Loading...
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
33#include <linux/kernel.h>
34#include <linux/module.h>
35#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
48static struct device balloon_dev;
49
50static int register_balloon(struct device *dev);
51
52/* 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}
70static struct xenbus_watch target_watch = {
71 .node = "memory/target",
72 .callback = watch_target,
73};
74
75
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
89static struct notifier_block xenstore_notifier = {
90 .notifier_call = balloon_init_watcher,
91};
92
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
100 register_balloon(&balloon_dev);
101
102 register_xen_selfballooning(&balloon_dev);
103
104 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...) \
119 static ssize_t show_##name(struct device *dev, \
120 struct device_attribute *attr, \
121 char *buf) \
122 { \
123 return sprintf(buf, format, ##args); \
124 } \
125 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
126
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
131static 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);
135
136static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
137 char *buf)
138{
139 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
140}
141
142static ssize_t store_target_kb(struct device *dev,
143 struct device_attribute *attr,
144 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
160static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
161 show_target_kb, store_target_kb);
162
163
164static ssize_t show_target(struct device *dev, struct device_attribute *attr,
165 char *buf)
166{
167 return sprintf(buf, "%llu\n",
168 (unsigned long long)balloon_stats.target_pages
169 << PAGE_SHIFT);
170}
171
172static ssize_t store_target(struct device *dev,
173 struct device_attribute *attr,
174 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
190static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
191 show_target, store_target);
192
193
194static 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
201};
202
203static struct attribute *balloon_info_attrs[] = {
204 &dev_attr_current_kb.attr,
205 &dev_attr_low_kb.attr,
206 &dev_attr_high_kb.attr,
207 NULL
208};
209
210static const struct attribute_group balloon_info_group = {
211 .name = "info",
212 .attrs = balloon_info_attrs
213};
214
215static struct bus_type balloon_subsys = {
216 .name = BALLOON_CLASS_NAME,
217 .dev_name = BALLOON_CLASS_NAME,
218};
219
220static int register_balloon(struct device *dev)
221{
222 int i, error;
223
224 error = subsys_system_register(&balloon_subsys, NULL);
225 if (error)
226 return error;
227
228 dev->id = 0;
229 dev->bus = &balloon_subsys;
230
231 error = device_register(dev);
232 if (error) {
233 bus_unregister(&balloon_subsys);
234 return error;
235 }
236
237 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
238 error = device_create_file(dev, balloon_attrs[i]);
239 if (error)
240 goto fail;
241 }
242
243 error = sysfs_create_group(&dev->kobj, &balloon_info_group);
244 if (error)
245 goto fail;
246
247 return 0;
248
249 fail:
250 while (--i >= 0)
251 device_remove_file(dev, balloon_attrs[i]);
252 device_unregister(dev);
253 bus_unregister(&balloon_subsys);
254 return error;
255}
256
257MODULE_LICENSE("GPL");
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
33#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35#include <linux/kernel.h>
36#include <linux/errno.h>
37#include <linux/mm_types.h>
38#include <linux/init.h>
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
52static struct device balloon_dev;
53
54static int register_balloon(struct device *dev);
55
56/* React to a change in the target key */
57static void watch_target(struct xenbus_watch *watch,
58 const char **vec, unsigned int len)
59{
60 unsigned long long new_target;
61 int err;
62
63 err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
64 if (err != 1) {
65 /* This is ok (for domain0 at least) - so just return */
66 return;
67 }
68
69 /* The given memory/target value is in KiB, so it needs converting to
70 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
71 */
72 balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
73}
74static struct xenbus_watch target_watch = {
75 .node = "memory/target",
76 .callback = watch_target,
77};
78
79
80static int balloon_init_watcher(struct notifier_block *notifier,
81 unsigned long event,
82 void *data)
83{
84 int err;
85
86 err = register_xenbus_watch(&target_watch);
87 if (err)
88 pr_err("Failed to set balloon watcher\n");
89
90 return NOTIFY_DONE;
91}
92
93static struct notifier_block xenstore_notifier = {
94 .notifier_call = balloon_init_watcher,
95};
96
97static int __init balloon_init(void)
98{
99 if (!xen_domain())
100 return -ENODEV;
101
102 pr_info("Initialising balloon driver\n");
103
104 register_balloon(&balloon_dev);
105
106 register_xen_selfballooning(&balloon_dev);
107
108 register_xenstore_notifier(&xenstore_notifier);
109
110 return 0;
111}
112subsys_initcall(balloon_init);
113
114#define BALLOON_SHOW(name, format, args...) \
115 static ssize_t show_##name(struct device *dev, \
116 struct device_attribute *attr, \
117 char *buf) \
118 { \
119 return sprintf(buf, format, ##args); \
120 } \
121 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
122
123BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
124BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
125BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
126
127static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
128static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
129static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
130static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
131
132static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
133 char *buf)
134{
135 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
136}
137
138static ssize_t store_target_kb(struct device *dev,
139 struct device_attribute *attr,
140 const char *buf,
141 size_t count)
142{
143 char *endchar;
144 unsigned long long target_bytes;
145
146 if (!capable(CAP_SYS_ADMIN))
147 return -EPERM;
148
149 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
150
151 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
152
153 return count;
154}
155
156static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
157 show_target_kb, store_target_kb);
158
159
160static ssize_t show_target(struct device *dev, struct device_attribute *attr,
161 char *buf)
162{
163 return sprintf(buf, "%llu\n",
164 (unsigned long long)balloon_stats.target_pages
165 << PAGE_SHIFT);
166}
167
168static ssize_t store_target(struct device *dev,
169 struct device_attribute *attr,
170 const char *buf,
171 size_t count)
172{
173 char *endchar;
174 unsigned long long target_bytes;
175
176 if (!capable(CAP_SYS_ADMIN))
177 return -EPERM;
178
179 target_bytes = memparse(buf, &endchar);
180
181 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
182
183 return count;
184}
185
186static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
187 show_target, store_target);
188
189
190static struct attribute *balloon_attrs[] = {
191 &dev_attr_target_kb.attr,
192 &dev_attr_target.attr,
193 &dev_attr_schedule_delay.attr.attr,
194 &dev_attr_max_schedule_delay.attr.attr,
195 &dev_attr_retry_count.attr.attr,
196 &dev_attr_max_retry_count.attr.attr,
197 NULL
198};
199
200static const struct attribute_group balloon_group = {
201 .attrs = balloon_attrs
202};
203
204static struct attribute *balloon_info_attrs[] = {
205 &dev_attr_current_kb.attr,
206 &dev_attr_low_kb.attr,
207 &dev_attr_high_kb.attr,
208 NULL
209};
210
211static const struct attribute_group balloon_info_group = {
212 .name = "info",
213 .attrs = balloon_info_attrs
214};
215
216static const struct attribute_group *balloon_groups[] = {
217 &balloon_group,
218 &balloon_info_group,
219 NULL
220};
221
222static struct bus_type balloon_subsys = {
223 .name = BALLOON_CLASS_NAME,
224 .dev_name = BALLOON_CLASS_NAME,
225};
226
227static int register_balloon(struct device *dev)
228{
229 int error;
230
231 error = subsys_system_register(&balloon_subsys, NULL);
232 if (error)
233 return error;
234
235 dev->id = 0;
236 dev->bus = &balloon_subsys;
237 dev->groups = balloon_groups;
238
239 error = device_register(dev);
240 if (error) {
241 bus_unregister(&balloon_subsys);
242 return error;
243 }
244
245 return 0;
246}