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