[linux-2.6-block.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.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 device balloon_dev;

static int register_balloon(struct device *dev);

/* 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)
		pr_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("Initialising balloon driver\n");

	register_balloon(&balloon_dev);

	register_xen_selfballooning(&balloon_dev);

	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 device *dev,			\
				   struct device_attribute *attr,	\
				   char *buf)				\
	{								\
		return sprintf(buf, format, ##args);			\
	}								\
	static DEVICE_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 DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);

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

static ssize_t store_target_kb(struct device *dev,
			       struct device_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 DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
		   show_target_kb, store_target_kb);


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

static ssize_t store_target(struct device *dev,
			    struct device_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 DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
		   show_target, store_target);


static struct attribute *balloon_attrs[] = {
	&dev_attr_target_kb.attr,
	&dev_attr_target.attr,
	&dev_attr_schedule_delay.attr.attr,
	&dev_attr_max_schedule_delay.attr.attr,
	&dev_attr_retry_count.attr.attr,
	&dev_attr_max_retry_count.attr.attr,
	NULL
};

static const struct attribute_group balloon_group = {
	.attrs = balloon_attrs
};

static struct attribute *balloon_info_attrs[] = {
	&dev_attr_current_kb.attr,
	&dev_attr_low_kb.attr,
	&dev_attr_high_kb.attr,
	NULL
};

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

static const struct attribute_group *balloon_groups[] = {
	&balloon_group,
	&balloon_info_group,
	NULL
};

static struct bus_type balloon_subsys = {
	.name = BALLOON_CLASS_NAME,
	.dev_name = BALLOON_CLASS_NAME,
};

static int register_balloon(struct device *dev)
{
	int error;

	error = subsys_system_register(&balloon_subsys, NULL);
	if (error)
		return error;

	dev->id = 0;
	dev->bus = &balloon_subsys;
	dev->groups = balloon_groups;

	error = device_register(dev);
	if (error) {
		bus_unregister(&balloon_subsys);
		return error;
	}

	return 0;
}

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
283c0972 JP	33	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
283c0972 JP	34
803eb047 DDG	35	#include <linux/kernel.h>
803eb047 DDG	36	#include <linux/module.h>
803eb047 DDG	37	#include <linux/capability.h>
	38
	39	#include <xen/xen.h>
	40	#include <xen/interface/xen.h>
	41	#include <xen/balloon.h>
	42	#include <xen/xenbus.h>
	43	#include <xen/features.h>
	44	#include <xen/page.h>
	45
	46	#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
	47
	48	#define BALLOON_CLASS_NAME "xen_memory"
	49
07068021	50	static struct device balloon_dev;
803eb047	51
07068021	52	static int register_balloon(struct device *dev);
803eb047	53
803eb047 DDG	54	/* React to a change in the target key */
	55	static void watch_target(struct xenbus_watch *watch,
	56	const char **vec, unsigned int len)
	57	{
	58	unsigned long long new_target;
	59	int err;
	60
	61	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	62	if (err != 1) {
	63	/* This is ok (for domain0 at least) - so just return */
	64	return;
	65	}
	66
	67	/* The given memory/target value is in KiB, so it needs converting to
	68	* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	69	*/
	70	balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
	71	}
6b71c52e OH	72	static struct xenbus_watch target_watch = {
	73	.node = "memory/target",
	74	.callback = watch_target,
	75	};
	76
803eb047 DDG	77
	78	static int balloon_init_watcher(struct notifier_block *notifier,
	79	unsigned long event,
	80	void *data)
	81	{
	82	int err;
	83
	84	err = register_xenbus_watch(&target_watch);
	85	if (err)
283c0972	86	pr_err("Failed to set balloon watcher\n");
803eb047 DDG	87
	88	return NOTIFY_DONE;
	89	}
	90
6b71c52e OH	91	static struct notifier_block xenstore_notifier = {
	92	.notifier_call = balloon_init_watcher,
	93	};
803eb047 DDG	94
	95	static int __init balloon_init(void)
	96	{
	97	if (!xen_domain())
	98	return -ENODEV;
	99
283c0972	100	pr_info("Initialising balloon driver\n");
803eb047	101
07068021	102	register_balloon(&balloon_dev);
803eb047	103
07068021	104	register_xen_selfballooning(&balloon_dev);
a50777c7	105
803eb047 DDG	106	register_xenstore_notifier(&xenstore_notifier);
	107
	108	return 0;
	109	}
	110	subsys_initcall(balloon_init);
	111
	112	static void balloon_exit(void)
	113	{
	114	/* XXX - release balloon here */
	115	return;
	116	}
	117
	118	module_exit(balloon_exit);
	119
	120	#define BALLOON_SHOW(name, format, args...) \
07068021 KS	121	static ssize_t show_##name(struct device *dev, \
07068021 KS	122	struct device_attribute *attr, \
803eb047 DDG	123	char *buf) \
	124	{ \
	125	return sprintf(buf, format, ##args); \
	126	} \
07068021	127	static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
803eb047 DDG	128
	129	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	130	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	131	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	132
07068021 KS	133	static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	134	static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	135	static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	136	static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
803eb047	137
07068021	138	static ssize_t show_target_kb(struct device dev, struct device_attribute attr,
803eb047 DDG	139	char *buf)
	140	{
	141	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	142	}
	143
07068021 KS	144	static ssize_t store_target_kb(struct device *dev,
07068021 KS	145	struct device_attribute *attr,
803eb047 DDG	146	const char *buf,
	147	size_t count)
	148	{
	149	char *endchar;
	150	unsigned long long target_bytes;
	151
	152	if (!capable(CAP_SYS_ADMIN))
	153	return -EPERM;
	154
	155	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	156
	157	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	158
	159	return count;
	160	}
	161
07068021	162	static DEVICE_ATTR(target_kb, S_IRUGO \| S_IWUSR,
803eb047 DDG	163	show_target_kb, store_target_kb);
	164
	165
07068021	166	static ssize_t show_target(struct device dev, struct device_attribute attr,
803eb047 DDG	167	char *buf)
	168	{
	169	return sprintf(buf, "%llu\n",
	170	(unsigned long long)balloon_stats.target_pages
	171	<< PAGE_SHIFT);
	172	}
	173
07068021 KS	174	static ssize_t store_target(struct device *dev,
07068021 KS	175	struct device_attribute *attr,
803eb047 DDG	176	const char *buf,
	177	size_t count)
	178	{
	179	char *endchar;
	180	unsigned long long target_bytes;
	181
	182	if (!capable(CAP_SYS_ADMIN))
	183	return -EPERM;
	184
	185	target_bytes = memparse(buf, &endchar);
	186
	187	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	188
	189	return count;
	190	}
	191
07068021	192	static DEVICE_ATTR(target, S_IRUGO \| S_IWUSR,
803eb047 DDG	193	show_target, store_target);
	194
	195
b6a473a7 TI	196	static struct attribute *balloon_attrs[] = {
	197	&dev_attr_target_kb.attr,
	198	&dev_attr_target.attr,
	199	&dev_attr_schedule_delay.attr.attr,
	200	&dev_attr_max_schedule_delay.attr.attr,
	201	&dev_attr_retry_count.attr.attr,
	202	&dev_attr_max_retry_count.attr.attr,
	203	NULL
	204	};
	205
	206	static const struct attribute_group balloon_group = {
	207	.attrs = balloon_attrs
803eb047 DDG	208	};
	209
	210	static struct attribute *balloon_info_attrs[] = {
07068021 KS	211	&dev_attr_current_kb.attr,
	212	&dev_attr_low_kb.attr,
	213	&dev_attr_high_kb.attr,
803eb047 DDG	214	NULL
	215	};
	216
ead1d014	217	static const struct attribute_group balloon_info_group = {
803eb047 DDG	218	.name = "info",
	219	.attrs = balloon_info_attrs
	220	};
	221
b6a473a7 TI	222	static const struct attribute_group *balloon_groups[] = {
	223	&balloon_group,
	224	&balloon_info_group,
	225	NULL
	226	};
	227
07068021 KS	228	static struct bus_type balloon_subsys = {
	229	.name = BALLOON_CLASS_NAME,
	230	.dev_name = BALLOON_CLASS_NAME,
803eb047 DDG	231	};
803eb047 DDG	232
07068021	233	static int register_balloon(struct device *dev)
803eb047	234	{
b6a473a7	235	int error;
803eb047	236
8ea11f7f	237	error = subsys_system_register(&balloon_subsys, NULL);
803eb047 DDG	238	if (error)
	239	return error;
	240
07068021 KS	241	dev->id = 0;
07068021 KS	242	dev->bus = &balloon_subsys;
b6a473a7	243	dev->groups = balloon_groups;
803eb047	244
07068021	245	error = device_register(dev);
803eb047	246	if (error) {
07068021	247	bus_unregister(&balloon_subsys);
803eb047 DDG	248	return error;
	249	}
	250
803eb047	251	return 0;
803eb047 DDG	252	}
	253
	254	MODULE_LICENSE("GPL");