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         if (xen_register_device_domain_owner(dev,
 245                                              pdev->xdev->otherend_id) != 0) {
 246                 dev_err(&dev->dev, "device has been assigned to another " \
 247                         "domain! Over-writting the ownership, but beware.\n");
 248                 xen_unregister_device_domain_owner(dev);
 249                 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
 250         }
 251
 252         /* TODO: It'd be nice to export a bridge and have all of its children
 253          * get exported with it. This may be best done in xend (which will
 254          * have to calculate resource usage anyway) but we probably want to
 255          * put something in here to ensure that if a bridge gets given to a
 256          * driver domain, that all devices under that bridge are not given
 257          * to other driver domains (as he who controls the bridge can disable
 258          * it and stop the other devices from working).
 259          */
 260 out:
 261         return err;
 262 }
 263
 264 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
 265                                  int domain, int bus, int slot, int func)
 266 {
 267         int err = 0;
 268         struct pci_dev *dev;
 269
 270         dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
 271                 domain, bus, slot, func);
 272
 273         dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
 274         if (!dev) {
 275                 err = -EINVAL;
 276                 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
 277                         "(%04x:%02x:%02x.%01x)! not owned by this domain\n",
 278                         domain, bus, slot, func);
 279                 goto out;
 280         }
 281
 282         dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
 283         xen_unregister_device_domain_owner(dev);
 284
 285         xen_pcibk_release_pci_dev(pdev, dev);
 286
 287 out:
 288         return err;
 289 }
 290
 291 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
 292                                     unsigned int domain, unsigned int bus)
 293 {
 294         unsigned int d, b;
 295         int i, root_num, len, err;
 296         char str[64];
 297
 298         dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
 299
 300         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 301                            "root_num", "%d", &root_num);
 302         if (err == 0 || err == -ENOENT)
 303                 root_num = 0;
 304         else if (err < 0)
 305                 goto out;
 306
 307         /* Verify that we haven't already published this pci root */
 308         for (i = 0; i < root_num; i++) {
 309                 len = snprintf(str, sizeof(str), "root-%d", i);
 310                 if (unlikely(len >= (sizeof(str) - 1))) {
 311                         err = -ENOMEM;
 312                         goto out;
 313                 }
 314
 315                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 316                                    str, "%x:%x", &d, &b);
 317                 if (err < 0)
 318                         goto out;
 319                 if (err != 2) {
 320                         err = -EINVAL;
 321                         goto out;
 322                 }
 323
 324                 if (d == domain && b == bus) {
 325                         err = 0;
 326                         goto out;
 327                 }
 328         }
 329
 330         len = snprintf(str, sizeof(str), "root-%d", root_num);
 331         if (unlikely(len >= (sizeof(str) - 1))) {
 332                 err = -ENOMEM;
 333                 goto out;
 334         }
 335
 336         dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
 337                 root_num, domain, bus);
 338
 339         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 340                             "%04x:%02x", domain, bus);
 341         if (err)
 342                 goto out;
 343
 344         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 345                             "root_num", "%d", (root_num + 1));
 346
 347 out:
 348         return err;
 349 }
 350
 351 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 352 {
 353         int err = 0;
 354         int num_devs;
 355         int domain, bus, slot, func;
 356         int substate;
 357         int i, len;
 358         char state_str[64];
 359         char dev_str[64];
 360
 361
 362         dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
 363
 364         mutex_lock(&pdev->dev_lock);
 365         /* Make sure we only reconfigure once */
 366         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 367             XenbusStateReconfiguring)
 368                 goto out;
 369
 370         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 371                            &num_devs);
 372         if (err != 1) {
 373                 if (err >= 0)
 374                         err = -EINVAL;
 375                 xenbus_dev_fatal(pdev->xdev, err,
 376                                  "Error reading number of devices");
 377                 goto out;
 378         }
 379
 380         for (i = 0; i < num_devs; i++) {
 381                 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
 382                 if (unlikely(len >= (sizeof(state_str) - 1))) {
 383                         err = -ENOMEM;
 384                         xenbus_dev_fatal(pdev->xdev, err,
 385                                          "String overflow while reading "
 386                                          "configuration");
 387                         goto out;
 388                 }
 389                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
 390                                    "%d", &substate);
 391                 if (err != 1)
 392                         substate = XenbusStateUnknown;
 393
 394                 switch (substate) {
 395                 case XenbusStateInitialising:
 396                         dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
 397
 398                         len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 399                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 400                                 err = -ENOMEM;
 401                                 xenbus_dev_fatal(pdev->xdev, err,
 402                                                  "String overflow while "
 403                                                  "reading configuration");
 404                                 goto out;
 405                         }
 406                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 407                                            dev_str, "%x:%x:%x.%x",
 408                                            &domain, &bus, &slot, &func);
 409                         if (err < 0) {
 410                                 xenbus_dev_fatal(pdev->xdev, err,
 411                                                  "Error reading device "
 412                                                  "configuration");
 413                                 goto out;
 414                         }
 415                         if (err != 4) {
 416                                 err = -EINVAL;
 417                                 xenbus_dev_fatal(pdev->xdev, err,
 418                                                  "Error parsing pci device "
 419                                                  "configuration");
 420                                 goto out;
 421                         }
 422
 423                         err = xen_pcibk_export_device(pdev, domain, bus, slot,
 424                                                     func, i);
 425                         if (err)
 426                                 goto out;
 427
 428                         /* Publish pci roots. */
 429                         err = xen_pcibk_publish_pci_roots(pdev,
 430                                                 xen_pcibk_publish_pci_root);
 431                         if (err) {
 432                                 xenbus_dev_fatal(pdev->xdev, err,
 433                                                  "Error while publish PCI root"
 434                                                  "buses for frontend");
 435                                 goto out;
 436                         }
 437
 438                         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 439                                             state_str, "%d",
 440                                             XenbusStateInitialised);
 441                         if (err) {
 442                                 xenbus_dev_fatal(pdev->xdev, err,
 443                                                  "Error switching substate of "
 444                                                  "dev-%d\n", i);
 445                                 goto out;
 446                         }
 447                         break;
 448
 449                 case XenbusStateClosing:
 450                         dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
 451
 452                         len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
 453                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 454                                 err = -ENOMEM;
 455                                 xenbus_dev_fatal(pdev->xdev, err,
 456                                                  "String overflow while "
 457                                                  "reading configuration");
 458                                 goto out;
 459                         }
 460                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 461                                            dev_str, "%x:%x:%x.%x",
 462                                            &domain, &bus, &slot, &func);
 463                         if (err < 0) {
 464                                 xenbus_dev_fatal(pdev->xdev, err,
 465                                                  "Error reading device "
 466                                                  "configuration");
 467                                 goto out;
 468                         }
 469                         if (err != 4) {
 470                                 err = -EINVAL;
 471                                 xenbus_dev_fatal(pdev->xdev, err,
 472                                                  "Error parsing pci device "
 473                                                  "configuration");
 474                                 goto out;
 475                         }
 476
 477                         err = xen_pcibk_remove_device(pdev, domain, bus, slot,
 478                                                     func);
 479                         if (err)
 480                                 goto out;
 481
 482                         /* TODO: If at some point we implement support for pci
 483                          * root hot-remove on pcifront side, we'll need to
 484                          * remove unnecessary xenstore nodes of pci roots here.
 485                          */
 486
 487                         break;
 488
 489                 default:
 490                         break;
 491                 }
 492         }
 493
 494         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
 495         if (err) {
 496                 xenbus_dev_fatal(pdev->xdev, err,
 497                                  "Error switching to reconfigured state!");
 498                 goto out;
 499         }
 500
 501 out:
 502         mutex_unlock(&pdev->dev_lock);
 503         return 0;
 504 }
 505
 506 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
 507                                      enum xenbus_state fe_state)
 508 {
 509         struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
 510
 511         dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
 512
 513         switch (fe_state) {
 514         case XenbusStateInitialised:
 515                 xen_pcibk_attach(pdev);
 516                 break;
 517
 518         case XenbusStateReconfiguring:
 519                 xen_pcibk_reconfigure(pdev);
 520                 break;
 521
 522         case XenbusStateConnected:
 523                 /* pcifront switched its state from reconfiguring to connected.
 524                  * Then switch to connected state.
 525                  */
 526                 xenbus_switch_state(xdev, XenbusStateConnected);
 527                 break;
 528
 529         case XenbusStateClosing:
 530                 xen_pcibk_disconnect(pdev);
 531                 xenbus_switch_state(xdev, XenbusStateClosing);
 532                 break;
 533
 534         case XenbusStateClosed:
 535                 xen_pcibk_disconnect(pdev);
 536                 xenbus_switch_state(xdev, XenbusStateClosed);
 537                 if (xenbus_dev_is_online(xdev))
 538                         break;
 539                 /* fall through if not online */
 540         case XenbusStateUnknown:
 541                 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
 542                 device_unregister(&xdev->dev);
 543                 break;
 544
 545         default:
 546                 break;
 547         }
 548 }
 549
 550 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
 551 {
 552         /* Get configuration from xend (if available now) */
 553         int domain, bus, slot, func;
 554         int err = 0;
 555         int i, num_devs;
 556         char dev_str[64];
 557         char state_str[64];
 558
 559         mutex_lock(&pdev->dev_lock);
 560         /* It's possible we could get the call to setup twice, so make sure
 561          * we're not already connected.
 562          */
 563         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 564             XenbusStateInitWait)
 565                 goto out;
 566
 567         dev_dbg(&pdev->xdev->dev, "getting be setup\n");
 568
 569         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 570                            &num_devs);
 571         if (err != 1) {
 572                 if (err >= 0)
 573                         err = -EINVAL;
 574                 xenbus_dev_fatal(pdev->xdev, err,
 575                                  "Error reading number of devices");
 576                 goto out;
 577         }
 578
 579         for (i = 0; i < num_devs; i++) {
 580                 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 581                 if (unlikely(l >= (sizeof(dev_str) - 1))) {
 582                         err = -ENOMEM;
 583                         xenbus_dev_fatal(pdev->xdev, err,
 584                                          "String overflow while reading "
 585                                          "configuration");
 586                         goto out;
 587                 }
 588
 589                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
 590                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
 591                 if (err < 0) {
 592                         xenbus_dev_fatal(pdev->xdev, err,
 593                                          "Error reading device configuration");
 594                         goto out;
 595                 }
 596                 if (err != 4) {
 597                         err = -EINVAL;
 598                         xenbus_dev_fatal(pdev->xdev, err,
 599                                          "Error parsing pci device "
 600                                          "configuration");
 601                         goto out;
 602                 }
 603
 604                 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
 605                 if (err)
 606                         goto out;
 607
 608                 /* Switch substate of this device. */
 609                 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
 610                 if (unlikely(l >= (sizeof(state_str) - 1))) {
 611                         err = -ENOMEM;
 612                         xenbus_dev_fatal(pdev->xdev, err,
 613                                          "String overflow while reading "
 614                                          "configuration");
 615                         goto out;
 616                 }
 617                 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
 618                                     "%d", XenbusStateInitialised);
 619                 if (err) {
 620                         xenbus_dev_fatal(pdev->xdev, err, "Error switching "
 621                                          "substate of dev-%d\n", i);
 622                         goto out;
 623                 }
 624         }
 625
 626         err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
 627         if (err) {
 628                 xenbus_dev_fatal(pdev->xdev, err,
 629                                  "Error while publish PCI root buses "
 630                                  "for frontend");
 631                 goto out;
 632         }
 633
 634         err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
 635         if (err)
 636                 xenbus_dev_fatal(pdev->xdev, err,
 637                                  "Error switching to initialised state!");
 638
 639 out:
 640         mutex_unlock(&pdev->dev_lock);
 641         if (!err)
 642                 /* see if pcifront is already configured (if not, we'll wait) */
 643                 xen_pcibk_attach(pdev);
 644         return err;
 645 }
 646
 647 static void xen_pcibk_be_watch(struct xenbus_watch *watch,
 648                              const char **vec, unsigned int len)
 649 {
 650         struct xen_pcibk_device *pdev =
 651             container_of(watch, struct xen_pcibk_device, be_watch);
 652
 653         switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
 654         case XenbusStateInitWait:
 655                 xen_pcibk_setup_backend(pdev);
 656                 break;
 657
 658         default:
 659                 break;
 660         }
 661 }
 662
 663 static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
 664                                 const struct xenbus_device_id *id)
 665 {
 666         int err = 0;
 667         struct xen_pcibk_device *pdev = alloc_pdev(dev);
 668
 669         if (pdev == NULL) {
 670                 err = -ENOMEM;
 671                 xenbus_dev_fatal(dev, err,
 672                                  "Error allocating xen_pcibk_device struct");
 673                 goto out;
 674         }
 675
 676         /* wait for xend to configure us */
 677         err = xenbus_switch_state(dev, XenbusStateInitWait);
 678         if (err)
 679                 goto out;
 680
 681         /* watch the backend node for backend configuration information */
 682         err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
 683                                 xen_pcibk_be_watch);
 684         if (err)
 685                 goto out;
 686
 687         pdev->be_watching = 1;
 688
 689         /* We need to force a call to our callback here in case
 690          * xend already configured us!
 691          */
 692         xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
 693
 694 out:
 695         return err;
 696 }
 697
 698 static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
 699 {
 700         struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
 701
 702         if (pdev != NULL)
 703                 free_pdev(pdev);
 704
 705         return 0;
 706 }
 707
 708 static const struct xenbus_device_id xenpci_ids[] = {
 709         {"pci"},
 710         {""},
 711 };
 712
 713 static struct xenbus_driver xenbus_xen_pcibk_driver = {
 714         .name                   = DRV_NAME,
 715         .owner                  = THIS_MODULE,
 716         .ids                    = xenpci_ids,
 717         .probe                  = xen_pcibk_xenbus_probe,
 718         .remove                 = xen_pcibk_xenbus_remove,
 719         .otherend_changed       = xen_pcibk_frontend_changed,
 720 };
 721
 722 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
 723
 724 int __init xen_pcibk_xenbus_register(void)
 725 {
 726         xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
 727         if (!xen_pcibk_wq) {
 728                 printk(KERN_ERR "%s: create"
 729                         "xen_pciback_workqueue failed\n", __func__);
 730                 return -EFAULT;
 731         }
 732         xen_pcibk_backend = &xen_pcibk_vpci_backend;
 733         if (passthrough)
 734                 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
 735         pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
 736         return xenbus_register_backend(&xenbus_xen_pcibk_driver);
 737 }
 738
 739 void __exit xen_pcibk_xenbus_unregister(void)
 740 {
 741         destroy_workqueue(xen_pcibk_wq);
 742         xenbus_unregister_driver(&xenbus_xen_pcibk_driver);
 743 }