[mirror_ubuntu-artful-kernel.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/errno.h>
#include <linux/mm_types.h>
#include <linux/init.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 *path, const char *token)
{
	unsigned long long new_target;
	int err;
	static bool watch_fired;
	static long target_diff;

	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.
	 */
	new_target >>= PAGE_SHIFT - 10;
	if (watch_fired) {
		balloon_set_new_target(new_target - target_diff);
		return;
	}

	watch_fired = true;
	target_diff = new_target - balloon_stats.target_pages;
}
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,
};

void xen_balloon_init(void)
{
	register_balloon(&balloon_dev);

	register_xen_selfballooning(&balloon_dev);

	register_xenstore_notifier(&xenstore_notifier);
}
EXPORT_SYMBOL_GPL(xen_balloon_init);

#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;
}
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	35	#include <linux/kernel.h>
106eaa8e PG	36	#include <linux/errno.h>
	37	#include <linux/mm_types.h>
	38	#include <linux/init.h>
803eb047 DDG	39	#include <linux/capability.h>
	40
	41	#include <xen/xen.h>
	42	#include <xen/interface/xen.h>
	43	#include <xen/balloon.h>
	44	#include <xen/xenbus.h>
	45	#include <xen/features.h>
	46	#include <xen/page.h>
	47
	48	#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
	49
	50	#define BALLOON_CLASS_NAME "xen_memory"
	51
07068021	52	static struct device balloon_dev;
803eb047	53
07068021	54	static int register_balloon(struct device *dev);
803eb047	55
803eb047 DDG	56	/* React to a change in the target key */
803eb047 DDG	57	static void watch_target(struct xenbus_watch *watch,
5584ea25	58	const char path, const char token)
803eb047 DDG	59	{
	60	unsigned long long new_target;
	61	int err;
96edd61d JG	62	static bool watch_fired;
96edd61d JG	63	static long target_diff;
803eb047 DDG	64
	65	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	66	if (err != 1) {
	67	/* This is ok (for domain0 at least) - so just return */
	68	return;
	69	}
	70
	71	/* The given memory/target value is in KiB, so it needs converting to
	72	* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	73	*/
96edd61d JG	74	new_target >>= PAGE_SHIFT - 10;
	75	if (watch_fired) {
	76	balloon_set_new_target(new_target - target_diff);
	77	return;
	78	}
	79
	80	watch_fired = true;
	81	target_diff = new_target - balloon_stats.target_pages;
803eb047	82	}
6b71c52e OH	83	static struct xenbus_watch target_watch = {
	84	.node = "memory/target",
	85	.callback = watch_target,
	86	};
	87
803eb047 DDG	88
	89	static int balloon_init_watcher(struct notifier_block *notifier,
	90	unsigned long event,
	91	void *data)
	92	{
	93	int err;
	94
	95	err = register_xenbus_watch(&target_watch);
	96	if (err)
283c0972	97	pr_err("Failed to set balloon watcher\n");
803eb047 DDG	98
	99	return NOTIFY_DONE;
	100	}
	101
6b71c52e OH	102	static struct notifier_block xenstore_notifier = {
	103	.notifier_call = balloon_init_watcher,
	104	};
803eb047	105
96edd61d	106	void xen_balloon_init(void)
803eb047	107	{
07068021	108	register_balloon(&balloon_dev);
803eb047	109
07068021	110	register_xen_selfballooning(&balloon_dev);
a50777c7	111
803eb047	112	register_xenstore_notifier(&xenstore_notifier);
803eb047	113	}
96edd61d	114	EXPORT_SYMBOL_GPL(xen_balloon_init);
803eb047	115
803eb047	116	#define BALLOON_SHOW(name, format, args...) \
07068021 KS	117	static ssize_t show_##name(struct device *dev, \
07068021 KS	118	struct device_attribute *attr, \
803eb047 DDG	119	char *buf) \
	120	{ \
	121	return sprintf(buf, format, ##args); \
	122	} \
07068021	123	static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
803eb047 DDG	124
	125	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	126	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	127	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	128
07068021 KS	129	static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	130	static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	131	static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	132	static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
803eb047	133
07068021	134	static ssize_t show_target_kb(struct device dev, struct device_attribute attr,
803eb047 DDG	135	char *buf)
	136	{
	137	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	138	}
	139
07068021 KS	140	static ssize_t store_target_kb(struct device *dev,
07068021 KS	141	struct device_attribute *attr,
803eb047 DDG	142	const char *buf,
	143	size_t count)
	144	{
	145	char *endchar;
	146	unsigned long long target_bytes;
	147
	148	if (!capable(CAP_SYS_ADMIN))
	149	return -EPERM;
	150
	151	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	152
	153	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	154
	155	return count;
	156	}
	157
07068021	158	static DEVICE_ATTR(target_kb, S_IRUGO \| S_IWUSR,
803eb047 DDG	159	show_target_kb, store_target_kb);
	160
	161
07068021	162	static ssize_t show_target(struct device dev, struct device_attribute attr,
803eb047 DDG	163	char *buf)
	164	{
	165	return sprintf(buf, "%llu\n",
	166	(unsigned long long)balloon_stats.target_pages
	167	<< PAGE_SHIFT);
	168	}
	169
07068021 KS	170	static ssize_t store_target(struct device *dev,
07068021 KS	171	struct device_attribute *attr,
803eb047 DDG	172	const char *buf,
	173	size_t count)
	174	{
	175	char *endchar;
	176	unsigned long long target_bytes;
	177
	178	if (!capable(CAP_SYS_ADMIN))
	179	return -EPERM;
	180
	181	target_bytes = memparse(buf, &endchar);
	182
	183	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	184
	185	return count;
	186	}
	187
07068021	188	static DEVICE_ATTR(target, S_IRUGO \| S_IWUSR,
803eb047 DDG	189	show_target, store_target);
	190
	191
b6a473a7 TI	192	static struct attribute *balloon_attrs[] = {
	193	&dev_attr_target_kb.attr,
	194	&dev_attr_target.attr,
	195	&dev_attr_schedule_delay.attr.attr,
	196	&dev_attr_max_schedule_delay.attr.attr,
	197	&dev_attr_retry_count.attr.attr,
	198	&dev_attr_max_retry_count.attr.attr,
	199	NULL
	200	};
	201
	202	static const struct attribute_group balloon_group = {
	203	.attrs = balloon_attrs
803eb047 DDG	204	};
	205
	206	static struct attribute *balloon_info_attrs[] = {
07068021 KS	207	&dev_attr_current_kb.attr,
	208	&dev_attr_low_kb.attr,
	209	&dev_attr_high_kb.attr,
803eb047 DDG	210	NULL
	211	};
	212
ead1d014	213	static const struct attribute_group balloon_info_group = {
803eb047 DDG	214	.name = "info",
	215	.attrs = balloon_info_attrs
	216	};
	217
b6a473a7 TI	218	static const struct attribute_group *balloon_groups[] = {
	219	&balloon_group,
	220	&balloon_info_group,
	221	NULL
	222	};
	223
07068021 KS	224	static struct bus_type balloon_subsys = {
	225	.name = BALLOON_CLASS_NAME,
	226	.dev_name = BALLOON_CLASS_NAME,
803eb047 DDG	227	};
803eb047 DDG	228
07068021	229	static int register_balloon(struct device *dev)
803eb047	230	{
b6a473a7	231	int error;
803eb047	232
8ea11f7f	233	error = subsys_system_register(&balloon_subsys, NULL);
803eb047 DDG	234	if (error)
	235	return error;
	236
07068021 KS	237	dev->id = 0;
07068021 KS	238	dev->bus = &balloon_subsys;
b6a473a7	239	dev->groups = balloon_groups;
803eb047	240
07068021	241	error = device_register(dev);
803eb047	242	if (error) {
07068021	243	bus_unregister(&balloon_subsys);
803eb047 DDG	244	return error;
	245	}
	246
803eb047	247	return 0;
803eb047	248	}