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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 | 35 | #include <linux/kernel.h> |
106eaa8e PG |
36 | #include <linux/errno.h> |
37 | #include <linux/mm_types.h> | |
38 | #include <linux/init.h> | |
803eb047 DDG |
39 | #include <linux/capability.h> |
40 | ||
41 | #include <xen/xen.h> | |
42 | #include <xen/interface/xen.h> | |
43 | #include <xen/balloon.h> | |
44 | #include <xen/xenbus.h> | |
45 | #include <xen/features.h> | |
46 | #include <xen/page.h> | |
47 | ||
48 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) | |
49 | ||
50 | #define BALLOON_CLASS_NAME "xen_memory" | |
51 | ||
07068021 | 52 | static struct device balloon_dev; |
803eb047 | 53 | |
07068021 | 54 | static int register_balloon(struct device *dev); |
803eb047 | 55 | |
803eb047 DDG |
56 | /* React to a change in the target key */ |
57 | static void watch_target(struct xenbus_watch *watch, | |
5584ea25 | 58 | const char *path, const char *token) |
803eb047 DDG |
59 | { |
60 | unsigned long long new_target; | |
61 | int err; | |
96edd61d JG |
62 | static bool watch_fired; |
63 | static long target_diff; | |
803eb047 DDG |
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 | */ | |
96edd61d JG |
74 | new_target >>= PAGE_SHIFT - 10; |
75 | if (watch_fired) { | |
76 | balloon_set_new_target(new_target - target_diff); | |
77 | return; | |
78 | } | |
79 | ||
80 | watch_fired = true; | |
81 | target_diff = new_target - balloon_stats.target_pages; | |
803eb047 | 82 | } |
6b71c52e OH |
83 | static struct xenbus_watch target_watch = { |
84 | .node = "memory/target", | |
85 | .callback = watch_target, | |
86 | }; | |
87 | ||
803eb047 DDG |
88 | |
89 | static int balloon_init_watcher(struct notifier_block *notifier, | |
90 | unsigned long event, | |
91 | void *data) | |
92 | { | |
93 | int err; | |
94 | ||
95 | err = register_xenbus_watch(&target_watch); | |
96 | if (err) | |
283c0972 | 97 | pr_err("Failed to set balloon watcher\n"); |
803eb047 DDG |
98 | |
99 | return NOTIFY_DONE; | |
100 | } | |
101 | ||
6b71c52e OH |
102 | static struct notifier_block xenstore_notifier = { |
103 | .notifier_call = balloon_init_watcher, | |
104 | }; | |
803eb047 | 105 | |
96edd61d | 106 | void xen_balloon_init(void) |
803eb047 | 107 | { |
07068021 | 108 | register_balloon(&balloon_dev); |
803eb047 | 109 | |
07068021 | 110 | register_xen_selfballooning(&balloon_dev); |
a50777c7 | 111 | |
803eb047 | 112 | register_xenstore_notifier(&xenstore_notifier); |
803eb047 | 113 | } |
96edd61d | 114 | EXPORT_SYMBOL_GPL(xen_balloon_init); |
803eb047 | 115 | |
803eb047 | 116 | #define BALLOON_SHOW(name, format, args...) \ |
07068021 KS |
117 | static ssize_t show_##name(struct device *dev, \ |
118 | struct device_attribute *attr, \ | |
803eb047 DDG |
119 | char *buf) \ |
120 | { \ | |
121 | return sprintf(buf, format, ##args); \ | |
122 | } \ | |
07068021 | 123 | static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) |
803eb047 DDG |
124 | |
125 | BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); | |
126 | BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); | |
127 | BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); | |
128 | ||
07068021 KS |
129 | static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay); |
130 | static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay); | |
131 | static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count); | |
132 | static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count); | |
803eb047 | 133 | |
07068021 | 134 | static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr, |
803eb047 DDG |
135 | char *buf) |
136 | { | |
137 | return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); | |
138 | } | |
139 | ||
07068021 KS |
140 | static ssize_t store_target_kb(struct device *dev, |
141 | struct device_attribute *attr, | |
803eb047 DDG |
142 | const char *buf, |
143 | size_t count) | |
144 | { | |
145 | char *endchar; | |
146 | unsigned long long target_bytes; | |
147 | ||
148 | if (!capable(CAP_SYS_ADMIN)) | |
149 | return -EPERM; | |
150 | ||
151 | target_bytes = simple_strtoull(buf, &endchar, 0) * 1024; | |
152 | ||
153 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); | |
154 | ||
155 | return count; | |
156 | } | |
157 | ||
07068021 | 158 | static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR, |
803eb047 DDG |
159 | show_target_kb, store_target_kb); |
160 | ||
161 | ||
07068021 | 162 | static ssize_t show_target(struct device *dev, struct device_attribute *attr, |
803eb047 DDG |
163 | char *buf) |
164 | { | |
165 | return sprintf(buf, "%llu\n", | |
166 | (unsigned long long)balloon_stats.target_pages | |
167 | << PAGE_SHIFT); | |
168 | } | |
169 | ||
07068021 KS |
170 | static ssize_t store_target(struct device *dev, |
171 | struct device_attribute *attr, | |
803eb047 DDG |
172 | const char *buf, |
173 | size_t count) | |
174 | { | |
175 | char *endchar; | |
176 | unsigned long long target_bytes; | |
177 | ||
178 | if (!capable(CAP_SYS_ADMIN)) | |
179 | return -EPERM; | |
180 | ||
181 | target_bytes = memparse(buf, &endchar); | |
182 | ||
183 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); | |
184 | ||
185 | return count; | |
186 | } | |
187 | ||
07068021 | 188 | static DEVICE_ATTR(target, S_IRUGO | S_IWUSR, |
803eb047 DDG |
189 | show_target, store_target); |
190 | ||
191 | ||
b6a473a7 TI |
192 | static struct attribute *balloon_attrs[] = { |
193 | &dev_attr_target_kb.attr, | |
194 | &dev_attr_target.attr, | |
195 | &dev_attr_schedule_delay.attr.attr, | |
196 | &dev_attr_max_schedule_delay.attr.attr, | |
197 | &dev_attr_retry_count.attr.attr, | |
198 | &dev_attr_max_retry_count.attr.attr, | |
199 | NULL | |
200 | }; | |
201 | ||
202 | static const struct attribute_group balloon_group = { | |
203 | .attrs = balloon_attrs | |
803eb047 DDG |
204 | }; |
205 | ||
206 | static struct attribute *balloon_info_attrs[] = { | |
07068021 KS |
207 | &dev_attr_current_kb.attr, |
208 | &dev_attr_low_kb.attr, | |
209 | &dev_attr_high_kb.attr, | |
803eb047 DDG |
210 | NULL |
211 | }; | |
212 | ||
ead1d014 | 213 | static const struct attribute_group balloon_info_group = { |
803eb047 DDG |
214 | .name = "info", |
215 | .attrs = balloon_info_attrs | |
216 | }; | |
217 | ||
b6a473a7 TI |
218 | static const struct attribute_group *balloon_groups[] = { |
219 | &balloon_group, | |
220 | &balloon_info_group, | |
221 | NULL | |
222 | }; | |
223 | ||
07068021 KS |
224 | static struct bus_type balloon_subsys = { |
225 | .name = BALLOON_CLASS_NAME, | |
226 | .dev_name = BALLOON_CLASS_NAME, | |
803eb047 DDG |
227 | }; |
228 | ||
07068021 | 229 | static int register_balloon(struct device *dev) |
803eb047 | 230 | { |
b6a473a7 | 231 | int error; |
803eb047 | 232 | |
8ea11f7f | 233 | error = subsys_system_register(&balloon_subsys, NULL); |
803eb047 DDG |
234 | if (error) |
235 | return error; | |
236 | ||
07068021 KS |
237 | dev->id = 0; |
238 | dev->bus = &balloon_subsys; | |
b6a473a7 | 239 | dev->groups = balloon_groups; |
803eb047 | 240 | |
07068021 | 241 | error = device_register(dev); |
803eb047 | 242 | if (error) { |
07068021 | 243 | bus_unregister(&balloon_subsys); |
803eb047 DDG |
244 | return error; |
245 | } | |
246 | ||
803eb047 | 247 | return 0; |
803eb047 | 248 | } |