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