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
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/vmalloc.h>
  13 #include <linux/workqueue.h>
  14 #include <xen/xenbus.h>
  15 #include <xen/events.h>
  16 #include <asm/xen/pci.h>
  17 #include "pciback.h"
  18
  19 #define INVALID_EVTCHN_IRQ  (-1)
  20 struct workqueue_struct *xen_pcibk_wq;
  21
  22 static bool __read_mostly passthrough;
  23 module_param(passthrough, bool, S_IRUGO);
  24 MODULE_PARM_DESC(passthrough,
  25         "Option to specify how to export PCI topology to guest:\n"\
  26         " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
  27         "   there is a single PCI bus with only the exported devices on it.\n"\
  28         "   For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
  29         "   while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
  30         " 1 - Passthrough provides a real view of the PCI topology to the\n"\
  31         "   frontend (for example, a device at 06:01.b will still appear at\n"\
  32         "   06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
  33         "   exposed PCI devices to its driver domains. This may be required\n"\
  34         "   for drivers which depend on finding their hardward in certain\n"\
  35         "   bus/slot locations.");
  36
  37 static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
  38 {
  39         struct xen_pcibk_device *pdev;
  40
  41         pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
  42         if (pdev == NULL)
  43                 goto out;
  44         dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
  45
  46         pdev->xdev = xdev;
  47         dev_set_drvdata(&xdev->dev, pdev);
  48
  49         mutex_init(&pdev->dev_lock);
  50
  51         pdev->sh_info = NULL;
  52         pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
  53         pdev->be_watching = 0;
  54
  55         INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
  56
  57         if (xen_pcibk_init_devices(pdev)) {
  58                 kfree(pdev);
  59                 pdev = NULL;
  60         }
  61 out:
  62         return pdev;
  63 }
  64
  65 static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
  66 {
  67         mutex_lock(&pdev->dev_lock);
  68         /* Ensure the guest can't trigger our handler before removing devices */
  69         if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
  70                 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
  71                 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
  72         }
  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         if (pdev->sh_info != NULL) {
  81                 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
  82                 pdev->sh_info = NULL;
  83         }
  84         mutex_unlock(&pdev->dev_lock);
  85 }
  86
  87 static void free_pdev(struct xen_pcibk_device *pdev)
  88 {
  89         if (pdev->be_watching) {
  90                 unregister_xenbus_watch(&pdev->be_watch);
  91                 pdev->be_watching = 0;
  92         }
  93
  94         xen_pcibk_disconnect(pdev);
  95
  96         xen_pcibk_release_devices(pdev);
  97
  98         dev_set_drvdata(&pdev->xdev->dev, NULL);
  99         pdev->xdev = NULL;
 100
 101         kfree(pdev);
 102 }
 103
 104 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
 105                              int remote_evtchn)
 106 {
 107         int err = 0;
 108         void *vaddr;
 109
 110         dev_dbg(&pdev->xdev->dev,
 111                 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
 112                 gnt_ref, remote_evtchn);
 113
 114         err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
 115         if (err < 0) {
 116                 xenbus_dev_fatal(pdev->xdev, err,
 117                                 "Error mapping other domain page in ours.");
 118                 goto out;
 119         }
 120
 121         pdev->sh_info = vaddr;
 122
 123         err = bind_interdomain_evtchn_to_irqhandler(
 124                 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
 125                 0, DRV_NAME, pdev);
 126         if (err < 0) {
 127                 xenbus_dev_fatal(pdev->xdev, err,
 128                                  "Error binding event channel to IRQ");
 129                 goto out;
 130         }
 131         pdev->evtchn_irq = err;
 132         err = 0;
 133
 134         dev_dbg(&pdev->xdev->dev, "Attached!\n");
 135 out:
 136         return err;
 137 }
 138
 139 static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
 140 {
 141         int err = 0;
 142         int gnt_ref, remote_evtchn;
 143         char *magic = NULL;
 144
 145
 146         mutex_lock(&pdev->dev_lock);
 147         /* Make sure we only do this setup once */
 148         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 149             XenbusStateInitialised)
 150                 goto out;
 151
 152         /* Wait for frontend to state that it has published the configuration */
 153         if (xenbus_read_driver_state(pdev->xdev->otherend) !=
 154             XenbusStateInitialised)
 155                 goto out;
 156
 157         dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
 158
 159         err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
 160                             "pci-op-ref", "%u", &gnt_ref,
 161                             "event-channel", "%u", &remote_evtchn,
 162                             "magic", NULL, &magic, NULL);
 163         if (err) {
 164                 /* If configuration didn't get read correctly, wait longer */
 165                 xenbus_dev_fatal(pdev->xdev, err,
 166                                  "Error reading configuration from frontend");
 167                 goto out;
 168         }
 169
 170         if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
 171                 xenbus_dev_fatal(pdev->xdev, -EFAULT,
 172                                  "version mismatch (%s/%s) with pcifront - "
 173                                  "halting " DRV_NAME,
 174                                  magic, XEN_PCI_MAGIC);
 175                 goto out;
 176         }
 177
 178         err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
 179         if (err)
 180                 goto out;
 181
 182         dev_dbg(&pdev->xdev->dev, "Connecting...\n");
 183
 184         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
 185         if (err)
 186                 xenbus_dev_fatal(pdev->xdev, err,
 187                                  "Error switching to connected state!");
 188
 189         dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
 190 out:
 191         mutex_unlock(&pdev->dev_lock);
 192
 193         kfree(magic);
 194
 195         return err;
 196 }
 197
 198 static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
 199                                    unsigned int domain, unsigned int bus,
 200                                    unsigned int devfn, unsigned int devid)
 201 {
 202         int err;
 203         int len;
 204         char str[64];
 205
 206         len = snprintf(str, sizeof(str), "vdev-%d", devid);
 207         if (unlikely(len >= (sizeof(str) - 1))) {
 208                 err = -ENOMEM;
 209                 goto out;
 210         }
 211
 212         /* Note: The PV protocol uses %02x, don't change it */
 213         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 214                             "%04x:%02x:%02x.%02x", domain, bus,
 215                             PCI_SLOT(devfn), PCI_FUNC(devfn));
 216
 217 out:
 218         return err;
 219 }
 220
 221 static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
 222                                  int domain, int bus, int slot, int func,
 223                                  int devid)
 224 {
 225         struct pci_dev *dev;
 226         int err = 0;
 227
 228         dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
 229                 domain, bus, slot, func);
 230
 231         dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
 232         if (!dev) {
 233                 err = -EINVAL;
 234                 xenbus_dev_fatal(pdev->xdev, err,
 235                                  "Couldn't locate PCI device "
 236                                  "(%04x:%02x:%02x.%d)! "
 237                                  "perhaps already in-use?",
 238                                  domain, bus, slot, func);
 239                 goto out;
 240         }
 241
 242         err = xen_pcibk_add_pci_dev(pdev, dev, devid,
 243                                     xen_pcibk_publish_pci_dev);
 244         if (err)
 245                 goto out;
 246
 247         dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
 248         if (xen_register_device_domain_owner(dev,
 249                                              pdev->xdev->otherend_id) != 0) {
 250                 dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
 251                         xen_find_device_domain_owner(dev));
 252                 xen_unregister_device_domain_owner(dev);
 253                 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
 254         }
 255
 256         /* TODO: It'd be nice to export a bridge and have all of its children
 257          * get exported with it. This may be best done in xend (which will
 258          * have to calculate resource usage anyway) but we probably want to
 259          * put something in here to ensure that if a bridge gets given to a
 260          * driver domain, that all devices under that bridge are not given
 261          * to other driver domains (as he who controls the bridge can disable
 262          * it and stop the other devices from working).
 263          */
 264 out:
 265         return err;
 266 }
 267
 268 static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
 269                                  int domain, int bus, int slot, int func)
 270 {
 271         int err = 0;
 272         struct pci_dev *dev;
 273
 274         dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
 275                 domain, bus, slot, func);
 276
 277         dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
 278         if (!dev) {
 279                 err = -EINVAL;
 280                 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
 281                         "(%04x:%02x:%02x.%d)! not owned by this domain\n",
 282                         domain, bus, slot, func);
 283                 goto out;
 284         }
 285
 286         dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
 287         xen_unregister_device_domain_owner(dev);
 288
 289         xen_pcibk_release_pci_dev(pdev, dev);
 290
 291 out:
 292         return err;
 293 }
 294
 295 static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
 296                                     unsigned int domain, unsigned int bus)
 297 {
 298         unsigned int d, b;
 299         int i, root_num, len, err;
 300         char str[64];
 301
 302         dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
 303
 304         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 305                            "root_num", "%d", &root_num);
 306         if (err == 0 || err == -ENOENT)
 307                 root_num = 0;
 308         else if (err < 0)
 309                 goto out;
 310
 311         /* Verify that we haven't already published this pci root */
 312         for (i = 0; i < root_num; i++) {
 313                 len = snprintf(str, sizeof(str), "root-%d", i);
 314                 if (unlikely(len >= (sizeof(str) - 1))) {
 315                         err = -ENOMEM;
 316                         goto out;
 317                 }
 318
 319                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 320                                    str, "%x:%x", &d, &b);
 321                 if (err < 0)
 322                         goto out;
 323                 if (err != 2) {
 324                         err = -EINVAL;
 325                         goto out;
 326                 }
 327
 328                 if (d == domain && b == bus) {
 329                         err = 0;
 330                         goto out;
 331                 }
 332         }
 333
 334         len = snprintf(str, sizeof(str), "root-%d", root_num);
 335         if (unlikely(len >= (sizeof(str) - 1))) {
 336                 err = -ENOMEM;
 337                 goto out;
 338         }
 339
 340         dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
 341                 root_num, domain, bus);
 342
 343         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
 344                             "%04x:%02x", domain, bus);
 345         if (err)
 346                 goto out;
 347
 348         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 349                             "root_num", "%d", (root_num + 1));
 350
 351 out:
 352         return err;
 353 }
 354
 355 static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 356 {
 357         int err = 0;
 358         int num_devs;
 359         int domain, bus, slot, func;
 360         int substate;
 361         int i, len;
 362         char state_str[64];
 363         char dev_str[64];
 364
 365
 366         dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
 367
 368         mutex_lock(&pdev->dev_lock);
 369         /* Make sure we only reconfigure once */
 370         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
 371             XenbusStateReconfiguring)
 372                 goto out;
 373
 374         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
 375                            &num_devs);
 376         if (err != 1) {
 377                 if (err >= 0)
 378                         err = -EINVAL;
 379                 xenbus_dev_fatal(pdev->xdev, err,
 380                                  "Error reading number of devices");
 381                 goto out;
 382         }
 383
 384         for (i = 0; i < num_devs; i++) {
 385                 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
 386                 if (unlikely(len >= (sizeof(state_str) - 1))) {
 387                         err = -ENOMEM;
 388                         xenbus_dev_fatal(pdev->xdev, err,
 389                                          "String overflow while reading "
 390                                          "configuration");
 391                         goto out;
 392                 }
 393                 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
 394                                    "%d", &substate);
 395                 if (err != 1)
 396                         substate = XenbusStateUnknown;
 397
 398                 switch (substate) {
 399                 case XenbusStateInitialising:
 400                         dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
 401
 402                         len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
 403                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 404                                 err = -ENOMEM;
 405                                 xenbus_dev_fatal(pdev->xdev, err,
 406                                                  "String overflow while "
 407                                                  "reading configuration");
 408                                 goto out;
 409                         }
 410                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 411                                            dev_str, "%x:%x:%x.%x",
 412                                            &domain, &bus, &slot, &func);
 413                         if (err < 0) {
 414                                 xenbus_dev_fatal(pdev->xdev, err,
 415                                                  "Error reading device "
 416                                                  "configuration");
 417                                 goto out;
 418                         }
 419                         if (err != 4) {
 420                                 err = -EINVAL;
 421                                 xenbus_dev_fatal(pdev->xdev, err,
 422                                                  "Error parsing pci device "
 423                                                  "configuration");
 424                                 goto out;
 425                         }
 426
 427                         err = xen_pcibk_export_device(pdev, domain, bus, slot,
 428                                                     func, i);
 429                         if (err)
 430                                 goto out;
 431
 432                         /* Publish pci roots. */
 433                         err = xen_pcibk_publish_pci_roots(pdev,
 434                                                 xen_pcibk_publish_pci_root);
 435                         if (err) {
 436                                 xenbus_dev_fatal(pdev->xdev, err,
 437                                                  "Error while publish PCI root"
 438                                                  "buses for frontend");
 439                                 goto out;
 440                         }
 441
 442                         err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
 443                                             state_str, "%d",
 444                                             XenbusStateInitialised);
 445                         if (err) {
 446                                 xenbus_dev_fatal(pdev->xdev, err,
 447                                                  "Error switching substate of "
 448                                                  "dev-%d\n", i);
 449                                 goto out;
 450                         }
 451                         break;
 452
 453                 case XenbusStateClosing:
 454                         dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
 455
 456                         len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
 457                         if (unlikely(len >= (sizeof(dev_str) - 1))) {
 458                                 err = -ENOMEM;
 459                                 xenbus_dev_fatal(pdev->xdev, err,
 460                                                  "String overflow while "
 461                                                  "reading configuration");
 462                                 goto out;
 463                         }
 464                         err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
 465                                            dev_str, "%x:%x:%x.%x",
 466                                            &domain, &bus, &slot, &func);
 467                         if (err < 0) {
 468                                 xenbus_dev_fatal(pdev->xdev, err,
 469                                                  "Error reading device "
 470                                                  "configuration");
 471                                 goto out;
 472                         }
 473                         if (err != 4) {
 474                                 err = -EINVAL;
 475                                 xenbus_dev_fatal(pdev->xdev, err,
 476                                                  "Error parsing pci device "
 477                                                  "configuration");
 478                                 goto out;
 479                         }
 480
 481                         err = xen_pcibk_remove_device(pdev, domain, bus, slot,
 482                                                     func);
 483                         if (err)
 484                                 goto out;
 485
 486                         /* TODO: If at some point we implement support for pci
 487                          * root hot-remove on pcifront side, we'll need to
 488                          * remove unnecessary xenstore nodes of pci roots here.
 489                          */
 490
 491                         break;
 492
 493                 default:
 494                         break;
 495                 }
 496         }
 497
 498         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
 499         if (err) {
 500                 xenbus_dev_fatal(pdev->xdev, err,
 501                                  "Error switching to reconfigured state!");
 502                 goto out;
 503         }
 504
 505 out:
 506         mutex_unlock(&pdev->dev_lock);
 507         return 0;
 508 }
 509
 510 static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
 511                                      enum xenbus_state fe_state)
 512 {
 513         struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
 514
 515         dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
 516
 517         switch (fe_state) {
 518         case XenbusStateInitialised:
 519                 xen_pcibk_attach(pdev);
 520                 break;
 521
 522         case XenbusStateReconfiguring:
 523                 xen_pcibk_reconfigure(pdev);
 524                 break;
 525
 526         case XenbusStateConnected:
 527                 /* pcifront switched its state from reconfiguring to connected.
 528                  * Then switch to connected state.
 529                  */
 530                 xenbus_switch_state(xdev, XenbusStateConnected);
 531                 break;
 532
 533         case XenbusStateClosing:
 534                 xen_pcibk_disconnect(pdev);
 535                 xenbus_switch_state(xdev, XenbusStateClosing);
 536                 break;
 537
 538         case XenbusStateClosed:
 539                 xen_pcibk_disconnect(pdev);
 540                 xenbus_switch_state(xdev, XenbusStateClosed);
 541                 if (xenbus_dev_is_online(xdev))
 542                         break;
 543                 /* fall through if not online */
 544         case XenbusStateUnknown:
 545                 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
 546                 device_unregister(&xdev->dev);
 547                 break;
 548
 549         default:
 550                 break;
 551         }
 552 }
 553
 554 static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
 555 {
 556         /* Get configuration from xend (if available now) */
 557         int domain, bus, slot, func;
 558         int err = 0;
 559         int i, num_devs;
 560         char dev_str[64];
 561         char state_str[64];
 562
 563         mutex_lock(&pdev->dev_lock);
 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         mutex_unlock(&pdev->dev_lock);
 645         if (!err)
 646                 /* see if pcifront is already configured (if not, we'll wait) */
 647                 xen_pcibk_attach(pdev);
 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 xen_pcibk_ids[] = {
 713         {"pci"},
 714         {""},
 715 };
 716
 717 static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
 718         .probe                  = xen_pcibk_xenbus_probe,
 719         .remove                 = xen_pcibk_xenbus_remove,
 720         .otherend_changed       = xen_pcibk_frontend_changed,
 721 );
 722
 723 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
 724
 725 int __init xen_pcibk_xenbus_register(void)
 726 {
 727         xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
 728         if (!xen_pcibk_wq) {
 729                 pr_err("%s: create 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("backend is %s\n", xen_pcibk_backend->name);
 736         return xenbus_register_backend(&xen_pcibk_driver);
 737 }
 738
 739 void __exit xen_pcibk_xenbus_unregister(void)
 740 {
 741         destroy_workqueue(xen_pcibk_wq);
 742         xenbus_unregister_driver(&xen_pcibk_driver);
 743 }