blob: 9cc2259c9992799dca480245b018ffb971541ed9 [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>
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
Daniel De Graaf803eb042011-03-14 11:29:37 -040053/* React to a change in the target key */
54static void watch_target(struct xenbus_watch *watch,
55 const char **vec, unsigned int len)
56{
57 unsigned long long new_target;
58 int err;
59
60 err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
61 if (err != 1) {
62 /* This is ok (for domain0 at least) - so just return */
63 return;
64 }
65
66 /* The given memory/target value is in KiB, so it needs converting to
67 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
68 */
69 balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
70}
Olaf Hering6b71c522011-07-28 15:23:03 +020071static struct xenbus_watch target_watch = {
72 .node = "memory/target",
73 .callback = watch_target,
74};
75
Daniel De Graaf803eb042011-03-14 11:29:37 -040076
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
Olaf Hering6b71c522011-07-28 15:23:03 +020090static struct notifier_block xenstore_notifier = {
91 .notifier_call = balloon_init_watcher,
92};
Daniel De Graaf803eb042011-03-14 11:29:37 -040093
94static int __init balloon_init(void)
95{
96 if (!xen_domain())
97 return -ENODEV;
98
99 pr_info("xen-balloon: Initialising balloon driver.\n");
100
101 register_balloon(&balloon_sysdev);
102
Dan Magenheimera50777c2011-07-08 12:26:21 -0600103 register_xen_selfballooning(&balloon_sysdev);
104
Daniel De Graaf803eb042011-03-14 11:29:37 -0400105 register_xenstore_notifier(&xenstore_notifier);
106
107 return 0;
108}
109subsys_initcall(balloon_init);
110
111static void balloon_exit(void)
112{
113 /* XXX - release balloon here */
114 return;
115}
116
117module_exit(balloon_exit);
118
119#define BALLOON_SHOW(name, format, args...) \
120 static ssize_t show_##name(struct sys_device *dev, \
121 struct sysdev_attribute *attr, \
122 char *buf) \
123 { \
124 return sprintf(buf, format, ##args); \
125 } \
126 static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
127
128BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
129BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
130BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
131
132static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
133static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
134static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
135static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
136
137static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
138 char *buf)
139{
140 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
141}
142
143static ssize_t store_target_kb(struct sys_device *dev,
144 struct sysdev_attribute *attr,
145 const char *buf,
146 size_t count)
147{
148 char *endchar;
149 unsigned long long target_bytes;
150
151 if (!capable(CAP_SYS_ADMIN))
152 return -EPERM;
153
154 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
155
156 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
157
158 return count;
159}
160
161static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
162 show_target_kb, store_target_kb);
163
164
165static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
166 char *buf)
167{
168 return sprintf(buf, "%llu\n",
169 (unsigned long long)balloon_stats.target_pages
170 << PAGE_SHIFT);
171}
172
173static ssize_t store_target(struct sys_device *dev,
174 struct sysdev_attribute *attr,
175 const char *buf,
176 size_t count)
177{
178 char *endchar;
179 unsigned long long target_bytes;
180
181 if (!capable(CAP_SYS_ADMIN))
182 return -EPERM;
183
184 target_bytes = memparse(buf, &endchar);
185
186 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
187
188 return count;
189}
190
191static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
192 show_target, store_target);
193
194
195static struct sysdev_attribute *balloon_attrs[] = {
196 &attr_target_kb,
197 &attr_target,
198 &attr_schedule_delay.attr,
199 &attr_max_schedule_delay.attr,
200 &attr_retry_count.attr,
201 &attr_max_retry_count.attr
202};
203
204static struct attribute *balloon_info_attrs[] = {
205 &attr_current_kb.attr,
206 &attr_low_kb.attr,
207 &attr_high_kb.attr,
208 NULL
209};
210
211static struct attribute_group balloon_info_group = {
212 .name = "info",
213 .attrs = balloon_info_attrs
214};
215
216static struct sysdev_class balloon_sysdev_class = {
217 .name = BALLOON_CLASS_NAME
218};
219
220static int register_balloon(struct sys_device *sysdev)
221{
222 int i, error;
223
224 error = sysdev_class_register(&balloon_sysdev_class);
225 if (error)
226 return error;
227
228 sysdev->id = 0;
229 sysdev->cls = &balloon_sysdev_class;
230
231 error = sysdev_register(sysdev);
232 if (error) {
233 sysdev_class_unregister(&balloon_sysdev_class);
234 return error;
235 }
236
237 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
238 error = sysdev_create_file(sysdev, balloon_attrs[i]);
239 if (error)
240 goto fail;
241 }
242
243 error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
244 if (error)
245 goto fail;
246
247 return 0;
248
249 fail:
250 while (--i >= 0)
251 sysdev_remove_file(sysdev, balloon_attrs[i]);
252 sysdev_unregister(sysdev);
253 sysdev_class_unregister(&balloon_sysdev_class);
254 return error;
255}
256
257MODULE_LICENSE("GPL");