) */
 561         int domain, bus, slot, func;
 562         int err = 0;
 563         int i, num_devs;
 564         char dev_str[64];
 565         char state_str[64];
 566
 567         /* It's possible we could get the call to setup twice, so make sure
 568          * we're not already connected.
 569          */
 570         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 571             XenbusStateInitWait)
 572                 goto out;
 573
 574         dev_dbg(&pdev->xdev->dev, "getting be setup\n");
 575
 576         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 577                            &num_devs);
 578         if (err != 1) {
 579                 if (err >= 0)
 580                         err = -EINVAL;
 581                 xenbus_dev_fatal(pdev->xdev, err,
 582                                  "Error reading number of devices");
 583                 goto out;
 584         }
 585
 586         for (i = 0; i < num_devs; i++) {
 587                 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 588                 if (unlikely(l >= (sizeof(dev_str) - 1))) {
 589                         err = -ENOMEM;
 590                         xenbus_dev_fatal(pdev->xdev, err,
 591                                          "String overflow while reading "
 592                                          "configuration");
 593                         goto out;
 594                 }
 595
 596                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
 597                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
 598                 if (err < 0) {
 599                         xenbus_dev_fatal(pdev->xdev, err,
 600                                          "Error reading device configuration");
 601                         goto out;
 602                 }
 603                 if (err != 4) {
 604                         err = -EINVAL;
 605                         xenbus_dev_fatal(pdev->xdev, err,
 606                                          "Error parsing pci device "
 607                                          "configuration");
 608                         goto out;
 609                 }
 610
 611                 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
 612                 if (err)
 613                         goto out;
 614
 615                 /* Switch substate of this device. */
 616                 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
 617                 if (unlikely(l >= (sizeof(state_str) - 1))) {
 618                         err = -ENOMEM;
 619                         xenbus_dev_fatal(pdev->xdev, err,
 620                                          "String overflow while reading "
 621                                          "configuration");
 622                         goto out;
 623                 }
 624                 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
 625                                     "%d", XenbusStateInitialised);
 626                 if (err) {
 627                         xenbus_dev_fatal(pdev->xdev, err, "Error switching "
 628                                          "substate of dev-%d\n", i);
 629                         goto out;
 630                 }
 631         }
 632
 633         err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
 634         if (err) {
 635                 xenbus_dev_fatal(pdev->xdev, err,
 636                                  "Error while publish PCI root buses "
 637                                  "for frontend");
 638                 goto out;
 639         }
 640
 641         err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 642         if (err)
 643                 xenbus_dev_fatal(pdev->xdev, err,
 644                                  "Error switching to initialised state!");
 645
 646 out:
 647         if (!err)
 648                 /* see if pcifront is already configured (if not, we'll wait) */
 649                 xen_pcibk_attach(pdev);
 650
 651         return err;
 652 }
 653
 654 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
 655                              const char **vec, unsigned int len)
 656 {
 657         struct xen_pcibk_device *pdev =
 658             container_of(watch, struct xen_pcibk_device, be_watch);
 659
 660         switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
 661         case XenbusStateInitWait:
 662                 xen_pcibk_setup_backend(pdev);
 663                 break;
 664
 665         default:
 666                 break;
 667         }
 668 }
 669
 670 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
 671                                 const struct xenbus_device_id *id)
 672 {
 673         int err = 0;
 674         struct xen_pcibk_device *pdev = alloc_pdev(dev);
 675
 676         if (pdev == NULL) {
 677                 err = -ENOMEM;
 678                 xenbus_dev_fatal(dev, err,
 679                                  "Error allocating xen_pcibk_device struct");
 680                 goto out;
 681         }
 682
 683         /* wait for xend to configure us */
 684         err = xenbus_switch_state(dev, XenbusStateInitWait);
 685         if (err)
 686                 goto out;
 687
 688         /* watch the backend node for backend configuration information */
 689         err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
 690                                 xen_pcibk_be_watch);
 691         if (err)
 692                 goto out;
 693
 694         pdev->be_watching = 1;
 695
 696         /* We need to force a call to our callback here in case
 697          * xend already configured us!
 698          */
 699         xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
 700
 701 out:
 702         return err;
 703 }
 704
 705 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
 706 {
 707         struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
 708
 709         if (pdev != NULL)
 710                 free_pdev(pdev);
 711
 712         return 0;
 713 }
 714
 715 static const struct xenbus_device_id xenpci_ids[] = {
 716         {"pci"},
 717         {""},
 718 };
 719
 720 static struct xenbus_driver xenbus_xen_pcibk_driver = {
 721         .name                   = DRV_NAME,
 722         .owner                  = THIS_MODULE,
 723         .ids                    = xenpci_ids,
 724         .probe                  = xen_pcibk_xenbus_probe,
 725         .remove                 = xen_pcibk_xenbus_remove,
 726         .otherend_changed       = xen_pcibk_frontend_changed,
 727 };
 728
 729 struct xen_pcibk_backend *xen_pcibk_backend;
 730
 731 int __init xen_pcibk_xenbus_register(void)
 732 {
 733         xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
 734         if (!xen_pcibk_wq) {
 735                 printk(KERN_ERR "%s: create"
 736                         "xen_pciback_workqueue failed\n", __func__);
 737                 return -EFAULT;
 738         }
 739         xen_pcibk_backend = &xen_pcibk_vpci_backend;
 740         if (passthrough)
 741                 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
 742         pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
 743         return xenbus_register_backend(&xenbus_xen_pcibk_driver);
 744 }
 745
 746 void __exit xen_pcibk_xenbus_unregister(void)
 747 {
 748         destroy_workqueue(xen_pcibk_wq);
 749         xenbus_unregister_driver(&xenbus_xen_pcibk_driver);
 750 }