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1/******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
3 *
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33#define DPRINTK(fmt, args...) \
34 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
35 __func__, __LINE__, ##args)
36
37#include <linux/kernel.h>
38#include <linux/err.h>
39#include <linux/string.h>
40#include <linux/ctype.h>
41#include <linux/fcntl.h>
42#include <linux/mm.h>
43#include <linux/proc_fs.h>
44#include <linux/notifier.h>
45#include <linux/kthread.h>
46#include <linux/mutex.h>
47#include <linux/io.h>
48#include <linux/slab.h>
49#include <linux/module.h>
50
51#include <asm/page.h>
52#include <asm/pgtable.h>
53#include <asm/xen/hypervisor.h>
54
55#include <xen/xen.h>
56#include <xen/xenbus.h>
57#include <xen/events.h>
58#include <xen/page.h>
59
60#include <xen/hvm.h>
61
62#include "xenbus_comms.h"
63#include "xenbus_probe.h"
64
65
66int xen_store_evtchn;
67EXPORT_SYMBOL_GPL(xen_store_evtchn);
68
69struct xenstore_domain_interface *xen_store_interface;
70EXPORT_SYMBOL_GPL(xen_store_interface);
71
72static unsigned long xen_store_mfn;
73
74static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
75
76/* If something in array of ids matches this device, return it. */
77static const struct xenbus_device_id *
78match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
79{
80 for (; *arr->devicetype != '\0'; arr++) {
81 if (!strcmp(arr->devicetype, dev->devicetype))
82 return arr;
83 }
84 return NULL;
85}
86
87int xenbus_match(struct device *_dev, struct device_driver *_drv)
88{
89 struct xenbus_driver *drv = to_xenbus_driver(_drv);
90
91 if (!drv->ids)
92 return 0;
93
94 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
95}
96EXPORT_SYMBOL_GPL(xenbus_match);
97
98
99static void free_otherend_details(struct xenbus_device *dev)
100{
101 kfree(dev->otherend);
102 dev->otherend = NULL;
103}
104
105
106static void free_otherend_watch(struct xenbus_device *dev)
107{
108 if (dev->otherend_watch.node) {
109 unregister_xenbus_watch(&dev->otherend_watch);
110 kfree(dev->otherend_watch.node);
111 dev->otherend_watch.node = NULL;
112 }
113}
114
115
116static int talk_to_otherend(struct xenbus_device *dev)
117{
118 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
119
120 free_otherend_watch(dev);
121 free_otherend_details(dev);
122
123 return drv->read_otherend_details(dev);
124}
125
126
127
128static int watch_otherend(struct xenbus_device *dev)
129{
130 struct xen_bus_type *bus =
131 container_of(dev->dev.bus, struct xen_bus_type, bus);
132
133 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
134 bus->otherend_changed,
135 "%s/%s", dev->otherend, "state");
136}
137
138
139int xenbus_read_otherend_details(struct xenbus_device *xendev,
140 char *id_node, char *path_node)
141{
142 int err = xenbus_gather(XBT_NIL, xendev->nodename,
143 id_node, "%i", &xendev->otherend_id,
144 path_node, NULL, &xendev->otherend,
145 NULL);
146 if (err) {
147 xenbus_dev_fatal(xendev, err,
148 "reading other end details from %s",
149 xendev->nodename);
150 return err;
151 }
152 if (strlen(xendev->otherend) == 0 ||
153 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
154 xenbus_dev_fatal(xendev, -ENOENT,
155 "unable to read other end from %s. "
156 "missing or inaccessible.",
157 xendev->nodename);
158 free_otherend_details(xendev);
159 return -ENOENT;
160 }
161
162 return 0;
163}
164EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
165
166void xenbus_otherend_changed(struct xenbus_watch *watch,
167 const char **vec, unsigned int len,
168 int ignore_on_shutdown)
169{
170 struct xenbus_device *dev =
171 container_of(watch, struct xenbus_device, otherend_watch);
172 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
173 enum xenbus_state state;
174
175 /* Protect us against watches firing on old details when the otherend
176 details change, say immediately after a resume. */
177 if (!dev->otherend ||
178 strncmp(dev->otherend, vec[XS_WATCH_PATH],
179 strlen(dev->otherend))) {
180 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
181 vec[XS_WATCH_PATH]);
182 return;
183 }
184
185 state = xenbus_read_driver_state(dev->otherend);
186
187 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
188 state, xenbus_strstate(state), dev->otherend_watch.node,
189 vec[XS_WATCH_PATH]);
190
191 /*
192 * Ignore xenbus transitions during shutdown. This prevents us doing
193 * work that can fail e.g., when the rootfs is gone.
194 */
195 if (system_state > SYSTEM_RUNNING) {
196 if (ignore_on_shutdown && (state == XenbusStateClosing))
197 xenbus_frontend_closed(dev);
198 return;
199 }
200
201 if (drv->otherend_changed)
202 drv->otherend_changed(dev, state);
203}
204EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
205
206int xenbus_dev_probe(struct device *_dev)
207{
208 struct xenbus_device *dev = to_xenbus_device(_dev);
209 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
210 const struct xenbus_device_id *id;
211 int err;
212
213 DPRINTK("%s", dev->nodename);
214
215 if (!drv->probe) {
216 err = -ENODEV;
217 goto fail;
218 }
219
220 id = match_device(drv->ids, dev);
221 if (!id) {
222 err = -ENODEV;
223 goto fail;
224 }
225
226 err = talk_to_otherend(dev);
227 if (err) {
228 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
229 dev->nodename);
230 return err;
231 }
232
233 err = drv->probe(dev, id);
234 if (err)
235 goto fail;
236
237 err = watch_otherend(dev);
238 if (err) {
239 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
240 dev->nodename);
241 return err;
242 }
243
244 return 0;
245fail:
246 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
247 xenbus_switch_state(dev, XenbusStateClosed);
248 return err;
249}
250EXPORT_SYMBOL_GPL(xenbus_dev_probe);
251
252int xenbus_dev_remove(struct device *_dev)
253{
254 struct xenbus_device *dev = to_xenbus_device(_dev);
255 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
256
257 DPRINTK("%s", dev->nodename);
258
259 free_otherend_watch(dev);
260
261 if (drv->remove)
262 drv->remove(dev);
263
264 free_otherend_details(dev);
265
266 xenbus_switch_state(dev, XenbusStateClosed);
267 return 0;
268}
269EXPORT_SYMBOL_GPL(xenbus_dev_remove);
270
271void xenbus_dev_shutdown(struct device *_dev)
272{
273 struct xenbus_device *dev = to_xenbus_device(_dev);
274 unsigned long timeout = 5*HZ;
275
276 DPRINTK("%s", dev->nodename);
277
278 get_device(&dev->dev);
279 if (dev->state != XenbusStateConnected) {
280 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
281 dev->nodename, xenbus_strstate(dev->state));
282 goto out;
283 }
284 xenbus_switch_state(dev, XenbusStateClosing);
285 timeout = wait_for_completion_timeout(&dev->down, timeout);
286 if (!timeout)
287 printk(KERN_INFO "%s: %s timeout closing device\n",
288 __func__, dev->nodename);
289 out:
290 put_device(&dev->dev);
291}
292EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
293
294int xenbus_register_driver_common(struct xenbus_driver *drv,
295 struct xen_bus_type *bus)
296{
297 drv->driver.bus = &bus->bus;
298
299 return driver_register(&drv->driver);
300}
301EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
302
303void xenbus_unregister_driver(struct xenbus_driver *drv)
304{
305 driver_unregister(&drv->driver);
306}
307EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
308
309struct xb_find_info {
310 struct xenbus_device *dev;
311 const char *nodename;
312};
313
314static int cmp_dev(struct device *dev, void *data)
315{
316 struct xenbus_device *xendev = to_xenbus_device(dev);
317 struct xb_find_info *info = data;
318
319 if (!strcmp(xendev->nodename, info->nodename)) {
320 info->dev = xendev;
321 get_device(dev);
322 return 1;
323 }
324 return 0;
325}
326
327struct xenbus_device *xenbus_device_find(const char *nodename,
328 struct bus_type *bus)
329{
330 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
331
332 bus_for_each_dev(bus, NULL, &info, cmp_dev);
333 return info.dev;
334}
335
336static int cleanup_dev(struct device *dev, void *data)
337{
338 struct xenbus_device *xendev = to_xenbus_device(dev);
339 struct xb_find_info *info = data;
340 int len = strlen(info->nodename);
341
342 DPRINTK("%s", info->nodename);
343
344 /* Match the info->nodename path, or any subdirectory of that path. */
345 if (strncmp(xendev->nodename, info->nodename, len))
346 return 0;
347
348 /* If the node name is longer, ensure it really is a subdirectory. */
349 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
350 return 0;
351
352 info->dev = xendev;
353 get_device(dev);
354 return 1;
355}
356
357static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
358{
359 struct xb_find_info info = { .nodename = path };
360
361 do {
362 info.dev = NULL;
363 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
364 if (info.dev) {
365 device_unregister(&info.dev->dev);
366 put_device(&info.dev->dev);
367 }
368 } while (info.dev);
369}
370
371static void xenbus_dev_release(struct device *dev)
372{
373 if (dev)
374 kfree(to_xenbus_device(dev));
375}
376
377static ssize_t nodename_show(struct device *dev,
378 struct device_attribute *attr, char *buf)
379{
380 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
381}
382
383static ssize_t devtype_show(struct device *dev,
384 struct device_attribute *attr, char *buf)
385{
386 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
387}
388
389static ssize_t modalias_show(struct device *dev,
390 struct device_attribute *attr, char *buf)
391{
392 return sprintf(buf, "%s:%s\n", dev->bus->name,
393 to_xenbus_device(dev)->devicetype);
394}
395
396struct device_attribute xenbus_dev_attrs[] = {
397 __ATTR_RO(nodename),
398 __ATTR_RO(devtype),
399 __ATTR_RO(modalias),
400 __ATTR_NULL
401};
402EXPORT_SYMBOL_GPL(xenbus_dev_attrs);
403
404int xenbus_probe_node(struct xen_bus_type *bus,
405 const char *type,
406 const char *nodename)
407{
408 char devname[XEN_BUS_ID_SIZE];
409 int err;
410 struct xenbus_device *xendev;
411 size_t stringlen;
412 char *tmpstring;
413
414 enum xenbus_state state = xenbus_read_driver_state(nodename);
415
416 if (state != XenbusStateInitialising) {
417 /* Device is not new, so ignore it. This can happen if a
418 device is going away after switching to Closed. */
419 return 0;
420 }
421
422 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
423 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
424 if (!xendev)
425 return -ENOMEM;
426
427 xendev->state = XenbusStateInitialising;
428
429 /* Copy the strings into the extra space. */
430
431 tmpstring = (char *)(xendev + 1);
432 strcpy(tmpstring, nodename);
433 xendev->nodename = tmpstring;
434
435 tmpstring += strlen(tmpstring) + 1;
436 strcpy(tmpstring, type);
437 xendev->devicetype = tmpstring;
438 init_completion(&xendev->down);
439
440 xendev->dev.bus = &bus->bus;
441 xendev->dev.release = xenbus_dev_release;
442
443 err = bus->get_bus_id(devname, xendev->nodename);
444 if (err)
445 goto fail;
446
447 dev_set_name(&xendev->dev, devname);
448
449 /* Register with generic device framework. */
450 err = device_register(&xendev->dev);
451 if (err)
452 goto fail;
453
454 return 0;
455fail:
456 kfree(xendev);
457 return err;
458}
459EXPORT_SYMBOL_GPL(xenbus_probe_node);
460
461static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
462{
463 int err = 0;
464 char **dir;
465 unsigned int dir_n = 0;
466 int i;
467
468 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
469 if (IS_ERR(dir))
470 return PTR_ERR(dir);
471
472 for (i = 0; i < dir_n; i++) {
473 err = bus->probe(bus, type, dir[i]);
474 if (err)
475 break;
476 }
477
478 kfree(dir);
479 return err;
480}
481
482int xenbus_probe_devices(struct xen_bus_type *bus)
483{
484 int err = 0;
485 char **dir;
486 unsigned int i, dir_n;
487
488 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
489 if (IS_ERR(dir))
490 return PTR_ERR(dir);
491
492 for (i = 0; i < dir_n; i++) {
493 err = xenbus_probe_device_type(bus, dir[i]);
494 if (err)
495 break;
496 }
497
498 kfree(dir);
499 return err;
500}
501EXPORT_SYMBOL_GPL(xenbus_probe_devices);
502
503static unsigned int char_count(const char *str, char c)
504{
505 unsigned int i, ret = 0;
506
507 for (i = 0; str[i]; i++)
508 if (str[i] == c)
509 ret++;
510 return ret;
511}
512
513static int strsep_len(const char *str, char c, unsigned int len)
514{
515 unsigned int i;
516
517 for (i = 0; str[i]; i++)
518 if (str[i] == c) {
519 if (len == 0)
520 return i;
521 len--;
522 }
523 return (len == 0) ? i : -ERANGE;
524}
525
526void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
527{
528 int exists, rootlen;
529 struct xenbus_device *dev;
530 char type[XEN_BUS_ID_SIZE];
531 const char *p, *root;
532
533 if (char_count(node, '/') < 2)
534 return;
535
536 exists = xenbus_exists(XBT_NIL, node, "");
537 if (!exists) {
538 xenbus_cleanup_devices(node, &bus->bus);
539 return;
540 }
541
542 /* backend/<type>/... or device/<type>/... */
543 p = strchr(node, '/') + 1;
544 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
545 type[XEN_BUS_ID_SIZE-1] = '\0';
546
547 rootlen = strsep_len(node, '/', bus->levels);
548 if (rootlen < 0)
549 return;
550 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
551 if (!root)
552 return;
553
554 dev = xenbus_device_find(root, &bus->bus);
555 if (!dev)
556 xenbus_probe_node(bus, type, root);
557 else
558 put_device(&dev->dev);
559
560 kfree(root);
561}
562EXPORT_SYMBOL_GPL(xenbus_dev_changed);
563
564int xenbus_dev_suspend(struct device *dev)
565{
566 int err = 0;
567 struct xenbus_driver *drv;
568 struct xenbus_device *xdev
569 = container_of(dev, struct xenbus_device, dev);
570
571 DPRINTK("%s", xdev->nodename);
572
573 if (dev->driver == NULL)
574 return 0;
575 drv = to_xenbus_driver(dev->driver);
576 if (drv->suspend)
577 err = drv->suspend(xdev);
578 if (err)
579 printk(KERN_WARNING
580 "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
581 return 0;
582}
583EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
584
585int xenbus_dev_resume(struct device *dev)
586{
587 int err;
588 struct xenbus_driver *drv;
589 struct xenbus_device *xdev
590 = container_of(dev, struct xenbus_device, dev);
591
592 DPRINTK("%s", xdev->nodename);
593
594 if (dev->driver == NULL)
595 return 0;
596 drv = to_xenbus_driver(dev->driver);
597 err = talk_to_otherend(xdev);
598 if (err) {
599 printk(KERN_WARNING
600 "xenbus: resume (talk_to_otherend) %s failed: %i\n",
601 dev_name(dev), err);
602 return err;
603 }
604
605 xdev->state = XenbusStateInitialising;
606
607 if (drv->resume) {
608 err = drv->resume(xdev);
609 if (err) {
610 printk(KERN_WARNING
611 "xenbus: resume %s failed: %i\n",
612 dev_name(dev), err);
613 return err;
614 }
615 }
616
617 err = watch_otherend(xdev);
618 if (err) {
619 printk(KERN_WARNING
620 "xenbus_probe: resume (watch_otherend) %s failed: "
621 "%d.\n", dev_name(dev), err);
622 return err;
623 }
624
625 return 0;
626}
627EXPORT_SYMBOL_GPL(xenbus_dev_resume);
628
629int xenbus_dev_cancel(struct device *dev)
630{
631 /* Do nothing */
632 DPRINTK("cancel");
633 return 0;
634}
635EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
636
637/* A flag to determine if xenstored is 'ready' (i.e. has started) */
638int xenstored_ready;
639
640
641int register_xenstore_notifier(struct notifier_block *nb)
642{
643 int ret = 0;
644
645 if (xenstored_ready > 0)
646 ret = nb->notifier_call(nb, 0, NULL);
647 else
648 blocking_notifier_chain_register(&xenstore_chain, nb);
649
650 return ret;
651}
652EXPORT_SYMBOL_GPL(register_xenstore_notifier);
653
654void unregister_xenstore_notifier(struct notifier_block *nb)
655{
656 blocking_notifier_chain_unregister(&xenstore_chain, nb);
657}
658EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
659
660void xenbus_probe(struct work_struct *unused)
661{
662 xenstored_ready = 1;
663
664 /* Notify others that xenstore is up */
665 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
666}
667EXPORT_SYMBOL_GPL(xenbus_probe);
668
669static int __init xenbus_probe_initcall(void)
670{
671 if (!xen_domain())
672 return -ENODEV;
673
674 if (xen_initial_domain() || xen_hvm_domain())
675 return 0;
676
677 xenbus_probe(NULL);
678 return 0;
679}
680
681device_initcall(xenbus_probe_initcall);
682
683/* Set up event channel for xenstored which is run as a local process
684 * (this is normally used only in dom0)
685 */
686static int __init xenstored_local_init(void)
687{
688 int err = 0;
689 unsigned long page = 0;
690 struct evtchn_alloc_unbound alloc_unbound;
691
692 /* Allocate Xenstore page */
693 page = get_zeroed_page(GFP_KERNEL);
694 if (!page)
695 goto out_err;
696
697 xen_store_mfn = xen_start_info->store_mfn =
698 pfn_to_mfn(virt_to_phys((void *)page) >>
699 PAGE_SHIFT);
700
701 /* Next allocate a local port which xenstored can bind to */
702 alloc_unbound.dom = DOMID_SELF;
703 alloc_unbound.remote_dom = DOMID_SELF;
704
705 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
706 &alloc_unbound);
707 if (err == -ENOSYS)
708 goto out_err;
709
710 BUG_ON(err);
711 xen_store_evtchn = xen_start_info->store_evtchn =
712 alloc_unbound.port;
713
714 return 0;
715
716 out_err:
717 if (page != 0)
718 free_page(page);
719 return err;
720}
721
722static int __init xenbus_init(void)
723{
724 int err = 0;
725
726 if (!xen_domain())
727 return -ENODEV;
728
729 xenbus_ring_ops_init();
730
731 if (xen_hvm_domain()) {
732 uint64_t v = 0;
733 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
734 if (err)
735 goto out_error;
736 xen_store_evtchn = (int)v;
737 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
738 if (err)
739 goto out_error;
740 xen_store_mfn = (unsigned long)v;
741 xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
742 } else {
743 xen_store_evtchn = xen_start_info->store_evtchn;
744 xen_store_mfn = xen_start_info->store_mfn;
745 if (xen_store_evtchn)
746 xenstored_ready = 1;
747 else {
748 err = xenstored_local_init();
749 if (err)
750 goto out_error;
751 }
752 xen_store_interface = mfn_to_virt(xen_store_mfn);
753 }
754
755 /* Initialize the interface to xenstore. */
756 err = xs_init();
757 if (err) {
758 printk(KERN_WARNING
759 "XENBUS: Error initializing xenstore comms: %i\n", err);
760 goto out_error;
761 }
762
763#ifdef CONFIG_XEN_COMPAT_XENFS
764 /*
765 * Create xenfs mountpoint in /proc for compatibility with
766 * utilities that expect to find "xenbus" under "/proc/xen".
767 */
768 proc_mkdir("xen", NULL);
769#endif
770
771out_error:
772 return err;
773}
774
775postcore_initcall(xenbus_init);
776
777MODULE_LICENSE("GPL");
1/******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
3 *
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34#define dev_fmt pr_fmt
35
36#define DPRINTK(fmt, args...) \
37 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
38 __func__, __LINE__, ##args)
39
40#include <linux/kernel.h>
41#include <linux/err.h>
42#include <linux/string.h>
43#include <linux/ctype.h>
44#include <linux/fcntl.h>
45#include <linux/mm.h>
46#include <linux/proc_fs.h>
47#include <linux/notifier.h>
48#include <linux/kthread.h>
49#include <linux/mutex.h>
50#include <linux/io.h>
51#include <linux/slab.h>
52#include <linux/module.h>
53
54#include <asm/page.h>
55#include <asm/xen/hypervisor.h>
56
57#include <xen/xen.h>
58#include <xen/xenbus.h>
59#include <xen/events.h>
60#include <xen/xen-ops.h>
61#include <xen/page.h>
62
63#include <xen/hvm.h>
64
65#include "xenbus.h"
66
67
68static int xs_init_irq;
69int xen_store_evtchn;
70EXPORT_SYMBOL_GPL(xen_store_evtchn);
71
72struct xenstore_domain_interface *xen_store_interface;
73EXPORT_SYMBOL_GPL(xen_store_interface);
74
75enum xenstore_init xen_store_domain_type;
76EXPORT_SYMBOL_GPL(xen_store_domain_type);
77
78static unsigned long xen_store_gfn;
79
80static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
81
82/* If something in array of ids matches this device, return it. */
83static const struct xenbus_device_id *
84match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
85{
86 for (; *arr->devicetype != '\0'; arr++) {
87 if (!strcmp(arr->devicetype, dev->devicetype))
88 return arr;
89 }
90 return NULL;
91}
92
93int xenbus_match(struct device *_dev, struct device_driver *_drv)
94{
95 struct xenbus_driver *drv = to_xenbus_driver(_drv);
96
97 if (!drv->ids)
98 return 0;
99
100 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
101}
102EXPORT_SYMBOL_GPL(xenbus_match);
103
104
105static void free_otherend_details(struct xenbus_device *dev)
106{
107 kfree(dev->otherend);
108 dev->otherend = NULL;
109}
110
111
112static void free_otherend_watch(struct xenbus_device *dev)
113{
114 if (dev->otherend_watch.node) {
115 unregister_xenbus_watch(&dev->otherend_watch);
116 kfree(dev->otherend_watch.node);
117 dev->otherend_watch.node = NULL;
118 }
119}
120
121
122static int talk_to_otherend(struct xenbus_device *dev)
123{
124 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
125
126 free_otherend_watch(dev);
127 free_otherend_details(dev);
128
129 return drv->read_otherend_details(dev);
130}
131
132
133
134static int watch_otherend(struct xenbus_device *dev)
135{
136 struct xen_bus_type *bus =
137 container_of(dev->dev.bus, struct xen_bus_type, bus);
138
139 return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
140 bus->otherend_will_handle,
141 bus->otherend_changed,
142 "%s/%s", dev->otherend, "state");
143}
144
145
146int xenbus_read_otherend_details(struct xenbus_device *xendev,
147 char *id_node, char *path_node)
148{
149 int err = xenbus_gather(XBT_NIL, xendev->nodename,
150 id_node, "%i", &xendev->otherend_id,
151 path_node, NULL, &xendev->otherend,
152 NULL);
153 if (err) {
154 xenbus_dev_fatal(xendev, err,
155 "reading other end details from %s",
156 xendev->nodename);
157 return err;
158 }
159 if (strlen(xendev->otherend) == 0 ||
160 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
161 xenbus_dev_fatal(xendev, -ENOENT,
162 "unable to read other end from %s. "
163 "missing or inaccessible.",
164 xendev->nodename);
165 free_otherend_details(xendev);
166 return -ENOENT;
167 }
168
169 return 0;
170}
171EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
172
173void xenbus_otherend_changed(struct xenbus_watch *watch,
174 const char *path, const char *token,
175 int ignore_on_shutdown)
176{
177 struct xenbus_device *dev =
178 container_of(watch, struct xenbus_device, otherend_watch);
179 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
180 enum xenbus_state state;
181
182 /* Protect us against watches firing on old details when the otherend
183 details change, say immediately after a resume. */
184 if (!dev->otherend ||
185 strncmp(dev->otherend, path, strlen(dev->otherend))) {
186 dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
187 return;
188 }
189
190 state = xenbus_read_driver_state(dev->otherend);
191
192 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
193 state, xenbus_strstate(state), dev->otherend_watch.node, path);
194
195 /*
196 * Ignore xenbus transitions during shutdown. This prevents us doing
197 * work that can fail e.g., when the rootfs is gone.
198 */
199 if (system_state > SYSTEM_RUNNING) {
200 if (ignore_on_shutdown && (state == XenbusStateClosing))
201 xenbus_frontend_closed(dev);
202 return;
203 }
204
205 if (drv->otherend_changed)
206 drv->otherend_changed(dev, state);
207}
208EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
209
210#define XENBUS_SHOW_STAT(name) \
211static ssize_t name##_show(struct device *_dev, \
212 struct device_attribute *attr, \
213 char *buf) \
214{ \
215 struct xenbus_device *dev = to_xenbus_device(_dev); \
216 \
217 return sprintf(buf, "%d\n", atomic_read(&dev->name)); \
218} \
219static DEVICE_ATTR_RO(name)
220
221XENBUS_SHOW_STAT(event_channels);
222XENBUS_SHOW_STAT(events);
223XENBUS_SHOW_STAT(spurious_events);
224XENBUS_SHOW_STAT(jiffies_eoi_delayed);
225
226static ssize_t spurious_threshold_show(struct device *_dev,
227 struct device_attribute *attr,
228 char *buf)
229{
230 struct xenbus_device *dev = to_xenbus_device(_dev);
231
232 return sprintf(buf, "%d\n", dev->spurious_threshold);
233}
234
235static ssize_t spurious_threshold_store(struct device *_dev,
236 struct device_attribute *attr,
237 const char *buf, size_t count)
238{
239 struct xenbus_device *dev = to_xenbus_device(_dev);
240 unsigned int val;
241 ssize_t ret;
242
243 ret = kstrtouint(buf, 0, &val);
244 if (ret)
245 return ret;
246
247 dev->spurious_threshold = val;
248
249 return count;
250}
251
252static DEVICE_ATTR_RW(spurious_threshold);
253
254static struct attribute *xenbus_attrs[] = {
255 &dev_attr_event_channels.attr,
256 &dev_attr_events.attr,
257 &dev_attr_spurious_events.attr,
258 &dev_attr_jiffies_eoi_delayed.attr,
259 &dev_attr_spurious_threshold.attr,
260 NULL
261};
262
263static const struct attribute_group xenbus_group = {
264 .name = "xenbus",
265 .attrs = xenbus_attrs,
266};
267
268int xenbus_dev_probe(struct device *_dev)
269{
270 struct xenbus_device *dev = to_xenbus_device(_dev);
271 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
272 const struct xenbus_device_id *id;
273 int err;
274
275 DPRINTK("%s", dev->nodename);
276
277 if (!drv->probe) {
278 err = -ENODEV;
279 goto fail;
280 }
281
282 id = match_device(drv->ids, dev);
283 if (!id) {
284 err = -ENODEV;
285 goto fail;
286 }
287
288 err = talk_to_otherend(dev);
289 if (err) {
290 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
291 dev->nodename);
292 return err;
293 }
294
295 if (!try_module_get(drv->driver.owner)) {
296 dev_warn(&dev->dev, "failed to acquire module reference on '%s'\n",
297 drv->driver.name);
298 err = -ESRCH;
299 goto fail;
300 }
301
302 down(&dev->reclaim_sem);
303 err = drv->probe(dev, id);
304 up(&dev->reclaim_sem);
305 if (err)
306 goto fail_put;
307
308 err = watch_otherend(dev);
309 if (err) {
310 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
311 dev->nodename);
312 return err;
313 }
314
315 dev->spurious_threshold = 1;
316 if (sysfs_create_group(&dev->dev.kobj, &xenbus_group))
317 dev_warn(&dev->dev, "sysfs_create_group on %s failed.\n",
318 dev->nodename);
319
320 return 0;
321fail_put:
322 module_put(drv->driver.owner);
323fail:
324 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
325 return err;
326}
327EXPORT_SYMBOL_GPL(xenbus_dev_probe);
328
329void xenbus_dev_remove(struct device *_dev)
330{
331 struct xenbus_device *dev = to_xenbus_device(_dev);
332 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
333
334 DPRINTK("%s", dev->nodename);
335
336 sysfs_remove_group(&dev->dev.kobj, &xenbus_group);
337
338 free_otherend_watch(dev);
339
340 if (drv->remove) {
341 down(&dev->reclaim_sem);
342 drv->remove(dev);
343 up(&dev->reclaim_sem);
344 }
345
346 module_put(drv->driver.owner);
347
348 free_otherend_details(dev);
349
350 /*
351 * If the toolstack has forced the device state to closing then set
352 * the state to closed now to allow it to be cleaned up.
353 * Similarly, if the driver does not support re-bind, set the
354 * closed.
355 */
356 if (!drv->allow_rebind ||
357 xenbus_read_driver_state(dev->nodename) == XenbusStateClosing)
358 xenbus_switch_state(dev, XenbusStateClosed);
359}
360EXPORT_SYMBOL_GPL(xenbus_dev_remove);
361
362int xenbus_register_driver_common(struct xenbus_driver *drv,
363 struct xen_bus_type *bus,
364 struct module *owner, const char *mod_name)
365{
366 drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
367 drv->driver.bus = &bus->bus;
368 drv->driver.owner = owner;
369 drv->driver.mod_name = mod_name;
370
371 return driver_register(&drv->driver);
372}
373EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
374
375void xenbus_unregister_driver(struct xenbus_driver *drv)
376{
377 driver_unregister(&drv->driver);
378}
379EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
380
381struct xb_find_info {
382 struct xenbus_device *dev;
383 const char *nodename;
384};
385
386static int cmp_dev(struct device *dev, void *data)
387{
388 struct xenbus_device *xendev = to_xenbus_device(dev);
389 struct xb_find_info *info = data;
390
391 if (!strcmp(xendev->nodename, info->nodename)) {
392 info->dev = xendev;
393 get_device(dev);
394 return 1;
395 }
396 return 0;
397}
398
399static struct xenbus_device *xenbus_device_find(const char *nodename,
400 struct bus_type *bus)
401{
402 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
403
404 bus_for_each_dev(bus, NULL, &info, cmp_dev);
405 return info.dev;
406}
407
408static int cleanup_dev(struct device *dev, void *data)
409{
410 struct xenbus_device *xendev = to_xenbus_device(dev);
411 struct xb_find_info *info = data;
412 int len = strlen(info->nodename);
413
414 DPRINTK("%s", info->nodename);
415
416 /* Match the info->nodename path, or any subdirectory of that path. */
417 if (strncmp(xendev->nodename, info->nodename, len))
418 return 0;
419
420 /* If the node name is longer, ensure it really is a subdirectory. */
421 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
422 return 0;
423
424 info->dev = xendev;
425 get_device(dev);
426 return 1;
427}
428
429static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
430{
431 struct xb_find_info info = { .nodename = path };
432
433 do {
434 info.dev = NULL;
435 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
436 if (info.dev) {
437 device_unregister(&info.dev->dev);
438 put_device(&info.dev->dev);
439 }
440 } while (info.dev);
441}
442
443static void xenbus_dev_release(struct device *dev)
444{
445 if (dev)
446 kfree(to_xenbus_device(dev));
447}
448
449static ssize_t nodename_show(struct device *dev,
450 struct device_attribute *attr, char *buf)
451{
452 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
453}
454static DEVICE_ATTR_RO(nodename);
455
456static ssize_t devtype_show(struct device *dev,
457 struct device_attribute *attr, char *buf)
458{
459 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
460}
461static DEVICE_ATTR_RO(devtype);
462
463static ssize_t modalias_show(struct device *dev,
464 struct device_attribute *attr, char *buf)
465{
466 return sprintf(buf, "%s:%s\n", dev->bus->name,
467 to_xenbus_device(dev)->devicetype);
468}
469static DEVICE_ATTR_RO(modalias);
470
471static ssize_t state_show(struct device *dev,
472 struct device_attribute *attr, char *buf)
473{
474 return sprintf(buf, "%s\n",
475 xenbus_strstate(to_xenbus_device(dev)->state));
476}
477static DEVICE_ATTR_RO(state);
478
479static struct attribute *xenbus_dev_attrs[] = {
480 &dev_attr_nodename.attr,
481 &dev_attr_devtype.attr,
482 &dev_attr_modalias.attr,
483 &dev_attr_state.attr,
484 NULL,
485};
486
487static const struct attribute_group xenbus_dev_group = {
488 .attrs = xenbus_dev_attrs,
489};
490
491const struct attribute_group *xenbus_dev_groups[] = {
492 &xenbus_dev_group,
493 NULL,
494};
495EXPORT_SYMBOL_GPL(xenbus_dev_groups);
496
497int xenbus_probe_node(struct xen_bus_type *bus,
498 const char *type,
499 const char *nodename)
500{
501 char devname[XEN_BUS_ID_SIZE];
502 int err;
503 struct xenbus_device *xendev;
504 size_t stringlen;
505 char *tmpstring;
506
507 enum xenbus_state state = xenbus_read_driver_state(nodename);
508
509 if (state != XenbusStateInitialising) {
510 /* Device is not new, so ignore it. This can happen if a
511 device is going away after switching to Closed. */
512 return 0;
513 }
514
515 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
516 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
517 if (!xendev)
518 return -ENOMEM;
519
520 xendev->state = XenbusStateInitialising;
521
522 /* Copy the strings into the extra space. */
523
524 tmpstring = (char *)(xendev + 1);
525 strcpy(tmpstring, nodename);
526 xendev->nodename = tmpstring;
527
528 tmpstring += strlen(tmpstring) + 1;
529 strcpy(tmpstring, type);
530 xendev->devicetype = tmpstring;
531 init_completion(&xendev->down);
532
533 xendev->dev.bus = &bus->bus;
534 xendev->dev.release = xenbus_dev_release;
535
536 err = bus->get_bus_id(devname, xendev->nodename);
537 if (err)
538 goto fail;
539
540 dev_set_name(&xendev->dev, "%s", devname);
541 sema_init(&xendev->reclaim_sem, 1);
542
543 /* Register with generic device framework. */
544 err = device_register(&xendev->dev);
545 if (err) {
546 put_device(&xendev->dev);
547 xendev = NULL;
548 goto fail;
549 }
550
551 return 0;
552fail:
553 kfree(xendev);
554 return err;
555}
556EXPORT_SYMBOL_GPL(xenbus_probe_node);
557
558static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
559{
560 int err = 0;
561 char **dir;
562 unsigned int dir_n = 0;
563 int i;
564
565 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
566 if (IS_ERR(dir))
567 return PTR_ERR(dir);
568
569 for (i = 0; i < dir_n; i++) {
570 err = bus->probe(bus, type, dir[i]);
571 if (err)
572 break;
573 }
574
575 kfree(dir);
576 return err;
577}
578
579int xenbus_probe_devices(struct xen_bus_type *bus)
580{
581 int err = 0;
582 char **dir;
583 unsigned int i, dir_n;
584
585 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
586 if (IS_ERR(dir))
587 return PTR_ERR(dir);
588
589 for (i = 0; i < dir_n; i++) {
590 err = xenbus_probe_device_type(bus, dir[i]);
591 if (err)
592 break;
593 }
594
595 kfree(dir);
596 return err;
597}
598EXPORT_SYMBOL_GPL(xenbus_probe_devices);
599
600static unsigned int char_count(const char *str, char c)
601{
602 unsigned int i, ret = 0;
603
604 for (i = 0; str[i]; i++)
605 if (str[i] == c)
606 ret++;
607 return ret;
608}
609
610static int strsep_len(const char *str, char c, unsigned int len)
611{
612 unsigned int i;
613
614 for (i = 0; str[i]; i++)
615 if (str[i] == c) {
616 if (len == 0)
617 return i;
618 len--;
619 }
620 return (len == 0) ? i : -ERANGE;
621}
622
623void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
624{
625 int exists, rootlen;
626 struct xenbus_device *dev;
627 char type[XEN_BUS_ID_SIZE];
628 const char *p, *root;
629
630 if (char_count(node, '/') < 2)
631 return;
632
633 exists = xenbus_exists(XBT_NIL, node, "");
634 if (!exists) {
635 xenbus_cleanup_devices(node, &bus->bus);
636 return;
637 }
638
639 /* backend/<type>/... or device/<type>/... */
640 p = strchr(node, '/') + 1;
641 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
642 type[XEN_BUS_ID_SIZE-1] = '\0';
643
644 rootlen = strsep_len(node, '/', bus->levels);
645 if (rootlen < 0)
646 return;
647 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
648 if (!root)
649 return;
650
651 dev = xenbus_device_find(root, &bus->bus);
652 if (!dev)
653 xenbus_probe_node(bus, type, root);
654 else
655 put_device(&dev->dev);
656
657 kfree(root);
658}
659EXPORT_SYMBOL_GPL(xenbus_dev_changed);
660
661int xenbus_dev_suspend(struct device *dev)
662{
663 int err = 0;
664 struct xenbus_driver *drv;
665 struct xenbus_device *xdev
666 = container_of(dev, struct xenbus_device, dev);
667
668 DPRINTK("%s", xdev->nodename);
669
670 if (dev->driver == NULL)
671 return 0;
672 drv = to_xenbus_driver(dev->driver);
673 if (drv->suspend)
674 err = drv->suspend(xdev);
675 if (err)
676 dev_warn(dev, "suspend failed: %i\n", err);
677 return 0;
678}
679EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
680
681int xenbus_dev_resume(struct device *dev)
682{
683 int err;
684 struct xenbus_driver *drv;
685 struct xenbus_device *xdev
686 = container_of(dev, struct xenbus_device, dev);
687
688 DPRINTK("%s", xdev->nodename);
689
690 if (dev->driver == NULL)
691 return 0;
692 drv = to_xenbus_driver(dev->driver);
693 err = talk_to_otherend(xdev);
694 if (err) {
695 dev_warn(dev, "resume (talk_to_otherend) failed: %i\n", err);
696 return err;
697 }
698
699 xdev->state = XenbusStateInitialising;
700
701 if (drv->resume) {
702 err = drv->resume(xdev);
703 if (err) {
704 dev_warn(dev, "resume failed: %i\n", err);
705 return err;
706 }
707 }
708
709 err = watch_otherend(xdev);
710 if (err) {
711 dev_warn(dev, "resume (watch_otherend) failed: %d\n", err);
712 return err;
713 }
714
715 return 0;
716}
717EXPORT_SYMBOL_GPL(xenbus_dev_resume);
718
719int xenbus_dev_cancel(struct device *dev)
720{
721 /* Do nothing */
722 DPRINTK("cancel");
723 return 0;
724}
725EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
726
727/* A flag to determine if xenstored is 'ready' (i.e. has started) */
728int xenstored_ready;
729
730
731int register_xenstore_notifier(struct notifier_block *nb)
732{
733 int ret = 0;
734
735 if (xenstored_ready > 0)
736 ret = nb->notifier_call(nb, 0, NULL);
737 else
738 blocking_notifier_chain_register(&xenstore_chain, nb);
739
740 return ret;
741}
742EXPORT_SYMBOL_GPL(register_xenstore_notifier);
743
744void unregister_xenstore_notifier(struct notifier_block *nb)
745{
746 blocking_notifier_chain_unregister(&xenstore_chain, nb);
747}
748EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
749
750static void xenbus_probe(void)
751{
752 xenstored_ready = 1;
753
754 if (!xen_store_interface) {
755 xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT,
756 XEN_PAGE_SIZE, MEMREMAP_WB);
757 /*
758 * Now it is safe to free the IRQ used for xenstore late
759 * initialization. No need to unbind: it is about to be
760 * bound again from xb_init_comms. Note that calling
761 * unbind_from_irqhandler now would result in xen_evtchn_close()
762 * being called and the event channel not being enabled again
763 * afterwards, resulting in missed event notifications.
764 */
765 free_irq(xs_init_irq, &xb_waitq);
766 }
767
768 /*
769 * In the HVM case, xenbus_init() deferred its call to
770 * xs_init() in case callbacks were not operational yet.
771 * So do it now.
772 */
773 if (xen_store_domain_type == XS_HVM)
774 xs_init();
775
776 /* Notify others that xenstore is up */
777 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
778}
779
780/*
781 * Returns true when XenStore init must be deferred in order to
782 * allow the PCI platform device to be initialised, before we
783 * can actually have event channel interrupts working.
784 */
785static bool xs_hvm_defer_init_for_callback(void)
786{
787#ifdef CONFIG_XEN_PVHVM
788 return xen_store_domain_type == XS_HVM &&
789 !xen_have_vector_callback;
790#else
791 return false;
792#endif
793}
794
795static int xenbus_probe_thread(void *unused)
796{
797 DEFINE_WAIT(w);
798
799 /*
800 * We actually just want to wait for *any* trigger of xb_waitq,
801 * and run xenbus_probe() the moment it occurs.
802 */
803 prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
804 schedule();
805 finish_wait(&xb_waitq, &w);
806
807 DPRINTK("probing");
808 xenbus_probe();
809 return 0;
810}
811
812static int __init xenbus_probe_initcall(void)
813{
814 /*
815 * Probe XenBus here in the XS_PV case, and also XS_HVM unless we
816 * need to wait for the platform PCI device to come up or
817 * xen_store_interface is not ready.
818 */
819 if (xen_store_domain_type == XS_PV ||
820 (xen_store_domain_type == XS_HVM &&
821 !xs_hvm_defer_init_for_callback() &&
822 xen_store_interface != NULL))
823 xenbus_probe();
824
825 /*
826 * For XS_LOCAL or when xen_store_interface is not ready, spawn a
827 * thread which will wait for xenstored or a xenstore-stubdom to be
828 * started, then probe. It will be triggered when communication
829 * starts happening, by waiting on xb_waitq.
830 */
831 if (xen_store_domain_type == XS_LOCAL || xen_store_interface == NULL) {
832 struct task_struct *probe_task;
833
834 probe_task = kthread_run(xenbus_probe_thread, NULL,
835 "xenbus_probe");
836 if (IS_ERR(probe_task))
837 return PTR_ERR(probe_task);
838 }
839 return 0;
840}
841device_initcall(xenbus_probe_initcall);
842
843int xen_set_callback_via(uint64_t via)
844{
845 struct xen_hvm_param a;
846 int ret;
847
848 a.domid = DOMID_SELF;
849 a.index = HVM_PARAM_CALLBACK_IRQ;
850 a.value = via;
851
852 ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a);
853 if (ret)
854 return ret;
855
856 /*
857 * If xenbus_probe_initcall() deferred the xenbus_probe()
858 * due to the callback not functioning yet, we can do it now.
859 */
860 if (!xenstored_ready && xs_hvm_defer_init_for_callback())
861 xenbus_probe();
862
863 return ret;
864}
865EXPORT_SYMBOL_GPL(xen_set_callback_via);
866
867/* Set up event channel for xenstored which is run as a local process
868 * (this is normally used only in dom0)
869 */
870static int __init xenstored_local_init(void)
871{
872 int err = -ENOMEM;
873 unsigned long page = 0;
874 struct evtchn_alloc_unbound alloc_unbound;
875
876 /* Allocate Xenstore page */
877 page = get_zeroed_page(GFP_KERNEL);
878 if (!page)
879 goto out_err;
880
881 xen_store_gfn = virt_to_gfn((void *)page);
882
883 /* Next allocate a local port which xenstored can bind to */
884 alloc_unbound.dom = DOMID_SELF;
885 alloc_unbound.remote_dom = DOMID_SELF;
886
887 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
888 &alloc_unbound);
889 if (err == -ENOSYS)
890 goto out_err;
891
892 BUG_ON(err);
893 xen_store_evtchn = alloc_unbound.port;
894
895 return 0;
896
897 out_err:
898 if (page != 0)
899 free_page(page);
900 return err;
901}
902
903static int xenbus_resume_cb(struct notifier_block *nb,
904 unsigned long action, void *data)
905{
906 int err = 0;
907
908 if (xen_hvm_domain()) {
909 uint64_t v = 0;
910
911 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
912 if (!err && v)
913 xen_store_evtchn = v;
914 else
915 pr_warn("Cannot update xenstore event channel: %d\n",
916 err);
917 } else
918 xen_store_evtchn = xen_start_info->store_evtchn;
919
920 return err;
921}
922
923static struct notifier_block xenbus_resume_nb = {
924 .notifier_call = xenbus_resume_cb,
925};
926
927static irqreturn_t xenbus_late_init(int irq, void *unused)
928{
929 int err;
930 uint64_t v = 0;
931
932 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
933 if (err || !v || !~v)
934 return IRQ_HANDLED;
935 xen_store_gfn = (unsigned long)v;
936
937 wake_up(&xb_waitq);
938 return IRQ_HANDLED;
939}
940
941static int __init xenbus_init(void)
942{
943 int err;
944 uint64_t v = 0;
945 bool wait = false;
946 xen_store_domain_type = XS_UNKNOWN;
947
948 if (!xen_domain())
949 return -ENODEV;
950
951 xenbus_ring_ops_init();
952
953 if (xen_pv_domain())
954 xen_store_domain_type = XS_PV;
955 if (xen_hvm_domain())
956 xen_store_domain_type = XS_HVM;
957 if (xen_hvm_domain() && xen_initial_domain())
958 xen_store_domain_type = XS_LOCAL;
959 if (xen_pv_domain() && !xen_start_info->store_evtchn)
960 xen_store_domain_type = XS_LOCAL;
961 if (xen_pv_domain() && xen_start_info->store_evtchn)
962 xenstored_ready = 1;
963
964 switch (xen_store_domain_type) {
965 case XS_LOCAL:
966 err = xenstored_local_init();
967 if (err)
968 goto out_error;
969 xen_store_interface = gfn_to_virt(xen_store_gfn);
970 break;
971 case XS_PV:
972 xen_store_evtchn = xen_start_info->store_evtchn;
973 xen_store_gfn = xen_start_info->store_mfn;
974 xen_store_interface = gfn_to_virt(xen_store_gfn);
975 break;
976 case XS_HVM:
977 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
978 if (err)
979 goto out_error;
980 xen_store_evtchn = (int)v;
981 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
982 if (err)
983 goto out_error;
984 /*
985 * Uninitialized hvm_params are zero and return no error.
986 * Although it is theoretically possible to have
987 * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is
988 * not zero when valid. If zero, it means that Xenstore hasn't
989 * been properly initialized. Instead of attempting to map a
990 * wrong guest physical address return error.
991 *
992 * Also recognize all bits set as an invalid/uninitialized value.
993 */
994 if (!v) {
995 err = -ENOENT;
996 goto out_error;
997 }
998 if (v == ~0ULL) {
999 wait = true;
1000 } else {
1001 /* Avoid truncation on 32-bit. */
1002#if BITS_PER_LONG == 32
1003 if (v > ULONG_MAX) {
1004 pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n",
1005 __func__, v);
1006 err = -EINVAL;
1007 goto out_error;
1008 }
1009#endif
1010 xen_store_gfn = (unsigned long)v;
1011 xen_store_interface =
1012 memremap(xen_store_gfn << XEN_PAGE_SHIFT,
1013 XEN_PAGE_SIZE, MEMREMAP_WB);
1014 if (xen_store_interface->connection != XENSTORE_CONNECTED)
1015 wait = true;
1016 }
1017 if (wait) {
1018 err = bind_evtchn_to_irqhandler(xen_store_evtchn,
1019 xenbus_late_init,
1020 0, "xenstore_late_init",
1021 &xb_waitq);
1022 if (err < 0) {
1023 pr_err("xenstore_late_init couldn't bind irq err=%d\n",
1024 err);
1025 return err;
1026 }
1027
1028 xs_init_irq = err;
1029 }
1030 break;
1031 default:
1032 pr_warn("Xenstore state unknown\n");
1033 break;
1034 }
1035
1036 /*
1037 * HVM domains may not have a functional callback yet. In that
1038 * case let xs_init() be called from xenbus_probe(), which will
1039 * get invoked at an appropriate time.
1040 */
1041 if (xen_store_domain_type != XS_HVM) {
1042 err = xs_init();
1043 if (err) {
1044 pr_warn("Error initializing xenstore comms: %i\n", err);
1045 goto out_error;
1046 }
1047 }
1048
1049 if ((xen_store_domain_type != XS_LOCAL) &&
1050 (xen_store_domain_type != XS_UNKNOWN))
1051 xen_resume_notifier_register(&xenbus_resume_nb);
1052
1053#ifdef CONFIG_XEN_COMPAT_XENFS
1054 /*
1055 * Create xenfs mountpoint in /proc for compatibility with
1056 * utilities that expect to find "xenbus" under "/proc/xen".
1057 */
1058 proc_create_mount_point("xen");
1059#endif
1060 return 0;
1061
1062out_error:
1063 xen_store_domain_type = XS_UNKNOWN;
1064 return err;
1065}
1066
1067postcore_initcall(xenbus_init);
1068
1069MODULE_LICENSE("GPL");