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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 | ||
803eb047 DDG |
53 | /* React to a change in the target key */ |
54 | static 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 | } | |
6b71c52e OH |
71 | static struct xenbus_watch target_watch = { |
72 | .node = "memory/target", | |
73 | .callback = watch_target, | |
74 | }; | |
75 | ||
803eb047 DDG |
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 | ||
6b71c52e OH |
90 | static struct notifier_block xenstore_notifier = { |
91 | .notifier_call = balloon_init_watcher, | |
92 | }; | |
803eb047 DDG |
93 | |
94 | static 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 | ||
a50777c7 DM |
103 | register_xen_selfballooning(&balloon_sysdev); |
104 | ||
803eb047 DDG |
105 | register_xenstore_notifier(&xenstore_notifier); |
106 | ||
107 | return 0; | |
108 | } | |
109 | subsys_initcall(balloon_init); | |
110 | ||
111 | static void balloon_exit(void) | |
112 | { | |
113 | /* XXX - release balloon here */ | |
114 | return; | |
115 | } | |
116 | ||
117 | module_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 | ||
128 | BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); | |
129 | BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); | |
130 | BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); | |
131 | ||
132 | static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay); | |
133 | static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay); | |
134 | static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count); | |
135 | static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count); | |
136 | ||
137 | static 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 | ||
143 | static 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 | ||
161 | static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR, | |
162 | show_target_kb, store_target_kb); | |
163 | ||
164 | ||
165 | static 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 | ||
173 | static 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 | ||
191 | static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR, | |
192 | show_target, store_target); | |
193 | ||
194 | ||
195 | static 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 | ||
204 | static struct attribute *balloon_info_attrs[] = { | |
205 | &attr_current_kb.attr, | |
206 | &attr_low_kb.attr, | |
207 | &attr_high_kb.attr, | |
208 | NULL | |
209 | }; | |
210 | ||
211 | static struct attribute_group balloon_info_group = { | |
212 | .name = "info", | |
213 | .attrs = balloon_info_attrs | |
214 | }; | |
215 | ||
216 | static struct sysdev_class balloon_sysdev_class = { | |
217 | .name = BALLOON_CLASS_NAME | |
218 | }; | |
219 | ||
220 | static 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 | ||
257 | MODULE_LICENSE("GPL"); |