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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 | ||
283c0972 JP |
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
34 | ||
803eb047 DDG |
35 | #include <linux/kernel.h> |
36 | #include <linux/module.h> | |
803eb047 DDG |
37 | #include <linux/capability.h> |
38 | ||
39 | #include <xen/xen.h> | |
40 | #include <xen/interface/xen.h> | |
41 | #include <xen/balloon.h> | |
42 | #include <xen/xenbus.h> | |
43 | #include <xen/features.h> | |
44 | #include <xen/page.h> | |
45 | ||
46 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) | |
47 | ||
48 | #define BALLOON_CLASS_NAME "xen_memory" | |
49 | ||
07068021 | 50 | static struct device balloon_dev; |
803eb047 | 51 | |
07068021 | 52 | static int register_balloon(struct device *dev); |
803eb047 | 53 | |
803eb047 DDG |
54 | /* React to a change in the target key */ |
55 | static void watch_target(struct xenbus_watch *watch, | |
56 | const char **vec, unsigned int len) | |
57 | { | |
58 | unsigned long long new_target; | |
59 | int err; | |
60 | ||
61 | err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); | |
62 | if (err != 1) { | |
63 | /* This is ok (for domain0 at least) - so just return */ | |
64 | return; | |
65 | } | |
66 | ||
67 | /* The given memory/target value is in KiB, so it needs converting to | |
68 | * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. | |
69 | */ | |
70 | balloon_set_new_target(new_target >> (PAGE_SHIFT - 10)); | |
71 | } | |
6b71c52e OH |
72 | static struct xenbus_watch target_watch = { |
73 | .node = "memory/target", | |
74 | .callback = watch_target, | |
75 | }; | |
76 | ||
803eb047 DDG |
77 | |
78 | static int balloon_init_watcher(struct notifier_block *notifier, | |
79 | unsigned long event, | |
80 | void *data) | |
81 | { | |
82 | int err; | |
83 | ||
84 | err = register_xenbus_watch(&target_watch); | |
85 | if (err) | |
283c0972 | 86 | pr_err("Failed to set balloon watcher\n"); |
803eb047 DDG |
87 | |
88 | return NOTIFY_DONE; | |
89 | } | |
90 | ||
6b71c52e OH |
91 | static struct notifier_block xenstore_notifier = { |
92 | .notifier_call = balloon_init_watcher, | |
93 | }; | |
803eb047 DDG |
94 | |
95 | static int __init balloon_init(void) | |
96 | { | |
97 | if (!xen_domain()) | |
98 | return -ENODEV; | |
99 | ||
283c0972 | 100 | pr_info("Initialising balloon driver\n"); |
803eb047 | 101 | |
07068021 | 102 | register_balloon(&balloon_dev); |
803eb047 | 103 | |
07068021 | 104 | register_xen_selfballooning(&balloon_dev); |
a50777c7 | 105 | |
803eb047 DDG |
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...) \ | |
07068021 KS |
121 | static ssize_t show_##name(struct device *dev, \ |
122 | struct device_attribute *attr, \ | |
803eb047 DDG |
123 | char *buf) \ |
124 | { \ | |
125 | return sprintf(buf, format, ##args); \ | |
126 | } \ | |
07068021 | 127 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) |
803eb047 DDG |
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 | ||
07068021 KS |
133 | static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay); |
134 | static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay); | |
135 | static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count); | |
136 | static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count); | |
803eb047 | 137 | |
07068021 | 138 | static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr, |
803eb047 DDG |
139 | char *buf) |
140 | { | |
141 | return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); | |
142 | } | |
143 | ||
07068021 KS |
144 | static ssize_t store_target_kb(struct device *dev, |
145 | struct device_attribute *attr, | |
803eb047 DDG |
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 | ||
07068021 | 162 | static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR, |
803eb047 DDG |
163 | show_target_kb, store_target_kb); |
164 | ||
165 | ||
07068021 | 166 | static ssize_t show_target(struct device *dev, struct device_attribute *attr, |
803eb047 DDG |
167 | char *buf) |
168 | { | |
169 | return sprintf(buf, "%llu\n", | |
170 | (unsigned long long)balloon_stats.target_pages | |
171 | << PAGE_SHIFT); | |
172 | } | |
173 | ||
07068021 KS |
174 | static ssize_t store_target(struct device *dev, |
175 | struct device_attribute *attr, | |
803eb047 DDG |
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 | ||
07068021 | 192 | static DEVICE_ATTR(target, S_IRUGO | S_IWUSR, |
803eb047 DDG |
193 | show_target, store_target); |
194 | ||
195 | ||
b6a473a7 TI |
196 | static struct attribute *balloon_attrs[] = { |
197 | &dev_attr_target_kb.attr, | |
198 | &dev_attr_target.attr, | |
199 | &dev_attr_schedule_delay.attr.attr, | |
200 | &dev_attr_max_schedule_delay.attr.attr, | |
201 | &dev_attr_retry_count.attr.attr, | |
202 | &dev_attr_max_retry_count.attr.attr, | |
203 | NULL | |
204 | }; | |
205 | ||
206 | static const struct attribute_group balloon_group = { | |
207 | .attrs = balloon_attrs | |
803eb047 DDG |
208 | }; |
209 | ||
210 | static struct attribute *balloon_info_attrs[] = { | |
07068021 KS |
211 | &dev_attr_current_kb.attr, |
212 | &dev_attr_low_kb.attr, | |
213 | &dev_attr_high_kb.attr, | |
803eb047 DDG |
214 | NULL |
215 | }; | |
216 | ||
ead1d014 | 217 | static const struct attribute_group balloon_info_group = { |
803eb047 DDG |
218 | .name = "info", |
219 | .attrs = balloon_info_attrs | |
220 | }; | |
221 | ||
b6a473a7 TI |
222 | static const struct attribute_group *balloon_groups[] = { |
223 | &balloon_group, | |
224 | &balloon_info_group, | |
225 | NULL | |
226 | }; | |
227 | ||
07068021 KS |
228 | static struct bus_type balloon_subsys = { |
229 | .name = BALLOON_CLASS_NAME, | |
230 | .dev_name = BALLOON_CLASS_NAME, | |
803eb047 DDG |
231 | }; |
232 | ||
07068021 | 233 | static int register_balloon(struct device *dev) |
803eb047 | 234 | { |
b6a473a7 | 235 | int error; |
803eb047 | 236 | |
8ea11f7f | 237 | error = subsys_system_register(&balloon_subsys, NULL); |
803eb047 DDG |
238 | if (error) |
239 | return error; | |
240 | ||
07068021 KS |
241 | dev->id = 0; |
242 | dev->bus = &balloon_subsys; | |
b6a473a7 | 243 | dev->groups = balloon_groups; |
803eb047 | 244 | |
07068021 | 245 | error = device_register(dev); |
803eb047 | 246 | if (error) { |
07068021 | 247 | bus_unregister(&balloon_subsys); |
803eb047 DDG |
248 | return error; |
249 | } | |
250 | ||
803eb047 | 251 | return 0; |
803eb047 DDG |
252 | } |
253 | ||
254 | MODULE_LICENSE("GPL"); |