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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35#include <linux/kernel.h>
36#include <linux/errno.h>
37#include <linux/mm_types.h>
38#include <linux/init.h>
39#include <linux/capability.h>
40#include <linux/memory_hotplug.h>
41
42#include <xen/xen.h>
43#include <xen/interface/xen.h>
44#include <xen/balloon.h>
45#include <xen/xenbus.h>
46#include <xen/features.h>
47#include <xen/page.h>
48#include <xen/mem-reservation.h>
49
50#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
51
52#define BALLOON_CLASS_NAME "xen_memory"
53
54#ifdef CONFIG_MEMORY_HOTPLUG
55u64 xen_saved_max_mem_size = 0;
56#endif
57
58static struct device balloon_dev;
59
60static int register_balloon(struct device *dev);
61
62/* React to a change in the target key */
63static void watch_target(struct xenbus_watch *watch,
64 const char *path, const char *token)
65{
66 unsigned long long new_target, static_max;
67 int err;
68 static bool watch_fired;
69 static long target_diff;
70
71#ifdef CONFIG_MEMORY_HOTPLUG
72 /* The balloon driver will take care of adding memory now. */
73 if (xen_saved_max_mem_size)
74 max_mem_size = xen_saved_max_mem_size;
75#endif
76
77 err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
78 if (err != 1) {
79 /* This is ok (for domain0 at least) - so just return */
80 return;
81 }
82
83 /* The given memory/target value is in KiB, so it needs converting to
84 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
85 */
86 new_target >>= PAGE_SHIFT - 10;
87
88 if (!watch_fired) {
89 watch_fired = true;
90
91 if ((xenbus_scanf(XBT_NIL, "memory", "static-max",
92 "%llu", &static_max) == 1) ||
93 (xenbus_scanf(XBT_NIL, "memory", "memory_static_max",
94 "%llu", &static_max) == 1))
95 static_max >>= PAGE_SHIFT - 10;
96 else
97 static_max = balloon_stats.current_pages;
98
99 target_diff = (xen_pv_domain() || xen_initial_domain()) ? 0
100 : static_max - balloon_stats.target_pages;
101 }
102
103 balloon_set_new_target(new_target - target_diff);
104}
105static struct xenbus_watch target_watch = {
106 .node = "memory/target",
107 .callback = watch_target,
108};
109
110
111static int balloon_init_watcher(struct notifier_block *notifier,
112 unsigned long event,
113 void *data)
114{
115 int err;
116
117 err = register_xenbus_watch(&target_watch);
118 if (err)
119 pr_err("Failed to set balloon watcher\n");
120
121 return NOTIFY_DONE;
122}
123
124static struct notifier_block xenstore_notifier = {
125 .notifier_call = balloon_init_watcher,
126};
127
128void xen_balloon_init(void)
129{
130 register_balloon(&balloon_dev);
131
132 register_xenstore_notifier(&xenstore_notifier);
133}
134EXPORT_SYMBOL_GPL(xen_balloon_init);
135
136#define BALLOON_SHOW(name, format, args...) \
137 static ssize_t name##_show(struct device *dev, \
138 struct device_attribute *attr, \
139 char *buf) \
140 { \
141 return sprintf(buf, format, ##args); \
142 } \
143 static DEVICE_ATTR_RO(name)
144
145BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
146BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
147BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
148
149static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
150static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
151static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
152static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
153static DEVICE_BOOL_ATTR(scrub_pages, 0644, xen_scrub_pages);
154
155static ssize_t target_kb_show(struct device *dev, struct device_attribute *attr,
156 char *buf)
157{
158 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
159}
160
161static ssize_t target_kb_store(struct device *dev,
162 struct device_attribute *attr,
163 const char *buf, size_t count)
164{
165 char *endchar;
166 unsigned long long target_bytes;
167
168 if (!capable(CAP_SYS_ADMIN))
169 return -EPERM;
170
171 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
172
173 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
174
175 return count;
176}
177
178static DEVICE_ATTR_RW(target_kb);
179
180static ssize_t target_show(struct device *dev, struct device_attribute *attr,
181 char *buf)
182{
183 return sprintf(buf, "%llu\n",
184 (unsigned long long)balloon_stats.target_pages
185 << PAGE_SHIFT);
186}
187
188static ssize_t target_store(struct device *dev,
189 struct device_attribute *attr,
190 const char *buf, size_t count)
191{
192 char *endchar;
193 unsigned long long target_bytes;
194
195 if (!capable(CAP_SYS_ADMIN))
196 return -EPERM;
197
198 target_bytes = memparse(buf, &endchar);
199
200 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
201
202 return count;
203}
204
205static DEVICE_ATTR_RW(target);
206
207static struct attribute *balloon_attrs[] = {
208 &dev_attr_target_kb.attr,
209 &dev_attr_target.attr,
210 &dev_attr_schedule_delay.attr.attr,
211 &dev_attr_max_schedule_delay.attr.attr,
212 &dev_attr_retry_count.attr.attr,
213 &dev_attr_max_retry_count.attr.attr,
214 &dev_attr_scrub_pages.attr.attr,
215 NULL
216};
217
218static const struct attribute_group balloon_group = {
219 .attrs = balloon_attrs
220};
221
222static struct attribute *balloon_info_attrs[] = {
223 &dev_attr_current_kb.attr,
224 &dev_attr_low_kb.attr,
225 &dev_attr_high_kb.attr,
226 NULL
227};
228
229static const struct attribute_group balloon_info_group = {
230 .name = "info",
231 .attrs = balloon_info_attrs
232};
233
234static const struct attribute_group *balloon_groups[] = {
235 &balloon_group,
236 &balloon_info_group,
237 NULL
238};
239
240static const struct bus_type balloon_subsys = {
241 .name = BALLOON_CLASS_NAME,
242 .dev_name = BALLOON_CLASS_NAME,
243};
244
245static int register_balloon(struct device *dev)
246{
247 int error;
248
249 error = subsys_system_register(&balloon_subsys, NULL);
250 if (error)
251 return error;
252
253 dev->id = 0;
254 dev->bus = &balloon_subsys;
255 dev->groups = balloon_groups;
256
257 error = device_register(dev);
258 if (error) {
259 bus_unregister(&balloon_subsys);
260 return error;
261 }
262
263 return 0;
264}
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/capability.h>
36
37#include <xen/xen.h>
38#include <xen/interface/xen.h>
39#include <xen/balloon.h>
40#include <xen/xenbus.h>
41#include <xen/features.h>
42#include <xen/page.h>
43
44#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
45
46#define BALLOON_CLASS_NAME "xen_memory"
47
48static struct device balloon_dev;
49
50static int register_balloon(struct device *dev);
51
52/* React to a change in the target key */
53static void watch_target(struct xenbus_watch *watch,
54 const char **vec, unsigned int len)
55{
56 unsigned long long new_target;
57 int err;
58
59 err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
60 if (err != 1) {
61 /* This is ok (for domain0 at least) - so just return */
62 return;
63 }
64
65 /* The given memory/target value is in KiB, so it needs converting to
66 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
67 */
68 balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
69}
70static struct xenbus_watch target_watch = {
71 .node = "memory/target",
72 .callback = watch_target,
73};
74
75
76static int balloon_init_watcher(struct notifier_block *notifier,
77 unsigned long event,
78 void *data)
79{
80 int err;
81
82 err = register_xenbus_watch(&target_watch);
83 if (err)
84 printk(KERN_ERR "Failed to set balloon watcher\n");
85
86 return NOTIFY_DONE;
87}
88
89static struct notifier_block xenstore_notifier = {
90 .notifier_call = balloon_init_watcher,
91};
92
93static int __init balloon_init(void)
94{
95 if (!xen_domain())
96 return -ENODEV;
97
98 pr_info("xen-balloon: Initialising balloon driver.\n");
99
100 register_balloon(&balloon_dev);
101
102 register_xen_selfballooning(&balloon_dev);
103
104 register_xenstore_notifier(&xenstore_notifier);
105
106 return 0;
107}
108subsys_initcall(balloon_init);
109
110static void balloon_exit(void)
111{
112 /* XXX - release balloon here */
113 return;
114}
115
116module_exit(balloon_exit);
117
118#define BALLOON_SHOW(name, format, args...) \
119 static ssize_t show_##name(struct device *dev, \
120 struct device_attribute *attr, \
121 char *buf) \
122 { \
123 return sprintf(buf, format, ##args); \
124 } \
125 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
126
127BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
128BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
129BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
130
131static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
132static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
133static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
134static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
135
136static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
137 char *buf)
138{
139 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
140}
141
142static ssize_t store_target_kb(struct device *dev,
143 struct device_attribute *attr,
144 const char *buf,
145 size_t count)
146{
147 char *endchar;
148 unsigned long long target_bytes;
149
150 if (!capable(CAP_SYS_ADMIN))
151 return -EPERM;
152
153 target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
154
155 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
156
157 return count;
158}
159
160static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
161 show_target_kb, store_target_kb);
162
163
164static ssize_t show_target(struct device *dev, struct device_attribute *attr,
165 char *buf)
166{
167 return sprintf(buf, "%llu\n",
168 (unsigned long long)balloon_stats.target_pages
169 << PAGE_SHIFT);
170}
171
172static ssize_t store_target(struct device *dev,
173 struct device_attribute *attr,
174 const char *buf,
175 size_t count)
176{
177 char *endchar;
178 unsigned long long target_bytes;
179
180 if (!capable(CAP_SYS_ADMIN))
181 return -EPERM;
182
183 target_bytes = memparse(buf, &endchar);
184
185 balloon_set_new_target(target_bytes >> PAGE_SHIFT);
186
187 return count;
188}
189
190static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
191 show_target, store_target);
192
193
194static struct device_attribute *balloon_attrs[] = {
195 &dev_attr_target_kb,
196 &dev_attr_target,
197 &dev_attr_schedule_delay.attr,
198 &dev_attr_max_schedule_delay.attr,
199 &dev_attr_retry_count.attr,
200 &dev_attr_max_retry_count.attr
201};
202
203static struct attribute *balloon_info_attrs[] = {
204 &dev_attr_current_kb.attr,
205 &dev_attr_low_kb.attr,
206 &dev_attr_high_kb.attr,
207 NULL
208};
209
210static const struct attribute_group balloon_info_group = {
211 .name = "info",
212 .attrs = balloon_info_attrs
213};
214
215static struct bus_type balloon_subsys = {
216 .name = BALLOON_CLASS_NAME,
217 .dev_name = BALLOON_CLASS_NAME,
218};
219
220static int register_balloon(struct device *dev)
221{
222 int i, error;
223
224 error = subsys_system_register(&balloon_subsys, NULL);
225 if (error)
226 return error;
227
228 dev->id = 0;
229 dev->bus = &balloon_subsys;
230
231 error = device_register(dev);
232 if (error) {
233 bus_unregister(&balloon_subsys);
234 return error;
235 }
236
237 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
238 error = device_create_file(dev, balloon_attrs[i]);
239 if (error)
240 goto fail;
241 }
242
243 error = sysfs_create_group(&dev->kobj, &balloon_info_group);
244 if (error)
245 goto fail;
246
247 return 0;
248
249 fail:
250 while (--i >= 0)
251 device_remove_file(dev, balloon_attrs[i]);
252 device_unregister(dev);
253 bus_unregister(&balloon_subsys);
254 return error;
255}
256
257MODULE_LICENSE("GPL");