Commit | Line | Data |
---|---|---|
1e214a5c SL |
1 | /* |
2 | * Virtio balloon implementation, inspired by Dor Laor and Marcelo | |
6b35e407 RR |
3 | * 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 | */ | |
1e214a5c | 21 | |
6b35e407 RR |
22 | #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> | |
6659a0f0 | 27 | #include <linux/delay.h> |
5a0e3ad6 | 28 | #include <linux/slab.h> |
b5a2c4f1 | 29 | #include <linux/module.h> |
e2250429 | 30 | #include <linux/balloon_compaction.h> |
6b35e407 | 31 | |
3ccc9372 MT |
32 | /* |
33 | * Balloon device works in 4K page units. So each page is pointed to by | |
34 | * multiple balloon pages. All memory counters in this driver are in balloon | |
35 | * page units. | |
36 | */ | |
e2250429 RA |
37 | #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) |
38 | #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 | |
3ccc9372 | 39 | |
6b35e407 RR |
40 | struct virtio_balloon |
41 | { | |
42 | struct virtio_device *vdev; | |
9564e138 | 43 | struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; |
6b35e407 RR |
44 | |
45 | /* Where the ballooning thread waits for config to change. */ | |
46 | wait_queue_head_t config_change; | |
47 | ||
48 | /* The thread servicing the balloon. */ | |
49 | struct task_struct *thread; | |
50 | ||
51 | /* Waiting for host to ack the pages we released. */ | |
9c378abc | 52 | wait_queue_head_t acked; |
6b35e407 | 53 | |
3ccc9372 | 54 | /* Number of balloon pages we've told the Host we're not using. */ |
6b35e407 | 55 | unsigned int num_pages; |
3ccc9372 | 56 | /* |
e2250429 RA |
57 | * The pages we've told the Host we're not using are enqueued |
58 | * at vb_dev_info->pages list. | |
3ccc9372 MT |
59 | * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE |
60 | * to num_pages above. | |
61 | */ | |
e2250429 RA |
62 | struct balloon_dev_info *vb_dev_info; |
63 | ||
64 | /* Synchronize access/update to this struct virtio_balloon elements */ | |
65 | struct mutex balloon_lock; | |
6b35e407 RR |
66 | |
67 | /* The array of pfns we tell the Host about. */ | |
68 | unsigned int num_pfns; | |
e2250429 | 69 | u32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; |
9564e138 AL |
70 | |
71 | /* Memory statistics */ | |
1f34c71a | 72 | int need_stats_update; |
9564e138 | 73 | struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; |
6b35e407 RR |
74 | }; |
75 | ||
76 | static struct virtio_device_id id_table[] = { | |
77 | { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID }, | |
78 | { 0 }, | |
79 | }; | |
80 | ||
1b4aa2fa HB |
81 | static u32 page_to_balloon_pfn(struct page *page) |
82 | { | |
83 | unsigned long pfn = page_to_pfn(page); | |
84 | ||
85 | BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); | |
86 | /* Convert pfn from Linux page size to balloon page size. */ | |
3ccc9372 MT |
87 | return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; |
88 | } | |
89 | ||
90 | static struct page *balloon_pfn_to_page(u32 pfn) | |
91 | { | |
92 | BUG_ON(pfn % VIRTIO_BALLOON_PAGES_PER_PAGE); | |
93 | return pfn_to_page(pfn / VIRTIO_BALLOON_PAGES_PER_PAGE); | |
1b4aa2fa HB |
94 | } |
95 | ||
6b35e407 RR |
96 | static void balloon_ack(struct virtqueue *vq) |
97 | { | |
9c378abc | 98 | struct virtio_balloon *vb = vq->vdev->priv; |
6b35e407 | 99 | |
9c378abc | 100 | wake_up(&vb->acked); |
6b35e407 RR |
101 | } |
102 | ||
103 | static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) | |
104 | { | |
105 | struct scatterlist sg; | |
9c378abc | 106 | unsigned int len; |
6b35e407 RR |
107 | |
108 | sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); | |
109 | ||
6b35e407 | 110 | /* We should always be able to add one buffer to an empty queue. */ |
92549abc | 111 | if (virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL) < 0) |
6b35e407 | 112 | BUG(); |
946cfe0e | 113 | virtqueue_kick(vq); |
6b35e407 RR |
114 | |
115 | /* When host has read buffer, this completes via balloon_ack */ | |
9c378abc | 116 | wait_event(vb->acked, virtqueue_get_buf(vq, &len)); |
6b35e407 RR |
117 | } |
118 | ||
3ccc9372 MT |
119 | static void set_page_pfns(u32 pfns[], struct page *page) |
120 | { | |
121 | unsigned int i; | |
122 | ||
123 | /* Set balloon pfns pointing at this page. | |
124 | * Note that the first pfn points at start of the page. */ | |
125 | for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++) | |
126 | pfns[i] = page_to_balloon_pfn(page) + i; | |
127 | } | |
128 | ||
6b35e407 RR |
129 | static void fill_balloon(struct virtio_balloon *vb, size_t num) |
130 | { | |
e2250429 RA |
131 | struct balloon_dev_info *vb_dev_info = vb->vb_dev_info; |
132 | ||
6b35e407 RR |
133 | /* We can only do one array worth at a time. */ |
134 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
135 | ||
e2250429 | 136 | mutex_lock(&vb->balloon_lock); |
3ccc9372 MT |
137 | for (vb->num_pfns = 0; vb->num_pfns < num; |
138 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
139 | struct page *page = balloon_page_enqueue(vb_dev_info); |
140 | ||
6b35e407 | 141 | if (!page) { |
800ba5ea | 142 | dev_info_ratelimited(&vb->vdev->dev, |
b7dfde95 LT |
143 | "Out of puff! Can't get %u pages\n", |
144 | VIRTIO_BALLOON_PAGES_PER_PAGE); | |
6b35e407 RR |
145 | /* Sleep for at least 1/5 of a second before retry. */ |
146 | msleep(200); | |
147 | break; | |
148 | } | |
3ccc9372 MT |
149 | set_page_pfns(vb->pfns + vb->num_pfns, page); |
150 | vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; | |
3dcc0571 | 151 | adjust_managed_page_count(page, -1); |
6b35e407 RR |
152 | } |
153 | ||
e2250429 RA |
154 | /* Did we get any? */ |
155 | if (vb->num_pfns != 0) | |
156 | tell_host(vb, vb->inflate_vq); | |
157 | mutex_unlock(&vb->balloon_lock); | |
6b35e407 RR |
158 | } |
159 | ||
160 | static void release_pages_by_pfn(const u32 pfns[], unsigned int num) | |
161 | { | |
162 | unsigned int i; | |
163 | ||
3ccc9372 MT |
164 | /* Find pfns pointing at start of each page, get pages and free them. */ |
165 | for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
3dcc0571 JL |
166 | struct page *page = balloon_pfn_to_page(pfns[i]); |
167 | balloon_page_free(page); | |
168 | adjust_managed_page_count(page, 1); | |
6b35e407 RR |
169 | } |
170 | } | |
171 | ||
172 | static void leak_balloon(struct virtio_balloon *vb, size_t num) | |
173 | { | |
174 | struct page *page; | |
e2250429 | 175 | struct balloon_dev_info *vb_dev_info = vb->vb_dev_info; |
6b35e407 RR |
176 | |
177 | /* We can only do one array worth at a time. */ | |
178 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
179 | ||
e2250429 | 180 | mutex_lock(&vb->balloon_lock); |
3ccc9372 MT |
181 | for (vb->num_pfns = 0; vb->num_pfns < num; |
182 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
183 | page = balloon_page_dequeue(vb_dev_info); |
184 | if (!page) | |
185 | break; | |
3ccc9372 MT |
186 | set_page_pfns(vb->pfns + vb->num_pfns, page); |
187 | vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; | |
6b35e407 RR |
188 | } |
189 | ||
bf50e69f DH |
190 | /* |
191 | * Note that if | |
192 | * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); | |
193 | * is true, we *have* to do it in this order | |
194 | */ | |
8c6bab4f LC |
195 | if (vb->num_pfns != 0) |
196 | tell_host(vb, vb->deflate_vq); | |
e2250429 | 197 | mutex_unlock(&vb->balloon_lock); |
bf50e69f | 198 | release_pages_by_pfn(vb->pfns, vb->num_pfns); |
6b35e407 RR |
199 | } |
200 | ||
9564e138 AL |
201 | static inline void update_stat(struct virtio_balloon *vb, int idx, |
202 | u16 tag, u64 val) | |
203 | { | |
204 | BUG_ON(idx >= VIRTIO_BALLOON_S_NR); | |
205 | vb->stats[idx].tag = tag; | |
206 | vb->stats[idx].val = val; | |
207 | } | |
208 | ||
209 | #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) | |
210 | ||
211 | static void update_balloon_stats(struct virtio_balloon *vb) | |
212 | { | |
213 | unsigned long events[NR_VM_EVENT_ITEMS]; | |
214 | struct sysinfo i; | |
215 | int idx = 0; | |
216 | ||
217 | all_vm_events(events); | |
218 | si_meminfo(&i); | |
219 | ||
220 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, | |
221 | pages_to_bytes(events[PSWPIN])); | |
222 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, | |
223 | pages_to_bytes(events[PSWPOUT])); | |
224 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); | |
225 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); | |
226 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, | |
227 | pages_to_bytes(i.freeram)); | |
228 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, | |
229 | pages_to_bytes(i.totalram)); | |
230 | } | |
231 | ||
232 | /* | |
233 | * While most virtqueues communicate guest-initiated requests to the hypervisor, | |
234 | * the stats queue operates in reverse. The driver initializes the virtqueue | |
235 | * with a single buffer. From that point forward, all conversations consist of | |
236 | * a hypervisor request (a call to this function) which directs us to refill | |
1f34c71a AL |
237 | * the virtqueue with a fresh stats buffer. Since stats collection can sleep, |
238 | * we notify our kthread which does the actual work via stats_handle_request(). | |
9564e138 | 239 | */ |
1f34c71a | 240 | static void stats_request(struct virtqueue *vq) |
9564e138 | 241 | { |
9c378abc | 242 | struct virtio_balloon *vb = vq->vdev->priv; |
9564e138 | 243 | |
1f34c71a AL |
244 | vb->need_stats_update = 1; |
245 | wake_up(&vb->config_change); | |
246 | } | |
247 | ||
248 | static void stats_handle_request(struct virtio_balloon *vb) | |
249 | { | |
250 | struct virtqueue *vq; | |
251 | struct scatterlist sg; | |
9c378abc | 252 | unsigned int len; |
9564e138 | 253 | |
1f34c71a | 254 | vb->need_stats_update = 0; |
9564e138 AL |
255 | update_balloon_stats(vb); |
256 | ||
1f34c71a | 257 | vq = vb->stats_vq; |
9c378abc MT |
258 | if (!virtqueue_get_buf(vq, &len)) |
259 | return; | |
9564e138 | 260 | sg_init_one(&sg, vb->stats, sizeof(vb->stats)); |
92549abc | 261 | if (virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL) < 0) |
9564e138 | 262 | BUG(); |
946cfe0e | 263 | virtqueue_kick(vq); |
9564e138 AL |
264 | } |
265 | ||
6b35e407 RR |
266 | static void virtballoon_changed(struct virtio_device *vdev) |
267 | { | |
268 | struct virtio_balloon *vb = vdev->priv; | |
269 | ||
270 | wake_up(&vb->config_change); | |
271 | } | |
272 | ||
bdc1681c | 273 | static inline s64 towards_target(struct virtio_balloon *vb) |
6b35e407 | 274 | { |
1a87228f DG |
275 | __le32 v; |
276 | s64 target; | |
277 | ||
72e61eb4 RR |
278 | vb->vdev->config->get(vb->vdev, |
279 | offsetof(struct virtio_balloon_config, num_pages), | |
280 | &v, sizeof(v)); | |
1a87228f DG |
281 | target = le32_to_cpu(v); |
282 | return target - vb->num_pages; | |
6b35e407 RR |
283 | } |
284 | ||
285 | static void update_balloon_size(struct virtio_balloon *vb) | |
286 | { | |
287 | __le32 actual = cpu_to_le32(vb->num_pages); | |
288 | ||
289 | vb->vdev->config->set(vb->vdev, | |
290 | offsetof(struct virtio_balloon_config, actual), | |
291 | &actual, sizeof(actual)); | |
292 | } | |
293 | ||
294 | static int balloon(void *_vballoon) | |
295 | { | |
296 | struct virtio_balloon *vb = _vballoon; | |
297 | ||
298 | set_freezable(); | |
299 | while (!kthread_should_stop()) { | |
bdc1681c | 300 | s64 diff; |
6b35e407 RR |
301 | |
302 | try_to_freeze(); | |
303 | wait_event_interruptible(vb->config_change, | |
304 | (diff = towards_target(vb)) != 0 | |
1f34c71a | 305 | || vb->need_stats_update |
84a139a9 MT |
306 | || kthread_should_stop() |
307 | || freezing(current)); | |
1f34c71a AL |
308 | if (vb->need_stats_update) |
309 | stats_handle_request(vb); | |
6b35e407 RR |
310 | if (diff > 0) |
311 | fill_balloon(vb, diff); | |
312 | else if (diff < 0) | |
313 | leak_balloon(vb, -diff); | |
314 | update_balloon_size(vb); | |
315 | } | |
316 | return 0; | |
317 | } | |
318 | ||
be91c33d | 319 | static int init_vqs(struct virtio_balloon *vb) |
6b35e407 | 320 | { |
9564e138 | 321 | struct virtqueue *vqs[3]; |
1f34c71a | 322 | vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; |
9564e138 AL |
323 | const char *names[] = { "inflate", "deflate", "stats" }; |
324 | int err, nvqs; | |
6b35e407 | 325 | |
be91c33d AS |
326 | /* |
327 | * We expect two virtqueues: inflate and deflate, and | |
328 | * optionally stat. | |
329 | */ | |
9564e138 | 330 | nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; |
be91c33d | 331 | err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names); |
d2a7ddda | 332 | if (err) |
be91c33d | 333 | return err; |
6b35e407 | 334 | |
d2a7ddda MT |
335 | vb->inflate_vq = vqs[0]; |
336 | vb->deflate_vq = vqs[1]; | |
9564e138 AL |
337 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { |
338 | struct scatterlist sg; | |
339 | vb->stats_vq = vqs[2]; | |
340 | ||
341 | /* | |
342 | * Prime this virtqueue with one buffer so the hypervisor can | |
343 | * use it to signal us later. | |
344 | */ | |
345 | sg_init_one(&sg, vb->stats, sizeof vb->stats); | |
92549abc | 346 | if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL) |
f96fde41 | 347 | < 0) |
9564e138 | 348 | BUG(); |
946cfe0e | 349 | virtqueue_kick(vb->stats_vq); |
9564e138 | 350 | } |
be91c33d AS |
351 | return 0; |
352 | } | |
353 | ||
e2250429 RA |
354 | static const struct address_space_operations virtio_balloon_aops; |
355 | #ifdef CONFIG_BALLOON_COMPACTION | |
356 | /* | |
357 | * virtballoon_migratepage - perform the balloon page migration on behalf of | |
358 | * a compation thread. (called under page lock) | |
359 | * @mapping: the page->mapping which will be assigned to the new migrated page. | |
360 | * @newpage: page that will replace the isolated page after migration finishes. | |
361 | * @page : the isolated (old) page that is about to be migrated to newpage. | |
362 | * @mode : compaction mode -- not used for balloon page migration. | |
363 | * | |
364 | * After a ballooned page gets isolated by compaction procedures, this is the | |
365 | * function that performs the page migration on behalf of a compaction thread | |
366 | * The page migration for virtio balloon is done in a simple swap fashion which | |
367 | * follows these two macro steps: | |
368 | * 1) insert newpage into vb->pages list and update the host about it; | |
369 | * 2) update the host about the old page removed from vb->pages list; | |
370 | * | |
371 | * This function preforms the balloon page migration task. | |
372 | * Called through balloon_mapping->a_ops->migratepage | |
373 | */ | |
374 | int virtballoon_migratepage(struct address_space *mapping, | |
375 | struct page *newpage, struct page *page, enum migrate_mode mode) | |
376 | { | |
377 | struct balloon_dev_info *vb_dev_info = balloon_page_device(page); | |
378 | struct virtio_balloon *vb; | |
379 | unsigned long flags; | |
380 | ||
381 | BUG_ON(!vb_dev_info); | |
382 | ||
383 | vb = vb_dev_info->balloon_device; | |
384 | ||
385 | /* | |
386 | * In order to avoid lock contention while migrating pages concurrently | |
387 | * to leak_balloon() or fill_balloon() we just give up the balloon_lock | |
388 | * this turn, as it is easier to retry the page migration later. | |
389 | * This also prevents fill_balloon() getting stuck into a mutex | |
390 | * recursion in the case it ends up triggering memory compaction | |
391 | * while it is attempting to inflate the ballon. | |
392 | */ | |
393 | if (!mutex_trylock(&vb->balloon_lock)) | |
394 | return -EAGAIN; | |
395 | ||
396 | /* balloon's page migration 1st step -- inflate "newpage" */ | |
397 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); | |
398 | balloon_page_insert(newpage, mapping, &vb_dev_info->pages); | |
399 | vb_dev_info->isolated_pages--; | |
400 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); | |
401 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
402 | set_page_pfns(vb->pfns, newpage); | |
403 | tell_host(vb, vb->inflate_vq); | |
404 | ||
405 | /* | |
406 | * balloon's page migration 2nd step -- deflate "page" | |
407 | * | |
408 | * It's safe to delete page->lru here because this page is at | |
409 | * an isolated migration list, and this step is expected to happen here | |
410 | */ | |
411 | balloon_page_delete(page); | |
412 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
413 | set_page_pfns(vb->pfns, page); | |
414 | tell_host(vb, vb->deflate_vq); | |
415 | ||
416 | mutex_unlock(&vb->balloon_lock); | |
417 | ||
418 | return MIGRATEPAGE_BALLOON_SUCCESS; | |
419 | } | |
420 | ||
421 | /* define the balloon_mapping->a_ops callback to allow balloon page migration */ | |
422 | static const struct address_space_operations virtio_balloon_aops = { | |
423 | .migratepage = virtballoon_migratepage, | |
424 | }; | |
425 | #endif /* CONFIG_BALLOON_COMPACTION */ | |
426 | ||
be91c33d AS |
427 | static int virtballoon_probe(struct virtio_device *vdev) |
428 | { | |
429 | struct virtio_balloon *vb; | |
e2250429 RA |
430 | struct address_space *vb_mapping; |
431 | struct balloon_dev_info *vb_devinfo; | |
be91c33d AS |
432 | int err; |
433 | ||
434 | vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL); | |
435 | if (!vb) { | |
436 | err = -ENOMEM; | |
437 | goto out; | |
438 | } | |
439 | ||
be91c33d | 440 | vb->num_pages = 0; |
e2250429 | 441 | mutex_init(&vb->balloon_lock); |
be91c33d | 442 | init_waitqueue_head(&vb->config_change); |
9c378abc | 443 | init_waitqueue_head(&vb->acked); |
be91c33d AS |
444 | vb->vdev = vdev; |
445 | vb->need_stats_update = 0; | |
446 | ||
e2250429 RA |
447 | vb_devinfo = balloon_devinfo_alloc(vb); |
448 | if (IS_ERR(vb_devinfo)) { | |
449 | err = PTR_ERR(vb_devinfo); | |
450 | goto out_free_vb; | |
451 | } | |
452 | ||
453 | vb_mapping = balloon_mapping_alloc(vb_devinfo, | |
454 | (balloon_compaction_check()) ? | |
455 | &virtio_balloon_aops : NULL); | |
456 | if (IS_ERR(vb_mapping)) { | |
457 | /* | |
458 | * IS_ERR(vb_mapping) && PTR_ERR(vb_mapping) == -EOPNOTSUPP | |
459 | * This means !CONFIG_BALLOON_COMPACTION, otherwise we get off. | |
460 | */ | |
461 | err = PTR_ERR(vb_mapping); | |
462 | if (err != -EOPNOTSUPP) | |
463 | goto out_free_vb_devinfo; | |
464 | } | |
465 | ||
466 | vb->vb_dev_info = vb_devinfo; | |
467 | ||
be91c33d AS |
468 | err = init_vqs(vb); |
469 | if (err) | |
e2250429 | 470 | goto out_free_vb_mapping; |
6b35e407 RR |
471 | |
472 | vb->thread = kthread_run(balloon, vb, "vballoon"); | |
473 | if (IS_ERR(vb->thread)) { | |
474 | err = PTR_ERR(vb->thread); | |
d2a7ddda | 475 | goto out_del_vqs; |
6b35e407 RR |
476 | } |
477 | ||
6b35e407 RR |
478 | return 0; |
479 | ||
d2a7ddda MT |
480 | out_del_vqs: |
481 | vdev->config->del_vqs(vdev); | |
e2250429 RA |
482 | out_free_vb_mapping: |
483 | balloon_mapping_free(vb_mapping); | |
484 | out_free_vb_devinfo: | |
485 | balloon_devinfo_free(vb_devinfo); | |
6b35e407 RR |
486 | out_free_vb: |
487 | kfree(vb); | |
488 | out: | |
489 | return err; | |
490 | } | |
491 | ||
c877bab5 | 492 | static void remove_common(struct virtio_balloon *vb) |
6b35e407 | 493 | { |
6b35e407 RR |
494 | /* There might be pages left in the balloon: free them. */ |
495 | while (vb->num_pages) | |
496 | leak_balloon(vb, vb->num_pages); | |
b8ae0eb3 | 497 | update_balloon_size(vb); |
6b35e407 RR |
498 | |
499 | /* Now we reset the device so we can clean up the queues. */ | |
c877bab5 | 500 | vb->vdev->config->reset(vb->vdev); |
6b35e407 | 501 | |
c877bab5 AS |
502 | vb->vdev->config->del_vqs(vb->vdev); |
503 | } | |
504 | ||
8590dbc7 | 505 | static void virtballoon_remove(struct virtio_device *vdev) |
c877bab5 AS |
506 | { |
507 | struct virtio_balloon *vb = vdev->priv; | |
508 | ||
509 | kthread_stop(vb->thread); | |
510 | remove_common(vb); | |
e2250429 RA |
511 | balloon_mapping_free(vb->vb_dev_info->mapping); |
512 | balloon_devinfo_free(vb->vb_dev_info); | |
6b35e407 RR |
513 | kfree(vb); |
514 | } | |
515 | ||
e562966d AS |
516 | #ifdef CONFIG_PM |
517 | static int virtballoon_freeze(struct virtio_device *vdev) | |
518 | { | |
4eb05d56 AS |
519 | struct virtio_balloon *vb = vdev->priv; |
520 | ||
e562966d AS |
521 | /* |
522 | * The kthread is already frozen by the PM core before this | |
523 | * function is called. | |
524 | */ | |
525 | ||
c877bab5 | 526 | remove_common(vb); |
e562966d AS |
527 | return 0; |
528 | } | |
529 | ||
c45b4166 | 530 | static int virtballoon_restore(struct virtio_device *vdev) |
4eb05d56 AS |
531 | { |
532 | struct virtio_balloon *vb = vdev->priv; | |
533 | int ret; | |
534 | ||
535 | ret = init_vqs(vdev->priv); | |
536 | if (ret) | |
537 | return ret; | |
538 | ||
539 | fill_balloon(vb, towards_target(vb)); | |
540 | update_balloon_size(vb); | |
541 | return 0; | |
542 | } | |
e562966d AS |
543 | #endif |
544 | ||
9564e138 AL |
545 | static unsigned int features[] = { |
546 | VIRTIO_BALLOON_F_MUST_TELL_HOST, | |
547 | VIRTIO_BALLOON_F_STATS_VQ, | |
548 | }; | |
c45a6816 | 549 | |
d817cd52 | 550 | static struct virtio_driver virtio_balloon_driver = { |
c45a6816 RR |
551 | .feature_table = features, |
552 | .feature_table_size = ARRAY_SIZE(features), | |
6b35e407 RR |
553 | .driver.name = KBUILD_MODNAME, |
554 | .driver.owner = THIS_MODULE, | |
555 | .id_table = id_table, | |
556 | .probe = virtballoon_probe, | |
8590dbc7 | 557 | .remove = virtballoon_remove, |
6b35e407 | 558 | .config_changed = virtballoon_changed, |
e562966d AS |
559 | #ifdef CONFIG_PM |
560 | .freeze = virtballoon_freeze, | |
561 | .restore = virtballoon_restore, | |
e562966d | 562 | #endif |
6b35e407 RR |
563 | }; |
564 | ||
b2a17029 | 565 | module_virtio_driver(virtio_balloon_driver); |
6b35e407 RR |
566 | MODULE_DEVICE_TABLE(virtio, id_table); |
567 | MODULE_DESCRIPTION("Virtio balloon driver"); | |
568 | MODULE_LICENSE("GPL"); |