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