[linux-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/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>
#include <xen/mem-reservation.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, static_max;
	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) {
		watch_fired = true;
		err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu",
				   &static_max);
		if (err != 1)
			static_max = new_target;
		else
			static_max >>= PAGE_SHIFT - 10;
		target_diff = (xen_pv_domain() || xen_initial_domain()) ? 0
				: static_max - balloon_stats.target_pages;
	}

	balloon_set_new_target(new_target - target_diff);
}
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 DEVICE_BOOL_ATTR(scrub_pages, 0644, xen_scrub_pages);

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,
	&dev_attr_scrub_pages.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>
197ecb38	47	#include <xen/mem-reservation.h>
803eb047 DDG	48
	49	#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
	50
	51	#define BALLOON_CLASS_NAME "xen_memory"
	52
07068021	53	static struct device balloon_dev;
803eb047	54
07068021	55	static int register_balloon(struct device *dev);
803eb047	56
803eb047 DDG	57	/* React to a change in the target key */
803eb047 DDG	58	static void watch_target(struct xenbus_watch *watch,
5584ea25	59	const char path, const char token)
803eb047	60	{
5266b8e4	61	unsigned long long new_target, static_max;
803eb047	62	int err;
96edd61d JG	63	static bool watch_fired;
96edd61d JG	64	static long target_diff;
803eb047 DDG	65
	66	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	67	if (err != 1) {
	68	/* This is ok (for domain0 at least) - so just return */
	69	return;
	70	}
	71
	72	/* The given memory/target value is in KiB, so it needs converting to
	73	* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	74	*/
96edd61d	75	new_target >>= PAGE_SHIFT - 10;
5266b8e4 JG	76
	77	if (!watch_fired) {
	78	watch_fired = true;
	79	err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu",
	80	&static_max);
	81	if (err != 1)
	82	static_max = new_target;
	83	else
	84	static_max >>= PAGE_SHIFT - 10;
3596924a	85	target_diff = (xen_pv_domain() \|\| xen_initial_domain()) ? 0
5266b8e4	86	: static_max - balloon_stats.target_pages;
96edd61d JG	87	}
96edd61d JG	88
5266b8e4	89	balloon_set_new_target(new_target - target_diff);
803eb047	90	}
6b71c52e OH	91	static struct xenbus_watch target_watch = {
	92	.node = "memory/target",
	93	.callback = watch_target,
	94	};
	95
803eb047 DDG	96
	97	static int balloon_init_watcher(struct notifier_block *notifier,
	98	unsigned long event,
	99	void *data)
	100	{
	101	int err;
	102
	103	err = register_xenbus_watch(&target_watch);
	104	if (err)
283c0972	105	pr_err("Failed to set balloon watcher\n");
803eb047 DDG	106
	107	return NOTIFY_DONE;
	108	}
	109
6b71c52e OH	110	static struct notifier_block xenstore_notifier = {
	111	.notifier_call = balloon_init_watcher,
	112	};
803eb047	113
96edd61d	114	void xen_balloon_init(void)
803eb047	115	{
07068021	116	register_balloon(&balloon_dev);
803eb047	117
07068021	118	register_xen_selfballooning(&balloon_dev);
a50777c7	119
803eb047	120	register_xenstore_notifier(&xenstore_notifier);
803eb047	121	}
96edd61d	122	EXPORT_SYMBOL_GPL(xen_balloon_init);
803eb047	123
803eb047	124	#define BALLOON_SHOW(name, format, args...) \
07068021 KS	125	static ssize_t show_##name(struct device *dev, \
07068021 KS	126	struct device_attribute *attr, \
803eb047 DDG	127	char *buf) \
	128	{ \
	129	return sprintf(buf, format, ##args); \
	130	} \
07068021	131	static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
803eb047 DDG	132
	133	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	134	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	135	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	136
07068021 KS	137	static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	138	static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	139	static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	140	static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
197ecb38	141	static DEVICE_BOOL_ATTR(scrub_pages, 0644, xen_scrub_pages);
803eb047	142
07068021	143	static ssize_t show_target_kb(struct device dev, struct device_attribute attr,
803eb047 DDG	144	char *buf)
	145	{
	146	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	147	}
	148
07068021 KS	149	static ssize_t store_target_kb(struct device *dev,
07068021 KS	150	struct device_attribute *attr,
803eb047 DDG	151	const char *buf,
	152	size_t count)
	153	{
	154	char *endchar;
	155	unsigned long long target_bytes;
	156
	157	if (!capable(CAP_SYS_ADMIN))
	158	return -EPERM;
	159
	160	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	161
	162	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	163
	164	return count;
	165	}
	166
07068021	167	static DEVICE_ATTR(target_kb, S_IRUGO \| S_IWUSR,
803eb047 DDG	168	show_target_kb, store_target_kb);
	169
	170
07068021	171	static ssize_t show_target(struct device dev, struct device_attribute attr,
803eb047 DDG	172	char *buf)
	173	{
	174	return sprintf(buf, "%llu\n",
	175	(unsigned long long)balloon_stats.target_pages
	176	<< PAGE_SHIFT);
	177	}
	178
07068021 KS	179	static ssize_t store_target(struct device *dev,
07068021 KS	180	struct device_attribute *attr,
803eb047 DDG	181	const char *buf,
	182	size_t count)
	183	{
	184	char *endchar;
	185	unsigned long long target_bytes;
	186
	187	if (!capable(CAP_SYS_ADMIN))
	188	return -EPERM;
	189
	190	target_bytes = memparse(buf, &endchar);
	191
	192	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	193
	194	return count;
	195	}
	196
07068021	197	static DEVICE_ATTR(target, S_IRUGO \| S_IWUSR,
803eb047 DDG	198	show_target, store_target);
	199
	200
b6a473a7 TI	201	static struct attribute *balloon_attrs[] = {
	202	&dev_attr_target_kb.attr,
	203	&dev_attr_target.attr,
	204	&dev_attr_schedule_delay.attr.attr,
	205	&dev_attr_max_schedule_delay.attr.attr,
	206	&dev_attr_retry_count.attr.attr,
	207	&dev_attr_max_retry_count.attr.attr,
197ecb38	208	&dev_attr_scrub_pages.attr.attr,
b6a473a7 TI	209	NULL
	210	};
	211
	212	static const struct attribute_group balloon_group = {
	213	.attrs = balloon_attrs
803eb047 DDG	214	};
	215
	216	static struct attribute *balloon_info_attrs[] = {
07068021 KS	217	&dev_attr_current_kb.attr,
	218	&dev_attr_low_kb.attr,
	219	&dev_attr_high_kb.attr,
803eb047 DDG	220	NULL
	221	};
	222
ead1d014	223	static const struct attribute_group balloon_info_group = {
803eb047 DDG	224	.name = "info",
	225	.attrs = balloon_info_attrs
	226	};
	227
b6a473a7 TI	228	static const struct attribute_group *balloon_groups[] = {
	229	&balloon_group,
	230	&balloon_info_group,
	231	NULL
	232	};
	233
07068021 KS	234	static struct bus_type balloon_subsys = {
	235	.name = BALLOON_CLASS_NAME,
	236	.dev_name = BALLOON_CLASS_NAME,
803eb047 DDG	237	};
803eb047 DDG	238
07068021	239	static int register_balloon(struct device *dev)
803eb047	240	{
b6a473a7	241	int error;
803eb047	242
8ea11f7f	243	error = subsys_system_register(&balloon_subsys, NULL);
803eb047 DDG	244	if (error)
	245	return error;
	246
07068021 KS	247	dev->id = 0;
07068021 KS	248	dev->bus = &balloon_subsys;
b6a473a7	249	dev->groups = balloon_groups;
803eb047	250
07068021	251	error = device_register(dev);
803eb047	252	if (error) {
07068021	253	bus_unregister(&balloon_subsys);
803eb047 DDG	254	return error;
	255	}
	256
803eb047	257	return 0;
803eb047	258	}