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
35#define DPRINTK(fmt, args...)				\
36	pr_debug("xenbus_probe (%s:%d) " fmt ".\n",	\
37		 __func__, __LINE__, ##args)
38
39#include <linux/kernel.h>
40#include <linux/err.h>
41#include <linux/string.h>
42#include <linux/ctype.h>
43#include <linux/fcntl.h>
44#include <linux/mm.h>
45#include <linux/proc_fs.h>
46#include <linux/notifier.h>
47#include <linux/kthread.h>
48#include <linux/mutex.h>
49#include <linux/io.h>
50#include <linux/slab.h>
51#include <linux/module.h>
52
53#include <asm/page.h>
54#include <asm/pgtable.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_comms.h"
66#include "xenbus_probe.h"
67
68
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_mfn;
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_changed,
141				    "%s/%s", dev->otherend, "state");
142}
143
144
145int xenbus_read_otherend_details(struct xenbus_device *xendev,
146				 char *id_node, char *path_node)
147{
148	int err = xenbus_gather(XBT_NIL, xendev->nodename,
149				id_node, "%i", &xendev->otherend_id,
150				path_node, NULL, &xendev->otherend,
151				NULL);
152	if (err) {
153		xenbus_dev_fatal(xendev, err,
154				 "reading other end details from %s",
155				 xendev->nodename);
156		return err;
157	}
158	if (strlen(xendev->otherend) == 0 ||
159	    !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
160		xenbus_dev_fatal(xendev, -ENOENT,
161				 "unable to read other end from %s.  "
162				 "missing or inaccessible.",
163				 xendev->nodename);
164		free_otherend_details(xendev);
165		return -ENOENT;
166	}
167
168	return 0;
169}
170EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
171
172void xenbus_otherend_changed(struct xenbus_watch *watch,
173			     const char **vec, unsigned int len,
174			     int ignore_on_shutdown)
175{
176	struct xenbus_device *dev =
177		container_of(watch, struct xenbus_device, otherend_watch);
178	struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
179	enum xenbus_state state;
180
181	/* Protect us against watches firing on old details when the otherend
182	   details change, say immediately after a resume. */
183	if (!dev->otherend ||
184	    strncmp(dev->otherend, vec[XS_WATCH_PATH],
185		    strlen(dev->otherend))) {
186		dev_dbg(&dev->dev, "Ignoring watch at %s\n",
187			vec[XS_WATCH_PATH]);
188		return;
189	}
190
191	state = xenbus_read_driver_state(dev->otherend);
192
193	dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
194		state, xenbus_strstate(state), dev->otherend_watch.node,
195		vec[XS_WATCH_PATH]);
196
197	/*
198	 * Ignore xenbus transitions during shutdown. This prevents us doing
199	 * work that can fail e.g., when the rootfs is gone.
200	 */
201	if (system_state > SYSTEM_RUNNING) {
202		if (ignore_on_shutdown && (state == XenbusStateClosing))
203			xenbus_frontend_closed(dev);
204		return;
205	}
206
207	if (drv->otherend_changed)
208		drv->otherend_changed(dev, state);
209}
210EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
211
212int xenbus_dev_probe(struct device *_dev)
213{
214	struct xenbus_device *dev = to_xenbus_device(_dev);
215	struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
216	const struct xenbus_device_id *id;
217	int err;
218
219	DPRINTK("%s", dev->nodename);
220
221	if (!drv->probe) {
222		err = -ENODEV;
223		goto fail;
224	}
225
226	id = match_device(drv->ids, dev);
227	if (!id) {
228		err = -ENODEV;
229		goto fail;
230	}
231
232	err = talk_to_otherend(dev);
233	if (err) {
234		dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
235			 dev->nodename);
236		return err;
237	}
238
239	err = drv->probe(dev, id);
240	if (err)
241		goto fail;
242
243	err = watch_otherend(dev);
244	if (err) {
245		dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
246		       dev->nodename);
247		return err;
248	}
249
250	return 0;
251fail:
252	xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
253	xenbus_switch_state(dev, XenbusStateClosed);
254	return err;
255}
256EXPORT_SYMBOL_GPL(xenbus_dev_probe);
257
258int xenbus_dev_remove(struct device *_dev)
259{
260	struct xenbus_device *dev = to_xenbus_device(_dev);
261	struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
262
263	DPRINTK("%s", dev->nodename);
264
265	free_otherend_watch(dev);
266
267	if (drv->remove)
268		drv->remove(dev);
269
270	free_otherend_details(dev);
271
272	xenbus_switch_state(dev, XenbusStateClosed);
273	return 0;
274}
275EXPORT_SYMBOL_GPL(xenbus_dev_remove);
276
277void xenbus_dev_shutdown(struct device *_dev)
278{
279	struct xenbus_device *dev = to_xenbus_device(_dev);
280	unsigned long timeout = 5*HZ;
281
282	DPRINTK("%s", dev->nodename);
283
284	get_device(&dev->dev);
285	if (dev->state != XenbusStateConnected) {
286		pr_info("%s: %s: %s != Connected, skipping\n",
287			__func__, dev->nodename, xenbus_strstate(dev->state));
288		goto out;
289	}
290	xenbus_switch_state(dev, XenbusStateClosing);
291	timeout = wait_for_completion_timeout(&dev->down, timeout);
292	if (!timeout)
293		pr_info("%s: %s timeout closing device\n",
294			__func__, dev->nodename);
295 out:
296	put_device(&dev->dev);
297}
298EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
299
300int xenbus_register_driver_common(struct xenbus_driver *drv,
301				  struct xen_bus_type *bus,
302				  struct module *owner, const char *mod_name)
303{
304	drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
305	drv->driver.bus = &bus->bus;
306	drv->driver.owner = owner;
307	drv->driver.mod_name = mod_name;
308
309	return driver_register(&drv->driver);
310}
311EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
312
313void xenbus_unregister_driver(struct xenbus_driver *drv)
314{
315	driver_unregister(&drv->driver);
316}
317EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
318
319struct xb_find_info {
320	struct xenbus_device *dev;
321	const char *nodename;
322};
323
324static int cmp_dev(struct device *dev, void *data)
325{
326	struct xenbus_device *xendev = to_xenbus_device(dev);
327	struct xb_find_info *info = data;
328
329	if (!strcmp(xendev->nodename, info->nodename)) {
330		info->dev = xendev;
331		get_device(dev);
332		return 1;
333	}
334	return 0;
335}
336
337static struct xenbus_device *xenbus_device_find(const char *nodename,
338						struct bus_type *bus)
339{
340	struct xb_find_info info = { .dev = NULL, .nodename = nodename };
341
342	bus_for_each_dev(bus, NULL, &info, cmp_dev);
343	return info.dev;
344}
345
346static int cleanup_dev(struct device *dev, void *data)
347{
348	struct xenbus_device *xendev = to_xenbus_device(dev);
349	struct xb_find_info *info = data;
350	int len = strlen(info->nodename);
351
352	DPRINTK("%s", info->nodename);
353
354	/* Match the info->nodename path, or any subdirectory of that path. */
355	if (strncmp(xendev->nodename, info->nodename, len))
356		return 0;
357
358	/* If the node name is longer, ensure it really is a subdirectory. */
359	if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
360		return 0;
361
362	info->dev = xendev;
363	get_device(dev);
364	return 1;
365}
366
367static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
368{
369	struct xb_find_info info = { .nodename = path };
370
371	do {
372		info.dev = NULL;
373		bus_for_each_dev(bus, NULL, &info, cleanup_dev);
374		if (info.dev) {
375			device_unregister(&info.dev->dev);
376			put_device(&info.dev->dev);
377		}
378	} while (info.dev);
379}
380
381static void xenbus_dev_release(struct device *dev)
382{
383	if (dev)
384		kfree(to_xenbus_device(dev));
385}
386
387static ssize_t nodename_show(struct device *dev,
388			     struct device_attribute *attr, char *buf)
389{
390	return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
391}
392static DEVICE_ATTR_RO(nodename);
393
394static ssize_t devtype_show(struct device *dev,
395			    struct device_attribute *attr, char *buf)
396{
397	return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
398}
399static DEVICE_ATTR_RO(devtype);
400
401static ssize_t modalias_show(struct device *dev,
402			     struct device_attribute *attr, char *buf)
403{
404	return sprintf(buf, "%s:%s\n", dev->bus->name,
405		       to_xenbus_device(dev)->devicetype);
406}
407static DEVICE_ATTR_RO(modalias);
408
409static struct attribute *xenbus_dev_attrs[] = {
410	&dev_attr_nodename.attr,
411	&dev_attr_devtype.attr,
412	&dev_attr_modalias.attr,
413	NULL,
414};
415
416static const struct attribute_group xenbus_dev_group = {
417	.attrs = xenbus_dev_attrs,
418};
419
420const struct attribute_group *xenbus_dev_groups[] = {
421	&xenbus_dev_group,
422	NULL,
423};
424EXPORT_SYMBOL_GPL(xenbus_dev_groups);
425
426int xenbus_probe_node(struct xen_bus_type *bus,
427		      const char *type,
428		      const char *nodename)
429{
430	char devname[XEN_BUS_ID_SIZE];
431	int err;
432	struct xenbus_device *xendev;
433	size_t stringlen;
434	char *tmpstring;
435
436	enum xenbus_state state = xenbus_read_driver_state(nodename);
437
438	if (state != XenbusStateInitialising) {
439		/* Device is not new, so ignore it.  This can happen if a
440		   device is going away after switching to Closed.  */
441		return 0;
442	}
443
444	stringlen = strlen(nodename) + 1 + strlen(type) + 1;
445	xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
446	if (!xendev)
447		return -ENOMEM;
448
449	xendev->state = XenbusStateInitialising;
450
451	/* Copy the strings into the extra space. */
452
453	tmpstring = (char *)(xendev + 1);
454	strcpy(tmpstring, nodename);
455	xendev->nodename = tmpstring;
456
457	tmpstring += strlen(tmpstring) + 1;
458	strcpy(tmpstring, type);
459	xendev->devicetype = tmpstring;
460	init_completion(&xendev->down);
461
462	xendev->dev.bus = &bus->bus;
463	xendev->dev.release = xenbus_dev_release;
464
465	err = bus->get_bus_id(devname, xendev->nodename);
466	if (err)
467		goto fail;
468
469	dev_set_name(&xendev->dev, "%s", devname);
470
471	/* Register with generic device framework. */
472	err = device_register(&xendev->dev);
473	if (err)
474		goto fail;
475
476	return 0;
477fail:
478	kfree(xendev);
479	return err;
480}
481EXPORT_SYMBOL_GPL(xenbus_probe_node);
482
483static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
484{
485	int err = 0;
486	char **dir;
487	unsigned int dir_n = 0;
488	int i;
489
490	dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
491	if (IS_ERR(dir))
492		return PTR_ERR(dir);
493
494	for (i = 0; i < dir_n; i++) {
495		err = bus->probe(bus, type, dir[i]);
496		if (err)
497			break;
498	}
499
500	kfree(dir);
501	return err;
502}
503
504int xenbus_probe_devices(struct xen_bus_type *bus)
505{
506	int err = 0;
507	char **dir;
508	unsigned int i, dir_n;
509
510	dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
511	if (IS_ERR(dir))
512		return PTR_ERR(dir);
513
514	for (i = 0; i < dir_n; i++) {
515		err = xenbus_probe_device_type(bus, dir[i]);
516		if (err)
517			break;
518	}
519
520	kfree(dir);
521	return err;
522}
523EXPORT_SYMBOL_GPL(xenbus_probe_devices);
524
525static unsigned int char_count(const char *str, char c)
526{
527	unsigned int i, ret = 0;
528
529	for (i = 0; str[i]; i++)
530		if (str[i] == c)
531			ret++;
532	return ret;
533}
534
535static int strsep_len(const char *str, char c, unsigned int len)
536{
537	unsigned int i;
538
539	for (i = 0; str[i]; i++)
540		if (str[i] == c) {
541			if (len == 0)
542				return i;
543			len--;
544		}
545	return (len == 0) ? i : -ERANGE;
546}
547
548void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
549{
550	int exists, rootlen;
551	struct xenbus_device *dev;
552	char type[XEN_BUS_ID_SIZE];
553	const char *p, *root;
554
555	if (char_count(node, '/') < 2)
556		return;
557
558	exists = xenbus_exists(XBT_NIL, node, "");
559	if (!exists) {
560		xenbus_cleanup_devices(node, &bus->bus);
561		return;
562	}
563
564	/* backend/<type>/... or device/<type>/... */
565	p = strchr(node, '/') + 1;
566	snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
567	type[XEN_BUS_ID_SIZE-1] = '\0';
568
569	rootlen = strsep_len(node, '/', bus->levels);
570	if (rootlen < 0)
571		return;
572	root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
573	if (!root)
574		return;
575
576	dev = xenbus_device_find(root, &bus->bus);
577	if (!dev)
578		xenbus_probe_node(bus, type, root);
579	else
580		put_device(&dev->dev);
581
582	kfree(root);
583}
584EXPORT_SYMBOL_GPL(xenbus_dev_changed);
585
586int xenbus_dev_suspend(struct device *dev)
587{
588	int err = 0;
589	struct xenbus_driver *drv;
590	struct xenbus_device *xdev
591		= container_of(dev, struct xenbus_device, dev);
592
593	DPRINTK("%s", xdev->nodename);
594
595	if (dev->driver == NULL)
596		return 0;
597	drv = to_xenbus_driver(dev->driver);
598	if (drv->suspend)
599		err = drv->suspend(xdev);
600	if (err)
601		pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
602	return 0;
603}
604EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
605
606int xenbus_dev_resume(struct device *dev)
607{
608	int err;
609	struct xenbus_driver *drv;
610	struct xenbus_device *xdev
611		= container_of(dev, struct xenbus_device, dev);
612
613	DPRINTK("%s", xdev->nodename);
614
615	if (dev->driver == NULL)
616		return 0;
617	drv = to_xenbus_driver(dev->driver);
618	err = talk_to_otherend(xdev);
619	if (err) {
620		pr_warn("resume (talk_to_otherend) %s failed: %i\n",
621			dev_name(dev), err);
622		return err;
623	}
624
625	xdev->state = XenbusStateInitialising;
626
627	if (drv->resume) {
628		err = drv->resume(xdev);
629		if (err) {
630			pr_warn("resume %s failed: %i\n", dev_name(dev), err);
631			return err;
632		}
633	}
634
635	err = watch_otherend(xdev);
636	if (err) {
637		pr_warn("resume (watch_otherend) %s failed: %d.\n",
638			dev_name(dev), err);
639		return err;
640	}
641
642	return 0;
643}
644EXPORT_SYMBOL_GPL(xenbus_dev_resume);
645
646int xenbus_dev_cancel(struct device *dev)
647{
648	/* Do nothing */
649	DPRINTK("cancel");
650	return 0;
651}
652EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
653
654/* A flag to determine if xenstored is 'ready' (i.e. has started) */
655int xenstored_ready;
656
657
658int register_xenstore_notifier(struct notifier_block *nb)
659{
660	int ret = 0;
661
662	if (xenstored_ready > 0)
663		ret = nb->notifier_call(nb, 0, NULL);
664	else
665		blocking_notifier_chain_register(&xenstore_chain, nb);
666
667	return ret;
668}
669EXPORT_SYMBOL_GPL(register_xenstore_notifier);
670
671void unregister_xenstore_notifier(struct notifier_block *nb)
672{
673	blocking_notifier_chain_unregister(&xenstore_chain, nb);
674}
675EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
676
677void xenbus_probe(struct work_struct *unused)
678{
679	xenstored_ready = 1;
680
681	/* Notify others that xenstore is up */
682	blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
683}
684EXPORT_SYMBOL_GPL(xenbus_probe);
685
686static int __init xenbus_probe_initcall(void)
687{
688	if (!xen_domain())
689		return -ENODEV;
690
691	if (xen_initial_domain() || xen_hvm_domain())
692		return 0;
693
694	xenbus_probe(NULL);
695	return 0;
696}
697
698device_initcall(xenbus_probe_initcall);
699
700/* Set up event channel for xenstored which is run as a local process
701 * (this is normally used only in dom0)
702 */
703static int __init xenstored_local_init(void)
704{
705	int err = 0;
706	unsigned long page = 0;
707	struct evtchn_alloc_unbound alloc_unbound;
708
709	/* Allocate Xenstore page */
710	page = get_zeroed_page(GFP_KERNEL);
711	if (!page)
712		goto out_err;
713
714	xen_store_mfn = xen_start_info->store_mfn =
715		pfn_to_mfn(virt_to_phys((void *)page) >>
716			   PAGE_SHIFT);
717
718	/* Next allocate a local port which xenstored can bind to */
719	alloc_unbound.dom        = DOMID_SELF;
720	alloc_unbound.remote_dom = DOMID_SELF;
721
722	err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
723					  &alloc_unbound);
724	if (err == -ENOSYS)
725		goto out_err;
726
727	BUG_ON(err);
728	xen_store_evtchn = xen_start_info->store_evtchn =
729		alloc_unbound.port;
730
731	return 0;
732
733 out_err:
734	if (page != 0)
735		free_page(page);
736	return err;
737}
738
739static int xenbus_resume_cb(struct notifier_block *nb,
740			    unsigned long action, void *data)
741{
742	int err = 0;
743
744	if (xen_hvm_domain()) {
745		uint64_t v;
746
747		err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
748		if (!err && v)
749			xen_store_evtchn = v;
750		else
751			pr_warn("Cannot update xenstore event channel: %d\n",
752				err);
753	} else
754		xen_store_evtchn = xen_start_info->store_evtchn;
755
756	return err;
757}
758
759static struct notifier_block xenbus_resume_nb = {
760	.notifier_call = xenbus_resume_cb,
761};
762
763static int __init xenbus_init(void)
764{
765	int err = 0;
766	uint64_t v = 0;
767	xen_store_domain_type = XS_UNKNOWN;
768
769	if (!xen_domain())
770		return -ENODEV;
771
772	xenbus_ring_ops_init();
773
774	if (xen_pv_domain())
775		xen_store_domain_type = XS_PV;
776	if (xen_hvm_domain())
777		xen_store_domain_type = XS_HVM;
778	if (xen_hvm_domain() && xen_initial_domain())
779		xen_store_domain_type = XS_LOCAL;
780	if (xen_pv_domain() && !xen_start_info->store_evtchn)
781		xen_store_domain_type = XS_LOCAL;
782	if (xen_pv_domain() && xen_start_info->store_evtchn)
783		xenstored_ready = 1;
784
785	switch (xen_store_domain_type) {
786	case XS_LOCAL:
787		err = xenstored_local_init();
788		if (err)
789			goto out_error;
790		xen_store_interface = mfn_to_virt(xen_store_mfn);
791		break;
792	case XS_PV:
793		xen_store_evtchn = xen_start_info->store_evtchn;
794		xen_store_mfn = xen_start_info->store_mfn;
795		xen_store_interface = mfn_to_virt(xen_store_mfn);
796		break;
797	case XS_HVM:
798		err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
799		if (err)
800			goto out_error;
801		xen_store_evtchn = (int)v;
802		err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
803		if (err)
804			goto out_error;
805		xen_store_mfn = (unsigned long)v;
806		xen_store_interface =
807			xen_remap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
808		break;
809	default:
810		pr_warn("Xenstore state unknown\n");
811		break;
812	}
813
814	/* Initialize the interface to xenstore. */
815	err = xs_init();
816	if (err) {
817		pr_warn("Error initializing xenstore comms: %i\n", err);
818		goto out_error;
819	}
820
821	if ((xen_store_domain_type != XS_LOCAL) &&
822	    (xen_store_domain_type != XS_UNKNOWN))
823		xen_resume_notifier_register(&xenbus_resume_nb);
824
825#ifdef CONFIG_XEN_COMPAT_XENFS
826	/*
827	 * Create xenfs mountpoint in /proc for compatibility with
828	 * utilities that expect to find "xenbus" under "/proc/xen".
829	 */
830	proc_mkdir("xen", NULL);
831#endif
832
833out_error:
834	return err;
835}
836
837postcore_initcall(xenbus_init);
838
839MODULE_LICENSE("GPL");
840