1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Virtio balloon implementation, inspired by Dor Laor and Marcelo 4 * Tosatti's implementations. 5 * 6 * Copyright 2008 Rusty Russell IBM Corporation 7 */ 8 9 #include <linux/virtio.h> 10 #include <linux/virtio_balloon.h> 11 #include <linux/swap.h> 12 #include <linux/workqueue.h> 13 #include <linux/delay.h> 14 #include <linux/slab.h> 15 #include <linux/module.h> 16 #include <linux/balloon_compaction.h> 17 #include <linux/oom.h> 18 #include <linux/wait.h> 19 #include <linux/mm.h> 20 #include <linux/page_reporting.h> 21 22 /* 23 * Balloon device works in 4K page units. So each page is pointed to by 24 * multiple balloon pages. All memory counters in this driver are in balloon 25 * page units. 26 */ 27 #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned int)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) 28 #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 29 /* Maximum number of (4k) pages to deflate on OOM notifications. */ 30 #define VIRTIO_BALLOON_OOM_NR_PAGES 256 31 #define VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY 80 32 33 #define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \ 34 __GFP_NOMEMALLOC) 35 /* The order of free page blocks to report to host */ 36 #define VIRTIO_BALLOON_HINT_BLOCK_ORDER MAX_PAGE_ORDER 37 /* The size of a free page block in bytes */ 38 #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \ 39 (1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT)) 40 #define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER) 41 42 enum virtio_balloon_vq { 43 VIRTIO_BALLOON_VQ_INFLATE, 44 VIRTIO_BALLOON_VQ_DEFLATE, 45 VIRTIO_BALLOON_VQ_STATS, 46 VIRTIO_BALLOON_VQ_FREE_PAGE, 47 VIRTIO_BALLOON_VQ_REPORTING, 48 VIRTIO_BALLOON_VQ_MAX 49 }; 50 51 enum virtio_balloon_config_read { 52 VIRTIO_BALLOON_CONFIG_READ_CMD_ID = 0, 53 }; 54 55 struct virtio_balloon { 56 struct virtio_device *vdev; 57 struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; 58 59 /* Balloon's own wq for cpu-intensive work items */ 60 struct workqueue_struct *balloon_wq; 61 /* The free page reporting work item submitted to the balloon wq */ 62 struct work_struct report_free_page_work; 63 64 /* The balloon servicing is delegated to a freezable workqueue. */ 65 struct work_struct update_balloon_stats_work; 66 struct work_struct update_balloon_size_work; 67 68 /* Prevent updating balloon when it is being canceled. */ 69 spinlock_t stop_update_lock; 70 bool stop_update; 71 /* Bitmap to indicate if reading the related config fields are needed */ 72 unsigned long config_read_bitmap; 73 74 /* The list of allocated free pages, waiting to be given back to mm */ 75 struct list_head free_page_list; 76 spinlock_t free_page_list_lock; 77 /* The number of free page blocks on the above list */ 78 unsigned long num_free_page_blocks; 79 /* 80 * The cmd id received from host. 81 * Read it via virtio_balloon_cmd_id_received to get the latest value 82 * sent from host. 83 */ 84 u32 cmd_id_received_cache; 85 /* The cmd id that is actively in use */ 86 __virtio32 cmd_id_active; 87 /* Buffer to store the stop sign */ 88 __virtio32 cmd_id_stop; 89 90 /* Waiting for host to ack the pages we released. */ 91 wait_queue_head_t acked; 92 93 /* Number of balloon pages we've told the Host we're not using. */ 94 unsigned int num_pages; 95 /* 96 * The pages we've told the Host we're not using are enqueued 97 * at vb_dev_info->pages list. 98 * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE 99 * to num_pages above. 100 */ 101 struct balloon_dev_info vb_dev_info; 102 103 /* Synchronize access/update to this struct virtio_balloon elements */ 104 struct mutex balloon_lock; 105 106 /* The array of pfns we tell the Host about. */ 107 unsigned int num_pfns; 108 __virtio32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; 109 110 /* Memory statistics */ 111 struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; 112 113 /* Shrinker to return free pages - VIRTIO_BALLOON_F_FREE_PAGE_HINT */ 114 struct shrinker *shrinker; 115 116 /* OOM notifier to deflate on OOM - VIRTIO_BALLOON_F_DEFLATE_ON_OOM */ 117 struct notifier_block oom_nb; 118 119 /* Free page reporting device */ 120 struct virtqueue *reporting_vq; 121 struct page_reporting_dev_info pr_dev_info; 122 123 /* State for keeping the wakeup_source active while adjusting the balloon */ 124 spinlock_t wakeup_lock; 125 bool processing_wakeup_event; 126 u32 wakeup_signal_mask; 127 }; 128 129 #define VIRTIO_BALLOON_WAKEUP_SIGNAL_ADJUST (1 << 0) 130 #define VIRTIO_BALLOON_WAKEUP_SIGNAL_STATS (1 << 1) 131 132 static const struct virtio_device_id id_table[] = { 133 { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID }, 134 { 0 }, 135 }; 136 137 static u32 page_to_balloon_pfn(struct page *page) 138 { 139 unsigned long pfn = page_to_pfn(page); 140 141 BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); 142 /* Convert pfn from Linux page size to balloon page size. */ 143 return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; 144 } 145 146 static void start_wakeup_event(struct virtio_balloon *vb, u32 mask) 147 { 148 unsigned long flags; 149 150 spin_lock_irqsave(&vb->wakeup_lock, flags); 151 vb->wakeup_signal_mask |= mask; 152 if (!vb->processing_wakeup_event) { 153 vb->processing_wakeup_event = true; 154 pm_stay_awake(&vb->vdev->dev); 155 } 156 spin_unlock_irqrestore(&vb->wakeup_lock, flags); 157 } 158 159 static void process_wakeup_event(struct virtio_balloon *vb, u32 mask) 160 { 161 spin_lock_irq(&vb->wakeup_lock); 162 vb->wakeup_signal_mask &= ~mask; 163 spin_unlock_irq(&vb->wakeup_lock); 164 } 165 166 static void finish_wakeup_event(struct virtio_balloon *vb) 167 { 168 spin_lock_irq(&vb->wakeup_lock); 169 if (!vb->wakeup_signal_mask && vb->processing_wakeup_event) { 170 vb->processing_wakeup_event = false; 171 pm_relax(&vb->vdev->dev); 172 } 173 spin_unlock_irq(&vb->wakeup_lock); 174 } 175 176 static void balloon_ack(struct virtqueue *vq) 177 { 178 struct virtio_balloon *vb = vq->vdev->priv; 179 180 wake_up(&vb->acked); 181 } 182 183 static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) 184 { 185 struct scatterlist sg; 186 unsigned int len; 187 188 sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); 189 190 /* We should always be able to add one buffer to an empty queue. */ 191 virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); 192 virtqueue_kick(vq); 193 194 /* When host has read buffer, this completes via balloon_ack */ 195 wait_event(vb->acked, virtqueue_get_buf(vq, &len)); 196 197 } 198 199 static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info, 200 struct scatterlist *sg, unsigned int nents) 201 { 202 struct virtio_balloon *vb = 203 container_of(pr_dev_info, struct virtio_balloon, pr_dev_info); 204 struct virtqueue *vq = vb->reporting_vq; 205 unsigned int unused, err; 206 207 /* We should always be able to add these buffers to an empty queue. */ 208 err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT | __GFP_NOWARN); 209 210 /* 211 * In the extremely unlikely case that something has occurred and we 212 * are able to trigger an error we will simply display a warning 213 * and exit without actually processing the pages. 214 */ 215 if (WARN_ON_ONCE(err)) 216 return err; 217 218 virtqueue_kick(vq); 219 220 /* When host has read buffer, this completes via balloon_ack */ 221 wait_event(vb->acked, virtqueue_get_buf(vq, &unused)); 222 223 return 0; 224 } 225 226 static void set_page_pfns(struct virtio_balloon *vb, 227 __virtio32 pfns[], struct page *page) 228 { 229 unsigned int i; 230 231 BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE > VIRTIO_BALLOON_ARRAY_PFNS_MAX); 232 233 /* 234 * Set balloon pfns pointing at this page. 235 * Note that the first pfn points at start of the page. 236 */ 237 for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++) 238 pfns[i] = cpu_to_virtio32(vb->vdev, 239 page_to_balloon_pfn(page) + i); 240 } 241 242 static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num) 243 { 244 unsigned int num_allocated_pages; 245 unsigned int num_pfns; 246 struct page *page; 247 LIST_HEAD(pages); 248 249 /* We can only do one array worth at a time. */ 250 num = min(num, ARRAY_SIZE(vb->pfns)); 251 252 for (num_pfns = 0; num_pfns < num; 253 num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { 254 struct page *page = balloon_page_alloc(); 255 256 if (!page) { 257 dev_info_ratelimited(&vb->vdev->dev, 258 "Out of puff! Can't get %u pages\n", 259 VIRTIO_BALLOON_PAGES_PER_PAGE); 260 /* Sleep for at least 1/5 of a second before retry. */ 261 msleep(200); 262 break; 263 } 264 265 balloon_page_push(&pages, page); 266 } 267 268 mutex_lock(&vb->balloon_lock); 269 270 vb->num_pfns = 0; 271 272 while ((page = balloon_page_pop(&pages))) { 273 balloon_page_enqueue(&vb->vb_dev_info, page); 274 275 set_page_pfns(vb, vb->pfns + vb->num_pfns, page); 276 vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; 277 if (!virtio_has_feature(vb->vdev, 278 VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) 279 adjust_managed_page_count(page, -1); 280 vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE; 281 } 282 283 num_allocated_pages = vb->num_pfns; 284 /* Did we get any? */ 285 if (vb->num_pfns != 0) 286 tell_host(vb, vb->inflate_vq); 287 mutex_unlock(&vb->balloon_lock); 288 289 return num_allocated_pages; 290 } 291 292 static void release_pages_balloon(struct virtio_balloon *vb, 293 struct list_head *pages) 294 { 295 struct page *page, *next; 296 297 list_for_each_entry_safe(page, next, pages, lru) { 298 if (!virtio_has_feature(vb->vdev, 299 VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) 300 adjust_managed_page_count(page, 1); 301 list_del(&page->lru); 302 put_page(page); /* balloon reference */ 303 } 304 } 305 306 static unsigned int leak_balloon(struct virtio_balloon *vb, size_t num) 307 { 308 unsigned int num_freed_pages; 309 struct page *page; 310 struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; 311 LIST_HEAD(pages); 312 313 /* We can only do one array worth at a time. */ 314 num = min(num, ARRAY_SIZE(vb->pfns)); 315 316 mutex_lock(&vb->balloon_lock); 317 /* We can't release more pages than taken */ 318 num = min(num, (size_t)vb->num_pages); 319 for (vb->num_pfns = 0; vb->num_pfns < num; 320 vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { 321 page = balloon_page_dequeue(vb_dev_info); 322 if (!page) 323 break; 324 set_page_pfns(vb, vb->pfns + vb->num_pfns, page); 325 list_add(&page->lru, &pages); 326 vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; 327 } 328 329 num_freed_pages = vb->num_pfns; 330 /* 331 * Note that if 332 * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); 333 * is true, we *have* to do it in this order 334 */ 335 if (vb->num_pfns != 0) 336 tell_host(vb, vb->deflate_vq); 337 release_pages_balloon(vb, &pages); 338 mutex_unlock(&vb->balloon_lock); 339 return num_freed_pages; 340 } 341 342 static inline void update_stat(struct virtio_balloon *vb, int idx, 343 u16 tag, u64 val) 344 { 345 BUG_ON(idx >= VIRTIO_BALLOON_S_NR); 346 vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag); 347 vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val); 348 } 349 350 #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) 351 352 #ifdef CONFIG_VM_EVENT_COUNTERS 353 /* Return the number of entries filled by vm events */ 354 static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb) 355 { 356 unsigned long events[NR_VM_EVENT_ITEMS]; 357 unsigned int idx = 0; 358 unsigned int zid; 359 unsigned long stall = 0; 360 361 all_vm_events(events); 362 update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, 363 pages_to_bytes(events[PSWPIN])); 364 update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, 365 pages_to_bytes(events[PSWPOUT])); 366 update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); 367 update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); 368 update_stat(vb, idx++, VIRTIO_BALLOON_S_OOM_KILL, events[OOM_KILL]); 369 370 /* sum all the stall events */ 371 for (zid = 0; zid < MAX_NR_ZONES; zid++) 372 stall += events[ALLOCSTALL_NORMAL - ZONE_NORMAL + zid]; 373 374 update_stat(vb, idx++, VIRTIO_BALLOON_S_ALLOC_STALL, stall); 375 376 update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_SCAN, 377 pages_to_bytes(events[PGSCAN_KSWAPD])); 378 update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_SCAN, 379 pages_to_bytes(events[PGSCAN_DIRECT])); 380 update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_RECLAIM, 381 pages_to_bytes(events[PGSTEAL_KSWAPD])); 382 update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_RECLAIM, 383 pages_to_bytes(events[PGSTEAL_DIRECT])); 384 385 #ifdef CONFIG_HUGETLB_PAGE 386 update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC, 387 events[HTLB_BUDDY_PGALLOC]); 388 update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGFAIL, 389 events[HTLB_BUDDY_PGALLOC_FAIL]); 390 #endif /* CONFIG_HUGETLB_PAGE */ 391 392 return idx; 393 } 394 #else /* CONFIG_VM_EVENT_COUNTERS */ 395 static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb) 396 { 397 return 0; 398 } 399 #endif /* CONFIG_VM_EVENT_COUNTERS */ 400 401 static unsigned int update_balloon_stats(struct virtio_balloon *vb) 402 { 403 struct sysinfo i; 404 unsigned int idx; 405 long available; 406 unsigned long caches; 407 408 idx = update_balloon_vm_stats(vb); 409 410 si_meminfo(&i); 411 available = si_mem_available(); 412 caches = global_node_page_state(NR_FILE_PAGES); 413 update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, 414 pages_to_bytes(i.freeram)); 415 update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, 416 pages_to_bytes(i.totalram)); 417 update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL, 418 pages_to_bytes(available)); 419 update_stat(vb, idx++, VIRTIO_BALLOON_S_CACHES, 420 pages_to_bytes(caches)); 421 422 return idx; 423 } 424 425 /* 426 * While most virtqueues communicate guest-initiated requests to the hypervisor, 427 * the stats queue operates in reverse. The driver initializes the virtqueue 428 * with a single buffer. From that point forward, all conversations consist of 429 * a hypervisor request (a call to this function) which directs us to refill 430 * the virtqueue with a fresh stats buffer. Since stats collection can sleep, 431 * we delegate the job to a freezable workqueue that will do the actual work via 432 * stats_handle_request(). 433 */ 434 static void stats_request(struct virtqueue *vq) 435 { 436 struct virtio_balloon *vb = vq->vdev->priv; 437 438 spin_lock(&vb->stop_update_lock); 439 if (!vb->stop_update) { 440 start_wakeup_event(vb, VIRTIO_BALLOON_WAKEUP_SIGNAL_STATS); 441 queue_work(system_freezable_wq, &vb->update_balloon_stats_work); 442 } 443 spin_unlock(&vb->stop_update_lock); 444 } 445 446 static void stats_handle_request(struct virtio_balloon *vb) 447 { 448 struct virtqueue *vq; 449 struct scatterlist sg; 450 unsigned int len, num_stats; 451 452 num_stats = update_balloon_stats(vb); 453 454 vq = vb->stats_vq; 455 if (!virtqueue_get_buf(vq, &len)) 456 return; 457 sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); 458 virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); 459 virtqueue_kick(vq); 460 } 461 462 static inline s64 towards_target(struct virtio_balloon *vb) 463 { 464 s64 target; 465 u32 num_pages; 466 467 /* Legacy balloon config space is LE, unlike all other devices. */ 468 virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages, 469 &num_pages); 470 471 /* 472 * Aligned up to guest page size to avoid inflating and deflating 473 * balloon endlessly. 474 */ 475 target = ALIGN(num_pages, VIRTIO_BALLOON_PAGES_PER_PAGE); 476 return target - vb->num_pages; 477 } 478 479 /* Gives back @num_to_return blocks of free pages to mm. */ 480 static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb, 481 unsigned long num_to_return) 482 { 483 struct page *page; 484 unsigned long num_returned; 485 486 spin_lock_irq(&vb->free_page_list_lock); 487 for (num_returned = 0; num_returned < num_to_return; num_returned++) { 488 page = balloon_page_pop(&vb->free_page_list); 489 if (!page) 490 break; 491 free_pages((unsigned long)page_address(page), 492 VIRTIO_BALLOON_HINT_BLOCK_ORDER); 493 } 494 vb->num_free_page_blocks -= num_returned; 495 spin_unlock_irq(&vb->free_page_list_lock); 496 497 return num_returned; 498 } 499 500 static void virtio_balloon_queue_free_page_work(struct virtio_balloon *vb) 501 { 502 if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 503 return; 504 505 /* No need to queue the work if the bit was already set. */ 506 if (test_and_set_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, 507 &vb->config_read_bitmap)) 508 return; 509 510 queue_work(vb->balloon_wq, &vb->report_free_page_work); 511 } 512 513 static void start_update_balloon_size(struct virtio_balloon *vb) 514 { 515 start_wakeup_event(vb, VIRTIO_BALLOON_WAKEUP_SIGNAL_ADJUST); 516 queue_work(system_freezable_wq, &vb->update_balloon_size_work); 517 } 518 519 static void virtballoon_changed(struct virtio_device *vdev) 520 { 521 struct virtio_balloon *vb = vdev->priv; 522 unsigned long flags; 523 524 spin_lock_irqsave(&vb->stop_update_lock, flags); 525 if (!vb->stop_update) { 526 start_update_balloon_size(vb); 527 virtio_balloon_queue_free_page_work(vb); 528 } 529 spin_unlock_irqrestore(&vb->stop_update_lock, flags); 530 } 531 532 static void update_balloon_size(struct virtio_balloon *vb) 533 { 534 u32 actual = vb->num_pages; 535 536 /* Legacy balloon config space is LE, unlike all other devices. */ 537 virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, actual, 538 &actual); 539 } 540 541 static void update_balloon_stats_func(struct work_struct *work) 542 { 543 struct virtio_balloon *vb; 544 545 vb = container_of(work, struct virtio_balloon, 546 update_balloon_stats_work); 547 548 process_wakeup_event(vb, VIRTIO_BALLOON_WAKEUP_SIGNAL_STATS); 549 stats_handle_request(vb); 550 finish_wakeup_event(vb); 551 } 552 553 static void update_balloon_size_func(struct work_struct *work) 554 { 555 struct virtio_balloon *vb; 556 s64 diff; 557 558 vb = container_of(work, struct virtio_balloon, 559 update_balloon_size_work); 560 561 process_wakeup_event(vb, VIRTIO_BALLOON_WAKEUP_SIGNAL_ADJUST); 562 563 diff = towards_target(vb); 564 565 if (diff) { 566 if (diff > 0) 567 diff -= fill_balloon(vb, diff); 568 else 569 diff += leak_balloon(vb, -diff); 570 update_balloon_size(vb); 571 } 572 573 if (diff) 574 queue_work(system_freezable_wq, work); 575 else 576 finish_wakeup_event(vb); 577 } 578 579 static int init_vqs(struct virtio_balloon *vb) 580 { 581 struct virtqueue_info vqs_info[VIRTIO_BALLOON_VQ_MAX] = {}; 582 struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX]; 583 int err; 584 585 /* 586 * Inflateq and deflateq are used unconditionally. The names[] 587 * will be NULL if the related feature is not enabled, which will 588 * cause no allocation for the corresponding virtqueue in find_vqs. 589 */ 590 vqs_info[VIRTIO_BALLOON_VQ_INFLATE].callback = balloon_ack; 591 vqs_info[VIRTIO_BALLOON_VQ_INFLATE].name = "inflate"; 592 vqs_info[VIRTIO_BALLOON_VQ_DEFLATE].callback = balloon_ack; 593 vqs_info[VIRTIO_BALLOON_VQ_DEFLATE].name = "deflate"; 594 595 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { 596 vqs_info[VIRTIO_BALLOON_VQ_STATS].name = "stats"; 597 vqs_info[VIRTIO_BALLOON_VQ_STATS].callback = stats_request; 598 } 599 600 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 601 vqs_info[VIRTIO_BALLOON_VQ_FREE_PAGE].name = "free_page_vq"; 602 603 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { 604 vqs_info[VIRTIO_BALLOON_VQ_REPORTING].name = "reporting_vq"; 605 vqs_info[VIRTIO_BALLOON_VQ_REPORTING].callback = balloon_ack; 606 } 607 608 err = virtio_find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, 609 vqs_info, NULL); 610 if (err) 611 return err; 612 613 vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; 614 vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; 615 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { 616 struct scatterlist sg; 617 unsigned int num_stats; 618 vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS]; 619 620 /* 621 * Prime this virtqueue with one buffer so the hypervisor can 622 * use it to signal us later (it can't be broken yet!). 623 */ 624 num_stats = update_balloon_stats(vb); 625 626 sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); 627 err = virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, 628 GFP_KERNEL); 629 if (err) { 630 dev_warn(&vb->vdev->dev, "%s: add stat_vq failed\n", 631 __func__); 632 return err; 633 } 634 virtqueue_kick(vb->stats_vq); 635 } 636 637 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 638 vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE]; 639 640 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) 641 vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING]; 642 643 return 0; 644 } 645 646 static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb) 647 { 648 if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, 649 &vb->config_read_bitmap)) { 650 /* Legacy balloon config space is LE, unlike all other devices. */ 651 virtio_cread_le(vb->vdev, struct virtio_balloon_config, 652 free_page_hint_cmd_id, 653 &vb->cmd_id_received_cache); 654 } 655 656 return vb->cmd_id_received_cache; 657 } 658 659 static int send_cmd_id_start(struct virtio_balloon *vb) 660 { 661 struct scatterlist sg; 662 struct virtqueue *vq = vb->free_page_vq; 663 int err, unused; 664 665 /* Detach all the used buffers from the vq */ 666 while (virtqueue_get_buf(vq, &unused)) 667 ; 668 669 vb->cmd_id_active = cpu_to_virtio32(vb->vdev, 670 virtio_balloon_cmd_id_received(vb)); 671 sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active)); 672 err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL); 673 if (!err) 674 virtqueue_kick(vq); 675 return err; 676 } 677 678 static int send_cmd_id_stop(struct virtio_balloon *vb) 679 { 680 struct scatterlist sg; 681 struct virtqueue *vq = vb->free_page_vq; 682 int err, unused; 683 684 /* Detach all the used buffers from the vq */ 685 while (virtqueue_get_buf(vq, &unused)) 686 ; 687 688 sg_init_one(&sg, &vb->cmd_id_stop, sizeof(vb->cmd_id_stop)); 689 err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_stop, GFP_KERNEL); 690 if (!err) 691 virtqueue_kick(vq); 692 return err; 693 } 694 695 static int get_free_page_and_send(struct virtio_balloon *vb) 696 { 697 struct virtqueue *vq = vb->free_page_vq; 698 struct page *page; 699 struct scatterlist sg; 700 int err, unused; 701 void *p; 702 703 /* Detach all the used buffers from the vq */ 704 while (virtqueue_get_buf(vq, &unused)) 705 ; 706 707 page = alloc_pages(VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG, 708 VIRTIO_BALLOON_HINT_BLOCK_ORDER); 709 /* 710 * When the allocation returns NULL, it indicates that we have got all 711 * the possible free pages, so return -EINTR to stop. 712 */ 713 if (!page) 714 return -EINTR; 715 716 p = page_address(page); 717 sg_init_one(&sg, p, VIRTIO_BALLOON_HINT_BLOCK_BYTES); 718 /* There is always 1 entry reserved for the cmd id to use. */ 719 if (vq->num_free > 1) { 720 err = virtqueue_add_inbuf(vq, &sg, 1, p, GFP_KERNEL); 721 if (unlikely(err)) { 722 free_pages((unsigned long)p, 723 VIRTIO_BALLOON_HINT_BLOCK_ORDER); 724 return err; 725 } 726 virtqueue_kick(vq); 727 spin_lock_irq(&vb->free_page_list_lock); 728 balloon_page_push(&vb->free_page_list, page); 729 vb->num_free_page_blocks++; 730 spin_unlock_irq(&vb->free_page_list_lock); 731 } else { 732 /* 733 * The vq has no available entry to add this page block, so 734 * just free it. 735 */ 736 free_pages((unsigned long)p, VIRTIO_BALLOON_HINT_BLOCK_ORDER); 737 } 738 739 return 0; 740 } 741 742 static int send_free_pages(struct virtio_balloon *vb) 743 { 744 int err; 745 u32 cmd_id_active; 746 747 while (1) { 748 /* 749 * If a stop id or a new cmd id was just received from host, 750 * stop the reporting. 751 */ 752 cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active); 753 if (unlikely(cmd_id_active != 754 virtio_balloon_cmd_id_received(vb))) 755 break; 756 757 /* 758 * The free page blocks are allocated and sent to host one by 759 * one. 760 */ 761 err = get_free_page_and_send(vb); 762 if (err == -EINTR) 763 break; 764 else if (unlikely(err)) 765 return err; 766 } 767 768 return 0; 769 } 770 771 static void virtio_balloon_report_free_page(struct virtio_balloon *vb) 772 { 773 int err; 774 struct device *dev = &vb->vdev->dev; 775 776 /* Start by sending the received cmd id to host with an outbuf. */ 777 err = send_cmd_id_start(vb); 778 if (unlikely(err)) 779 dev_err(dev, "Failed to send a start id, err = %d\n", err); 780 781 err = send_free_pages(vb); 782 if (unlikely(err)) 783 dev_err(dev, "Failed to send a free page, err = %d\n", err); 784 785 /* End by sending a stop id to host with an outbuf. */ 786 err = send_cmd_id_stop(vb); 787 if (unlikely(err)) 788 dev_err(dev, "Failed to send a stop id, err = %d\n", err); 789 } 790 791 static void report_free_page_func(struct work_struct *work) 792 { 793 struct virtio_balloon *vb = container_of(work, struct virtio_balloon, 794 report_free_page_work); 795 u32 cmd_id_received; 796 797 cmd_id_received = virtio_balloon_cmd_id_received(vb); 798 if (cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { 799 /* Pass ULONG_MAX to give back all the free pages */ 800 return_free_pages_to_mm(vb, ULONG_MAX); 801 } else if (cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && 802 cmd_id_received != 803 virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) { 804 virtio_balloon_report_free_page(vb); 805 } 806 } 807 808 #ifdef CONFIG_BALLOON_COMPACTION 809 /* 810 * virtballoon_migratepage - perform the balloon page migration on behalf of 811 * a compaction thread. (called under page lock) 812 * @vb_dev_info: the balloon device 813 * @newpage: page that will replace the isolated page after migration finishes. 814 * @page : the isolated (old) page that is about to be migrated to newpage. 815 * @mode : compaction mode -- not used for balloon page migration. 816 * 817 * After a ballooned page gets isolated by compaction procedures, this is the 818 * function that performs the page migration on behalf of a compaction thread 819 * The page migration for virtio balloon is done in a simple swap fashion which 820 * follows these two macro steps: 821 * 1) insert newpage into vb->pages list and update the host about it; 822 * 2) update the host about the old page removed from vb->pages list; 823 * 824 * This function preforms the balloon page migration task. 825 * Called through movable_operations->migrate_page 826 */ 827 static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, 828 struct page *newpage, struct page *page, enum migrate_mode mode) 829 { 830 struct virtio_balloon *vb = container_of(vb_dev_info, 831 struct virtio_balloon, vb_dev_info); 832 unsigned long flags; 833 834 /* 835 * In order to avoid lock contention while migrating pages concurrently 836 * to leak_balloon() or fill_balloon() we just give up the balloon_lock 837 * this turn, as it is easier to retry the page migration later. 838 * This also prevents fill_balloon() getting stuck into a mutex 839 * recursion in the case it ends up triggering memory compaction 840 * while it is attempting to inflate the ballon. 841 */ 842 if (!mutex_trylock(&vb->balloon_lock)) 843 return -EAGAIN; 844 845 get_page(newpage); /* balloon reference */ 846 847 /* 848 * When we migrate a page to a different zone and adjusted the 849 * managed page count when inflating, we have to fixup the count of 850 * both involved zones. 851 */ 852 if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) && 853 page_zone(page) != page_zone(newpage)) { 854 adjust_managed_page_count(page, 1); 855 adjust_managed_page_count(newpage, -1); 856 } 857 858 /* balloon's page migration 1st step -- inflate "newpage" */ 859 spin_lock_irqsave(&vb_dev_info->pages_lock, flags); 860 balloon_page_insert(vb_dev_info, newpage); 861 vb_dev_info->isolated_pages--; 862 __count_vm_event(BALLOON_MIGRATE); 863 spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); 864 vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; 865 set_page_pfns(vb, vb->pfns, newpage); 866 tell_host(vb, vb->inflate_vq); 867 868 /* balloon's page migration 2nd step -- deflate "page" */ 869 spin_lock_irqsave(&vb_dev_info->pages_lock, flags); 870 balloon_page_delete(page); 871 spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); 872 vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; 873 set_page_pfns(vb, vb->pfns, page); 874 tell_host(vb, vb->deflate_vq); 875 876 mutex_unlock(&vb->balloon_lock); 877 878 put_page(page); /* balloon reference */ 879 880 return MIGRATEPAGE_SUCCESS; 881 } 882 #endif /* CONFIG_BALLOON_COMPACTION */ 883 884 static unsigned long shrink_free_pages(struct virtio_balloon *vb, 885 unsigned long pages_to_free) 886 { 887 unsigned long blocks_to_free, blocks_freed; 888 889 pages_to_free = round_up(pages_to_free, 890 VIRTIO_BALLOON_HINT_BLOCK_PAGES); 891 blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES; 892 blocks_freed = return_free_pages_to_mm(vb, blocks_to_free); 893 894 return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES; 895 } 896 897 static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker, 898 struct shrink_control *sc) 899 { 900 struct virtio_balloon *vb = shrinker->private_data; 901 902 return shrink_free_pages(vb, sc->nr_to_scan); 903 } 904 905 static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker, 906 struct shrink_control *sc) 907 { 908 struct virtio_balloon *vb = shrinker->private_data; 909 910 return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES; 911 } 912 913 static int virtio_balloon_oom_notify(struct notifier_block *nb, 914 unsigned long dummy, void *parm) 915 { 916 struct virtio_balloon *vb = container_of(nb, 917 struct virtio_balloon, oom_nb); 918 unsigned long *freed = parm; 919 920 *freed += leak_balloon(vb, VIRTIO_BALLOON_OOM_NR_PAGES) / 921 VIRTIO_BALLOON_PAGES_PER_PAGE; 922 update_balloon_size(vb); 923 924 return NOTIFY_OK; 925 } 926 927 static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb) 928 { 929 shrinker_free(vb->shrinker); 930 } 931 932 static int virtio_balloon_register_shrinker(struct virtio_balloon *vb) 933 { 934 vb->shrinker = shrinker_alloc(0, "virtio-balloon"); 935 if (!vb->shrinker) 936 return -ENOMEM; 937 938 vb->shrinker->scan_objects = virtio_balloon_shrinker_scan; 939 vb->shrinker->count_objects = virtio_balloon_shrinker_count; 940 vb->shrinker->private_data = vb; 941 942 shrinker_register(vb->shrinker); 943 944 return 0; 945 } 946 947 static int virtballoon_probe(struct virtio_device *vdev) 948 { 949 struct virtio_balloon *vb; 950 int err; 951 952 if (!vdev->config->get) { 953 dev_err(&vdev->dev, "%s failure: config access disabled\n", 954 __func__); 955 return -EINVAL; 956 } 957 958 vdev->priv = vb = kzalloc(sizeof(*vb), GFP_KERNEL); 959 if (!vb) { 960 err = -ENOMEM; 961 goto out; 962 } 963 964 INIT_WORK(&vb->update_balloon_stats_work, update_balloon_stats_func); 965 INIT_WORK(&vb->update_balloon_size_work, update_balloon_size_func); 966 spin_lock_init(&vb->stop_update_lock); 967 mutex_init(&vb->balloon_lock); 968 init_waitqueue_head(&vb->acked); 969 vb->vdev = vdev; 970 971 balloon_devinfo_init(&vb->vb_dev_info); 972 973 err = init_vqs(vb); 974 if (err) 975 goto out_free_vb; 976 977 #ifdef CONFIG_BALLOON_COMPACTION 978 vb->vb_dev_info.migratepage = virtballoon_migratepage; 979 #endif 980 if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 981 /* 982 * There is always one entry reserved for cmd id, so the ring 983 * size needs to be at least two to report free page hints. 984 */ 985 if (virtqueue_get_vring_size(vb->free_page_vq) < 2) { 986 err = -ENOSPC; 987 goto out_del_vqs; 988 } 989 vb->balloon_wq = alloc_workqueue("balloon-wq", 990 WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0); 991 if (!vb->balloon_wq) { 992 err = -ENOMEM; 993 goto out_del_vqs; 994 } 995 INIT_WORK(&vb->report_free_page_work, report_free_page_func); 996 vb->cmd_id_received_cache = VIRTIO_BALLOON_CMD_ID_STOP; 997 vb->cmd_id_active = cpu_to_virtio32(vb->vdev, 998 VIRTIO_BALLOON_CMD_ID_STOP); 999 vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, 1000 VIRTIO_BALLOON_CMD_ID_STOP); 1001 spin_lock_init(&vb->free_page_list_lock); 1002 INIT_LIST_HEAD(&vb->free_page_list); 1003 /* 1004 * We're allowed to reuse any free pages, even if they are 1005 * still to be processed by the host. 1006 */ 1007 err = virtio_balloon_register_shrinker(vb); 1008 if (err) 1009 goto out_del_balloon_wq; 1010 } 1011 1012 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) { 1013 vb->oom_nb.notifier_call = virtio_balloon_oom_notify; 1014 vb->oom_nb.priority = VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY; 1015 err = register_oom_notifier(&vb->oom_nb); 1016 if (err < 0) 1017 goto out_unregister_shrinker; 1018 } 1019 1020 if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { 1021 /* Start with poison val of 0 representing general init */ 1022 __u32 poison_val = 0; 1023 1024 /* 1025 * Let the hypervisor know that we are expecting a 1026 * specific value to be written back in balloon pages. 1027 * 1028 * If the PAGE_POISON value was larger than a byte we would 1029 * need to byte swap poison_val here to guarantee it is 1030 * little-endian. However for now it is a single byte so we 1031 * can pass it as-is. 1032 */ 1033 if (!want_init_on_free()) 1034 memset(&poison_val, PAGE_POISON, sizeof(poison_val)); 1035 1036 virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, 1037 poison_val, &poison_val); 1038 } 1039 1040 vb->pr_dev_info.report = virtballoon_free_page_report; 1041 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { 1042 unsigned int capacity; 1043 1044 capacity = virtqueue_get_vring_size(vb->reporting_vq); 1045 if (capacity < PAGE_REPORTING_CAPACITY) { 1046 err = -ENOSPC; 1047 goto out_unregister_oom; 1048 } 1049 1050 /* 1051 * The default page reporting order is @pageblock_order, which 1052 * corresponds to 512MB in size on ARM64 when 64KB base page 1053 * size is used. The page reporting won't be triggered if the 1054 * freeing page can't come up with a free area like that huge. 1055 * So we specify the page reporting order to 5, corresponding 1056 * to 2MB. It helps to avoid THP splitting if 4KB base page 1057 * size is used by host. 1058 * 1059 * Ideally, the page reporting order is selected based on the 1060 * host's base page size. However, it needs more work to report 1061 * that value. The hard-coded order would be fine currently. 1062 */ 1063 #if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES) 1064 vb->pr_dev_info.order = 5; 1065 #endif 1066 1067 err = page_reporting_register(&vb->pr_dev_info); 1068 if (err) 1069 goto out_unregister_oom; 1070 } 1071 1072 spin_lock_init(&vb->wakeup_lock); 1073 1074 /* 1075 * The virtio balloon itself can't wake up the device, but it is 1076 * responsible for processing wakeup events passed up from the transport 1077 * layer. Wakeup sources don't support nesting/chaining calls, so we use 1078 * our own wakeup source to ensure wakeup events are properly handled 1079 * without trampling on the transport layer's wakeup source. 1080 */ 1081 device_set_wakeup_capable(&vb->vdev->dev, true); 1082 1083 virtio_device_ready(vdev); 1084 1085 if (towards_target(vb)) 1086 virtballoon_changed(vdev); 1087 return 0; 1088 1089 out_unregister_oom: 1090 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) 1091 unregister_oom_notifier(&vb->oom_nb); 1092 out_unregister_shrinker: 1093 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 1094 virtio_balloon_unregister_shrinker(vb); 1095 out_del_balloon_wq: 1096 if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 1097 destroy_workqueue(vb->balloon_wq); 1098 out_del_vqs: 1099 vdev->config->del_vqs(vdev); 1100 out_free_vb: 1101 kfree(vb); 1102 out: 1103 return err; 1104 } 1105 1106 static void remove_common(struct virtio_balloon *vb) 1107 { 1108 /* There might be pages left in the balloon: free them. */ 1109 while (vb->num_pages) 1110 leak_balloon(vb, vb->num_pages); 1111 update_balloon_size(vb); 1112 1113 /* There might be free pages that are being reported: release them. */ 1114 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 1115 return_free_pages_to_mm(vb, ULONG_MAX); 1116 1117 /* Now we reset the device so we can clean up the queues. */ 1118 virtio_reset_device(vb->vdev); 1119 1120 vb->vdev->config->del_vqs(vb->vdev); 1121 } 1122 1123 static void virtballoon_remove(struct virtio_device *vdev) 1124 { 1125 struct virtio_balloon *vb = vdev->priv; 1126 1127 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) 1128 page_reporting_unregister(&vb->pr_dev_info); 1129 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) 1130 unregister_oom_notifier(&vb->oom_nb); 1131 if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) 1132 virtio_balloon_unregister_shrinker(vb); 1133 spin_lock_irq(&vb->stop_update_lock); 1134 vb->stop_update = true; 1135 spin_unlock_irq(&vb->stop_update_lock); 1136 cancel_work_sync(&vb->update_balloon_size_work); 1137 cancel_work_sync(&vb->update_balloon_stats_work); 1138 1139 if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 1140 cancel_work_sync(&vb->report_free_page_work); 1141 destroy_workqueue(vb->balloon_wq); 1142 } 1143 1144 remove_common(vb); 1145 kfree(vb); 1146 } 1147 1148 #ifdef CONFIG_PM_SLEEP 1149 static int virtballoon_freeze(struct virtio_device *vdev) 1150 { 1151 struct virtio_balloon *vb = vdev->priv; 1152 1153 /* 1154 * The workqueue is already frozen by the PM core before this 1155 * function is called. 1156 */ 1157 remove_common(vb); 1158 return 0; 1159 } 1160 1161 static int virtballoon_restore(struct virtio_device *vdev) 1162 { 1163 struct virtio_balloon *vb = vdev->priv; 1164 int ret; 1165 1166 ret = init_vqs(vdev->priv); 1167 if (ret) 1168 return ret; 1169 1170 virtio_device_ready(vdev); 1171 1172 if (towards_target(vb)) 1173 virtballoon_changed(vdev); 1174 update_balloon_size(vb); 1175 return 0; 1176 } 1177 #endif 1178 1179 static int virtballoon_validate(struct virtio_device *vdev) 1180 { 1181 /* 1182 * Inform the hypervisor that our pages are poisoned or 1183 * initialized. If we cannot do that then we should disable 1184 * page reporting as it could potentially change the contents 1185 * of our free pages. 1186 */ 1187 if (!want_init_on_free() && !page_poisoning_enabled_static()) 1188 __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON); 1189 else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) 1190 __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING); 1191 1192 __virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM); 1193 return 0; 1194 } 1195 1196 static unsigned int features[] = { 1197 VIRTIO_BALLOON_F_MUST_TELL_HOST, 1198 VIRTIO_BALLOON_F_STATS_VQ, 1199 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, 1200 VIRTIO_BALLOON_F_FREE_PAGE_HINT, 1201 VIRTIO_BALLOON_F_PAGE_POISON, 1202 VIRTIO_BALLOON_F_REPORTING, 1203 }; 1204 1205 static struct virtio_driver virtio_balloon_driver = { 1206 .feature_table = features, 1207 .feature_table_size = ARRAY_SIZE(features), 1208 .driver.name = KBUILD_MODNAME, 1209 .id_table = id_table, 1210 .validate = virtballoon_validate, 1211 .probe = virtballoon_probe, 1212 .remove = virtballoon_remove, 1213 .config_changed = virtballoon_changed, 1214 #ifdef CONFIG_PM_SLEEP 1215 .freeze = virtballoon_freeze, 1216 .restore = virtballoon_restore, 1217 #endif 1218 }; 1219 1220 module_virtio_driver(virtio_balloon_driver); 1221 MODULE_DEVICE_TABLE(virtio, id_table); 1222 MODULE_DESCRIPTION("Virtio balloon driver"); 1223 MODULE_LICENSE("GPL"); 1224