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