blob: 3832e303c33aca5ceabf0bb1540e02a28b7765bc [file] [log] [blame]
Daniel De Graaf803eb042011-03-14 11:29:37 -04001/******************************************************************************
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>
Daniel De Graaf803eb042011-03-14 11:29:37 -040035#include <linux/capability.h>
36
37#include <xen/xen.h>
38#include <xen/interface/xen.h>
39#include <xen/balloon.h>
40#include <xen/xenbus.h>
41#include <xen/features.h>
42#include <xen/page.h>
43
44#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
45
46#define BALLOON_CLASS_NAME "xen_memory"
47
Kay Sievers07068022011-12-14 15:32:50 -080048static struct device balloon_dev;
Daniel De Graaf803eb042011-03-14 11:29:37 -040049
Kay Sievers07068022011-12-14 15:32:50 -080050static int register_balloon(struct device *dev);
Daniel De Graaf803eb042011-03-14 11:29:37 -040051
Daniel De Graaf803eb042011-03-14 11:29:37 -040052/* React to a change in the target key */
53static void watch_target(struct xenbus_watch *watch,
54 const char **vec, unsigned int len)
55{
56 unsigned long long new_target;
57 int err;
58
59 err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
60 if (err != 1) {
61 /* This is ok (for domain0 at least) - so just return */
62 return;
63 }
64
65 /* The given memory/target value is in KiB, so it needs converting to
66 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
67 */
68 balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
69}
Olaf Hering6b71c522011-07-28 15:23:03 +020070static struct xenbus_watch target_watch = {
71 .node = "memory/target",
72 .callback = watch_target,
73};
74
Daniel De Graaf803eb042011-03-14 11:29:37 -040075
76static int balloon_init_watcher(struct notifier_block *notifier,
77 unsigned long event,
78 void *data)
79{
80 int err;
81
82 err = register_xenbus_watch(&target_watch);
83 if (err)
84 printk(KERN_ERR "Failed to set balloon watcher\n");
85
86 return NOTIFY_DONE;
87}
88
Olaf Hering6b71c522011-07-28 15:23:03 +020089static struct notifier_block xenstore_notifier = {
90 .notifier_call = balloon_init_watcher,
91};
Daniel De Graaf803eb042011-03-14 11:29:37 -040092
93static int __init balloon_init(void)
94{
95 if (!xen_domain())
96 return -ENODEV;
97
98 pr_info("xen-balloon: Initialising balloon driver.\n");
99
Kay Sievers07068022011-12-14 15:32:50 -0800100 register_balloon(&balloon_dev);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400101
Kay Sievers07068022011-12-14 15:32:50 -0800102 register_xen_selfballooning(&balloon_dev);
Dan Magenheimera50777c2011-07-08 12:26:21 -0600103
Daniel De Graaf803eb042011-03-14 11:29:37 -0400104 register_xenstore_notifier(&xenstore_notifier);
105
106 return 0;
107}
108subsys_initcall(balloon_init);
109
110static void balloon_exit(void)
111{
112 /* XXX - release balloon here */
113 return;
114}
115
116module_exit(balloon_exit);
117
118#define BALLOON_SHOW(name, format, args...) \
Kay Sievers07068022011-12-14 15:32:50 -0800119 static ssize_t show_##name(struct device *dev, \
120 struct device_attribute *attr, \
Daniel De Graaf803eb042011-03-14 11:29:37 -0400121 char *buf) \
122 { \
123 return sprintf(buf, format, ##args); \
124 } \
Kay Sievers07068022011-12-14 15:32:50 -0800125 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
Daniel De Graaf803eb042011-03-14 11:29:37 -0400126
127BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
128BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
129BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
130
Kay Sievers07068022011-12-14 15:32:50 -0800131static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
132static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
133static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
134static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400135
Kay Sievers07068022011-12-14 15:32:50 -0800136static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400137 char *buf)
138{
139 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
140}
141
Kay Sievers07068022011-12-14 15:32:50 -0800142static ssize_t store_target_kb(struct device *dev,
143 struct device_attribute *attr,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400144 const char *buf,
145 size_t count)
146{
147 char *endchar;
148 unsigned long long target_bytes;
149
150 if (!capable(CAP_SYS_ADMIN))
151 return -EPERM;
152
153 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
154
155 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
156
157 return count;
158}
159
Kay Sievers07068022011-12-14 15:32:50 -0800160static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400161 show_target_kb, store_target_kb);
162
163
Kay Sievers07068022011-12-14 15:32:50 -0800164static ssize_t show_target(struct device *dev, struct device_attribute *attr,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400165 char *buf)
166{
167 return sprintf(buf, "%llu\n",
168 (unsigned long long)balloon_stats.target_pages
169 << PAGE_SHIFT);
170}
171
Kay Sievers07068022011-12-14 15:32:50 -0800172static ssize_t store_target(struct device *dev,
173 struct device_attribute *attr,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400174 const char *buf,
175 size_t count)
176{
177 char *endchar;
178 unsigned long long target_bytes;
179
180 if (!capable(CAP_SYS_ADMIN))
181 return -EPERM;
182
183 target_bytes = memparse(buf, &endchar);
184
185 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
186
187 return count;
188}
189
Kay Sievers07068022011-12-14 15:32:50 -0800190static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400191 show_target, store_target);
192
193
Kay Sievers07068022011-12-14 15:32:50 -0800194static struct device_attribute *balloon_attrs[] = {
195 &dev_attr_target_kb,
196 &dev_attr_target,
197 &dev_attr_schedule_delay.attr,
198 &dev_attr_max_schedule_delay.attr,
199 &dev_attr_retry_count.attr,
200 &dev_attr_max_retry_count.attr
Daniel De Graaf803eb042011-03-14 11:29:37 -0400201};
202
203static struct attribute *balloon_info_attrs[] = {
Kay Sievers07068022011-12-14 15:32:50 -0800204 &dev_attr_current_kb.attr,
205 &dev_attr_low_kb.attr,
206 &dev_attr_high_kb.attr,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400207 NULL
208};
209
210static struct attribute_group balloon_info_group = {
211 .name = "info",
212 .attrs = balloon_info_attrs
213};
214
Kay Sievers07068022011-12-14 15:32:50 -0800215static struct bus_type balloon_subsys = {
216 .name = BALLOON_CLASS_NAME,
217 .dev_name = BALLOON_CLASS_NAME,
Daniel De Graaf803eb042011-03-14 11:29:37 -0400218};
219
Kay Sievers07068022011-12-14 15:32:50 -0800220static int register_balloon(struct device *dev)
Daniel De Graaf803eb042011-03-14 11:29:37 -0400221{
222 int i, error;
223
Kay Sievers07068022011-12-14 15:32:50 -0800224 error = bus_register(&balloon_subsys);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400225 if (error)
226 return error;
227
Kay Sievers07068022011-12-14 15:32:50 -0800228 dev->id = 0;
229 dev->bus = &balloon_subsys;
Daniel De Graaf803eb042011-03-14 11:29:37 -0400230
Kay Sievers07068022011-12-14 15:32:50 -0800231 error = device_register(dev);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400232 if (error) {
Kay Sievers07068022011-12-14 15:32:50 -0800233 bus_unregister(&balloon_subsys);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400234 return error;
235 }
236
237 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
Kay Sievers07068022011-12-14 15:32:50 -0800238 error = device_create_file(dev, balloon_attrs[i]);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400239 if (error)
240 goto fail;
241 }
242
Kay Sievers07068022011-12-14 15:32:50 -0800243 error = sysfs_create_group(&dev->kobj, &balloon_info_group);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400244 if (error)
245 goto fail;
246
247 return 0;
248
249 fail:
250 while (--i >= 0)
Kay Sievers07068022011-12-14 15:32:50 -0800251 device_remove_file(dev, balloon_attrs[i]);
252 device_unregister(dev);
253 bus_unregister(&balloon_subsys);
Daniel De Graaf803eb042011-03-14 11:29:37 -0400254 return error;
255}
256
257MODULE_LICENSE("GPL");