blob: 586395cca5fe129b4e2ecd4706e395ee567f5adb [file] [log] [blame]
Sasha Levin1e214a52011-11-03 10:20:04 +02001/*
2 * Virtio balloon implementation, inspired by Dor Laor and Marcelo
Rusty Russell6b35e402008-02-04 23:50:12 -05003 * Tosatti's implementations.
4 *
5 * Copyright 2008 Rusty Russell IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 */
Sasha Levin1e214a52011-11-03 10:20:04 +020021
Rusty Russell6b35e402008-02-04 23:50:12 -050022#include <linux/virtio.h>
23#include <linux/virtio_balloon.h>
24#include <linux/swap.h>
25#include <linux/kthread.h>
26#include <linux/freezer.h>
Johann Felix Soden6659a0f2008-02-06 01:40:22 -080027#include <linux/delay.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090028#include <linux/slab.h>
Paul Gortmakerb5a2c4f2011-07-03 16:20:30 -040029#include <linux/module.h>
Rusty Russell6b35e402008-02-04 23:50:12 -050030
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +030031/*
32 * Balloon device works in 4K page units. So each page is pointed to by
33 * multiple balloon pages. All memory counters in this driver are in balloon
34 * page units.
35 */
36#define VIRTIO_BALLOON_PAGES_PER_PAGE (PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)
37
Rusty Russell6b35e402008-02-04 23:50:12 -050038struct virtio_balloon
39{
40 struct virtio_device *vdev;
Adam Litke9564e132009-11-30 10:14:15 -060041 struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
Rusty Russell6b35e402008-02-04 23:50:12 -050042
43 /* Where the ballooning thread waits for config to change. */
44 wait_queue_head_t config_change;
45
46 /* The thread servicing the balloon. */
47 struct task_struct *thread;
48
49 /* Waiting for host to ack the pages we released. */
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +030050 wait_queue_head_t acked;
Rusty Russell6b35e402008-02-04 23:50:12 -050051
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +030052 /* Number of balloon pages we've told the Host we're not using. */
Rusty Russell6b35e402008-02-04 23:50:12 -050053 unsigned int num_pages;
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +030054 /*
55 * The pages we've told the Host we're not using.
56 * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE
57 * to num_pages above.
58 */
Rusty Russell6b35e402008-02-04 23:50:12 -050059 struct list_head pages;
60
61 /* The array of pfns we tell the Host about. */
62 unsigned int num_pfns;
63 u32 pfns[256];
Adam Litke9564e132009-11-30 10:14:15 -060064
65 /* Memory statistics */
Adam Litke1f34c712009-12-10 16:35:15 -060066 int need_stats_update;
Adam Litke9564e132009-11-30 10:14:15 -060067 struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR];
Rusty Russell6b35e402008-02-04 23:50:12 -050068};
69
70static struct virtio_device_id id_table[] = {
71 { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID },
72 { 0 },
73};
74
Hollis Blanchard1b4aa2f2008-11-13 15:48:33 -060075static u32 page_to_balloon_pfn(struct page *page)
76{
77 unsigned long pfn = page_to_pfn(page);
78
79 BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT);
80 /* Convert pfn from Linux page size to balloon page size. */
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +030081 return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE;
82}
83
84static struct page *balloon_pfn_to_page(u32 pfn)
85{
86 BUG_ON(pfn % VIRTIO_BALLOON_PAGES_PER_PAGE);
87 return pfn_to_page(pfn / VIRTIO_BALLOON_PAGES_PER_PAGE);
Hollis Blanchard1b4aa2f2008-11-13 15:48:33 -060088}
89
Rusty Russell6b35e402008-02-04 23:50:12 -050090static void balloon_ack(struct virtqueue *vq)
91{
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +030092 struct virtio_balloon *vb = vq->vdev->priv;
Rusty Russell6b35e402008-02-04 23:50:12 -050093
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +030094 wake_up(&vb->acked);
Rusty Russell6b35e402008-02-04 23:50:12 -050095}
96
97static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
98{
99 struct scatterlist sg;
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300100 unsigned int len;
Rusty Russell6b35e402008-02-04 23:50:12 -0500101
102 sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
103
Rusty Russell6b35e402008-02-04 23:50:12 -0500104 /* We should always be able to add one buffer to an empty queue. */
Rusty Russellf96fde42012-01-12 15:44:42 +1030105 if (virtqueue_add_buf(vq, &sg, 1, 0, vb, GFP_KERNEL) < 0)
Rusty Russell6b35e402008-02-04 23:50:12 -0500106 BUG();
Michael S. Tsirkin946cfe02010-04-12 16:18:28 +0300107 virtqueue_kick(vq);
Rusty Russell6b35e402008-02-04 23:50:12 -0500108
109 /* When host has read buffer, this completes via balloon_ack */
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300110 wait_event(vb->acked, virtqueue_get_buf(vq, &len));
Rusty Russell6b35e402008-02-04 23:50:12 -0500111}
112
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300113static void set_page_pfns(u32 pfns[], struct page *page)
114{
115 unsigned int i;
116
117 /* Set balloon pfns pointing at this page.
118 * Note that the first pfn points at start of the page. */
119 for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++)
120 pfns[i] = page_to_balloon_pfn(page) + i;
121}
122
Rusty Russell6b35e402008-02-04 23:50:12 -0500123static void fill_balloon(struct virtio_balloon *vb, size_t num)
124{
125 /* We can only do one array worth at a time. */
126 num = min(num, ARRAY_SIZE(vb->pfns));
127
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300128 for (vb->num_pfns = 0; vb->num_pfns < num;
129 vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
Balbir Singh61fb06c2010-04-22 12:22:34 +0930130 struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
131 __GFP_NOMEMALLOC | __GFP_NOWARN);
Rusty Russell6b35e402008-02-04 23:50:12 -0500132 if (!page) {
Joe Perches800ba5e2012-10-31 09:27:22 +1030133 dev_info_ratelimited(&vb->vdev->dev,
134 "Out of puff! Can't get %zu pages\n",
135 num);
Rusty Russell6b35e402008-02-04 23:50:12 -0500136 /* Sleep for at least 1/5 of a second before retry. */
137 msleep(200);
138 break;
139 }
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300140 set_page_pfns(vb->pfns + vb->num_pfns, page);
141 vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
Rusty Russell6b35e402008-02-04 23:50:12 -0500142 totalram_pages--;
Rusty Russell6b35e402008-02-04 23:50:12 -0500143 list_add(&page->lru, &vb->pages);
144 }
145
146 /* Didn't get any? Oh well. */
147 if (vb->num_pfns == 0)
148 return;
149
150 tell_host(vb, vb->inflate_vq);
151}
152
153static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
154{
155 unsigned int i;
156
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300157 /* Find pfns pointing at start of each page, get pages and free them. */
158 for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
159 __free_page(balloon_pfn_to_page(pfns[i]));
Rusty Russell6b35e402008-02-04 23:50:12 -0500160 totalram_pages++;
161 }
162}
163
164static void leak_balloon(struct virtio_balloon *vb, size_t num)
165{
166 struct page *page;
167
168 /* We can only do one array worth at a time. */
169 num = min(num, ARRAY_SIZE(vb->pfns));
170
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300171 for (vb->num_pfns = 0; vb->num_pfns < num;
172 vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
Rusty Russell6b35e402008-02-04 23:50:12 -0500173 page = list_first_entry(&vb->pages, struct page, lru);
174 list_del(&page->lru);
Michael S. Tsirkin3ccc9372012-04-12 16:38:00 +0300175 set_page_pfns(vb->pfns + vb->num_pfns, page);
176 vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
Rusty Russell6b35e402008-02-04 23:50:12 -0500177 }
178
Dave Hansenbf50e692011-04-07 10:43:25 -0700179 /*
180 * Note that if
181 * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
182 * is true, we *have* to do it in this order
183 */
184 tell_host(vb, vb->deflate_vq);
185 release_pages_by_pfn(vb->pfns, vb->num_pfns);
Rusty Russell6b35e402008-02-04 23:50:12 -0500186}
187
Adam Litke9564e132009-11-30 10:14:15 -0600188static inline void update_stat(struct virtio_balloon *vb, int idx,
189 u16 tag, u64 val)
190{
191 BUG_ON(idx >= VIRTIO_BALLOON_S_NR);
192 vb->stats[idx].tag = tag;
193 vb->stats[idx].val = val;
194}
195
196#define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT)
197
198static void update_balloon_stats(struct virtio_balloon *vb)
199{
200 unsigned long events[NR_VM_EVENT_ITEMS];
201 struct sysinfo i;
202 int idx = 0;
203
204 all_vm_events(events);
205 si_meminfo(&i);
206
207 update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
208 pages_to_bytes(events[PSWPIN]));
209 update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
210 pages_to_bytes(events[PSWPOUT]));
211 update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
212 update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
213 update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
214 pages_to_bytes(i.freeram));
215 update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,
216 pages_to_bytes(i.totalram));
217}
218
219/*
220 * While most virtqueues communicate guest-initiated requests to the hypervisor,
221 * the stats queue operates in reverse. The driver initializes the virtqueue
222 * with a single buffer. From that point forward, all conversations consist of
223 * a hypervisor request (a call to this function) which directs us to refill
Adam Litke1f34c712009-12-10 16:35:15 -0600224 * the virtqueue with a fresh stats buffer. Since stats collection can sleep,
225 * we notify our kthread which does the actual work via stats_handle_request().
Adam Litke9564e132009-11-30 10:14:15 -0600226 */
Adam Litke1f34c712009-12-10 16:35:15 -0600227static void stats_request(struct virtqueue *vq)
Adam Litke9564e132009-11-30 10:14:15 -0600228{
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300229 struct virtio_balloon *vb = vq->vdev->priv;
Adam Litke9564e132009-11-30 10:14:15 -0600230
Adam Litke1f34c712009-12-10 16:35:15 -0600231 vb->need_stats_update = 1;
232 wake_up(&vb->config_change);
233}
Adam Litke9564e132009-11-30 10:14:15 -0600234
Adam Litke1f34c712009-12-10 16:35:15 -0600235static void stats_handle_request(struct virtio_balloon *vb)
236{
237 struct virtqueue *vq;
238 struct scatterlist sg;
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300239 unsigned int len;
Adam Litke1f34c712009-12-10 16:35:15 -0600240
241 vb->need_stats_update = 0;
Adam Litke9564e132009-11-30 10:14:15 -0600242 update_balloon_stats(vb);
243
Adam Litke1f34c712009-12-10 16:35:15 -0600244 vq = vb->stats_vq;
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300245 if (!virtqueue_get_buf(vq, &len))
246 return;
Adam Litke9564e132009-11-30 10:14:15 -0600247 sg_init_one(&sg, vb->stats, sizeof(vb->stats));
Rusty Russellf96fde42012-01-12 15:44:42 +1030248 if (virtqueue_add_buf(vq, &sg, 1, 0, vb, GFP_KERNEL) < 0)
Adam Litke9564e132009-11-30 10:14:15 -0600249 BUG();
Michael S. Tsirkin946cfe02010-04-12 16:18:28 +0300250 virtqueue_kick(vq);
Adam Litke9564e132009-11-30 10:14:15 -0600251}
252
Rusty Russell6b35e402008-02-04 23:50:12 -0500253static void virtballoon_changed(struct virtio_device *vdev)
254{
255 struct virtio_balloon *vb = vdev->priv;
256
257 wake_up(&vb->config_change);
258}
259
Rusty Russellbdc16812008-03-17 22:58:15 -0500260static inline s64 towards_target(struct virtio_balloon *vb)
Rusty Russell6b35e402008-02-04 23:50:12 -0500261{
David Gibson1a872282012-04-12 15:36:34 +1000262 __le32 v;
263 s64 target;
264
Rusty Russell72e61eb2008-05-02 21:50:49 -0500265 vb->vdev->config->get(vb->vdev,
266 offsetof(struct virtio_balloon_config, num_pages),
267 &v, sizeof(v));
David Gibson1a872282012-04-12 15:36:34 +1000268 target = le32_to_cpu(v);
269 return target - vb->num_pages;
Rusty Russell6b35e402008-02-04 23:50:12 -0500270}
271
272static void update_balloon_size(struct virtio_balloon *vb)
273{
274 __le32 actual = cpu_to_le32(vb->num_pages);
275
276 vb->vdev->config->set(vb->vdev,
277 offsetof(struct virtio_balloon_config, actual),
278 &actual, sizeof(actual));
279}
280
281static int balloon(void *_vballoon)
282{
283 struct virtio_balloon *vb = _vballoon;
284
285 set_freezable();
286 while (!kthread_should_stop()) {
Rusty Russellbdc16812008-03-17 22:58:15 -0500287 s64 diff;
Rusty Russell6b35e402008-02-04 23:50:12 -0500288
289 try_to_freeze();
290 wait_event_interruptible(vb->config_change,
291 (diff = towards_target(vb)) != 0
Adam Litke1f34c712009-12-10 16:35:15 -0600292 || vb->need_stats_update
Marcelo Tosatti84a139a2009-04-16 21:14:04 -0300293 || kthread_should_stop()
294 || freezing(current));
Adam Litke1f34c712009-12-10 16:35:15 -0600295 if (vb->need_stats_update)
296 stats_handle_request(vb);
Rusty Russell6b35e402008-02-04 23:50:12 -0500297 if (diff > 0)
298 fill_balloon(vb, diff);
299 else if (diff < 0)
300 leak_balloon(vb, -diff);
301 update_balloon_size(vb);
302 }
303 return 0;
304}
305
Amit Shahbe91c332011-12-22 16:58:34 +0530306static int init_vqs(struct virtio_balloon *vb)
Rusty Russell6b35e402008-02-04 23:50:12 -0500307{
Adam Litke9564e132009-11-30 10:14:15 -0600308 struct virtqueue *vqs[3];
Adam Litke1f34c712009-12-10 16:35:15 -0600309 vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request };
Adam Litke9564e132009-11-30 10:14:15 -0600310 const char *names[] = { "inflate", "deflate", "stats" };
311 int err, nvqs;
Rusty Russell6b35e402008-02-04 23:50:12 -0500312
Amit Shahbe91c332011-12-22 16:58:34 +0530313 /*
314 * We expect two virtqueues: inflate and deflate, and
315 * optionally stat.
316 */
Adam Litke9564e132009-11-30 10:14:15 -0600317 nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
Amit Shahbe91c332011-12-22 16:58:34 +0530318 err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names);
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600319 if (err)
Amit Shahbe91c332011-12-22 16:58:34 +0530320 return err;
Rusty Russell6b35e402008-02-04 23:50:12 -0500321
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600322 vb->inflate_vq = vqs[0];
323 vb->deflate_vq = vqs[1];
Adam Litke9564e132009-11-30 10:14:15 -0600324 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
325 struct scatterlist sg;
326 vb->stats_vq = vqs[2];
327
328 /*
329 * Prime this virtqueue with one buffer so the hypervisor can
330 * use it to signal us later.
331 */
332 sg_init_one(&sg, vb->stats, sizeof vb->stats);
Rusty Russellf96fde42012-01-12 15:44:42 +1030333 if (virtqueue_add_buf(vb->stats_vq, &sg, 1, 0, vb, GFP_KERNEL)
334 < 0)
Adam Litke9564e132009-11-30 10:14:15 -0600335 BUG();
Michael S. Tsirkin946cfe02010-04-12 16:18:28 +0300336 virtqueue_kick(vb->stats_vq);
Adam Litke9564e132009-11-30 10:14:15 -0600337 }
Amit Shahbe91c332011-12-22 16:58:34 +0530338 return 0;
339}
340
341static int virtballoon_probe(struct virtio_device *vdev)
342{
343 struct virtio_balloon *vb;
344 int err;
345
346 vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL);
347 if (!vb) {
348 err = -ENOMEM;
349 goto out;
350 }
351
352 INIT_LIST_HEAD(&vb->pages);
353 vb->num_pages = 0;
354 init_waitqueue_head(&vb->config_change);
Michael S. Tsirkin9c378ab2012-07-02 10:33:08 +0300355 init_waitqueue_head(&vb->acked);
Amit Shahbe91c332011-12-22 16:58:34 +0530356 vb->vdev = vdev;
357 vb->need_stats_update = 0;
358
359 err = init_vqs(vb);
360 if (err)
361 goto out_free_vb;
Rusty Russell6b35e402008-02-04 23:50:12 -0500362
363 vb->thread = kthread_run(balloon, vb, "vballoon");
364 if (IS_ERR(vb->thread)) {
365 err = PTR_ERR(vb->thread);
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600366 goto out_del_vqs;
Rusty Russell6b35e402008-02-04 23:50:12 -0500367 }
368
Rusty Russell6b35e402008-02-04 23:50:12 -0500369 return 0;
370
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600371out_del_vqs:
372 vdev->config->del_vqs(vdev);
Rusty Russell6b35e402008-02-04 23:50:12 -0500373out_free_vb:
374 kfree(vb);
375out:
376 return err;
377}
378
Amit Shahc877bab2012-04-27 00:45:57 +0530379static void remove_common(struct virtio_balloon *vb)
Rusty Russell6b35e402008-02-04 23:50:12 -0500380{
Rusty Russell6b35e402008-02-04 23:50:12 -0500381 /* There might be pages left in the balloon: free them. */
382 while (vb->num_pages)
383 leak_balloon(vb, vb->num_pages);
Amit Shahb8ae0eb2012-04-27 00:45:56 +0530384 update_balloon_size(vb);
Rusty Russell6b35e402008-02-04 23:50:12 -0500385
386 /* Now we reset the device so we can clean up the queues. */
Amit Shahc877bab2012-04-27 00:45:57 +0530387 vb->vdev->config->reset(vb->vdev);
Rusty Russell6b35e402008-02-04 23:50:12 -0500388
Amit Shahc877bab2012-04-27 00:45:57 +0530389 vb->vdev->config->del_vqs(vb->vdev);
390}
391
392static void __devexit virtballoon_remove(struct virtio_device *vdev)
393{
394 struct virtio_balloon *vb = vdev->priv;
395
396 kthread_stop(vb->thread);
397 remove_common(vb);
Rusty Russell6b35e402008-02-04 23:50:12 -0500398 kfree(vb);
399}
400
Amit Shahe5629662011-12-22 16:58:35 +0530401#ifdef CONFIG_PM
402static int virtballoon_freeze(struct virtio_device *vdev)
403{
Amit Shah4eb05d52012-02-29 17:42:51 +0530404 struct virtio_balloon *vb = vdev->priv;
405
Amit Shahe5629662011-12-22 16:58:35 +0530406 /*
407 * The kthread is already frozen by the PM core before this
408 * function is called.
409 */
410
Amit Shahc877bab2012-04-27 00:45:57 +0530411 remove_common(vb);
Amit Shahe5629662011-12-22 16:58:35 +0530412 return 0;
413}
414
Amit Shahc45b4162012-04-27 00:45:55 +0530415static int virtballoon_restore(struct virtio_device *vdev)
Amit Shah4eb05d52012-02-29 17:42:51 +0530416{
417 struct virtio_balloon *vb = vdev->priv;
418 int ret;
419
420 ret = init_vqs(vdev->priv);
421 if (ret)
422 return ret;
423
424 fill_balloon(vb, towards_target(vb));
425 update_balloon_size(vb);
426 return 0;
427}
Amit Shahe5629662011-12-22 16:58:35 +0530428#endif
429
Adam Litke9564e132009-11-30 10:14:15 -0600430static unsigned int features[] = {
431 VIRTIO_BALLOON_F_MUST_TELL_HOST,
432 VIRTIO_BALLOON_F_STATS_VQ,
433};
Rusty Russellc45a6812008-05-02 21:50:50 -0500434
Jeff Mahoneyd817cd52010-01-15 17:01:26 -0800435static struct virtio_driver virtio_balloon_driver = {
Rusty Russellc45a6812008-05-02 21:50:50 -0500436 .feature_table = features,
437 .feature_table_size = ARRAY_SIZE(features),
Rusty Russell6b35e402008-02-04 23:50:12 -0500438 .driver.name = KBUILD_MODNAME,
439 .driver.owner = THIS_MODULE,
440 .id_table = id_table,
441 .probe = virtballoon_probe,
442 .remove = __devexit_p(virtballoon_remove),
443 .config_changed = virtballoon_changed,
Amit Shahe5629662011-12-22 16:58:35 +0530444#ifdef CONFIG_PM
445 .freeze = virtballoon_freeze,
446 .restore = virtballoon_restore,
Amit Shahe5629662011-12-22 16:58:35 +0530447#endif
Rusty Russell6b35e402008-02-04 23:50:12 -0500448};
449
450static int __init init(void)
451{
Jeff Mahoneyd817cd52010-01-15 17:01:26 -0800452 return register_virtio_driver(&virtio_balloon_driver);
Rusty Russell6b35e402008-02-04 23:50:12 -0500453}
454
455static void __exit fini(void)
456{
Jeff Mahoneyd817cd52010-01-15 17:01:26 -0800457 unregister_virtio_driver(&virtio_balloon_driver);
Rusty Russell6b35e402008-02-04 23:50:12 -0500458}
459module_init(init);
460module_exit(fini);
461
462MODULE_DEVICE_TABLE(virtio, id_table);
463MODULE_DESCRIPTION("Virtio balloon driver");
464MODULE_LICENSE("GPL");