[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, 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() ? 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 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	59	{
d2f7f4bd	60	unsigned long long new_target, static_max;
803eb047	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	74	new_target >>= PAGE_SHIFT - 10;
d2f7f4bd JG	75
	76	if (!watch_fired) {
	77	watch_fired = true;
	78	err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu",
	79	&static_max);
	80	if (err != 1)
	81	static_max = new_target;
	82	else
	83	static_max >>= PAGE_SHIFT - 10;
	84	target_diff = xen_pv_domain() ? 0
	85	: static_max - balloon_stats.target_pages;
96edd61d JG	86	}
96edd61d JG	87
d2f7f4bd	88	balloon_set_new_target(new_target - target_diff);
803eb047	89	}
6b71c52e OH	90	static struct xenbus_watch target_watch = {
	91	.node = "memory/target",
	92	.callback = watch_target,
	93	};
	94
803eb047 DDG	95
	96	static int balloon_init_watcher(struct notifier_block *notifier,
	97	unsigned long event,
	98	void *data)
	99	{
	100	int err;
	101
	102	err = register_xenbus_watch(&target_watch);
	103	if (err)
283c0972	104	pr_err("Failed to set balloon watcher\n");
803eb047 DDG	105
	106	return NOTIFY_DONE;
	107	}
	108
6b71c52e OH	109	static struct notifier_block xenstore_notifier = {
	110	.notifier_call = balloon_init_watcher,
	111	};
803eb047	112
96edd61d	113	void xen_balloon_init(void)
803eb047	114	{
07068021	115	register_balloon(&balloon_dev);
803eb047	116
07068021	117	register_xen_selfballooning(&balloon_dev);
a50777c7	118
803eb047	119	register_xenstore_notifier(&xenstore_notifier);
803eb047	120	}
96edd61d	121	EXPORT_SYMBOL_GPL(xen_balloon_init);
803eb047	122
803eb047	123	#define BALLOON_SHOW(name, format, args...) \
07068021 KS	124	static ssize_t show_##name(struct device *dev, \
07068021 KS	125	struct device_attribute *attr, \
803eb047 DDG	126	char *buf) \
	127	{ \
	128	return sprintf(buf, format, ##args); \
	129	} \
07068021	130	static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
803eb047 DDG	131
	132	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	133	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	134	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	135
07068021 KS	136	static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	137	static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	138	static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	139	static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
803eb047	140
07068021	141	static ssize_t show_target_kb(struct device dev, struct device_attribute attr,
803eb047 DDG	142	char *buf)
	143	{
	144	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	145	}
	146
07068021 KS	147	static ssize_t store_target_kb(struct device *dev,
07068021 KS	148	struct device_attribute *attr,
803eb047 DDG	149	const char *buf,
	150	size_t count)
	151	{
	152	char *endchar;
	153	unsigned long long target_bytes;
	154
	155	if (!capable(CAP_SYS_ADMIN))
	156	return -EPERM;
	157
	158	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	159
	160	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	161
	162	return count;
	163	}
	164
07068021	165	static DEVICE_ATTR(target_kb, S_IRUGO \| S_IWUSR,
803eb047 DDG	166	show_target_kb, store_target_kb);
	167
	168
07068021	169	static ssize_t show_target(struct device dev, struct device_attribute attr,
803eb047 DDG	170	char *buf)
	171	{
	172	return sprintf(buf, "%llu\n",
	173	(unsigned long long)balloon_stats.target_pages
	174	<< PAGE_SHIFT);
	175	}
	176
07068021 KS	177	static ssize_t store_target(struct device *dev,
07068021 KS	178	struct device_attribute *attr,
803eb047 DDG	179	const char *buf,
	180	size_t count)
	181	{
	182	char *endchar;
	183	unsigned long long target_bytes;
	184
	185	if (!capable(CAP_SYS_ADMIN))
	186	return -EPERM;
	187
	188	target_bytes = memparse(buf, &endchar);
	189
	190	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	191
	192	return count;
	193	}
	194
07068021	195	static DEVICE_ATTR(target, S_IRUGO \| S_IWUSR,
803eb047 DDG	196	show_target, store_target);
	197
	198
b6a473a7 TI	199	static struct attribute *balloon_attrs[] = {
	200	&dev_attr_target_kb.attr,
	201	&dev_attr_target.attr,
	202	&dev_attr_schedule_delay.attr.attr,
	203	&dev_attr_max_schedule_delay.attr.attr,
	204	&dev_attr_retry_count.attr.attr,
	205	&dev_attr_max_retry_count.attr.attr,
	206	NULL
	207	};
	208
	209	static const struct attribute_group balloon_group = {
	210	.attrs = balloon_attrs
803eb047 DDG	211	};
	212
	213	static struct attribute *balloon_info_attrs[] = {
07068021 KS	214	&dev_attr_current_kb.attr,
	215	&dev_attr_low_kb.attr,
	216	&dev_attr_high_kb.attr,
803eb047 DDG	217	NULL
	218	};
	219
ead1d014	220	static const struct attribute_group balloon_info_group = {
803eb047 DDG	221	.name = "info",
	222	.attrs = balloon_info_attrs
	223	};
	224
b6a473a7 TI	225	static const struct attribute_group *balloon_groups[] = {
	226	&balloon_group,
	227	&balloon_info_group,
	228	NULL
	229	};
	230
07068021 KS	231	static struct bus_type balloon_subsys = {
	232	.name = BALLOON_CLASS_NAME,
	233	.dev_name = BALLOON_CLASS_NAME,
803eb047 DDG	234	};
803eb047 DDG	235
07068021	236	static int register_balloon(struct device *dev)
803eb047	237	{
b6a473a7	238	int error;
803eb047	239
8ea11f7f	240	error = subsys_system_register(&balloon_subsys, NULL);
803eb047 DDG	241	if (error)
	242	return error;
	243
07068021 KS	244	dev->id = 0;
07068021 KS	245	dev->bus = &balloon_subsys;
b6a473a7	246	dev->groups = balloon_groups;
803eb047	247
07068021	248	error = device_register(dev);
803eb047	249	if (error) {
07068021	250	bus_unregister(&balloon_subsys);
803eb047 DDG	251	return error;
	252	}
	253
803eb047	254	return 0;
803eb047	255	}