Commit | Line | Data |
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fd534e9b | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1e214a5c SL |
2 | /* |
3 | * Virtio balloon implementation, inspired by Dor Laor and Marcelo | |
6b35e407 RR |
4 | * Tosatti's implementations. |
5 | * | |
6 | * Copyright 2008 Rusty Russell IBM Corporation | |
6b35e407 | 7 | */ |
1e214a5c | 8 | |
6b35e407 RR |
9 | #include <linux/virtio.h> |
10 | #include <linux/virtio_balloon.h> | |
11 | #include <linux/swap.h> | |
fad7b7b2 | 12 | #include <linux/workqueue.h> |
6659a0f0 | 13 | #include <linux/delay.h> |
5a0e3ad6 | 14 | #include <linux/slab.h> |
b5a2c4f1 | 15 | #include <linux/module.h> |
e2250429 | 16 | #include <linux/balloon_compaction.h> |
da10329c | 17 | #include <linux/oom.h> |
3d2a3774 | 18 | #include <linux/wait.h> |
5057dcd0 | 19 | #include <linux/mm.h> |
b0c504f1 | 20 | #include <linux/page_reporting.h> |
6b35e407 | 21 | |
3ccc9372 MT |
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 | */ | |
31532340 | 27 | #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned int)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) |
e2250429 | 28 | #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 |
da10329c DH |
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 | |
5a10b7db | 32 | |
86a55978 WW |
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 */ | |
2a946fa1 | 36 | #define VIRTIO_BALLOON_HINT_BLOCK_ORDER (MAX_ORDER - 1) |
86a55978 | 37 | /* The size of a free page block in bytes */ |
2a946fa1 MT |
38 | #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \ |
39 | (1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT)) | |
63b9b80e | 40 | #define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER) |
86a55978 | 41 | |
86a55978 WW |
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, | |
b0c504f1 | 47 | VIRTIO_BALLOON_VQ_REPORTING, |
86a55978 WW |
48 | VIRTIO_BALLOON_VQ_MAX |
49 | }; | |
50 | ||
bf4dc0b2 WW |
51 | enum virtio_balloon_config_read { |
52 | VIRTIO_BALLOON_CONFIG_READ_CMD_ID = 0, | |
53 | }; | |
54 | ||
25e65e4e | 55 | struct virtio_balloon { |
6b35e407 | 56 | struct virtio_device *vdev; |
86a55978 WW |
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; | |
6b35e407 | 63 | |
fad7b7b2 | 64 | /* The balloon servicing is delegated to a freezable workqueue. */ |
fd0e21c3 PM |
65 | struct work_struct update_balloon_stats_work; |
66 | struct work_struct update_balloon_size_work; | |
6b35e407 | 67 | |
fad7b7b2 PM |
68 | /* Prevent updating balloon when it is being canceled. */ |
69 | spinlock_t stop_update_lock; | |
70 | bool stop_update; | |
bf4dc0b2 WW |
71 | /* Bitmap to indicate if reading the related config fields are needed */ |
72 | unsigned long config_read_bitmap; | |
6b35e407 | 73 | |
86a55978 WW |
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; | |
bf4dc0b2 WW |
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; | |
86a55978 WW |
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 | ||
6b35e407 | 90 | /* Waiting for host to ack the pages we released. */ |
9c378abc | 91 | wait_queue_head_t acked; |
6b35e407 | 92 | |
3ccc9372 | 93 | /* Number of balloon pages we've told the Host we're not using. */ |
6b35e407 | 94 | unsigned int num_pages; |
3ccc9372 | 95 | /* |
e2250429 RA |
96 | * The pages we've told the Host we're not using are enqueued |
97 | * at vb_dev_info->pages list. | |
3ccc9372 MT |
98 | * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE |
99 | * to num_pages above. | |
100 | */ | |
9d1ba805 | 101 | struct balloon_dev_info vb_dev_info; |
e2250429 RA |
102 | |
103 | /* Synchronize access/update to this struct virtio_balloon elements */ | |
104 | struct mutex balloon_lock; | |
6b35e407 RR |
105 | |
106 | /* The array of pfns we tell the Host about. */ | |
107 | unsigned int num_pfns; | |
87c9403b | 108 | __virtio32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; |
9564e138 AL |
109 | |
110 | /* Memory statistics */ | |
111 | struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; | |
5a10b7db | 112 | |
da10329c | 113 | /* Shrinker to return free pages - VIRTIO_BALLOON_F_FREE_PAGE_HINT */ |
71994620 | 114 | struct shrinker shrinker; |
b0c504f1 | 115 | |
da10329c DH |
116 | /* OOM notifier to deflate on OOM - VIRTIO_BALLOON_F_DEFLATE_ON_OOM */ |
117 | struct notifier_block oom_nb; | |
118 | ||
b0c504f1 AD |
119 | /* Free page reporting device */ |
120 | struct virtqueue *reporting_vq; | |
121 | struct page_reporting_dev_info pr_dev_info; | |
6b35e407 RR |
122 | }; |
123 | ||
bfec6c83 | 124 | static const struct virtio_device_id id_table[] = { |
6b35e407 RR |
125 | { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID }, |
126 | { 0 }, | |
127 | }; | |
128 | ||
1b4aa2fa HB |
129 | static u32 page_to_balloon_pfn(struct page *page) |
130 | { | |
131 | unsigned long pfn = page_to_pfn(page); | |
132 | ||
133 | BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); | |
134 | /* Convert pfn from Linux page size to balloon page size. */ | |
3ccc9372 MT |
135 | return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; |
136 | } | |
137 | ||
6b35e407 RR |
138 | static void balloon_ack(struct virtqueue *vq) |
139 | { | |
9c378abc | 140 | struct virtio_balloon *vb = vq->vdev->priv; |
6b35e407 | 141 | |
9c378abc | 142 | wake_up(&vb->acked); |
6b35e407 RR |
143 | } |
144 | ||
145 | static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) | |
146 | { | |
147 | struct scatterlist sg; | |
9c378abc | 148 | unsigned int len; |
6b35e407 RR |
149 | |
150 | sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); | |
151 | ||
6b35e407 | 152 | /* We should always be able to add one buffer to an empty queue. */ |
4951cc90 | 153 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 154 | virtqueue_kick(vq); |
6b35e407 RR |
155 | |
156 | /* When host has read buffer, this completes via balloon_ack */ | |
9c378abc | 157 | wait_event(vb->acked, virtqueue_get_buf(vq, &len)); |
fd0e21c3 | 158 | |
6b35e407 RR |
159 | } |
160 | ||
dc39cbb4 | 161 | static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info, |
b0c504f1 AD |
162 | struct scatterlist *sg, unsigned int nents) |
163 | { | |
164 | struct virtio_balloon *vb = | |
165 | container_of(pr_dev_info, struct virtio_balloon, pr_dev_info); | |
166 | struct virtqueue *vq = vb->reporting_vq; | |
167 | unsigned int unused, err; | |
168 | ||
169 | /* We should always be able to add these buffers to an empty queue. */ | |
170 | err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT | __GFP_NOWARN); | |
171 | ||
172 | /* | |
173 | * In the extremely unlikely case that something has occurred and we | |
174 | * are able to trigger an error we will simply display a warning | |
175 | * and exit without actually processing the pages. | |
176 | */ | |
177 | if (WARN_ON_ONCE(err)) | |
178 | return err; | |
179 | ||
180 | virtqueue_kick(vq); | |
181 | ||
182 | /* When host has read buffer, this completes via balloon_ack */ | |
183 | wait_event(vb->acked, virtqueue_get_buf(vq, &unused)); | |
184 | ||
185 | return 0; | |
186 | } | |
187 | ||
87c9403b MT |
188 | static void set_page_pfns(struct virtio_balloon *vb, |
189 | __virtio32 pfns[], struct page *page) | |
3ccc9372 MT |
190 | { |
191 | unsigned int i; | |
192 | ||
6e9826e7 MT |
193 | BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE > VIRTIO_BALLOON_ARRAY_PFNS_MAX); |
194 | ||
f9aada5f WW |
195 | /* |
196 | * Set balloon pfns pointing at this page. | |
197 | * Note that the first pfn points at start of the page. | |
198 | */ | |
3ccc9372 | 199 | for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++) |
87c9403b MT |
200 | pfns[i] = cpu_to_virtio32(vb->vdev, |
201 | page_to_balloon_pfn(page) + i); | |
3ccc9372 MT |
202 | } |
203 | ||
31532340 | 204 | static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 205 | { |
31532340 ST |
206 | unsigned int num_allocated_pages; |
207 | unsigned int num_pfns; | |
c7cdff0e MT |
208 | struct page *page; |
209 | LIST_HEAD(pages); | |
e2250429 | 210 | |
6b35e407 RR |
211 | /* We can only do one array worth at a time. */ |
212 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
213 | ||
c7cdff0e MT |
214 | for (num_pfns = 0; num_pfns < num; |
215 | num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
216 | struct page *page = balloon_page_alloc(); | |
e2250429 | 217 | |
6b35e407 | 218 | if (!page) { |
800ba5ea | 219 | dev_info_ratelimited(&vb->vdev->dev, |
b7dfde95 LT |
220 | "Out of puff! Can't get %u pages\n", |
221 | VIRTIO_BALLOON_PAGES_PER_PAGE); | |
6b35e407 RR |
222 | /* Sleep for at least 1/5 of a second before retry. */ |
223 | msleep(200); | |
224 | break; | |
225 | } | |
c7cdff0e MT |
226 | |
227 | balloon_page_push(&pages, page); | |
228 | } | |
229 | ||
230 | mutex_lock(&vb->balloon_lock); | |
231 | ||
232 | vb->num_pfns = 0; | |
233 | ||
234 | while ((page = balloon_page_pop(&pages))) { | |
235 | balloon_page_enqueue(&vb->vb_dev_info, page); | |
236 | ||
87c9403b | 237 | set_page_pfns(vb, vb->pfns + vb->num_pfns, page); |
3ccc9372 | 238 | vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; |
997e1208 DL |
239 | if (!virtio_has_feature(vb->vdev, |
240 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
241 | adjust_managed_page_count(page, -1); | |
d9e427f6 | 242 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE; |
6b35e407 RR |
243 | } |
244 | ||
fad7b7b2 | 245 | num_allocated_pages = vb->num_pfns; |
e2250429 RA |
246 | /* Did we get any? */ |
247 | if (vb->num_pfns != 0) | |
248 | tell_host(vb, vb->inflate_vq); | |
249 | mutex_unlock(&vb->balloon_lock); | |
fad7b7b2 PM |
250 | |
251 | return num_allocated_pages; | |
6b35e407 RR |
252 | } |
253 | ||
195a8c43 LL |
254 | static void release_pages_balloon(struct virtio_balloon *vb, |
255 | struct list_head *pages) | |
6b35e407 | 256 | { |
195a8c43 | 257 | struct page *page, *next; |
6b35e407 | 258 | |
195a8c43 | 259 | list_for_each_entry_safe(page, next, pages, lru) { |
997e1208 DL |
260 | if (!virtio_has_feature(vb->vdev, |
261 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
262 | adjust_managed_page_count(page, 1); | |
195a8c43 | 263 | list_del(&page->lru); |
d6d86c0a | 264 | put_page(page); /* balloon reference */ |
6b35e407 RR |
265 | } |
266 | } | |
267 | ||
31532340 | 268 | static unsigned int leak_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 269 | { |
31532340 | 270 | unsigned int num_freed_pages; |
6b35e407 | 271 | struct page *page; |
9d1ba805 | 272 | struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; |
195a8c43 | 273 | LIST_HEAD(pages); |
6b35e407 RR |
274 | |
275 | /* We can only do one array worth at a time. */ | |
276 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
277 | ||
e2250429 | 278 | mutex_lock(&vb->balloon_lock); |
37cf99e0 KN |
279 | /* We can't release more pages than taken */ |
280 | num = min(num, (size_t)vb->num_pages); | |
3ccc9372 MT |
281 | for (vb->num_pfns = 0; vb->num_pfns < num; |
282 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
283 | page = balloon_page_dequeue(vb_dev_info); |
284 | if (!page) | |
285 | break; | |
87c9403b | 286 | set_page_pfns(vb, vb->pfns + vb->num_pfns, page); |
195a8c43 | 287 | list_add(&page->lru, &pages); |
3ccc9372 | 288 | vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; |
6b35e407 RR |
289 | } |
290 | ||
1fd9c672 | 291 | num_freed_pages = vb->num_pfns; |
bf50e69f DH |
292 | /* |
293 | * Note that if | |
294 | * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); | |
295 | * is true, we *have* to do it in this order | |
296 | */ | |
8c6bab4f LC |
297 | if (vb->num_pfns != 0) |
298 | tell_host(vb, vb->deflate_vq); | |
195a8c43 | 299 | release_pages_balloon(vb, &pages); |
f68b992b | 300 | mutex_unlock(&vb->balloon_lock); |
1fd9c672 | 301 | return num_freed_pages; |
6b35e407 RR |
302 | } |
303 | ||
9564e138 AL |
304 | static inline void update_stat(struct virtio_balloon *vb, int idx, |
305 | u16 tag, u64 val) | |
306 | { | |
307 | BUG_ON(idx >= VIRTIO_BALLOON_S_NR); | |
df81b29c MT |
308 | vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag); |
309 | vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val); | |
9564e138 AL |
310 | } |
311 | ||
312 | #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) | |
313 | ||
9646b26e | 314 | static unsigned int update_balloon_stats(struct virtio_balloon *vb) |
9564e138 AL |
315 | { |
316 | unsigned long events[NR_VM_EVENT_ITEMS]; | |
317 | struct sysinfo i; | |
9646b26e | 318 | unsigned int idx = 0; |
5057dcd0 | 319 | long available; |
4d32029b | 320 | unsigned long caches; |
9564e138 AL |
321 | |
322 | all_vm_events(events); | |
323 | si_meminfo(&i); | |
324 | ||
5057dcd0 | 325 | available = si_mem_available(); |
4d32029b | 326 | caches = global_node_page_state(NR_FILE_PAGES); |
5057dcd0 | 327 | |
f0bb2d50 | 328 | #ifdef CONFIG_VM_EVENT_COUNTERS |
9564e138 AL |
329 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, |
330 | pages_to_bytes(events[PSWPIN])); | |
331 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, | |
332 | pages_to_bytes(events[PSWPOUT])); | |
333 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); | |
334 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); | |
6c64fe7f JH |
335 | #ifdef CONFIG_HUGETLB_PAGE |
336 | update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC, | |
337 | events[HTLB_BUDDY_PGALLOC]); | |
338 | update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGFAIL, | |
339 | events[HTLB_BUDDY_PGALLOC_FAIL]); | |
340 | #endif | |
f0bb2d50 | 341 | #endif |
9564e138 AL |
342 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, |
343 | pages_to_bytes(i.freeram)); | |
344 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, | |
345 | pages_to_bytes(i.totalram)); | |
5057dcd0 IR |
346 | update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL, |
347 | pages_to_bytes(available)); | |
4d32029b TG |
348 | update_stat(vb, idx++, VIRTIO_BALLOON_S_CACHES, |
349 | pages_to_bytes(caches)); | |
9646b26e LP |
350 | |
351 | return idx; | |
9564e138 AL |
352 | } |
353 | ||
354 | /* | |
355 | * While most virtqueues communicate guest-initiated requests to the hypervisor, | |
356 | * the stats queue operates in reverse. The driver initializes the virtqueue | |
357 | * with a single buffer. From that point forward, all conversations consist of | |
358 | * a hypervisor request (a call to this function) which directs us to refill | |
1f34c71a | 359 | * the virtqueue with a fresh stats buffer. Since stats collection can sleep, |
fad7b7b2 PM |
360 | * we delegate the job to a freezable workqueue that will do the actual work via |
361 | * stats_handle_request(). | |
9564e138 | 362 | */ |
1f34c71a | 363 | static void stats_request(struct virtqueue *vq) |
9564e138 | 364 | { |
9c378abc | 365 | struct virtio_balloon *vb = vq->vdev->priv; |
9564e138 | 366 | |
fad7b7b2 PM |
367 | spin_lock(&vb->stop_update_lock); |
368 | if (!vb->stop_update) | |
fd0e21c3 | 369 | queue_work(system_freezable_wq, &vb->update_balloon_stats_work); |
fad7b7b2 | 370 | spin_unlock(&vb->stop_update_lock); |
1f34c71a AL |
371 | } |
372 | ||
373 | static void stats_handle_request(struct virtio_balloon *vb) | |
374 | { | |
375 | struct virtqueue *vq; | |
376 | struct scatterlist sg; | |
9646b26e | 377 | unsigned int len, num_stats; |
9564e138 | 378 | |
9646b26e | 379 | num_stats = update_balloon_stats(vb); |
9564e138 | 380 | |
1f34c71a | 381 | vq = vb->stats_vq; |
9c378abc MT |
382 | if (!virtqueue_get_buf(vq, &len)) |
383 | return; | |
9646b26e | 384 | sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); |
4951cc90 | 385 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 386 | virtqueue_kick(vq); |
9564e138 AL |
387 | } |
388 | ||
bdc1681c | 389 | static inline s64 towards_target(struct virtio_balloon *vb) |
6b35e407 | 390 | { |
1a87228f | 391 | s64 target; |
df81b29c | 392 | u32 num_pages; |
1a87228f | 393 | |
df81b29c | 394 | /* Legacy balloon config space is LE, unlike all other devices. */ |
805769d7 MT |
395 | virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages, |
396 | &num_pages); | |
df81b29c MT |
397 | |
398 | target = num_pages; | |
1a87228f | 399 | return target - vb->num_pages; |
6b35e407 RR |
400 | } |
401 | ||
86a55978 WW |
402 | /* Gives back @num_to_return blocks of free pages to mm. */ |
403 | static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb, | |
404 | unsigned long num_to_return) | |
405 | { | |
406 | struct page *page; | |
407 | unsigned long num_returned; | |
408 | ||
409 | spin_lock_irq(&vb->free_page_list_lock); | |
410 | for (num_returned = 0; num_returned < num_to_return; num_returned++) { | |
411 | page = balloon_page_pop(&vb->free_page_list); | |
412 | if (!page) | |
413 | break; | |
414 | free_pages((unsigned long)page_address(page), | |
2a946fa1 | 415 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
416 | } |
417 | vb->num_free_page_blocks -= num_returned; | |
418 | spin_unlock_irq(&vb->free_page_list_lock); | |
419 | ||
420 | return num_returned; | |
421 | } | |
422 | ||
bf4dc0b2 WW |
423 | static void virtio_balloon_queue_free_page_work(struct virtio_balloon *vb) |
424 | { | |
425 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
426 | return; | |
427 | ||
428 | /* No need to queue the work if the bit was already set. */ | |
429 | if (test_and_set_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, | |
430 | &vb->config_read_bitmap)) | |
431 | return; | |
432 | ||
433 | queue_work(vb->balloon_wq, &vb->report_free_page_work); | |
434 | } | |
435 | ||
86a55978 WW |
436 | static void virtballoon_changed(struct virtio_device *vdev) |
437 | { | |
438 | struct virtio_balloon *vb = vdev->priv; | |
439 | unsigned long flags; | |
86a55978 | 440 | |
bf4dc0b2 WW |
441 | spin_lock_irqsave(&vb->stop_update_lock, flags); |
442 | if (!vb->stop_update) { | |
443 | queue_work(system_freezable_wq, | |
444 | &vb->update_balloon_size_work); | |
445 | virtio_balloon_queue_free_page_work(vb); | |
86a55978 | 446 | } |
bf4dc0b2 | 447 | spin_unlock_irqrestore(&vb->stop_update_lock, flags); |
86a55978 WW |
448 | } |
449 | ||
6b35e407 RR |
450 | static void update_balloon_size(struct virtio_balloon *vb) |
451 | { | |
df81b29c MT |
452 | u32 actual = vb->num_pages; |
453 | ||
454 | /* Legacy balloon config space is LE, unlike all other devices. */ | |
805769d7 MT |
455 | virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, actual, |
456 | &actual); | |
6b35e407 RR |
457 | } |
458 | ||
fd0e21c3 | 459 | static void update_balloon_stats_func(struct work_struct *work) |
6b35e407 | 460 | { |
fd0e21c3 | 461 | struct virtio_balloon *vb; |
3d2a3774 | 462 | |
fd0e21c3 PM |
463 | vb = container_of(work, struct virtio_balloon, |
464 | update_balloon_stats_work); | |
465 | stats_handle_request(vb); | |
466 | } | |
1f74ef0f | 467 | |
fd0e21c3 | 468 | static void update_balloon_size_func(struct work_struct *work) |
6b35e407 | 469 | { |
fad7b7b2 PM |
470 | struct virtio_balloon *vb; |
471 | s64 diff; | |
3d2a3774 | 472 | |
fd0e21c3 PM |
473 | vb = container_of(work, struct virtio_balloon, |
474 | update_balloon_size_work); | |
fad7b7b2 | 475 | diff = towards_target(vb); |
1f74ef0f | 476 | |
53e946cb WW |
477 | if (!diff) |
478 | return; | |
479 | ||
fad7b7b2 PM |
480 | if (diff > 0) |
481 | diff -= fill_balloon(vb, diff); | |
53e946cb | 482 | else |
fad7b7b2 PM |
483 | diff += leak_balloon(vb, -diff); |
484 | update_balloon_size(vb); | |
485 | ||
486 | if (diff) | |
487 | queue_work(system_freezable_wq, work); | |
6b35e407 RR |
488 | } |
489 | ||
be91c33d | 490 | static int init_vqs(struct virtio_balloon *vb) |
6b35e407 | 491 | { |
86a55978 WW |
492 | struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX]; |
493 | vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX]; | |
494 | const char *names[VIRTIO_BALLOON_VQ_MAX]; | |
495 | int err; | |
6b35e407 | 496 | |
be91c33d | 497 | /* |
86a55978 WW |
498 | * Inflateq and deflateq are used unconditionally. The names[] |
499 | * will be NULL if the related feature is not enabled, which will | |
500 | * cause no allocation for the corresponding virtqueue in find_vqs. | |
be91c33d | 501 | */ |
86a55978 WW |
502 | callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack; |
503 | names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate"; | |
504 | callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack; | |
505 | names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; | |
5790b533 | 506 | callbacks[VIRTIO_BALLOON_VQ_STATS] = NULL; |
86a55978 | 507 | names[VIRTIO_BALLOON_VQ_STATS] = NULL; |
5790b533 | 508 | callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; |
86a55978 | 509 | names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; |
b0c504f1 | 510 | names[VIRTIO_BALLOON_VQ_REPORTING] = NULL; |
86a55978 WW |
511 | |
512 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { | |
513 | names[VIRTIO_BALLOON_VQ_STATS] = "stats"; | |
514 | callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request; | |
515 | } | |
516 | ||
517 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { | |
518 | names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq"; | |
519 | callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; | |
520 | } | |
521 | ||
b0c504f1 AD |
522 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { |
523 | names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq"; | |
524 | callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack; | |
525 | } | |
526 | ||
81a83d7f XT |
527 | err = virtio_find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, |
528 | callbacks, names, NULL); | |
d2a7ddda | 529 | if (err) |
be91c33d | 530 | return err; |
6b35e407 | 531 | |
86a55978 WW |
532 | vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; |
533 | vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; | |
9564e138 AL |
534 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { |
535 | struct scatterlist sg; | |
9646b26e | 536 | unsigned int num_stats; |
86a55978 | 537 | vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS]; |
9564e138 AL |
538 | |
539 | /* | |
540 | * Prime this virtqueue with one buffer so the hypervisor can | |
4951cc90 | 541 | * use it to signal us later (it can't be broken yet!). |
9564e138 | 542 | */ |
9646b26e | 543 | num_stats = update_balloon_stats(vb); |
fc865322 | 544 | |
9646b26e | 545 | sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); |
74cf5b16 WW |
546 | err = virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, |
547 | GFP_KERNEL); | |
548 | if (err) { | |
549 | dev_warn(&vb->vdev->dev, "%s: add stat_vq failed\n", | |
550 | __func__); | |
551 | return err; | |
552 | } | |
946cfe0e | 553 | virtqueue_kick(vb->stats_vq); |
9564e138 | 554 | } |
86a55978 WW |
555 | |
556 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
557 | vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE]; | |
558 | ||
b0c504f1 AD |
559 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) |
560 | vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING]; | |
561 | ||
86a55978 WW |
562 | return 0; |
563 | } | |
564 | ||
bf4dc0b2 WW |
565 | static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb) |
566 | { | |
567 | if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, | |
168c358a | 568 | &vb->config_read_bitmap)) { |
168c358a | 569 | /* Legacy balloon config space is LE, unlike all other devices. */ |
805769d7 MT |
570 | virtio_cread_le(vb->vdev, struct virtio_balloon_config, |
571 | free_page_hint_cmd_id, | |
572 | &vb->cmd_id_received_cache); | |
168c358a | 573 | } |
bf4dc0b2 WW |
574 | |
575 | return vb->cmd_id_received_cache; | |
576 | } | |
577 | ||
86a55978 WW |
578 | static int send_cmd_id_start(struct virtio_balloon *vb) |
579 | { | |
580 | struct scatterlist sg; | |
581 | struct virtqueue *vq = vb->free_page_vq; | |
582 | int err, unused; | |
583 | ||
584 | /* Detach all the used buffers from the vq */ | |
585 | while (virtqueue_get_buf(vq, &unused)) | |
586 | ; | |
587 | ||
8875bbba | 588 | vb->cmd_id_active = cpu_to_virtio32(vb->vdev, |
bf4dc0b2 | 589 | virtio_balloon_cmd_id_received(vb)); |
86a55978 WW |
590 | sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active)); |
591 | err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL); | |
592 | if (!err) | |
593 | virtqueue_kick(vq); | |
594 | return err; | |
595 | } | |
596 | ||
597 | static int send_cmd_id_stop(struct virtio_balloon *vb) | |
598 | { | |
599 | struct scatterlist sg; | |
600 | struct virtqueue *vq = vb->free_page_vq; | |
601 | int err, unused; | |
602 | ||
603 | /* Detach all the used buffers from the vq */ | |
604 | while (virtqueue_get_buf(vq, &unused)) | |
605 | ; | |
606 | ||
607 | sg_init_one(&sg, &vb->cmd_id_stop, sizeof(vb->cmd_id_stop)); | |
608 | err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_stop, GFP_KERNEL); | |
609 | if (!err) | |
610 | virtqueue_kick(vq); | |
611 | return err; | |
612 | } | |
613 | ||
614 | static int get_free_page_and_send(struct virtio_balloon *vb) | |
615 | { | |
616 | struct virtqueue *vq = vb->free_page_vq; | |
617 | struct page *page; | |
618 | struct scatterlist sg; | |
619 | int err, unused; | |
620 | void *p; | |
621 | ||
622 | /* Detach all the used buffers from the vq */ | |
623 | while (virtqueue_get_buf(vq, &unused)) | |
624 | ; | |
625 | ||
626 | page = alloc_pages(VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG, | |
2a946fa1 | 627 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
628 | /* |
629 | * When the allocation returns NULL, it indicates that we have got all | |
630 | * the possible free pages, so return -EINTR to stop. | |
631 | */ | |
632 | if (!page) | |
633 | return -EINTR; | |
634 | ||
635 | p = page_address(page); | |
2a946fa1 | 636 | sg_init_one(&sg, p, VIRTIO_BALLOON_HINT_BLOCK_BYTES); |
86a55978 WW |
637 | /* There is always 1 entry reserved for the cmd id to use. */ |
638 | if (vq->num_free > 1) { | |
639 | err = virtqueue_add_inbuf(vq, &sg, 1, p, GFP_KERNEL); | |
640 | if (unlikely(err)) { | |
641 | free_pages((unsigned long)p, | |
2a946fa1 | 642 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
643 | return err; |
644 | } | |
645 | virtqueue_kick(vq); | |
646 | spin_lock_irq(&vb->free_page_list_lock); | |
647 | balloon_page_push(&vb->free_page_list, page); | |
648 | vb->num_free_page_blocks++; | |
649 | spin_unlock_irq(&vb->free_page_list_lock); | |
650 | } else { | |
651 | /* | |
652 | * The vq has no available entry to add this page block, so | |
653 | * just free it. | |
654 | */ | |
2a946fa1 | 655 | free_pages((unsigned long)p, VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
656 | } |
657 | ||
be91c33d AS |
658 | return 0; |
659 | } | |
660 | ||
86a55978 WW |
661 | static int send_free_pages(struct virtio_balloon *vb) |
662 | { | |
663 | int err; | |
664 | u32 cmd_id_active; | |
665 | ||
666 | while (1) { | |
667 | /* | |
668 | * If a stop id or a new cmd id was just received from host, | |
669 | * stop the reporting. | |
670 | */ | |
671 | cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active); | |
bf4dc0b2 WW |
672 | if (unlikely(cmd_id_active != |
673 | virtio_balloon_cmd_id_received(vb))) | |
86a55978 WW |
674 | break; |
675 | ||
676 | /* | |
677 | * The free page blocks are allocated and sent to host one by | |
678 | * one. | |
679 | */ | |
680 | err = get_free_page_and_send(vb); | |
681 | if (err == -EINTR) | |
682 | break; | |
683 | else if (unlikely(err)) | |
684 | return err; | |
685 | } | |
686 | ||
687 | return 0; | |
688 | } | |
689 | ||
bf4dc0b2 | 690 | static void virtio_balloon_report_free_page(struct virtio_balloon *vb) |
86a55978 WW |
691 | { |
692 | int err; | |
86a55978 WW |
693 | struct device *dev = &vb->vdev->dev; |
694 | ||
695 | /* Start by sending the received cmd id to host with an outbuf. */ | |
696 | err = send_cmd_id_start(vb); | |
697 | if (unlikely(err)) | |
698 | dev_err(dev, "Failed to send a start id, err = %d\n", err); | |
699 | ||
700 | err = send_free_pages(vb); | |
701 | if (unlikely(err)) | |
702 | dev_err(dev, "Failed to send a free page, err = %d\n", err); | |
703 | ||
704 | /* End by sending a stop id to host with an outbuf. */ | |
705 | err = send_cmd_id_stop(vb); | |
706 | if (unlikely(err)) | |
707 | dev_err(dev, "Failed to send a stop id, err = %d\n", err); | |
708 | } | |
709 | ||
bf4dc0b2 WW |
710 | static void report_free_page_func(struct work_struct *work) |
711 | { | |
712 | struct virtio_balloon *vb = container_of(work, struct virtio_balloon, | |
713 | report_free_page_work); | |
714 | u32 cmd_id_received; | |
715 | ||
716 | cmd_id_received = virtio_balloon_cmd_id_received(vb); | |
717 | if (cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { | |
718 | /* Pass ULONG_MAX to give back all the free pages */ | |
719 | return_free_pages_to_mm(vb, ULONG_MAX); | |
720 | } else if (cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && | |
721 | cmd_id_received != | |
722 | virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) { | |
723 | virtio_balloon_report_free_page(vb); | |
724 | } | |
725 | } | |
726 | ||
e2250429 RA |
727 | #ifdef CONFIG_BALLOON_COMPACTION |
728 | /* | |
729 | * virtballoon_migratepage - perform the balloon page migration on behalf of | |
3fd02fbb | 730 | * a compaction thread. (called under page lock) |
9d1ba805 | 731 | * @vb_dev_info: the balloon device |
e2250429 RA |
732 | * @newpage: page that will replace the isolated page after migration finishes. |
733 | * @page : the isolated (old) page that is about to be migrated to newpage. | |
734 | * @mode : compaction mode -- not used for balloon page migration. | |
735 | * | |
736 | * After a ballooned page gets isolated by compaction procedures, this is the | |
737 | * function that performs the page migration on behalf of a compaction thread | |
738 | * The page migration for virtio balloon is done in a simple swap fashion which | |
739 | * follows these two macro steps: | |
740 | * 1) insert newpage into vb->pages list and update the host about it; | |
741 | * 2) update the host about the old page removed from vb->pages list; | |
742 | * | |
743 | * This function preforms the balloon page migration task. | |
744 | * Called through balloon_mapping->a_ops->migratepage | |
745 | */ | |
9d1ba805 | 746 | static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, |
e2250429 RA |
747 | struct page *newpage, struct page *page, enum migrate_mode mode) |
748 | { | |
9d1ba805 KK |
749 | struct virtio_balloon *vb = container_of(vb_dev_info, |
750 | struct virtio_balloon, vb_dev_info); | |
e2250429 RA |
751 | unsigned long flags; |
752 | ||
e2250429 RA |
753 | /* |
754 | * In order to avoid lock contention while migrating pages concurrently | |
755 | * to leak_balloon() or fill_balloon() we just give up the balloon_lock | |
756 | * this turn, as it is easier to retry the page migration later. | |
757 | * This also prevents fill_balloon() getting stuck into a mutex | |
758 | * recursion in the case it ends up triggering memory compaction | |
759 | * while it is attempting to inflate the ballon. | |
760 | */ | |
761 | if (!mutex_trylock(&vb->balloon_lock)) | |
762 | return -EAGAIN; | |
763 | ||
d6d86c0a KK |
764 | get_page(newpage); /* balloon reference */ |
765 | ||
63341ab0 DH |
766 | /* |
767 | * When we migrate a page to a different zone and adjusted the | |
768 | * managed page count when inflating, we have to fixup the count of | |
769 | * both involved zones. | |
770 | */ | |
771 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) && | |
772 | page_zone(page) != page_zone(newpage)) { | |
773 | adjust_managed_page_count(page, 1); | |
774 | adjust_managed_page_count(newpage, -1); | |
775 | } | |
776 | ||
e2250429 RA |
777 | /* balloon's page migration 1st step -- inflate "newpage" */ |
778 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); | |
9d1ba805 | 779 | balloon_page_insert(vb_dev_info, newpage); |
e2250429 | 780 | vb_dev_info->isolated_pages--; |
09316c09 | 781 | __count_vm_event(BALLOON_MIGRATE); |
e2250429 RA |
782 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
783 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
87c9403b | 784 | set_page_pfns(vb, vb->pfns, newpage); |
e2250429 RA |
785 | tell_host(vb, vb->inflate_vq); |
786 | ||
d6d86c0a | 787 | /* balloon's page migration 2nd step -- deflate "page" */ |
89da619b | 788 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); |
e2250429 | 789 | balloon_page_delete(page); |
89da619b | 790 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
e2250429 | 791 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; |
87c9403b | 792 | set_page_pfns(vb, vb->pfns, page); |
e2250429 RA |
793 | tell_host(vb, vb->deflate_vq); |
794 | ||
795 | mutex_unlock(&vb->balloon_lock); | |
796 | ||
d6d86c0a KK |
797 | put_page(page); /* balloon reference */ |
798 | ||
dd4123f3 | 799 | return MIGRATEPAGE_SUCCESS; |
e2250429 | 800 | } |
e2250429 RA |
801 | #endif /* CONFIG_BALLOON_COMPACTION */ |
802 | ||
86a55978 WW |
803 | static unsigned long shrink_free_pages(struct virtio_balloon *vb, |
804 | unsigned long pages_to_free) | |
71994620 | 805 | { |
86a55978 | 806 | unsigned long blocks_to_free, blocks_freed; |
71994620 | 807 | |
86a55978 | 808 | pages_to_free = round_up(pages_to_free, |
63b9b80e MT |
809 | VIRTIO_BALLOON_HINT_BLOCK_PAGES); |
810 | blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES; | |
86a55978 WW |
811 | blocks_freed = return_free_pages_to_mm(vb, blocks_to_free); |
812 | ||
63b9b80e | 813 | return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES; |
86a55978 WW |
814 | } |
815 | ||
86a55978 WW |
816 | static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker, |
817 | struct shrink_control *sc) | |
818 | { | |
86a55978 WW |
819 | struct virtio_balloon *vb = container_of(shrinker, |
820 | struct virtio_balloon, shrinker); | |
821 | ||
da10329c | 822 | return shrink_free_pages(vb, sc->nr_to_scan); |
71994620 WW |
823 | } |
824 | ||
825 | static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker, | |
826 | struct shrink_control *sc) | |
827 | { | |
828 | struct virtio_balloon *vb = container_of(shrinker, | |
829 | struct virtio_balloon, shrinker); | |
830 | ||
da10329c DH |
831 | return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES; |
832 | } | |
833 | ||
834 | static int virtio_balloon_oom_notify(struct notifier_block *nb, | |
835 | unsigned long dummy, void *parm) | |
836 | { | |
837 | struct virtio_balloon *vb = container_of(nb, | |
838 | struct virtio_balloon, oom_nb); | |
839 | unsigned long *freed = parm; | |
840 | ||
841 | *freed += leak_balloon(vb, VIRTIO_BALLOON_OOM_NR_PAGES) / | |
842 | VIRTIO_BALLOON_PAGES_PER_PAGE; | |
843 | update_balloon_size(vb); | |
86a55978 | 844 | |
da10329c | 845 | return NOTIFY_OK; |
71994620 WW |
846 | } |
847 | ||
848 | static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb) | |
849 | { | |
850 | unregister_shrinker(&vb->shrinker); | |
851 | } | |
852 | ||
853 | static int virtio_balloon_register_shrinker(struct virtio_balloon *vb) | |
854 | { | |
855 | vb->shrinker.scan_objects = virtio_balloon_shrinker_scan; | |
856 | vb->shrinker.count_objects = virtio_balloon_shrinker_count; | |
857 | vb->shrinker.seeks = DEFAULT_SEEKS; | |
858 | ||
e33c267a | 859 | return register_shrinker(&vb->shrinker, "virtio-balloon"); |
71994620 WW |
860 | } |
861 | ||
be91c33d AS |
862 | static int virtballoon_probe(struct virtio_device *vdev) |
863 | { | |
864 | struct virtio_balloon *vb; | |
865 | int err; | |
866 | ||
2d9becc1 MT |
867 | if (!vdev->config->get) { |
868 | dev_err(&vdev->dev, "%s failure: config access disabled\n", | |
869 | __func__); | |
870 | return -EINVAL; | |
871 | } | |
872 | ||
c51d8fca | 873 | vdev->priv = vb = kzalloc(sizeof(*vb), GFP_KERNEL); |
be91c33d AS |
874 | if (!vb) { |
875 | err = -ENOMEM; | |
876 | goto out; | |
877 | } | |
878 | ||
fd0e21c3 PM |
879 | INIT_WORK(&vb->update_balloon_stats_work, update_balloon_stats_func); |
880 | INIT_WORK(&vb->update_balloon_size_work, update_balloon_size_func); | |
fad7b7b2 | 881 | spin_lock_init(&vb->stop_update_lock); |
e2250429 | 882 | mutex_init(&vb->balloon_lock); |
9c378abc | 883 | init_waitqueue_head(&vb->acked); |
be91c33d | 884 | vb->vdev = vdev; |
be91c33d | 885 | |
9d1ba805 | 886 | balloon_devinfo_init(&vb->vb_dev_info); |
e2250429 | 887 | |
be91c33d AS |
888 | err = init_vqs(vb); |
889 | if (err) | |
9d1ba805 | 890 | goto out_free_vb; |
6b35e407 | 891 | |
b1123ea6 | 892 | #ifdef CONFIG_BALLOON_COMPACTION |
b1123ea6 | 893 | vb->vb_dev_info.migratepage = virtballoon_migratepage; |
b1123ea6 | 894 | #endif |
86a55978 WW |
895 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { |
896 | /* | |
897 | * There is always one entry reserved for cmd id, so the ring | |
898 | * size needs to be at least two to report free page hints. | |
899 | */ | |
900 | if (virtqueue_get_vring_size(vb->free_page_vq) < 2) { | |
901 | err = -ENOSPC; | |
68f2736a | 902 | goto out_del_vqs; |
86a55978 WW |
903 | } |
904 | vb->balloon_wq = alloc_workqueue("balloon-wq", | |
905 | WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0); | |
906 | if (!vb->balloon_wq) { | |
907 | err = -ENOMEM; | |
68f2736a | 908 | goto out_del_vqs; |
86a55978 WW |
909 | } |
910 | INIT_WORK(&vb->report_free_page_work, report_free_page_func); | |
bf4dc0b2 | 911 | vb->cmd_id_received_cache = VIRTIO_BALLOON_CMD_ID_STOP; |
86a55978 WW |
912 | vb->cmd_id_active = cpu_to_virtio32(vb->vdev, |
913 | VIRTIO_BALLOON_CMD_ID_STOP); | |
914 | vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, | |
915 | VIRTIO_BALLOON_CMD_ID_STOP); | |
86a55978 WW |
916 | spin_lock_init(&vb->free_page_list_lock); |
917 | INIT_LIST_HEAD(&vb->free_page_list); | |
da10329c DH |
918 | /* |
919 | * We're allowed to reuse any free pages, even if they are | |
920 | * still to be processed by the host. | |
921 | */ | |
922 | err = virtio_balloon_register_shrinker(vb); | |
923 | if (err) | |
924 | goto out_del_balloon_wq; | |
925 | } | |
926 | ||
927 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) { | |
928 | vb->oom_nb.notifier_call = virtio_balloon_oom_notify; | |
929 | vb->oom_nb.priority = VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY; | |
930 | err = register_oom_notifier(&vb->oom_nb); | |
931 | if (err < 0) | |
932 | goto out_unregister_shrinker; | |
d74b78fa | 933 | } |
da10329c | 934 | |
d74b78fa AD |
935 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { |
936 | /* Start with poison val of 0 representing general init */ | |
937 | __u32 poison_val = 0; | |
938 | ||
939 | /* | |
940 | * Let the hypervisor know that we are expecting a | |
941 | * specific value to be written back in balloon pages. | |
ca72cc34 AD |
942 | * |
943 | * If the PAGE_POISON value was larger than a byte we would | |
944 | * need to byte swap poison_val here to guarantee it is | |
945 | * little-endian. However for now it is a single byte so we | |
946 | * can pass it as-is. | |
d74b78fa AD |
947 | */ |
948 | if (!want_init_on_free()) | |
2e991629 | 949 | memset(&poison_val, PAGE_POISON, sizeof(poison_val)); |
d74b78fa | 950 | |
805769d7 MT |
951 | virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, |
952 | poison_val, &poison_val); | |
86a55978 | 953 | } |
b0c504f1 AD |
954 | |
955 | vb->pr_dev_info.report = virtballoon_free_page_report; | |
956 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { | |
957 | unsigned int capacity; | |
958 | ||
959 | capacity = virtqueue_get_vring_size(vb->reporting_vq); | |
960 | if (capacity < PAGE_REPORTING_CAPACITY) { | |
961 | err = -ENOSPC; | |
da10329c | 962 | goto out_unregister_oom; |
b0c504f1 AD |
963 | } |
964 | ||
f8af4d08 GS |
965 | /* |
966 | * The default page reporting order is @pageblock_order, which | |
967 | * corresponds to 512MB in size on ARM64 when 64KB base page | |
968 | * size is used. The page reporting won't be triggered if the | |
969 | * freeing page can't come up with a free area like that huge. | |
970 | * So we specify the page reporting order to 5, corresponding | |
971 | * to 2MB. It helps to avoid THP splitting if 4KB base page | |
972 | * size is used by host. | |
973 | * | |
974 | * Ideally, the page reporting order is selected based on the | |
975 | * host's base page size. However, it needs more work to report | |
976 | * that value. The hard-coded order would be fine currently. | |
977 | */ | |
978 | #if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES) | |
979 | vb->pr_dev_info.order = 5; | |
980 | #endif | |
981 | ||
b0c504f1 AD |
982 | err = page_reporting_register(&vb->pr_dev_info); |
983 | if (err) | |
da10329c | 984 | goto out_unregister_oom; |
b0c504f1 AD |
985 | } |
986 | ||
88660f7f MT |
987 | virtio_device_ready(vdev); |
988 | ||
8424af53 KN |
989 | if (towards_target(vb)) |
990 | virtballoon_changed(vdev); | |
6b35e407 RR |
991 | return 0; |
992 | ||
da10329c | 993 | out_unregister_oom: |
b0c504f1 | 994 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) |
da10329c DH |
995 | unregister_oom_notifier(&vb->oom_nb); |
996 | out_unregister_shrinker: | |
997 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
b0c504f1 | 998 | virtio_balloon_unregister_shrinker(vb); |
86a55978 WW |
999 | out_del_balloon_wq: |
1000 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
1001 | destroy_workqueue(vb->balloon_wq); | |
b1123ea6 | 1002 | out_del_vqs: |
d2a7ddda | 1003 | vdev->config->del_vqs(vdev); |
6b35e407 RR |
1004 | out_free_vb: |
1005 | kfree(vb); | |
1006 | out: | |
1007 | return err; | |
1008 | } | |
1009 | ||
c877bab5 | 1010 | static void remove_common(struct virtio_balloon *vb) |
6b35e407 | 1011 | { |
6b35e407 RR |
1012 | /* There might be pages left in the balloon: free them. */ |
1013 | while (vb->num_pages) | |
1014 | leak_balloon(vb, vb->num_pages); | |
b8ae0eb3 | 1015 | update_balloon_size(vb); |
6b35e407 | 1016 | |
6c22dc61 DH |
1017 | /* There might be free pages that are being reported: release them. */ |
1018 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
1019 | return_free_pages_to_mm(vb, ULONG_MAX); | |
1020 | ||
6b35e407 | 1021 | /* Now we reset the device so we can clean up the queues. */ |
d9679d00 | 1022 | virtio_reset_device(vb->vdev); |
6b35e407 | 1023 | |
c877bab5 AS |
1024 | vb->vdev->config->del_vqs(vb->vdev); |
1025 | } | |
1026 | ||
8590dbc7 | 1027 | static void virtballoon_remove(struct virtio_device *vdev) |
c877bab5 AS |
1028 | { |
1029 | struct virtio_balloon *vb = vdev->priv; | |
1030 | ||
b0c504f1 AD |
1031 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) |
1032 | page_reporting_unregister(&vb->pr_dev_info); | |
71994620 | 1033 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) |
da10329c DH |
1034 | unregister_oom_notifier(&vb->oom_nb); |
1035 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
71994620 | 1036 | virtio_balloon_unregister_shrinker(vb); |
fad7b7b2 PM |
1037 | spin_lock_irq(&vb->stop_update_lock); |
1038 | vb->stop_update = true; | |
1039 | spin_unlock_irq(&vb->stop_update_lock); | |
fd0e21c3 PM |
1040 | cancel_work_sync(&vb->update_balloon_size_work); |
1041 | cancel_work_sync(&vb->update_balloon_stats_work); | |
fad7b7b2 | 1042 | |
86a55978 WW |
1043 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { |
1044 | cancel_work_sync(&vb->report_free_page_work); | |
1045 | destroy_workqueue(vb->balloon_wq); | |
1046 | } | |
1047 | ||
c877bab5 | 1048 | remove_common(vb); |
6b35e407 RR |
1049 | kfree(vb); |
1050 | } | |
1051 | ||
89107000 | 1052 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
1053 | static int virtballoon_freeze(struct virtio_device *vdev) |
1054 | { | |
4eb05d56 AS |
1055 | struct virtio_balloon *vb = vdev->priv; |
1056 | ||
e562966d | 1057 | /* |
fad7b7b2 | 1058 | * The workqueue is already frozen by the PM core before this |
e562966d AS |
1059 | * function is called. |
1060 | */ | |
c877bab5 | 1061 | remove_common(vb); |
e562966d AS |
1062 | return 0; |
1063 | } | |
1064 | ||
c45b4166 | 1065 | static int virtballoon_restore(struct virtio_device *vdev) |
4eb05d56 AS |
1066 | { |
1067 | struct virtio_balloon *vb = vdev->priv; | |
1068 | int ret; | |
1069 | ||
1070 | ret = init_vqs(vdev->priv); | |
1071 | if (ret) | |
1072 | return ret; | |
1073 | ||
486d2e63 MT |
1074 | virtio_device_ready(vdev); |
1075 | ||
fad7b7b2 PM |
1076 | if (towards_target(vb)) |
1077 | virtballoon_changed(vdev); | |
4eb05d56 AS |
1078 | update_balloon_size(vb); |
1079 | return 0; | |
1080 | } | |
e562966d AS |
1081 | #endif |
1082 | ||
e41b1355 MT |
1083 | static int virtballoon_validate(struct virtio_device *vdev) |
1084 | { | |
fb69c2c8 AD |
1085 | /* |
1086 | * Inform the hypervisor that our pages are poisoned or | |
1087 | * initialized. If we cannot do that then we should disable | |
1088 | * page reporting as it could potentially change the contents | |
1089 | * of our free pages. | |
1090 | */ | |
8f424750 | 1091 | if (!want_init_on_free() && !page_poisoning_enabled_static()) |
2e991629 | 1092 | __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON); |
fb69c2c8 AD |
1093 | else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) |
1094 | __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING); | |
2e991629 | 1095 | |
321bd212 | 1096 | __virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM); |
e41b1355 MT |
1097 | return 0; |
1098 | } | |
1099 | ||
9564e138 AL |
1100 | static unsigned int features[] = { |
1101 | VIRTIO_BALLOON_F_MUST_TELL_HOST, | |
1102 | VIRTIO_BALLOON_F_STATS_VQ, | |
5a10b7db | 1103 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM, |
86a55978 | 1104 | VIRTIO_BALLOON_F_FREE_PAGE_HINT, |
2e991629 | 1105 | VIRTIO_BALLOON_F_PAGE_POISON, |
b0c504f1 | 1106 | VIRTIO_BALLOON_F_REPORTING, |
9564e138 | 1107 | }; |
c45a6816 | 1108 | |
d817cd52 | 1109 | static struct virtio_driver virtio_balloon_driver = { |
c45a6816 RR |
1110 | .feature_table = features, |
1111 | .feature_table_size = ARRAY_SIZE(features), | |
6b35e407 RR |
1112 | .driver.name = KBUILD_MODNAME, |
1113 | .driver.owner = THIS_MODULE, | |
1114 | .id_table = id_table, | |
e41b1355 | 1115 | .validate = virtballoon_validate, |
6b35e407 | 1116 | .probe = virtballoon_probe, |
8590dbc7 | 1117 | .remove = virtballoon_remove, |
6b35e407 | 1118 | .config_changed = virtballoon_changed, |
89107000 | 1119 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
1120 | .freeze = virtballoon_freeze, |
1121 | .restore = virtballoon_restore, | |
e562966d | 1122 | #endif |
6b35e407 RR |
1123 | }; |
1124 | ||
b2a17029 | 1125 | module_virtio_driver(virtio_balloon_driver); |
6b35e407 RR |
1126 | MODULE_DEVICE_TABLE(virtio, id_table); |
1127 | MODULE_DESCRIPTION("Virtio balloon driver"); | |
1128 | MODULE_LICENSE("GPL"); |