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