[deliverable/linux.git] / drivers / xen / xen-balloon.c

/******************************************************************************
 * Xen balloon driver - enables returning/claiming memory to/from Xen.
 *
 * Copyright (c) 2003, B Dragovic
 * Copyright (c) 2003-2004, M Williamson, K Fraser
 * Copyright (c) 2005 Dan M. Smith, IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/capability.h>

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/balloon.h>
#include <xen/xenbus.h>
#include <xen/features.h>
#include <xen/page.h>

#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))

#define BALLOON_CLASS_NAME "xen_memory"

static struct sys_device balloon_sysdev;

static int register_balloon(struct sys_device *sysdev);

/* React to a change in the target key */
static void watch_target(struct xenbus_watch *watch,
			 const char **vec, unsigned int len)
{
	unsigned long long new_target;
	int err;

	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	if (err != 1) {
		/* This is ok (for domain0 at least) - so just return */
		return;
	}

	/* The given memory/target value is in KiB, so it needs converting to
	 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	 */
	balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
}
static struct xenbus_watch target_watch = {
	.node = "memory/target",
	.callback = watch_target,
};


static int balloon_init_watcher(struct notifier_block *notifier,
				unsigned long event,
				void *data)
{
	int err;

	err = register_xenbus_watch(&target_watch);
	if (err)
		printk(KERN_ERR "Failed to set balloon watcher\n");

	return NOTIFY_DONE;
}

static struct notifier_block xenstore_notifier = {
	.notifier_call = balloon_init_watcher,
};

static int __init balloon_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	pr_info("xen-balloon: Initialising balloon driver.\n");

	register_balloon(&balloon_sysdev);

	register_xen_selfballooning(&balloon_sysdev);

	register_xenstore_notifier(&xenstore_notifier);

	return 0;
}
subsys_initcall(balloon_init);

static void balloon_exit(void)
{
    /* XXX - release balloon here */
    return;
}

module_exit(balloon_exit);

#define BALLOON_SHOW(name, format, args...)				\
	static ssize_t show_##name(struct sys_device *dev,		\
				   struct sysdev_attribute *attr,	\
				   char *buf)				\
	{								\
		return sprintf(buf, format, ##args);			\
	}								\
	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)

BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));

static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);

static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
			      char *buf)
{
	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
}

static ssize_t store_target_kb(struct sys_device *dev,
			       struct sysdev_attribute *attr,
			       const char *buf,
			       size_t count)
{
	char *endchar;
	unsigned long long target_bytes;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;

	balloon_set_new_target(target_bytes >> PAGE_SHIFT);

	return count;
}

static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
		   show_target_kb, store_target_kb);


static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
			      char *buf)
{
	return sprintf(buf, "%llu\n",
		       (unsigned long long)balloon_stats.target_pages
		       << PAGE_SHIFT);
}

static ssize_t store_target(struct sys_device *dev,
			    struct sysdev_attribute *attr,
			    const char *buf,
			    size_t count)
{
	char *endchar;
	unsigned long long target_bytes;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	target_bytes = memparse(buf, &endchar);

	balloon_set_new_target(target_bytes >> PAGE_SHIFT);

	return count;
}

static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
		   show_target, store_target);


static struct sysdev_attribute *balloon_attrs[] = {
	&attr_target_kb,
	&attr_target,
	&attr_schedule_delay.attr,
	&attr_max_schedule_delay.attr,
	&attr_retry_count.attr,
	&attr_max_retry_count.attr
};

static struct attribute *balloon_info_attrs[] = {
	&attr_current_kb.attr,
	&attr_low_kb.attr,
	&attr_high_kb.attr,
	NULL
};

static struct attribute_group balloon_info_group = {
	.name = "info",
	.attrs = balloon_info_attrs
};

static struct sysdev_class balloon_sysdev_class = {
	.name = BALLOON_CLASS_NAME
};

static int register_balloon(struct sys_device *sysdev)
{
	int i, error;

	error = sysdev_class_register(&balloon_sysdev_class);
	if (error)
		return error;

	sysdev->id = 0;
	sysdev->cls = &balloon_sysdev_class;

	error = sysdev_register(sysdev);
	if (error) {
		sysdev_class_unregister(&balloon_sysdev_class);
		return error;
	}

	for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
		error = sysdev_create_file(sysdev, balloon_attrs[i]);
		if (error)
			goto fail;
	}

	error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
	if (error)
		goto fail;

	return 0;

 fail:
	while (--i >= 0)
		sysdev_remove_file(sysdev, balloon_attrs[i]);
	sysdev_unregister(sysdev);
	sysdev_class_unregister(&balloon_sysdev_class);
	return error;
}

MODULE_LICENSE("GPL");
Commit	Line	Data
803eb047 DDG	1	/******************************************************************************
	2	* Xen balloon driver - enables returning/claiming memory to/from Xen.
	3	*
	4	* Copyright (c) 2003, B Dragovic
	5	* Copyright (c) 2003-2004, M Williamson, K Fraser
	6	* Copyright (c) 2005 Dan M. Smith, IBM Corporation
	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	#include <linux/kernel.h>
	34	#include <linux/module.h>
	35	#include <linux/sysdev.h>
	36	#include <linux/capability.h>
	37
	38	#include <xen/xen.h>
	39	#include <xen/interface/xen.h>
	40	#include <xen/balloon.h>
	41	#include <xen/xenbus.h>
	42	#include <xen/features.h>
	43	#include <xen/page.h>
	44
	45	#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
	46
	47	#define BALLOON_CLASS_NAME "xen_memory"
	48
	49	static struct sys_device balloon_sysdev;
	50
	51	static int register_balloon(struct sys_device *sysdev);
	52
803eb047 DDG	53	/* React to a change in the target key */
	54	static void watch_target(struct xenbus_watch *watch,
	55	const char **vec, unsigned int len)
	56	{
	57	unsigned long long new_target;
	58	int err;
	59
	60	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	61	if (err != 1) {
	62	/* This is ok (for domain0 at least) - so just return */
	63	return;
	64	}
	65
	66	/* The given memory/target value is in KiB, so it needs converting to
	67	* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	68	*/
	69	balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
	70	}
6b71c52e OH	71	static struct xenbus_watch target_watch = {
	72	.node = "memory/target",
	73	.callback = watch_target,
	74	};
	75
803eb047 DDG	76
	77	static int balloon_init_watcher(struct notifier_block *notifier,
	78	unsigned long event,
	79	void *data)
	80	{
	81	int err;
	82
	83	err = register_xenbus_watch(&target_watch);
	84	if (err)
	85	printk(KERN_ERR "Failed to set balloon watcher\n");
	86
	87	return NOTIFY_DONE;
	88	}
	89
6b71c52e OH	90	static struct notifier_block xenstore_notifier = {
	91	.notifier_call = balloon_init_watcher,
	92	};
803eb047 DDG	93
	94	static int __init balloon_init(void)
	95	{
	96	if (!xen_domain())
	97	return -ENODEV;
	98
	99	pr_info("xen-balloon: Initialising balloon driver.\n");
	100
	101	register_balloon(&balloon_sysdev);
	102
a50777c7 DM	103	register_xen_selfballooning(&balloon_sysdev);
a50777c7 DM	104
803eb047 DDG	105	register_xenstore_notifier(&xenstore_notifier);
	106
	107	return 0;
	108	}
	109	subsys_initcall(balloon_init);
	110
	111	static void balloon_exit(void)
	112	{
	113	/* XXX - release balloon here */
	114	return;
	115	}
	116
	117	module_exit(balloon_exit);
	118
	119	#define BALLOON_SHOW(name, format, args...) \
	120	static ssize_t show_##name(struct sys_device *dev, \
	121	struct sysdev_attribute *attr, \
	122	char *buf) \
	123	{ \
	124	return sprintf(buf, format, ##args); \
	125	} \
	126	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
	127
	128	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	129	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	130	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	131
	132	static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	133	static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	134	static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	135	static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
	136
	137	static ssize_t show_target_kb(struct sys_device dev, struct sysdev_attribute attr,
	138	char *buf)
	139	{
	140	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	141	}
	142
	143	static ssize_t store_target_kb(struct sys_device *dev,
	144	struct sysdev_attribute *attr,
	145	const char *buf,
	146	size_t count)
	147	{
	148	char *endchar;
	149	unsigned long long target_bytes;
	150
	151	if (!capable(CAP_SYS_ADMIN))
	152	return -EPERM;
	153
	154	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	155
	156	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	157
	158	return count;
	159	}
	160
	161	static SYSDEV_ATTR(target_kb, S_IRUGO \| S_IWUSR,
	162	show_target_kb, store_target_kb);
	163
	164
	165	static ssize_t show_target(struct sys_device dev, struct sysdev_attribute attr,
	166	char *buf)
	167	{
	168	return sprintf(buf, "%llu\n",
169	(unsigned long long)balloon_stats.target_pages
170	<< PAGE_SHIFT);
171	}
172
173	static ssize_t store_target(struct sys_device *dev,
174	struct sysdev_attribute *attr,
175	const char *buf,
176	size_t count)
177	{
178	char *endchar;
179	unsigned long long target_bytes;
180
181	if (!capable(CAP_SYS_ADMIN))
182	return -EPERM;
183
184	target_bytes = memparse(buf, &endchar);
185
186	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
187
188	return count;
189	}
190
191	static SYSDEV_ATTR(target, S_IRUGO \| S_IWUSR,
192	show_target, store_target);
193
194
195	static struct sysdev_attribute *balloon_attrs[] = {
196	&attr_target_kb,
197	&attr_target,
198	&attr_schedule_delay.attr,
199	&attr_max_schedule_delay.attr,
200	&attr_retry_count.attr,
201	&attr_max_retry_count.attr
202	};
203
204	static struct attribute *balloon_info_attrs[] = {
205	&attr_current_kb.attr,
206	&attr_low_kb.attr,
207	&attr_high_kb.attr,
208	NULL
209	};
210
211	static struct attribute_group balloon_info_group = {
212	.name = "info",
213	.attrs = balloon_info_attrs
214	};
215
216	static struct sysdev_class balloon_sysdev_class = {
217	.name = BALLOON_CLASS_NAME
218	};
219
220	static int register_balloon(struct sys_device *sysdev)
221	{
222	int i, error;
223
224	error = sysdev_class_register(&balloon_sysdev_class);
225	if (error)
226	return error;
227
228	sysdev->id = 0;
229	sysdev->cls = &balloon_sysdev_class;
230
231	error = sysdev_register(sysdev);
232	if (error) {
233	sysdev_class_unregister(&balloon_sysdev_class);
234	return error;
235	}
236
237	for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
238	error = sysdev_create_file(sysdev, balloon_attrs[i]);
239	if (error)
240	goto fail;
241	}
242
243	error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
244	if (error)
245	goto fail;
246
247	return 0;
248
249	fail:
250	while (--i >= 0)
251	sysdev_remove_file(sysdev, balloon_attrs[i]);
252	sysdev_unregister(sysdev);
253	sysdev_class_unregister(&balloon_sysdev_class);
254	return error;
255	}
256
257	MODULE_LICENSE("GPL");