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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 DRV_NAME "xen-pciback"
17#define INVALID_EVTCHN_IRQ (-1)
18struct workqueue_struct *xen_pcibk_wq;
19
20static int __read_mostly passthrough;
21module_param(passthrough, bool, S_IRUGO);
22MODULE_PARM_DESC(passthrough,
23 "Option to specify how to export PCI topology to guest:\n"\
24 " 0 - (default) Hide the true PCI topology and makes the frontend\n"\
25 " there is a single PCI bus with only the exported devices on it.\n"\
26 " For example, a device at 03:05.0 will be re-assigned to 00:00.0\n"\
27 " while second device at 02:1a.1 will be re-assigned to 00:01.1.\n"\
28 " 1 - Passthrough provides a real view of the PCI topology to the\n"\
29 " frontend (for example, a device at 06:01.b will still appear at\n"\
30 " 06:01.b to the frontend). This is similar to how Xen 2.0.x\n"\
31 " exposed PCI devices to its driver domains. This may be required\n"\
32 " for drivers which depend on finding their hardward in certain\n"\
33 " bus/slot locations.");
34
35static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
36{
37 struct xen_pcibk_device *pdev;
38
39 pdev = kzalloc(sizeof(struct xen_pcibk_device), GFP_KERNEL);
40 if (pdev == NULL)
41 goto out;
42 dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev);
43
44 pdev->xdev = xdev;
45 dev_set_drvdata(&xdev->dev, pdev);
46
47 spin_lock_init(&pdev->dev_lock);
48
49 pdev->sh_info = NULL;
50 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
51 pdev->be_watching = 0;
52
53 INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
54
55 if (xen_pcibk_init_devices(pdev)) {
56 kfree(pdev);
57 pdev = NULL;
58 }
59out:
60 return pdev;
61}
62
63static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
64{
65 spin_lock(&pdev->dev_lock);
66
67 /* Ensure the guest can't trigger our handler before removing devices */
68 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
69 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
70 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
71 }
72 spin_unlock(&pdev->dev_lock);
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 spin_lock(&pdev->dev_lock);
81 if (pdev->sh_info != NULL) {
82 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
83 pdev->sh_info = NULL;
84 }
85 spin_unlock(&pdev->dev_lock);
86
87}
88
89static void free_pdev(struct xen_pcibk_device *pdev)
90{
91 if (pdev->be_watching) {
92 unregister_xenbus_watch(&pdev->be_watch);
93 pdev->be_watching = 0;
94 }
95
96 xen_pcibk_disconnect(pdev);
97
98 xen_pcibk_release_devices(pdev);
99
100 dev_set_drvdata(&pdev->xdev->dev, NULL);
101 pdev->xdev = NULL;
102
103 kfree(pdev);
104}
105
106static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
107 int remote_evtchn)
108{
109 int err = 0;
110 void *vaddr;
111
112 dev_dbg(&pdev->xdev->dev,
113 "Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
114 gnt_ref, remote_evtchn);
115
116 err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
117 if (err < 0) {
118 xenbus_dev_fatal(pdev->xdev, err,
119 "Error mapping other domain page in ours.");
120 goto out;
121 }
122
123 spin_lock(&pdev->dev_lock);
124 pdev->sh_info = vaddr;
125 spin_unlock(&pdev->dev_lock);
126
127 err = bind_interdomain_evtchn_to_irqhandler(
128 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
129 0, DRV_NAME, pdev);
130 if (err < 0) {
131 xenbus_dev_fatal(pdev->xdev, err,
132 "Error binding event channel to IRQ");
133 goto out;
134 }
135
136 spin_lock(&pdev->dev_lock);
137 pdev->evtchn_irq = err;
138 spin_unlock(&pdev->dev_lock);
139 err = 0;
140
141 dev_dbg(&pdev->xdev->dev, "Attached!\n");
142out:
143 return err;
144}
145
146static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
147{
148 int err = 0;
149 int gnt_ref, remote_evtchn;
150 char *magic = NULL;
151
152
153 /* Make sure we only do this setup once */
154 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
155 XenbusStateInitialised)
156 goto out;
157
158 /* Wait for frontend to state that it has published the configuration */
159 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
160 XenbusStateInitialised)
161 goto out;
162
163 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
164
165 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
166 "pci-op-ref", "%u", &gnt_ref,
167 "event-channel", "%u", &remote_evtchn,
168 "magic", NULL, &magic, NULL);
169 if (err) {
170 /* If configuration didn't get read correctly, wait longer */
171 xenbus_dev_fatal(pdev->xdev, err,
172 "Error reading configuration from frontend");
173 goto out;
174 }
175
176 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
177 xenbus_dev_fatal(pdev->xdev, -EFAULT,
178 "version mismatch (%s/%s) with pcifront - "
179 "halting xen_pcibk",
180 magic, XEN_PCI_MAGIC);
181 goto out;
182 }
183
184 err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
185 if (err)
186 goto out;
187
188 dev_dbg(&pdev->xdev->dev, "Connecting...\n");
189
190 err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
191 if (err)
192 xenbus_dev_fatal(pdev->xdev, err,
193 "Error switching to connected state!");
194
195 dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
196out:
197
198 kfree(magic);
199
200 return err;
201}
202
203static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
204 unsigned int domain, unsigned int bus,
205 unsigned int devfn, unsigned int devid)
206{
207 int err;
208 int len;
209 char str[64];
210
211 len = snprintf(str, sizeof(str), "vdev-%d", devid);
212 if (unlikely(len >= (sizeof(str) - 1))) {
213 err = -ENOMEM;
214 goto out;
215 }
216
217 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
218 "%04x:%02x:%02x.%02x", domain, bus,
219 PCI_SLOT(devfn), PCI_FUNC(devfn));
220
221out:
222 return err;
223}
224
225static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
226 int domain, int bus, int slot, int func,
227 int devid)
228{
229 struct pci_dev *dev;
230 int err = 0;
231
232 dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
233 domain, bus, slot, func);
234
235 dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
236 if (!dev) {
237 err = -EINVAL;
238 xenbus_dev_fatal(pdev->xdev, err,
239 "Couldn't locate PCI device "
240 "(%04x:%02x:%02x.%01x)! "
241 "perhaps already in-use?",
242 domain, bus, slot, func);
243 goto out;
244 }
245
246 err = xen_pcibk_add_pci_dev(pdev, dev, devid,
247 xen_pcibk_publish_pci_dev);
248 if (err)
249 goto out;
250
251 dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
252 if (xen_register_device_domain_owner(dev,
253 pdev->xdev->otherend_id) != 0) {
254 dev_err(&dev->dev, "device has been assigned to another " \
255 "domain! Over-writting the ownership, but beware.\n");
256 xen_unregister_device_domain_owner(dev);
257 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
258 }
259
260 /* TODO: It'd be nice to export a bridge and have all of its children
261 * get exported with it. This may be best done in xend (which will
262 * have to calculate resource usage anyway) but we probably want to
263 * put something in here to ensure that if a bridge gets given to a
264 * driver domain, that all devices under that bridge are not given
265 * to other driver domains (as he who controls the bridge can disable
266 * it and stop the other devices from working).
267 */
268out:
269 return err;
270}
271
272static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
273 int domain, int bus, int slot, int func)
274{
275 int err = 0;
276 struct pci_dev *dev;
277
278 dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
279 domain, bus, slot, func);
280
281 dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
282 if (!dev) {
283 err = -EINVAL;
284 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
285 "(%04x:%02x:%02x.%01x)! not owned by this domain\n",
286 domain, bus, slot, func);
287 goto out;
288 }
289
290 dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
291 xen_unregister_device_domain_owner(dev);
292
293 xen_pcibk_release_pci_dev(pdev, dev);
294
295out:
296 return err;
297}
298
299static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
300 unsigned int domain, unsigned int bus)
301{
302 unsigned int d, b;
303 int i, root_num, len, err;
304 char str[64];
305
306 dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
307
308 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
309 "root_num", "%d", &root_num);
310 if (err == 0 || err == -ENOENT)
311 root_num = 0;
312 else if (err < 0)
313 goto out;
314
315 /* Verify that we haven't already published this pci root */
316 for (i = 0; i < root_num; i++) {
317 len = snprintf(str, sizeof(str), "root-%d", i);
318 if (unlikely(len >= (sizeof(str) - 1))) {
319 err = -ENOMEM;
320 goto out;
321 }
322
323 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
324 str, "%x:%x", &d, &b);
325 if (err < 0)
326 goto out;
327 if (err != 2) {
328 err = -EINVAL;
329 goto out;
330 }
331
332 if (d == domain && b == bus) {
333 err = 0;
334 goto out;
335 }
336 }
337
338 len = snprintf(str, sizeof(str), "root-%d", root_num);
339 if (unlikely(len >= (sizeof(str) - 1))) {
340 err = -ENOMEM;
341 goto out;
342 }
343
344 dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
345 root_num, domain, bus);
346
347 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
348 "%04x:%02x", domain, bus);
349 if (err)
350 goto out;
351
352 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
353 "root_num", "%d", (root_num + 1));
354
355out:
356 return err;
357}
358
359static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
360{
361 int err = 0;
362 int num_devs;
363 int domain, bus, slot, func;
364 int substate;
365 int i, len;
366 char state_str[64];
367 char dev_str[64];
368
369
370 dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
371
372 /* Make sure we only reconfigure once */
373 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
374 XenbusStateReconfiguring)
375 goto out;
376
377 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
378 &num_devs);
379 if (err != 1) {
380 if (err >= 0)
381 err = -EINVAL;
382 xenbus_dev_fatal(pdev->xdev, err,
383 "Error reading number of devices");
384 goto out;
385 }
386
387 for (i = 0; i < num_devs; i++) {
388 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
389 if (unlikely(len >= (sizeof(state_str) - 1))) {
390 err = -ENOMEM;
391 xenbus_dev_fatal(pdev->xdev, err,
392 "String overflow while reading "
393 "configuration");
394 goto out;
395 }
396 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
397 "%d", &substate);
398 if (err != 1)
399 substate = XenbusStateUnknown;
400
401 switch (substate) {
402 case XenbusStateInitialising:
403 dev_dbg(&pdev->xdev->dev, "Attaching dev-%d ...\n", i);
404
405 len = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
406 if (unlikely(len >= (sizeof(dev_str) - 1))) {
407 err = -ENOMEM;
408 xenbus_dev_fatal(pdev->xdev, err,
409 "String overflow while "
410 "reading configuration");
411 goto out;
412 }
413 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
414 dev_str, "%x:%x:%x.%x",
415 &domain, &bus, &slot, &func);
416 if (err < 0) {
417 xenbus_dev_fatal(pdev->xdev, err,
418 "Error reading device "
419 "configuration");
420 goto out;
421 }
422 if (err != 4) {
423 err = -EINVAL;
424 xenbus_dev_fatal(pdev->xdev, err,
425 "Error parsing pci device "
426 "configuration");
427 goto out;
428 }
429
430 err = xen_pcibk_export_device(pdev, domain, bus, slot,
431 func, i);
432 if (err)
433 goto out;
434
435 /* Publish pci roots. */
436 err = xen_pcibk_publish_pci_roots(pdev,
437 xen_pcibk_publish_pci_root);
438 if (err) {
439 xenbus_dev_fatal(pdev->xdev, err,
440 "Error while publish PCI root"
441 "buses for frontend");
442 goto out;
443 }
444
445 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
446 state_str, "%d",
447 XenbusStateInitialised);
448 if (err) {
449 xenbus_dev_fatal(pdev->xdev, err,
450 "Error switching substate of "
451 "dev-%d\n", i);
452 goto out;
453 }
454 break;
455
456 case XenbusStateClosing:
457 dev_dbg(&pdev->xdev->dev, "Detaching dev-%d ...\n", i);
458
459 len = snprintf(dev_str, sizeof(dev_str), "vdev-%d", i);
460 if (unlikely(len >= (sizeof(dev_str) - 1))) {
461 err = -ENOMEM;
462 xenbus_dev_fatal(pdev->xdev, err,
463 "String overflow while "
464 "reading configuration");
465 goto out;
466 }
467 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
468 dev_str, "%x:%x:%x.%x",
469 &domain, &bus, &slot, &func);
470 if (err < 0) {
471 xenbus_dev_fatal(pdev->xdev, err,
472 "Error reading device "
473 "configuration");
474 goto out;
475 }
476 if (err != 4) {
477 err = -EINVAL;
478 xenbus_dev_fatal(pdev->xdev, err,
479 "Error parsing pci device "
480 "configuration");
481 goto out;
482 }
483
484 err = xen_pcibk_remove_device(pdev, domain, bus, slot,
485 func);
486 if (err)
487 goto out;
488
489 /* TODO: If at some point we implement support for pci
490 * root hot-remove on pcifront side, we'll need to
491 * remove unnecessary xenstore nodes of pci roots here.
492 */
493
494 break;
495
496 default:
497 break;
498 }
499 }
500
501 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
502 if (err) {
503 xenbus_dev_fatal(pdev->xdev, err,
504 "Error switching to reconfigured state!");
505 goto out;
506 }
507
508out:
509 return 0;
510}
511
512static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
513 enum xenbus_state fe_state)
514{
515 struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
516
517 dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
518
519 switch (fe_state) {
520 case XenbusStateInitialised:
521 xen_pcibk_attach(pdev);
522 break;
523
524 case XenbusStateReconfiguring:
525 xen_pcibk_reconfigure(pdev);
526 break;
527
528 case XenbusStateConnected:
529 /* pcifront switched its state from reconfiguring to connected.
530 * Then switch to connected state.
531 */
532 xenbus_switch_state(xdev, XenbusStateConnected);
533 break;
534
535 case XenbusStateClosing:
536 xen_pcibk_disconnect(pdev);
537 xenbus_switch_state(xdev, XenbusStateClosing);
538 break;
539
540 case XenbusStateClosed:
541 xen_pcibk_disconnect(pdev);
542 xenbus_switch_state(xdev, XenbusStateClosed);
543 if (xenbus_dev_is_online(xdev))
544 break;
545 /* fall through if not online */
546 case XenbusStateUnknown:
547 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
548 device_unregister(&xdev->dev);
549 break;
550
551 default:
552 break;
553 }
554}
555
556static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
557{
558 /* Get configuration from xend (if available now) */
559 int domain, bus, slot, func;
560 int err = 0;
561 int i, num_devs;
562 char dev_str[64];
563 char state_str[64];
564
565 /* It's possible we could get the call to setup twice, so make sure
566 * we're not already connected.
567 */
568 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
569 XenbusStateInitWait)
570 goto out;
571
572 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
573
574 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
575 &num_devs);
576 if (err != 1) {
577 if (err >= 0)
578 err = -EINVAL;
579 xenbus_dev_fatal(pdev->xdev, err,
580 "Error reading number of devices");
581 goto out;
582 }
583
584 for (i = 0; i < num_devs; i++) {
585 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
586 if (unlikely(l >= (sizeof(dev_str) - 1))) {
587 err = -ENOMEM;
588 xenbus_dev_fatal(pdev->xdev, err,
589 "String overflow while reading "
590 "configuration");
591 goto out;
592 }
593
594 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
595 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
596 if (err < 0) {
597 xenbus_dev_fatal(pdev->xdev, err,
598 "Error reading device configuration");
599 goto out;
600 }
601 if (err != 4) {
602 err = -EINVAL;
603 xenbus_dev_fatal(pdev->xdev, err,
604 "Error parsing pci device "
605 "configuration");
606 goto out;
607 }
608
609 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
610 if (err)
611 goto out;
612
613 /* Switch substate of this device. */
614 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
615 if (unlikely(l >= (sizeof(state_str) - 1))) {
616 err = -ENOMEM;
617 xenbus_dev_fatal(pdev->xdev, err,
618 "String overflow while reading "
619 "configuration");
620 goto out;
621 }
622 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
623 "%d", XenbusStateInitialised);
624 if (err) {
625 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
626 "substate of dev-%d\n", i);
627 goto out;
628 }
629 }
630
631 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
632 if (err) {
633 xenbus_dev_fatal(pdev->xdev, err,
634 "Error while publish PCI root buses "
635 "for frontend");
636 goto out;
637 }
638
639 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
640 if (err)
641 xenbus_dev_fatal(pdev->xdev, err,
642 "Error switching to initialised state!");
643
644out:
645 if (!err)
646 /* see if pcifront is already configured (if not, we'll wait) */
647 xen_pcibk_attach(pdev);
648
649 return err;
650}
651
652static void xen_pcibk_be_watch(struct xenbus_watch *watch,
653 const char **vec, unsigned int len)
654{
655 struct xen_pcibk_device *pdev =
656 container_of(watch, struct xen_pcibk_device, be_watch);
657
658 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
659 case XenbusStateInitWait:
660 xen_pcibk_setup_backend(pdev);
661 break;
662
663 default:
664 break;
665 }
666}
667
668static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
669 const struct xenbus_device_id *id)
670{
671 int err = 0;
672 struct xen_pcibk_device *pdev = alloc_pdev(dev);
673
674 if (pdev == NULL) {
675 err = -ENOMEM;
676 xenbus_dev_fatal(dev, err,
677 "Error allocating xen_pcibk_device struct");
678 goto out;
679 }
680
681 /* wait for xend to configure us */
682 err = xenbus_switch_state(dev, XenbusStateInitWait);
683 if (err)
684 goto out;
685
686 /* watch the backend node for backend configuration information */
687 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
688 xen_pcibk_be_watch);
689 if (err)
690 goto out;
691
692 pdev->be_watching = 1;
693
694 /* We need to force a call to our callback here in case
695 * xend already configured us!
696 */
697 xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
698
699out:
700 return err;
701}
702
703static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
704{
705 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
706
707 if (pdev != NULL)
708 free_pdev(pdev);
709
710 return 0;
711}
712
713static const struct xenbus_device_id xenpci_ids[] = {
714 {"pci"},
715 {""},
716};
717
718static struct xenbus_driver xenbus_xen_pcibk_driver = {
719 .name = DRV_NAME,
720 .owner = THIS_MODULE,
721 .ids = xenpci_ids,
722 .probe = xen_pcibk_xenbus_probe,
723 .remove = xen_pcibk_xenbus_remove,
724 .otherend_changed = xen_pcibk_frontend_changed,
725};
726
727struct xen_pcibk_backend *xen_pcibk_backend;
728
729int __init xen_pcibk_xenbus_register(void)
730{
731 xen_pcibk_wq = create_workqueue("xen_pciback_workqueue");
732 if (!xen_pcibk_wq) {
733 printk(KERN_ERR "%s: create"
734 "xen_pciback_workqueue failed\n", __func__);
735 return -EFAULT;
736 }
737 xen_pcibk_backend = &xen_pcibk_vpci_backend;
738 if (passthrough)
739 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
740 pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
741 return xenbus_register_backend(&xenbus_xen_pcibk_driver);
742}
743
744void __exit xen_pcibk_xenbus_unregister(void)
745{
746 destroy_workqueue(xen_pcibk_wq);
747 xenbus_unregister_driver(&xenbus_xen_pcibk_driver);
748}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * PCI Backend Xenbus Setup - handles setup with frontend and xend
4 *
5 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/moduleparam.h>
11#include <linux/init.h>
12#include <linux/list.h>
13#include <linux/vmalloc.h>
14#include <linux/workqueue.h>
15#include <xen/xenbus.h>
16#include <xen/events.h>
17#include <xen/pci.h>
18#include "pciback.h"
19
20#define INVALID_EVTCHN_IRQ (-1)
21
22static bool __read_mostly passthrough;
23module_param(passthrough, bool, S_IRUGO);
24MODULE_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 hardware in certain\n"\
35 " bus/slot locations.");
36
37static 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
48 mutex_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
61 dev_set_drvdata(&xdev->dev, pdev);
62
63out:
64 return pdev;
65}
66
67static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
68{
69 mutex_lock(&pdev->dev_lock);
70 /* Ensure the guest can't trigger our handler before removing devices */
71 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
72 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
73 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
74 }
75
76 /* If the driver domain started an op, make sure we complete it
77 * before releasing the shared memory */
78
79 flush_work(&pdev->op_work);
80
81 if (pdev->sh_info != NULL) {
82 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
83 pdev->sh_info = NULL;
84 }
85 mutex_unlock(&pdev->dev_lock);
86}
87
88static 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 /* N.B. This calls pcistub_put_pci_dev which does the FLR on all
98 * of the PCIe devices. */
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
107static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
108 evtchn_port_t 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=%u\n",
115 gnt_ref, remote_evtchn);
116
117 err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &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 pdev->sh_info = vaddr;
125
126 err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
127 pdev->xdev, 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 pdev->evtchn_irq = err;
135 err = 0;
136
137 dev_dbg(&pdev->xdev->dev, "Attached!\n");
138out:
139 return err;
140}
141
142static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
143{
144 int err = 0;
145 int gnt_ref;
146 evtchn_port_t remote_evtchn;
147 char *magic = NULL;
148
149
150 mutex_lock(&pdev->dev_lock);
151 /* Make sure we only do this setup once */
152 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
153 XenbusStateInitialised)
154 goto out;
155
156 /* Wait for frontend to state that it has published the configuration */
157 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
158 XenbusStateInitialised)
159 goto out;
160
161 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
162
163 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
164 "pci-op-ref", "%u", &gnt_ref,
165 "event-channel", "%u", &remote_evtchn,
166 "magic", NULL, &magic, NULL);
167 if (err) {
168 /* If configuration didn't get read correctly, wait longer */
169 xenbus_dev_fatal(pdev->xdev, err,
170 "Error reading configuration from frontend");
171 goto out;
172 }
173
174 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
175 xenbus_dev_fatal(pdev->xdev, -EFAULT,
176 "version mismatch (%s/%s) with pcifront - "
177 "halting " DRV_NAME,
178 magic, XEN_PCI_MAGIC);
179 err = -EFAULT;
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);
195out:
196 mutex_unlock(&pdev->dev_lock);
197
198 kfree(magic);
199
200 return err;
201}
202
203static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
204 unsigned int domain, unsigned int bus,
205 unsigned int devfn, unsigned int devid)
206{
207 int err;
208 int len;
209 char str[64];
210
211 len = snprintf(str, sizeof(str), "vdev-%d", devid);
212 if (unlikely(len >= (sizeof(str) - 1))) {
213 err = -ENOMEM;
214 goto out;
215 }
216
217 /* Note: The PV protocol uses %02x, don't change it */
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
222out:
223 return err;
224}
225
226static 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.%d)! "
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_info(&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, "Stealing ownership from dom%d.\n",
256 xen_find_device_domain_owner(dev));
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 */
269out:
270 return err;
271}
272
273static 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.%d)! 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 /* N.B. This ends up calling pcistub_put_pci_dev which ends up
295 * doing the FLR. */
296 xen_pcibk_release_pci_dev(pdev, dev, true /* use the lock. */);
297
298out:
299 return err;
300}
301
302static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
303 unsigned int domain, unsigned int bus)
304{
305 unsigned int d, b;
306 int i, root_num, len, err;
307 char str[64];
308
309 dev_dbg(&pdev->xdev->dev, "Publishing pci roots\n");
310
311 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
312 "root_num", "%d", &root_num);
313 if (err == 0 || err == -ENOENT)
314 root_num = 0;
315 else if (err < 0)
316 goto out;
317
318 /* Verify that we haven't already published this pci root */
319 for (i = 0; i < root_num; i++) {
320 len = snprintf(str, sizeof(str), "root-%d", i);
321 if (unlikely(len >= (sizeof(str) - 1))) {
322 err = -ENOMEM;
323 goto out;
324 }
325
326 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename,
327 str, "%x:%x", &d, &b);
328 if (err < 0)
329 goto out;
330 if (err != 2) {
331 err = -EINVAL;
332 goto out;
333 }
334
335 if (d == domain && b == bus) {
336 err = 0;
337 goto out;
338 }
339 }
340
341 len = snprintf(str, sizeof(str), "root-%d", root_num);
342 if (unlikely(len >= (sizeof(str) - 1))) {
343 err = -ENOMEM;
344 goto out;
345 }
346
347 dev_dbg(&pdev->xdev->dev, "writing root %d at %04x:%02x\n",
348 root_num, domain, bus);
349
350 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
351 "%04x:%02x", domain, bus);
352 if (err)
353 goto out;
354
355 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename,
356 "root_num", "%d", (root_num + 1));
357
358out:
359 return err;
360}
361
362static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev,
363 enum xenbus_state state)
364{
365 int err = 0;
366 int num_devs;
367 int domain, bus, slot, func;
368 unsigned int substate;
369 int i, len;
370 char state_str[64];
371 char dev_str[64];
372
373
374 dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
375
376 mutex_lock(&pdev->dev_lock);
377 if (xenbus_read_driver_state(pdev->xdev->nodename) != state)
378 goto out;
379
380 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
381 &num_devs);
382 if (err != 1) {
383 if (err >= 0)
384 err = -EINVAL;
385 xenbus_dev_fatal(pdev->xdev, err,
386 "Error reading number of devices");
387 goto out;
388 }
389
390 for (i = 0; i < num_devs; i++) {
391 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
392 if (unlikely(len >= (sizeof(state_str) - 1))) {
393 err = -ENOMEM;
394 xenbus_dev_fatal(pdev->xdev, err,
395 "String overflow while reading "
396 "configuration");
397 goto out;
398 }
399 substate = xenbus_read_unsigned(pdev->xdev->nodename, state_str,
400 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 if (state != XenbusStateReconfiguring)
503 /* Make sure we only reconfigure once. */
504 goto out;
505
506 err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
507 if (err) {
508 xenbus_dev_fatal(pdev->xdev, err,
509 "Error switching to reconfigured state!");
510 goto out;
511 }
512
513out:
514 mutex_unlock(&pdev->dev_lock);
515 return 0;
516}
517
518static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
519 enum xenbus_state fe_state)
520{
521 struct xen_pcibk_device *pdev = dev_get_drvdata(&xdev->dev);
522
523 dev_dbg(&xdev->dev, "fe state changed %d\n", fe_state);
524
525 switch (fe_state) {
526 case XenbusStateInitialised:
527 xen_pcibk_attach(pdev);
528 break;
529
530 case XenbusStateReconfiguring:
531 xen_pcibk_reconfigure(pdev, XenbusStateReconfiguring);
532 break;
533
534 case XenbusStateConnected:
535 /* pcifront switched its state from reconfiguring to connected.
536 * Then switch to connected state.
537 */
538 xenbus_switch_state(xdev, XenbusStateConnected);
539 break;
540
541 case XenbusStateClosing:
542 xen_pcibk_disconnect(pdev);
543 xenbus_switch_state(xdev, XenbusStateClosing);
544 break;
545
546 case XenbusStateClosed:
547 xen_pcibk_disconnect(pdev);
548 xenbus_switch_state(xdev, XenbusStateClosed);
549 if (xenbus_dev_is_online(xdev))
550 break;
551 fallthrough; /* if not online */
552 case XenbusStateUnknown:
553 dev_dbg(&xdev->dev, "frontend is gone! unregister device\n");
554 device_unregister(&xdev->dev);
555 break;
556
557 default:
558 break;
559 }
560}
561
562static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
563{
564 /* Get configuration from xend (if available now) */
565 int domain, bus, slot, func;
566 int err = 0;
567 int i, num_devs;
568 char dev_str[64];
569 char state_str[64];
570
571 mutex_lock(&pdev->dev_lock);
572 /* It's possible we could get the call to setup twice, so make sure
573 * we're not already connected.
574 */
575 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
576 XenbusStateInitWait)
577 goto out;
578
579 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
580
581 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
582 &num_devs);
583 if (err != 1) {
584 if (err >= 0)
585 err = -EINVAL;
586 xenbus_dev_fatal(pdev->xdev, err,
587 "Error reading number of devices");
588 goto out;
589 }
590
591 for (i = 0; i < num_devs; i++) {
592 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
593 if (unlikely(l >= (sizeof(dev_str) - 1))) {
594 err = -ENOMEM;
595 xenbus_dev_fatal(pdev->xdev, err,
596 "String overflow while reading "
597 "configuration");
598 goto out;
599 }
600
601 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
602 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
603 if (err < 0) {
604 xenbus_dev_fatal(pdev->xdev, err,
605 "Error reading device configuration");
606 goto out;
607 }
608 if (err != 4) {
609 err = -EINVAL;
610 xenbus_dev_fatal(pdev->xdev, err,
611 "Error parsing pci device "
612 "configuration");
613 goto out;
614 }
615
616 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
617 if (err)
618 goto out;
619
620 /* Switch substate of this device. */
621 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
622 if (unlikely(l >= (sizeof(state_str) - 1))) {
623 err = -ENOMEM;
624 xenbus_dev_fatal(pdev->xdev, err,
625 "String overflow while reading "
626 "configuration");
627 goto out;
628 }
629 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
630 "%d", XenbusStateInitialised);
631 if (err) {
632 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
633 "substate of dev-%d\n", i);
634 goto out;
635 }
636 }
637
638 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
639 if (err) {
640 xenbus_dev_fatal(pdev->xdev, err,
641 "Error while publish PCI root buses "
642 "for frontend");
643 goto out;
644 }
645
646 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
647 if (err)
648 xenbus_dev_fatal(pdev->xdev, err,
649 "Error switching to initialised state!");
650
651out:
652 mutex_unlock(&pdev->dev_lock);
653 if (!err)
654 /* see if pcifront is already configured (if not, we'll wait) */
655 xen_pcibk_attach(pdev);
656 return err;
657}
658
659static void xen_pcibk_be_watch(struct xenbus_watch *watch,
660 const char *path, const char *token)
661{
662 struct xen_pcibk_device *pdev =
663 container_of(watch, struct xen_pcibk_device, be_watch);
664
665 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
666 case XenbusStateInitWait:
667 xen_pcibk_setup_backend(pdev);
668 break;
669
670 case XenbusStateInitialised:
671 /*
672 * We typically move to Initialised when the first device was
673 * added. Hence subsequent devices getting added may need
674 * reconfiguring.
675 */
676 xen_pcibk_reconfigure(pdev, XenbusStateInitialised);
677 break;
678
679 default:
680 break;
681 }
682}
683
684static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
685 const struct xenbus_device_id *id)
686{
687 int err = 0;
688 struct xen_pcibk_device *pdev = alloc_pdev(dev);
689
690 if (pdev == NULL) {
691 err = -ENOMEM;
692 xenbus_dev_fatal(dev, err,
693 "Error allocating xen_pcibk_device struct");
694 goto out;
695 }
696
697 /* wait for xend to configure us */
698 err = xenbus_switch_state(dev, XenbusStateInitWait);
699 if (err)
700 goto out;
701
702 /* watch the backend node for backend configuration information */
703 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
704 NULL, xen_pcibk_be_watch);
705 if (err)
706 goto out;
707
708 pdev->be_watching = 1;
709
710 /* We need to force a call to our callback here in case
711 * xend already configured us!
712 */
713 xen_pcibk_be_watch(&pdev->be_watch, NULL, NULL);
714
715out:
716 return err;
717}
718
719static void xen_pcibk_xenbus_remove(struct xenbus_device *dev)
720{
721 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
722
723 if (pdev != NULL)
724 free_pdev(pdev);
725}
726
727static const struct xenbus_device_id xen_pcibk_ids[] = {
728 {"pci"},
729 {""},
730};
731
732static struct xenbus_driver xen_pcibk_driver = {
733 .name = DRV_NAME,
734 .ids = xen_pcibk_ids,
735 .probe = xen_pcibk_xenbus_probe,
736 .remove = xen_pcibk_xenbus_remove,
737 .otherend_changed = xen_pcibk_frontend_changed,
738};
739
740const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
741
742int __init xen_pcibk_xenbus_register(void)
743{
744 if (!xen_pcibk_pv_support())
745 return 0;
746
747 xen_pcibk_backend = &xen_pcibk_vpci_backend;
748 if (passthrough)
749 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
750 pr_info("backend is %s\n", xen_pcibk_backend->name);
751 return xenbus_register_backend(&xen_pcibk_driver);
752}
753
754void __exit xen_pcibk_xenbus_unregister(void)
755{
756 if (xen_pcibk_pv_support())
757 xenbus_unregister_driver(&xen_pcibk_driver);
758}