Loading...
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/*
2 * PCI Backend Xenbus Setup - handles setup with frontend and xend
3 *
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/moduleparam.h>
10#include <linux/init.h>
11#include <linux/list.h>
12#include <linux/vmalloc.h>
13#include <linux/workqueue.h>
14#include <xen/xenbus.h>
15#include <xen/events.h>
16#include <asm/xen/pci.h>
17#include "pciback.h"
18
19#define INVALID_EVTCHN_IRQ (-1)
20
21static bool __read_mostly passthrough;
22module_param(passthrough, bool, S_IRUGO);
23MODULE_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
36static 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
47 mutex_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 }
59
60 dev_set_drvdata(&xdev->dev, pdev);
61
62out:
63 return pdev;
64}
65
66static void xen_pcibk_disconnect(struct xen_pcibk_device *pdev)
67{
68 mutex_lock(&pdev->dev_lock);
69 /* Ensure the guest can't trigger our handler before removing devices */
70 if (pdev->evtchn_irq != INVALID_EVTCHN_IRQ) {
71 unbind_from_irqhandler(pdev->evtchn_irq, pdev);
72 pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
73 }
74
75 /* If the driver domain started an op, make sure we complete it
76 * before releasing the shared memory */
77
78 flush_work(&pdev->op_work);
79
80 if (pdev->sh_info != NULL) {
81 xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
82 pdev->sh_info = NULL;
83 }
84 mutex_unlock(&pdev->dev_lock);
85}
86
87static void free_pdev(struct xen_pcibk_device *pdev)
88{
89 if (pdev->be_watching) {
90 unregister_xenbus_watch(&pdev->be_watch);
91 pdev->be_watching = 0;
92 }
93
94 xen_pcibk_disconnect(pdev);
95
96 /* N.B. This calls pcistub_put_pci_dev which does the FLR on all
97 * of the PCIe devices. */
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, 1, &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 pdev->sh_info = vaddr;
124
125 err = bind_interdomain_evtchn_to_irqhandler(
126 pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
127 0, DRV_NAME, pdev);
128 if (err < 0) {
129 xenbus_dev_fatal(pdev->xdev, err,
130 "Error binding event channel to IRQ");
131 goto out;
132 }
133 pdev->evtchn_irq = err;
134 err = 0;
135
136 dev_dbg(&pdev->xdev->dev, "Attached!\n");
137out:
138 return err;
139}
140
141static int xen_pcibk_attach(struct xen_pcibk_device *pdev)
142{
143 int err = 0;
144 int gnt_ref, remote_evtchn;
145 char *magic = NULL;
146
147
148 mutex_lock(&pdev->dev_lock);
149 /* Make sure we only do this setup once */
150 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
151 XenbusStateInitialised)
152 goto out;
153
154 /* Wait for frontend to state that it has published the configuration */
155 if (xenbus_read_driver_state(pdev->xdev->otherend) !=
156 XenbusStateInitialised)
157 goto out;
158
159 dev_dbg(&pdev->xdev->dev, "Reading frontend config\n");
160
161 err = xenbus_gather(XBT_NIL, pdev->xdev->otherend,
162 "pci-op-ref", "%u", &gnt_ref,
163 "event-channel", "%u", &remote_evtchn,
164 "magic", NULL, &magic, NULL);
165 if (err) {
166 /* If configuration didn't get read correctly, wait longer */
167 xenbus_dev_fatal(pdev->xdev, err,
168 "Error reading configuration from frontend");
169 goto out;
170 }
171
172 if (magic == NULL || strcmp(magic, XEN_PCI_MAGIC) != 0) {
173 xenbus_dev_fatal(pdev->xdev, -EFAULT,
174 "version mismatch (%s/%s) with pcifront - "
175 "halting " DRV_NAME,
176 magic, XEN_PCI_MAGIC);
177 err = -EFAULT;
178 goto out;
179 }
180
181 err = xen_pcibk_do_attach(pdev, gnt_ref, remote_evtchn);
182 if (err)
183 goto out;
184
185 dev_dbg(&pdev->xdev->dev, "Connecting...\n");
186
187 err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
188 if (err)
189 xenbus_dev_fatal(pdev->xdev, err,
190 "Error switching to connected state!");
191
192 dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
193out:
194 mutex_unlock(&pdev->dev_lock);
195
196 kfree(magic);
197
198 return err;
199}
200
201static int xen_pcibk_publish_pci_dev(struct xen_pcibk_device *pdev,
202 unsigned int domain, unsigned int bus,
203 unsigned int devfn, unsigned int devid)
204{
205 int err;
206 int len;
207 char str[64];
208
209 len = snprintf(str, sizeof(str), "vdev-%d", devid);
210 if (unlikely(len >= (sizeof(str) - 1))) {
211 err = -ENOMEM;
212 goto out;
213 }
214
215 /* Note: The PV protocol uses %02x, don't change it */
216 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, str,
217 "%04x:%02x:%02x.%02x", domain, bus,
218 PCI_SLOT(devfn), PCI_FUNC(devfn));
219
220out:
221 return err;
222}
223
224static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
225 int domain, int bus, int slot, int func,
226 int devid)
227{
228 struct pci_dev *dev;
229 int err = 0;
230
231 dev_dbg(&pdev->xdev->dev, "exporting dom %x bus %x slot %x func %x\n",
232 domain, bus, slot, func);
233
234 dev = pcistub_get_pci_dev_by_slot(pdev, domain, bus, slot, func);
235 if (!dev) {
236 err = -EINVAL;
237 xenbus_dev_fatal(pdev->xdev, err,
238 "Couldn't locate PCI device "
239 "(%04x:%02x:%02x.%d)! "
240 "perhaps already in-use?",
241 domain, bus, slot, func);
242 goto out;
243 }
244
245 err = xen_pcibk_add_pci_dev(pdev, dev, devid,
246 xen_pcibk_publish_pci_dev);
247 if (err)
248 goto out;
249
250 dev_info(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
251 if (xen_register_device_domain_owner(dev,
252 pdev->xdev->otherend_id) != 0) {
253 dev_err(&dev->dev, "Stealing ownership from dom%d.\n",
254 xen_find_device_domain_owner(dev));
255 xen_unregister_device_domain_owner(dev);
256 xen_register_device_domain_owner(dev, pdev->xdev->otherend_id);
257 }
258
259 /* TODO: It'd be nice to export a bridge and have all of its children
260 * get exported with it. This may be best done in xend (which will
261 * have to calculate resource usage anyway) but we probably want to
262 * put something in here to ensure that if a bridge gets given to a
263 * driver domain, that all devices under that bridge are not given
264 * to other driver domains (as he who controls the bridge can disable
265 * it and stop the other devices from working).
266 */
267out:
268 return err;
269}
270
271static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
272 int domain, int bus, int slot, int func)
273{
274 int err = 0;
275 struct pci_dev *dev;
276
277 dev_dbg(&pdev->xdev->dev, "removing dom %x bus %x slot %x func %x\n",
278 domain, bus, slot, func);
279
280 dev = xen_pcibk_get_pci_dev(pdev, domain, bus, PCI_DEVFN(slot, func));
281 if (!dev) {
282 err = -EINVAL;
283 dev_dbg(&pdev->xdev->dev, "Couldn't locate PCI device "
284 "(%04x:%02x:%02x.%d)! not owned by this domain\n",
285 domain, bus, slot, func);
286 goto out;
287 }
288
289 dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
290 xen_unregister_device_domain_owner(dev);
291
292 /* N.B. This ends up calling pcistub_put_pci_dev which ends up
293 * doing the FLR. */
294 xen_pcibk_release_pci_dev(pdev, dev, true /* use the lock. */);
295
296out:
297 return err;
298}
299
300static 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
356out:
357 return err;
358}
359
360static 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 unsigned 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 mutex_lock(&pdev->dev_lock);
374 /* Make sure we only reconfigure once */
375 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
376 XenbusStateReconfiguring)
377 goto out;
378
379 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
380 &num_devs);
381 if (err != 1) {
382 if (err >= 0)
383 err = -EINVAL;
384 xenbus_dev_fatal(pdev->xdev, err,
385 "Error reading number of devices");
386 goto out;
387 }
388
389 for (i = 0; i < num_devs; i++) {
390 len = snprintf(state_str, sizeof(state_str), "state-%d", i);
391 if (unlikely(len >= (sizeof(state_str) - 1))) {
392 err = -ENOMEM;
393 xenbus_dev_fatal(pdev->xdev, err,
394 "String overflow while reading "
395 "configuration");
396 goto out;
397 }
398 substate = xenbus_read_unsigned(pdev->xdev->nodename, state_str,
399 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 mutex_unlock(&pdev->dev_lock);
510 return 0;
511}
512
513static 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
557static 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 mutex_lock(&pdev->dev_lock);
567 /* It's possible we could get the call to setup twice, so make sure
568 * we're not already connected.
569 */
570 if (xenbus_read_driver_state(pdev->xdev->nodename) !=
571 XenbusStateInitWait)
572 goto out;
573
574 dev_dbg(&pdev->xdev->dev, "getting be setup\n");
575
576 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
577 &num_devs);
578 if (err != 1) {
579 if (err >= 0)
580 err = -EINVAL;
581 xenbus_dev_fatal(pdev->xdev, err,
582 "Error reading number of devices");
583 goto out;
584 }
585
586 for (i = 0; i < num_devs; i++) {
587 int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
588 if (unlikely(l >= (sizeof(dev_str) - 1))) {
589 err = -ENOMEM;
590 xenbus_dev_fatal(pdev->xdev, err,
591 "String overflow while reading "
592 "configuration");
593 goto out;
594 }
595
596 err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
597 "%x:%x:%x.%x", &domain, &bus, &slot, &func);
598 if (err < 0) {
599 xenbus_dev_fatal(pdev->xdev, err,
600 "Error reading device configuration");
601 goto out;
602 }
603 if (err != 4) {
604 err = -EINVAL;
605 xenbus_dev_fatal(pdev->xdev, err,
606 "Error parsing pci device "
607 "configuration");
608 goto out;
609 }
610
611 err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
612 if (err)
613 goto out;
614
615 /* Switch substate of this device. */
616 l = snprintf(state_str, sizeof(state_str), "state-%d", i);
617 if (unlikely(l >= (sizeof(state_str) - 1))) {
618 err = -ENOMEM;
619 xenbus_dev_fatal(pdev->xdev, err,
620 "String overflow while reading "
621 "configuration");
622 goto out;
623 }
624 err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
625 "%d", XenbusStateInitialised);
626 if (err) {
627 xenbus_dev_fatal(pdev->xdev, err, "Error switching "
628 "substate of dev-%d\n", i);
629 goto out;
630 }
631 }
632
633 err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
634 if (err) {
635 xenbus_dev_fatal(pdev->xdev, err,
636 "Error while publish PCI root buses "
637 "for frontend");
638 goto out;
639 }
640
641 err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
642 if (err)
643 xenbus_dev_fatal(pdev->xdev, err,
644 "Error switching to initialised state!");
645
646out:
647 mutex_unlock(&pdev->dev_lock);
648 if (!err)
649 /* see if pcifront is already configured (if not, we'll wait) */
650 xen_pcibk_attach(pdev);
651 return err;
652}
653
654static void xen_pcibk_be_watch(struct xenbus_watch *watch,
655 const char **vec, unsigned int len)
656{
657 struct xen_pcibk_device *pdev =
658 container_of(watch, struct xen_pcibk_device, be_watch);
659
660 switch (xenbus_read_driver_state(pdev->xdev->nodename)) {
661 case XenbusStateInitWait:
662 xen_pcibk_setup_backend(pdev);
663 break;
664
665 default:
666 break;
667 }
668}
669
670static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
671 const struct xenbus_device_id *id)
672{
673 int err = 0;
674 struct xen_pcibk_device *pdev = alloc_pdev(dev);
675
676 if (pdev == NULL) {
677 err = -ENOMEM;
678 xenbus_dev_fatal(dev, err,
679 "Error allocating xen_pcibk_device struct");
680 goto out;
681 }
682
683 /* wait for xend to configure us */
684 err = xenbus_switch_state(dev, XenbusStateInitWait);
685 if (err)
686 goto out;
687
688 /* watch the backend node for backend configuration information */
689 err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
690 xen_pcibk_be_watch);
691 if (err)
692 goto out;
693
694 pdev->be_watching = 1;
695
696 /* We need to force a call to our callback here in case
697 * xend already configured us!
698 */
699 xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
700
701out:
702 return err;
703}
704
705static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
706{
707 struct xen_pcibk_device *pdev = dev_get_drvdata(&dev->dev);
708
709 if (pdev != NULL)
710 free_pdev(pdev);
711
712 return 0;
713}
714
715static const struct xenbus_device_id xen_pcibk_ids[] = {
716 {"pci"},
717 {""},
718};
719
720static struct xenbus_driver xen_pcibk_driver = {
721 .name = DRV_NAME,
722 .ids = xen_pcibk_ids,
723 .probe = xen_pcibk_xenbus_probe,
724 .remove = xen_pcibk_xenbus_remove,
725 .otherend_changed = xen_pcibk_frontend_changed,
726};
727
728const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
729
730int __init xen_pcibk_xenbus_register(void)
731{
732 xen_pcibk_backend = &xen_pcibk_vpci_backend;
733 if (passthrough)
734 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
735 pr_info("backend is %s\n", xen_pcibk_backend->name);
736 return xenbus_register_backend(&xen_pcibk_driver);
737}
738
739void __exit xen_pcibk_xenbus_unregister(void)
740{
741 xenbus_unregister_driver(&xen_pcibk_driver);
742}