xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback
[linux-2.6.git] / 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 bool __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, "Stealing ownership from dom%d.\n",
247                         xen_find_device_domain_owner(dev));
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 xen_pcibk_ids[] = {
709         {"pci"},
710         {""},
711 };
712
713 static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
714         .probe                  = xen_pcibk_xenbus_probe,
715         .remove                 = xen_pcibk_xenbus_remove,
716         .otherend_changed       = xen_pcibk_frontend_changed,
717 );
718
719 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
720
721 int __init xen_pcibk_xenbus_register(void)
722 {
723         xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
724         if (!xen_pcibk_wq) {
725                 printk(KERN_ERR "%s: create"
726                         "xen_pciback_workqueue failed\n", __func__);
727                 return -EFAULT;
728         }
729         xen_pcibk_backend = &xen_pcibk_vpci_backend;
730         if (passthrough)
731                 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
732         pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
733         return xenbus_register_backend(&xen_pcibk_driver);
734 }
735
736 void __exit xen_pcibk_xenbus_unregister(void)
737 {
738         destroy_workqueue(xen_pcibk_wq);
739         xenbus_unregister_driver(&xen_pcibk_driver);
740 }