hwmon: (it87) Add chassis intrusion detection support
[linux-2.6.git] / drivers / xen / xen-balloon.c
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
49 static struct sys_device balloon_sysdev;
50
51 static int register_balloon(struct sys_device *sysdev);
52
53 static struct xenbus_watch target_watch =
54 {
55         .node = "memory/target"
56 };
57
58 /* React to a change in the target key */
59 static 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
77 static 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
90 static struct notifier_block xenstore_notifier;
91
92 static 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 }
110 subsys_initcall(balloon_init);
111
112 static void balloon_exit(void)
113 {
114     /* XXX - release balloon here */
115     return;
116 }
117
118 module_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
129 BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
130 BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
131 BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
132
133 static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
134 static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
135 static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
136 static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
137
138 static 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
144 static 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
162 static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
163                    show_target_kb, store_target_kb);
164
165
166 static 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
174 static 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
192 static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
193                    show_target, store_target);
194
195
196 static 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
205 static struct attribute *balloon_info_attrs[] = {
206         &attr_current_kb.attr,
207         &attr_low_kb.attr,
208         &attr_high_kb.attr,
209         NULL
210 };
211
212 static struct attribute_group balloon_info_group = {
213         .name = "info",
214         .attrs = balloon_info_attrs
215 };
216
217 static struct sysdev_class balloon_sysdev_class = {
218         .name = BALLOON_CLASS_NAME
219 };
220
221 static 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
258 MODULE_LICENSE("GPL");