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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/sysdev.h>
36#include <linux/capability.h>
37
38#include <xen/xen.h>
39#include <xen/interface/xen.h>
40#include <xen/balloon.h>
41#include <xen/xenbus.h>
42#include <xen/features.h>
43#include <xen/page.h>
44
45#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
46
47#define BALLOON_CLASS_NAME "xen_memory"
48
49static struct sys_device balloon_sysdev;
50
51static int register_balloon(struct sys_device *sysdev);
52
53static struct xenbus_watch target_watch =
54{
55 .node = "memory/target"
56};
57
58/* React to a change in the target key */
59static void watch_target(struct xenbus_watch *watch,
60 const char **vec, unsigned int len)
61{
62 unsigned long long new_target;
63 int err;
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 */
74 balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
75}
76
77static int balloon_init_watcher(struct notifier_block *notifier,
78 unsigned long event,
79 void *data)
80{
81 int err;
82
83 err = register_xenbus_watch(&target_watch);
84 if (err)
85 printk(KERN_ERR "Failed to set balloon watcher\n");
86
87 return NOTIFY_DONE;
88}
89
90static struct notifier_block xenstore_notifier;
91
92static int __init balloon_init(void)
93{
94 if (!xen_domain())
95 return -ENODEV;
96
97 pr_info("xen-balloon: Initialising balloon driver.\n");
98
99 register_balloon(&balloon_sysdev);
100
101 register_xen_selfballooning(&balloon_sysdev);
102
103 target_watch.callback = watch_target;
104 xenstore_notifier.notifier_call = balloon_init_watcher;
105
106 register_xenstore_notifier(&xenstore_notifier);
107
108 return 0;
109}
110subsys_initcall(balloon_init);
111
112static void balloon_exit(void)
113{
114 /* XXX - release balloon here */
115 return;
116}
117
118module_exit(balloon_exit);
119
120#define BALLOON_SHOW(name, format, args...) \
121 static ssize_t show_##name(struct sys_device *dev, \
122 struct sysdev_attribute *attr, \
123 char *buf) \
124 { \
125 return sprintf(buf, format, ##args); \
126 } \
127 static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
128
129BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
130BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
131BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
132
133static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
134static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
135static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
136static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
137
138static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
139 char *buf)
140{
141 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
142}
143
144static ssize_t store_target_kb(struct sys_device *dev,
145 struct sysdev_attribute *attr,
146 const char *buf,
147 size_t count)
148{
149 char *endchar;
150 unsigned long long target_bytes;
151
152 if (!capable(CAP_SYS_ADMIN))
153 return -EPERM;
154
155 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
156
157 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
158
159 return count;
160}
161
162static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
163 show_target_kb, store_target_kb);
164
165
166static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
167 char *buf)
168{
169 return sprintf(buf, "%llu\n",
170 (unsigned long long)balloon_stats.target_pages
171 << PAGE_SHIFT);
172}
173
174static ssize_t store_target(struct sys_device *dev,
175 struct sysdev_attribute *attr,
176 const char *buf,
177 size_t count)
178{
179 char *endchar;
180 unsigned long long target_bytes;
181
182 if (!capable(CAP_SYS_ADMIN))
183 return -EPERM;
184
185 target_bytes = memparse(buf, &endchar);
186
187 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
188
189 return count;
190}
191
192static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
193 show_target, store_target);
194
195
196static struct sysdev_attribute *balloon_attrs[] = {
197 &attr_target_kb,
198 &attr_target,
199 &attr_schedule_delay.attr,
200 &attr_max_schedule_delay.attr,
201 &attr_retry_count.attr,
202 &attr_max_retry_count.attr
203};
204
205static struct attribute *balloon_info_attrs[] = {
206 &attr_current_kb.attr,
207 &attr_low_kb.attr,
208 &attr_high_kb.attr,
209 NULL
210};
211
212static struct attribute_group balloon_info_group = {
213 .name = "info",
214 .attrs = balloon_info_attrs
215};
216
217static struct sysdev_class balloon_sysdev_class = {
218 .name = BALLOON_CLASS_NAME
219};
220
221static int register_balloon(struct sys_device *sysdev)
222{
223 int i, error;
224
225 error = sysdev_class_register(&balloon_sysdev_class);
226 if (error)
227 return error;
228
229 sysdev->id = 0;
230 sysdev->cls = &balloon_sysdev_class;
231
232 error = sysdev_register(sysdev);
233 if (error) {
234 sysdev_class_unregister(&balloon_sysdev_class);
235 return error;
236 }
237
238 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
239 error = sysdev_create_file(sysdev, balloon_attrs[i]);
240 if (error)
241 goto fail;
242 }
243
244 error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
245 if (error)
246 goto fail;
247
248 return 0;
249
250 fail:
251 while (--i >= 0)
252 sysdev_remove_file(sysdev, balloon_attrs[i]);
253 sysdev_unregister(sysdev);
254 sysdev_class_unregister(&balloon_sysdev_class);
255 return error;
256}
257
258MODULE_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}