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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35#include <linux/kernel.h>
36#include <linux/module.h>
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
50static struct device balloon_dev;
51
52static int register_balloon(struct device *dev);
53
54/* React to a change in the target key */
55static 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}
72static struct xenbus_watch target_watch = {
73 .node = "memory/target",
74 .callback = watch_target,
75};
76
77
78static 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)
86 pr_err("Failed to set balloon watcher\n");
87
88 return NOTIFY_DONE;
89}
90
91static struct notifier_block xenstore_notifier = {
92 .notifier_call = balloon_init_watcher,
93};
94
95static int __init balloon_init(void)
96{
97 if (!xen_domain())
98 return -ENODEV;
99
100 pr_info("Initialising balloon driver\n");
101
102 register_balloon(&balloon_dev);
103
104 register_xen_selfballooning(&balloon_dev);
105
106 register_xenstore_notifier(&xenstore_notifier);
107
108 return 0;
109}
110subsys_initcall(balloon_init);
111
112static void balloon_exit(void)
113{
114 /* XXX - release balloon here */
115 return;
116}
117
118module_exit(balloon_exit);
119
120#define BALLOON_SHOW(name, format, args...) \
121 static ssize_t show_##name(struct device *dev, \
122 struct device_attribute *attr, \
123 char *buf) \
124 { \
125 return sprintf(buf, format, ##args); \
126 } \
127 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
128
129BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
130BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
131BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
132
133static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
134static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
135static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
136static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
137
138static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
139 char *buf)
140{
141 return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
142}
143
144static ssize_t store_target_kb(struct device *dev,
145 struct device_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
162static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR,
163 show_target_kb, store_target_kb);
164
165
166static ssize_t show_target(struct device *dev, struct device_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
174static ssize_t store_target(struct device *dev,
175 struct device_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
192static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
193 show_target, store_target);
194
195
196static struct device_attribute *balloon_attrs[] = {
197 &dev_attr_target_kb,
198 &dev_attr_target,
199 &dev_attr_schedule_delay.attr,
200 &dev_attr_max_schedule_delay.attr,
201 &dev_attr_retry_count.attr,
202 &dev_attr_max_retry_count.attr
203};
204
205static struct attribute *balloon_info_attrs[] = {
206 &dev_attr_current_kb.attr,
207 &dev_attr_low_kb.attr,
208 &dev_attr_high_kb.attr,
209 NULL
210};
211
212static const struct attribute_group balloon_info_group = {
213 .name = "info",
214 .attrs = balloon_info_attrs
215};
216
217static struct bus_type balloon_subsys = {
218 .name = BALLOON_CLASS_NAME,
219 .dev_name = BALLOON_CLASS_NAME,
220};
221
222static int register_balloon(struct device *dev)
223{
224 int i, error;
225
226 error = subsys_system_register(&balloon_subsys, NULL);
227 if (error)
228 return error;
229
230 dev->id = 0;
231 dev->bus = &balloon_subsys;
232
233 error = device_register(dev);
234 if (error) {
235 bus_unregister(&balloon_subsys);
236 return error;
237 }
238
239 for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
240 error = device_create_file(dev, balloon_attrs[i]);
241 if (error)
242 goto fail;
243 }
244
245 error = sysfs_create_group(&dev->kobj, &balloon_info_group);
246 if (error)
247 goto fail;
248
249 return 0;
250
251 fail:
252 while (--i >= 0)
253 device_remove_file(dev, balloon_attrs[i]);
254 device_unregister(dev);
255 bus_unregister(&balloon_subsys);
256 return error;
257}
258
259MODULE_LICENSE("GPL");