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803eb047 DDG |
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 | ||
a50777c7 DM |
101 | register_xen_selfballooning(&balloon_sysdev); |
102 | ||
803eb047 DDG |
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"); |