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(size: 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(objp: pdev);
58 pdev = NULL;
59 }
60
61 dev_set_drvdata(dev: &xdev->dev, data: 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(irq: pdev->evtchn_irq, dev_id: 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(work: &pdev->op_work);
80
81 if (pdev->sh_info != NULL) {
82 xenbus_unmap_ring_vfree(dev: pdev->xdev, vaddr: pdev->sh_info);
83 pdev->sh_info = NULL;
84 }
85 mutex_unlock(lock: &pdev->dev_lock);
86}
87
88static void free_pdev(struct xen_pcibk_device *pdev)
89{
90 if (pdev->be_watching) {
91 unregister_xenbus_watch(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(dev: &pdev->xdev->dev, NULL);
102 pdev->xdev = NULL;
103
104 kfree(objp: 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(dev: pdev->xdev, gnt_refs: &gnt_ref, nr_grefs: 1, vaddr: &vaddr);
118 if (err < 0) {
119 xenbus_dev_fatal(dev: pdev->xdev, err,
120 fmt: "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 dev: pdev->xdev, remote_port: remote_evtchn, handler: xen_pcibk_handle_event,
128 irqflags: 0, DRV_NAME, dev_id: pdev);
129 if (err < 0) {
130 xenbus_dev_fatal(dev: pdev->xdev, err,
131 fmt: "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(path: 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(path: 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, dir: 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(buf: str, size: sizeof(str), fmt: "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, dir: pdev->xdev->nodename, node: str,
219 fmt: "%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(dev: pdev->xdev, err,
240 fmt: "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 publish_cb: 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 domain: 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, domain: 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, lock: 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, dir: pdev->xdev->nodename,
312 node: "root_num", fmt: "%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(path: pdev->xdev->nodename) != state)
378 goto out;
379
380 err = xenbus_scanf(XBT_NIL, dir: pdev->xdev->nodename, node: "num_devs", fmt: "%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(dev: &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, state: 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(dev: xdev, new_state: XenbusStateConnected);
539 break;
540
541 case XenbusStateClosing:
542 xen_pcibk_disconnect(pdev);
543 xenbus_switch_state(dev: xdev, new_state: XenbusStateClosing);
544 break;
545
546 case XenbusStateClosed:
547 xen_pcibk_disconnect(pdev);
548 xenbus_switch_state(dev: xdev, new_state: XenbusStateClosed);
549 if (xenbus_dev_is_online(dev: 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(dev: &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(path: 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, dir: pdev->xdev->nodename, node: "num_devs", fmt: "%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(path: 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, state: 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(xdev: dev);
689
690 if (pdev == NULL) {
691 err = -ENOMEM;
692 xenbus_dev_fatal(dev, err,
693 fmt: "Error allocating xen_pcibk_device struct");
694 goto out;
695 }
696
697 /* wait for xend to configure us */
698 err = xenbus_switch_state(dev, new_state: XenbusStateInitWait);
699 if (err)
700 goto out;
701
702 /* watch the backend node for backend configuration information */
703 err = xenbus_watch_path(dev, path: dev->nodename, watch: &pdev->be_watch,
704 NULL, callback: 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(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->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(drv: &xen_pcibk_driver);
758}
759

source code of linux/drivers/xen/xen-pciback/xenbus.c