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> |
b1123ea6 | 20 | #include <linux/mount.h> |
50d34394 | 21 | #include <linux/magic.h> |
99558d20 | 22 | #include <linux/pseudo_fs.h> |
b0c504f1 | 23 | #include <linux/page_reporting.h> |
6b35e407 | 24 | |
3ccc9372 MT |
25 | /* |
26 | * Balloon device works in 4K page units. So each page is pointed to by | |
27 | * multiple balloon pages. All memory counters in this driver are in balloon | |
28 | * page units. | |
29 | */ | |
e2250429 RA |
30 | #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) |
31 | #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 | |
da10329c DH |
32 | /* Maximum number of (4k) pages to deflate on OOM notifications. */ |
33 | #define VIRTIO_BALLOON_OOM_NR_PAGES 256 | |
34 | #define VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY 80 | |
5a10b7db | 35 | |
86a55978 WW |
36 | #define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \ |
37 | __GFP_NOMEMALLOC) | |
38 | /* The order of free page blocks to report to host */ | |
2a946fa1 | 39 | #define VIRTIO_BALLOON_HINT_BLOCK_ORDER (MAX_ORDER - 1) |
86a55978 | 40 | /* The size of a free page block in bytes */ |
2a946fa1 MT |
41 | #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \ |
42 | (1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT)) | |
63b9b80e | 43 | #define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER) |
86a55978 | 44 | |
b1123ea6 MK |
45 | #ifdef CONFIG_BALLOON_COMPACTION |
46 | static struct vfsmount *balloon_mnt; | |
47 | #endif | |
48 | ||
86a55978 WW |
49 | enum virtio_balloon_vq { |
50 | VIRTIO_BALLOON_VQ_INFLATE, | |
51 | VIRTIO_BALLOON_VQ_DEFLATE, | |
52 | VIRTIO_BALLOON_VQ_STATS, | |
53 | VIRTIO_BALLOON_VQ_FREE_PAGE, | |
b0c504f1 | 54 | VIRTIO_BALLOON_VQ_REPORTING, |
86a55978 WW |
55 | VIRTIO_BALLOON_VQ_MAX |
56 | }; | |
57 | ||
bf4dc0b2 WW |
58 | enum virtio_balloon_config_read { |
59 | VIRTIO_BALLOON_CONFIG_READ_CMD_ID = 0, | |
60 | }; | |
61 | ||
25e65e4e | 62 | struct virtio_balloon { |
6b35e407 | 63 | struct virtio_device *vdev; |
86a55978 WW |
64 | struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; |
65 | ||
66 | /* Balloon's own wq for cpu-intensive work items */ | |
67 | struct workqueue_struct *balloon_wq; | |
68 | /* The free page reporting work item submitted to the balloon wq */ | |
69 | struct work_struct report_free_page_work; | |
6b35e407 | 70 | |
fad7b7b2 | 71 | /* The balloon servicing is delegated to a freezable workqueue. */ |
fd0e21c3 PM |
72 | struct work_struct update_balloon_stats_work; |
73 | struct work_struct update_balloon_size_work; | |
6b35e407 | 74 | |
fad7b7b2 PM |
75 | /* Prevent updating balloon when it is being canceled. */ |
76 | spinlock_t stop_update_lock; | |
77 | bool stop_update; | |
bf4dc0b2 WW |
78 | /* Bitmap to indicate if reading the related config fields are needed */ |
79 | unsigned long config_read_bitmap; | |
6b35e407 | 80 | |
86a55978 WW |
81 | /* The list of allocated free pages, waiting to be given back to mm */ |
82 | struct list_head free_page_list; | |
83 | spinlock_t free_page_list_lock; | |
84 | /* The number of free page blocks on the above list */ | |
85 | unsigned long num_free_page_blocks; | |
bf4dc0b2 WW |
86 | /* |
87 | * The cmd id received from host. | |
88 | * Read it via virtio_balloon_cmd_id_received to get the latest value | |
89 | * sent from host. | |
90 | */ | |
91 | u32 cmd_id_received_cache; | |
86a55978 WW |
92 | /* The cmd id that is actively in use */ |
93 | __virtio32 cmd_id_active; | |
94 | /* Buffer to store the stop sign */ | |
95 | __virtio32 cmd_id_stop; | |
96 | ||
6b35e407 | 97 | /* Waiting for host to ack the pages we released. */ |
9c378abc | 98 | wait_queue_head_t acked; |
6b35e407 | 99 | |
3ccc9372 | 100 | /* Number of balloon pages we've told the Host we're not using. */ |
6b35e407 | 101 | unsigned int num_pages; |
3ccc9372 | 102 | /* |
e2250429 RA |
103 | * The pages we've told the Host we're not using are enqueued |
104 | * at vb_dev_info->pages list. | |
3ccc9372 MT |
105 | * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE |
106 | * to num_pages above. | |
107 | */ | |
9d1ba805 | 108 | struct balloon_dev_info vb_dev_info; |
e2250429 RA |
109 | |
110 | /* Synchronize access/update to this struct virtio_balloon elements */ | |
111 | struct mutex balloon_lock; | |
6b35e407 RR |
112 | |
113 | /* The array of pfns we tell the Host about. */ | |
114 | unsigned int num_pfns; | |
87c9403b | 115 | __virtio32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; |
9564e138 AL |
116 | |
117 | /* Memory statistics */ | |
118 | struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; | |
5a10b7db | 119 | |
da10329c | 120 | /* Shrinker to return free pages - VIRTIO_BALLOON_F_FREE_PAGE_HINT */ |
71994620 | 121 | struct shrinker shrinker; |
b0c504f1 | 122 | |
da10329c DH |
123 | /* OOM notifier to deflate on OOM - VIRTIO_BALLOON_F_DEFLATE_ON_OOM */ |
124 | struct notifier_block oom_nb; | |
125 | ||
b0c504f1 AD |
126 | /* Free page reporting device */ |
127 | struct virtqueue *reporting_vq; | |
128 | struct page_reporting_dev_info pr_dev_info; | |
6b35e407 RR |
129 | }; |
130 | ||
bfec6c83 | 131 | static const struct virtio_device_id id_table[] = { |
6b35e407 RR |
132 | { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID }, |
133 | { 0 }, | |
134 | }; | |
135 | ||
1b4aa2fa HB |
136 | static u32 page_to_balloon_pfn(struct page *page) |
137 | { | |
138 | unsigned long pfn = page_to_pfn(page); | |
139 | ||
140 | BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); | |
141 | /* Convert pfn from Linux page size to balloon page size. */ | |
3ccc9372 MT |
142 | return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; |
143 | } | |
144 | ||
6b35e407 RR |
145 | static void balloon_ack(struct virtqueue *vq) |
146 | { | |
9c378abc | 147 | struct virtio_balloon *vb = vq->vdev->priv; |
6b35e407 | 148 | |
9c378abc | 149 | wake_up(&vb->acked); |
6b35e407 RR |
150 | } |
151 | ||
152 | static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) | |
153 | { | |
154 | struct scatterlist sg; | |
9c378abc | 155 | unsigned int len; |
6b35e407 RR |
156 | |
157 | sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); | |
158 | ||
6b35e407 | 159 | /* We should always be able to add one buffer to an empty queue. */ |
4951cc90 | 160 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 161 | virtqueue_kick(vq); |
6b35e407 RR |
162 | |
163 | /* When host has read buffer, this completes via balloon_ack */ | |
9c378abc | 164 | wait_event(vb->acked, virtqueue_get_buf(vq, &len)); |
fd0e21c3 | 165 | |
6b35e407 RR |
166 | } |
167 | ||
dc39cbb4 | 168 | static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info, |
b0c504f1 AD |
169 | struct scatterlist *sg, unsigned int nents) |
170 | { | |
171 | struct virtio_balloon *vb = | |
172 | container_of(pr_dev_info, struct virtio_balloon, pr_dev_info); | |
173 | struct virtqueue *vq = vb->reporting_vq; | |
174 | unsigned int unused, err; | |
175 | ||
176 | /* We should always be able to add these buffers to an empty queue. */ | |
177 | err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT | __GFP_NOWARN); | |
178 | ||
179 | /* | |
180 | * In the extremely unlikely case that something has occurred and we | |
181 | * are able to trigger an error we will simply display a warning | |
182 | * and exit without actually processing the pages. | |
183 | */ | |
184 | if (WARN_ON_ONCE(err)) | |
185 | return err; | |
186 | ||
187 | virtqueue_kick(vq); | |
188 | ||
189 | /* When host has read buffer, this completes via balloon_ack */ | |
190 | wait_event(vb->acked, virtqueue_get_buf(vq, &unused)); | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
87c9403b MT |
195 | static void set_page_pfns(struct virtio_balloon *vb, |
196 | __virtio32 pfns[], struct page *page) | |
3ccc9372 MT |
197 | { |
198 | unsigned int i; | |
199 | ||
6e9826e7 MT |
200 | BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE > VIRTIO_BALLOON_ARRAY_PFNS_MAX); |
201 | ||
f9aada5f WW |
202 | /* |
203 | * Set balloon pfns pointing at this page. | |
204 | * Note that the first pfn points at start of the page. | |
205 | */ | |
3ccc9372 | 206 | for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++) |
87c9403b MT |
207 | pfns[i] = cpu_to_virtio32(vb->vdev, |
208 | page_to_balloon_pfn(page) + i); | |
3ccc9372 MT |
209 | } |
210 | ||
fad7b7b2 | 211 | static unsigned fill_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 212 | { |
fad7b7b2 | 213 | unsigned num_allocated_pages; |
c7cdff0e MT |
214 | unsigned num_pfns; |
215 | struct page *page; | |
216 | LIST_HEAD(pages); | |
e2250429 | 217 | |
6b35e407 RR |
218 | /* We can only do one array worth at a time. */ |
219 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
220 | ||
c7cdff0e MT |
221 | for (num_pfns = 0; num_pfns < num; |
222 | num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
223 | struct page *page = balloon_page_alloc(); | |
e2250429 | 224 | |
6b35e407 | 225 | if (!page) { |
800ba5ea | 226 | dev_info_ratelimited(&vb->vdev->dev, |
b7dfde95 LT |
227 | "Out of puff! Can't get %u pages\n", |
228 | VIRTIO_BALLOON_PAGES_PER_PAGE); | |
6b35e407 RR |
229 | /* Sleep for at least 1/5 of a second before retry. */ |
230 | msleep(200); | |
231 | break; | |
232 | } | |
c7cdff0e MT |
233 | |
234 | balloon_page_push(&pages, page); | |
235 | } | |
236 | ||
237 | mutex_lock(&vb->balloon_lock); | |
238 | ||
239 | vb->num_pfns = 0; | |
240 | ||
241 | while ((page = balloon_page_pop(&pages))) { | |
242 | balloon_page_enqueue(&vb->vb_dev_info, page); | |
243 | ||
87c9403b | 244 | set_page_pfns(vb, vb->pfns + vb->num_pfns, page); |
3ccc9372 | 245 | vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; |
997e1208 DL |
246 | if (!virtio_has_feature(vb->vdev, |
247 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
248 | adjust_managed_page_count(page, -1); | |
d9e427f6 | 249 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE; |
6b35e407 RR |
250 | } |
251 | ||
fad7b7b2 | 252 | num_allocated_pages = vb->num_pfns; |
e2250429 RA |
253 | /* Did we get any? */ |
254 | if (vb->num_pfns != 0) | |
255 | tell_host(vb, vb->inflate_vq); | |
256 | mutex_unlock(&vb->balloon_lock); | |
fad7b7b2 PM |
257 | |
258 | return num_allocated_pages; | |
6b35e407 RR |
259 | } |
260 | ||
195a8c43 LL |
261 | static void release_pages_balloon(struct virtio_balloon *vb, |
262 | struct list_head *pages) | |
6b35e407 | 263 | { |
195a8c43 | 264 | struct page *page, *next; |
6b35e407 | 265 | |
195a8c43 | 266 | list_for_each_entry_safe(page, next, pages, lru) { |
997e1208 DL |
267 | if (!virtio_has_feature(vb->vdev, |
268 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
269 | adjust_managed_page_count(page, 1); | |
195a8c43 | 270 | list_del(&page->lru); |
d6d86c0a | 271 | put_page(page); /* balloon reference */ |
6b35e407 RR |
272 | } |
273 | } | |
274 | ||
1fd9c672 | 275 | static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 276 | { |
1fd9c672 | 277 | unsigned num_freed_pages; |
6b35e407 | 278 | struct page *page; |
9d1ba805 | 279 | struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; |
195a8c43 | 280 | LIST_HEAD(pages); |
6b35e407 RR |
281 | |
282 | /* We can only do one array worth at a time. */ | |
283 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
284 | ||
e2250429 | 285 | mutex_lock(&vb->balloon_lock); |
37cf99e0 KN |
286 | /* We can't release more pages than taken */ |
287 | num = min(num, (size_t)vb->num_pages); | |
3ccc9372 MT |
288 | for (vb->num_pfns = 0; vb->num_pfns < num; |
289 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
290 | page = balloon_page_dequeue(vb_dev_info); |
291 | if (!page) | |
292 | break; | |
87c9403b | 293 | set_page_pfns(vb, vb->pfns + vb->num_pfns, page); |
195a8c43 | 294 | list_add(&page->lru, &pages); |
3ccc9372 | 295 | vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; |
6b35e407 RR |
296 | } |
297 | ||
1fd9c672 | 298 | num_freed_pages = vb->num_pfns; |
bf50e69f DH |
299 | /* |
300 | * Note that if | |
301 | * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); | |
302 | * is true, we *have* to do it in this order | |
303 | */ | |
8c6bab4f LC |
304 | if (vb->num_pfns != 0) |
305 | tell_host(vb, vb->deflate_vq); | |
195a8c43 | 306 | release_pages_balloon(vb, &pages); |
f68b992b | 307 | mutex_unlock(&vb->balloon_lock); |
1fd9c672 | 308 | return num_freed_pages; |
6b35e407 RR |
309 | } |
310 | ||
9564e138 AL |
311 | static inline void update_stat(struct virtio_balloon *vb, int idx, |
312 | u16 tag, u64 val) | |
313 | { | |
314 | BUG_ON(idx >= VIRTIO_BALLOON_S_NR); | |
df81b29c MT |
315 | vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag); |
316 | vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val); | |
9564e138 AL |
317 | } |
318 | ||
319 | #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) | |
320 | ||
9646b26e | 321 | static unsigned int update_balloon_stats(struct virtio_balloon *vb) |
9564e138 AL |
322 | { |
323 | unsigned long events[NR_VM_EVENT_ITEMS]; | |
324 | struct sysinfo i; | |
9646b26e | 325 | unsigned int idx = 0; |
5057dcd0 | 326 | long available; |
4d32029b | 327 | unsigned long caches; |
9564e138 AL |
328 | |
329 | all_vm_events(events); | |
330 | si_meminfo(&i); | |
331 | ||
5057dcd0 | 332 | available = si_mem_available(); |
4d32029b | 333 | caches = global_node_page_state(NR_FILE_PAGES); |
5057dcd0 | 334 | |
f0bb2d50 | 335 | #ifdef CONFIG_VM_EVENT_COUNTERS |
9564e138 AL |
336 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, |
337 | pages_to_bytes(events[PSWPIN])); | |
338 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, | |
339 | pages_to_bytes(events[PSWPOUT])); | |
340 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); | |
341 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); | |
6c64fe7f JH |
342 | #ifdef CONFIG_HUGETLB_PAGE |
343 | update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC, | |
344 | events[HTLB_BUDDY_PGALLOC]); | |
345 | update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGFAIL, | |
346 | events[HTLB_BUDDY_PGALLOC_FAIL]); | |
347 | #endif | |
f0bb2d50 | 348 | #endif |
9564e138 AL |
349 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, |
350 | pages_to_bytes(i.freeram)); | |
351 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, | |
352 | pages_to_bytes(i.totalram)); | |
5057dcd0 IR |
353 | update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL, |
354 | pages_to_bytes(available)); | |
4d32029b TG |
355 | update_stat(vb, idx++, VIRTIO_BALLOON_S_CACHES, |
356 | pages_to_bytes(caches)); | |
9646b26e LP |
357 | |
358 | return idx; | |
9564e138 AL |
359 | } |
360 | ||
361 | /* | |
362 | * While most virtqueues communicate guest-initiated requests to the hypervisor, | |
363 | * the stats queue operates in reverse. The driver initializes the virtqueue | |
364 | * with a single buffer. From that point forward, all conversations consist of | |
365 | * a hypervisor request (a call to this function) which directs us to refill | |
1f34c71a | 366 | * the virtqueue with a fresh stats buffer. Since stats collection can sleep, |
fad7b7b2 PM |
367 | * we delegate the job to a freezable workqueue that will do the actual work via |
368 | * stats_handle_request(). | |
9564e138 | 369 | */ |
1f34c71a | 370 | static void stats_request(struct virtqueue *vq) |
9564e138 | 371 | { |
9c378abc | 372 | struct virtio_balloon *vb = vq->vdev->priv; |
9564e138 | 373 | |
fad7b7b2 PM |
374 | spin_lock(&vb->stop_update_lock); |
375 | if (!vb->stop_update) | |
fd0e21c3 | 376 | queue_work(system_freezable_wq, &vb->update_balloon_stats_work); |
fad7b7b2 | 377 | spin_unlock(&vb->stop_update_lock); |
1f34c71a AL |
378 | } |
379 | ||
380 | static void stats_handle_request(struct virtio_balloon *vb) | |
381 | { | |
382 | struct virtqueue *vq; | |
383 | struct scatterlist sg; | |
9646b26e | 384 | unsigned int len, num_stats; |
9564e138 | 385 | |
9646b26e | 386 | num_stats = update_balloon_stats(vb); |
9564e138 | 387 | |
1f34c71a | 388 | vq = vb->stats_vq; |
9c378abc MT |
389 | if (!virtqueue_get_buf(vq, &len)) |
390 | return; | |
9646b26e | 391 | sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); |
4951cc90 | 392 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 393 | virtqueue_kick(vq); |
9564e138 AL |
394 | } |
395 | ||
bdc1681c | 396 | static inline s64 towards_target(struct virtio_balloon *vb) |
6b35e407 | 397 | { |
1a87228f | 398 | s64 target; |
df81b29c | 399 | u32 num_pages; |
1a87228f | 400 | |
df81b29c | 401 | /* Legacy balloon config space is LE, unlike all other devices. */ |
805769d7 MT |
402 | virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages, |
403 | &num_pages); | |
df81b29c MT |
404 | |
405 | target = num_pages; | |
1a87228f | 406 | return target - vb->num_pages; |
6b35e407 RR |
407 | } |
408 | ||
86a55978 WW |
409 | /* Gives back @num_to_return blocks of free pages to mm. */ |
410 | static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb, | |
411 | unsigned long num_to_return) | |
412 | { | |
413 | struct page *page; | |
414 | unsigned long num_returned; | |
415 | ||
416 | spin_lock_irq(&vb->free_page_list_lock); | |
417 | for (num_returned = 0; num_returned < num_to_return; num_returned++) { | |
418 | page = balloon_page_pop(&vb->free_page_list); | |
419 | if (!page) | |
420 | break; | |
421 | free_pages((unsigned long)page_address(page), | |
2a946fa1 | 422 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
423 | } |
424 | vb->num_free_page_blocks -= num_returned; | |
425 | spin_unlock_irq(&vb->free_page_list_lock); | |
426 | ||
427 | return num_returned; | |
428 | } | |
429 | ||
bf4dc0b2 WW |
430 | static void virtio_balloon_queue_free_page_work(struct virtio_balloon *vb) |
431 | { | |
432 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
433 | return; | |
434 | ||
435 | /* No need to queue the work if the bit was already set. */ | |
436 | if (test_and_set_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, | |
437 | &vb->config_read_bitmap)) | |
438 | return; | |
439 | ||
440 | queue_work(vb->balloon_wq, &vb->report_free_page_work); | |
441 | } | |
442 | ||
86a55978 WW |
443 | static void virtballoon_changed(struct virtio_device *vdev) |
444 | { | |
445 | struct virtio_balloon *vb = vdev->priv; | |
446 | unsigned long flags; | |
86a55978 | 447 | |
bf4dc0b2 WW |
448 | spin_lock_irqsave(&vb->stop_update_lock, flags); |
449 | if (!vb->stop_update) { | |
450 | queue_work(system_freezable_wq, | |
451 | &vb->update_balloon_size_work); | |
452 | virtio_balloon_queue_free_page_work(vb); | |
86a55978 | 453 | } |
bf4dc0b2 | 454 | spin_unlock_irqrestore(&vb->stop_update_lock, flags); |
86a55978 WW |
455 | } |
456 | ||
6b35e407 RR |
457 | static void update_balloon_size(struct virtio_balloon *vb) |
458 | { | |
df81b29c MT |
459 | u32 actual = vb->num_pages; |
460 | ||
461 | /* Legacy balloon config space is LE, unlike all other devices. */ | |
805769d7 MT |
462 | virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, actual, |
463 | &actual); | |
6b35e407 RR |
464 | } |
465 | ||
fd0e21c3 | 466 | static void update_balloon_stats_func(struct work_struct *work) |
6b35e407 | 467 | { |
fd0e21c3 | 468 | struct virtio_balloon *vb; |
3d2a3774 | 469 | |
fd0e21c3 PM |
470 | vb = container_of(work, struct virtio_balloon, |
471 | update_balloon_stats_work); | |
472 | stats_handle_request(vb); | |
473 | } | |
1f74ef0f | 474 | |
fd0e21c3 | 475 | static void update_balloon_size_func(struct work_struct *work) |
6b35e407 | 476 | { |
fad7b7b2 PM |
477 | struct virtio_balloon *vb; |
478 | s64 diff; | |
3d2a3774 | 479 | |
fd0e21c3 PM |
480 | vb = container_of(work, struct virtio_balloon, |
481 | update_balloon_size_work); | |
fad7b7b2 | 482 | diff = towards_target(vb); |
1f74ef0f | 483 | |
53e946cb WW |
484 | if (!diff) |
485 | return; | |
486 | ||
fad7b7b2 PM |
487 | if (diff > 0) |
488 | diff -= fill_balloon(vb, diff); | |
53e946cb | 489 | else |
fad7b7b2 PM |
490 | diff += leak_balloon(vb, -diff); |
491 | update_balloon_size(vb); | |
492 | ||
493 | if (diff) | |
494 | queue_work(system_freezable_wq, work); | |
6b35e407 RR |
495 | } |
496 | ||
be91c33d | 497 | static int init_vqs(struct virtio_balloon *vb) |
6b35e407 | 498 | { |
86a55978 WW |
499 | struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX]; |
500 | vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX]; | |
501 | const char *names[VIRTIO_BALLOON_VQ_MAX]; | |
502 | int err; | |
6b35e407 | 503 | |
be91c33d | 504 | /* |
86a55978 WW |
505 | * Inflateq and deflateq are used unconditionally. The names[] |
506 | * will be NULL if the related feature is not enabled, which will | |
507 | * cause no allocation for the corresponding virtqueue in find_vqs. | |
be91c33d | 508 | */ |
86a55978 WW |
509 | callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack; |
510 | names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate"; | |
511 | callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack; | |
512 | names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; | |
5790b533 | 513 | callbacks[VIRTIO_BALLOON_VQ_STATS] = NULL; |
86a55978 | 514 | names[VIRTIO_BALLOON_VQ_STATS] = NULL; |
5790b533 | 515 | callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; |
86a55978 | 516 | names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; |
b0c504f1 | 517 | names[VIRTIO_BALLOON_VQ_REPORTING] = NULL; |
86a55978 WW |
518 | |
519 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { | |
520 | names[VIRTIO_BALLOON_VQ_STATS] = "stats"; | |
521 | callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request; | |
522 | } | |
523 | ||
524 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { | |
525 | names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq"; | |
526 | callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; | |
527 | } | |
528 | ||
b0c504f1 AD |
529 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { |
530 | names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq"; | |
531 | callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack; | |
532 | } | |
533 | ||
81a83d7f XT |
534 | err = virtio_find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, |
535 | callbacks, names, NULL); | |
d2a7ddda | 536 | if (err) |
be91c33d | 537 | return err; |
6b35e407 | 538 | |
86a55978 WW |
539 | vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; |
540 | vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; | |
9564e138 AL |
541 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { |
542 | struct scatterlist sg; | |
9646b26e | 543 | unsigned int num_stats; |
86a55978 | 544 | vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS]; |
9564e138 AL |
545 | |
546 | /* | |
547 | * Prime this virtqueue with one buffer so the hypervisor can | |
4951cc90 | 548 | * use it to signal us later (it can't be broken yet!). |
9564e138 | 549 | */ |
9646b26e | 550 | num_stats = update_balloon_stats(vb); |
fc865322 | 551 | |
9646b26e | 552 | sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); |
74cf5b16 WW |
553 | err = virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, |
554 | GFP_KERNEL); | |
555 | if (err) { | |
556 | dev_warn(&vb->vdev->dev, "%s: add stat_vq failed\n", | |
557 | __func__); | |
558 | return err; | |
559 | } | |
946cfe0e | 560 | virtqueue_kick(vb->stats_vq); |
9564e138 | 561 | } |
86a55978 WW |
562 | |
563 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
564 | vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE]; | |
565 | ||
b0c504f1 AD |
566 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) |
567 | vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING]; | |
568 | ||
86a55978 WW |
569 | return 0; |
570 | } | |
571 | ||
bf4dc0b2 WW |
572 | static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb) |
573 | { | |
574 | if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, | |
168c358a | 575 | &vb->config_read_bitmap)) { |
168c358a | 576 | /* Legacy balloon config space is LE, unlike all other devices. */ |
805769d7 MT |
577 | virtio_cread_le(vb->vdev, struct virtio_balloon_config, |
578 | free_page_hint_cmd_id, | |
579 | &vb->cmd_id_received_cache); | |
168c358a | 580 | } |
bf4dc0b2 WW |
581 | |
582 | return vb->cmd_id_received_cache; | |
583 | } | |
584 | ||
86a55978 WW |
585 | static int send_cmd_id_start(struct virtio_balloon *vb) |
586 | { | |
587 | struct scatterlist sg; | |
588 | struct virtqueue *vq = vb->free_page_vq; | |
589 | int err, unused; | |
590 | ||
591 | /* Detach all the used buffers from the vq */ | |
592 | while (virtqueue_get_buf(vq, &unused)) | |
593 | ; | |
594 | ||
8875bbba | 595 | vb->cmd_id_active = cpu_to_virtio32(vb->vdev, |
bf4dc0b2 | 596 | virtio_balloon_cmd_id_received(vb)); |
86a55978 WW |
597 | sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active)); |
598 | err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL); | |
599 | if (!err) | |
600 | virtqueue_kick(vq); | |
601 | return err; | |
602 | } | |
603 | ||
604 | static int send_cmd_id_stop(struct virtio_balloon *vb) | |
605 | { | |
606 | struct scatterlist sg; | |
607 | struct virtqueue *vq = vb->free_page_vq; | |
608 | int err, unused; | |
609 | ||
610 | /* Detach all the used buffers from the vq */ | |
611 | while (virtqueue_get_buf(vq, &unused)) | |
612 | ; | |
613 | ||
614 | sg_init_one(&sg, &vb->cmd_id_stop, sizeof(vb->cmd_id_stop)); | |
615 | err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_stop, GFP_KERNEL); | |
616 | if (!err) | |
617 | virtqueue_kick(vq); | |
618 | return err; | |
619 | } | |
620 | ||
621 | static int get_free_page_and_send(struct virtio_balloon *vb) | |
622 | { | |
623 | struct virtqueue *vq = vb->free_page_vq; | |
624 | struct page *page; | |
625 | struct scatterlist sg; | |
626 | int err, unused; | |
627 | void *p; | |
628 | ||
629 | /* Detach all the used buffers from the vq */ | |
630 | while (virtqueue_get_buf(vq, &unused)) | |
631 | ; | |
632 | ||
633 | page = alloc_pages(VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG, | |
2a946fa1 | 634 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
635 | /* |
636 | * When the allocation returns NULL, it indicates that we have got all | |
637 | * the possible free pages, so return -EINTR to stop. | |
638 | */ | |
639 | if (!page) | |
640 | return -EINTR; | |
641 | ||
642 | p = page_address(page); | |
2a946fa1 | 643 | sg_init_one(&sg, p, VIRTIO_BALLOON_HINT_BLOCK_BYTES); |
86a55978 WW |
644 | /* There is always 1 entry reserved for the cmd id to use. */ |
645 | if (vq->num_free > 1) { | |
646 | err = virtqueue_add_inbuf(vq, &sg, 1, p, GFP_KERNEL); | |
647 | if (unlikely(err)) { | |
648 | free_pages((unsigned long)p, | |
2a946fa1 | 649 | VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
650 | return err; |
651 | } | |
652 | virtqueue_kick(vq); | |
653 | spin_lock_irq(&vb->free_page_list_lock); | |
654 | balloon_page_push(&vb->free_page_list, page); | |
655 | vb->num_free_page_blocks++; | |
656 | spin_unlock_irq(&vb->free_page_list_lock); | |
657 | } else { | |
658 | /* | |
659 | * The vq has no available entry to add this page block, so | |
660 | * just free it. | |
661 | */ | |
2a946fa1 | 662 | free_pages((unsigned long)p, VIRTIO_BALLOON_HINT_BLOCK_ORDER); |
86a55978 WW |
663 | } |
664 | ||
be91c33d AS |
665 | return 0; |
666 | } | |
667 | ||
86a55978 WW |
668 | static int send_free_pages(struct virtio_balloon *vb) |
669 | { | |
670 | int err; | |
671 | u32 cmd_id_active; | |
672 | ||
673 | while (1) { | |
674 | /* | |
675 | * If a stop id or a new cmd id was just received from host, | |
676 | * stop the reporting. | |
677 | */ | |
678 | cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active); | |
bf4dc0b2 WW |
679 | if (unlikely(cmd_id_active != |
680 | virtio_balloon_cmd_id_received(vb))) | |
86a55978 WW |
681 | break; |
682 | ||
683 | /* | |
684 | * The free page blocks are allocated and sent to host one by | |
685 | * one. | |
686 | */ | |
687 | err = get_free_page_and_send(vb); | |
688 | if (err == -EINTR) | |
689 | break; | |
690 | else if (unlikely(err)) | |
691 | return err; | |
692 | } | |
693 | ||
694 | return 0; | |
695 | } | |
696 | ||
bf4dc0b2 | 697 | static void virtio_balloon_report_free_page(struct virtio_balloon *vb) |
86a55978 WW |
698 | { |
699 | int err; | |
86a55978 WW |
700 | struct device *dev = &vb->vdev->dev; |
701 | ||
702 | /* Start by sending the received cmd id to host with an outbuf. */ | |
703 | err = send_cmd_id_start(vb); | |
704 | if (unlikely(err)) | |
705 | dev_err(dev, "Failed to send a start id, err = %d\n", err); | |
706 | ||
707 | err = send_free_pages(vb); | |
708 | if (unlikely(err)) | |
709 | dev_err(dev, "Failed to send a free page, err = %d\n", err); | |
710 | ||
711 | /* End by sending a stop id to host with an outbuf. */ | |
712 | err = send_cmd_id_stop(vb); | |
713 | if (unlikely(err)) | |
714 | dev_err(dev, "Failed to send a stop id, err = %d\n", err); | |
715 | } | |
716 | ||
bf4dc0b2 WW |
717 | static void report_free_page_func(struct work_struct *work) |
718 | { | |
719 | struct virtio_balloon *vb = container_of(work, struct virtio_balloon, | |
720 | report_free_page_work); | |
721 | u32 cmd_id_received; | |
722 | ||
723 | cmd_id_received = virtio_balloon_cmd_id_received(vb); | |
724 | if (cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { | |
725 | /* Pass ULONG_MAX to give back all the free pages */ | |
726 | return_free_pages_to_mm(vb, ULONG_MAX); | |
727 | } else if (cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && | |
728 | cmd_id_received != | |
729 | virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) { | |
730 | virtio_balloon_report_free_page(vb); | |
731 | } | |
732 | } | |
733 | ||
e2250429 RA |
734 | #ifdef CONFIG_BALLOON_COMPACTION |
735 | /* | |
736 | * virtballoon_migratepage - perform the balloon page migration on behalf of | |
3fd02fbb | 737 | * a compaction thread. (called under page lock) |
9d1ba805 | 738 | * @vb_dev_info: the balloon device |
e2250429 RA |
739 | * @newpage: page that will replace the isolated page after migration finishes. |
740 | * @page : the isolated (old) page that is about to be migrated to newpage. | |
741 | * @mode : compaction mode -- not used for balloon page migration. | |
742 | * | |
743 | * After a ballooned page gets isolated by compaction procedures, this is the | |
744 | * function that performs the page migration on behalf of a compaction thread | |
745 | * The page migration for virtio balloon is done in a simple swap fashion which | |
746 | * follows these two macro steps: | |
747 | * 1) insert newpage into vb->pages list and update the host about it; | |
748 | * 2) update the host about the old page removed from vb->pages list; | |
749 | * | |
750 | * This function preforms the balloon page migration task. | |
751 | * Called through balloon_mapping->a_ops->migratepage | |
752 | */ | |
9d1ba805 | 753 | static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, |
e2250429 RA |
754 | struct page *newpage, struct page *page, enum migrate_mode mode) |
755 | { | |
9d1ba805 KK |
756 | struct virtio_balloon *vb = container_of(vb_dev_info, |
757 | struct virtio_balloon, vb_dev_info); | |
e2250429 RA |
758 | unsigned long flags; |
759 | ||
e2250429 RA |
760 | /* |
761 | * In order to avoid lock contention while migrating pages concurrently | |
762 | * to leak_balloon() or fill_balloon() we just give up the balloon_lock | |
763 | * this turn, as it is easier to retry the page migration later. | |
764 | * This also prevents fill_balloon() getting stuck into a mutex | |
765 | * recursion in the case it ends up triggering memory compaction | |
766 | * while it is attempting to inflate the ballon. | |
767 | */ | |
768 | if (!mutex_trylock(&vb->balloon_lock)) | |
769 | return -EAGAIN; | |
770 | ||
d6d86c0a KK |
771 | get_page(newpage); /* balloon reference */ |
772 | ||
63341ab0 DH |
773 | /* |
774 | * When we migrate a page to a different zone and adjusted the | |
775 | * managed page count when inflating, we have to fixup the count of | |
776 | * both involved zones. | |
777 | */ | |
778 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) && | |
779 | page_zone(page) != page_zone(newpage)) { | |
780 | adjust_managed_page_count(page, 1); | |
781 | adjust_managed_page_count(newpage, -1); | |
782 | } | |
783 | ||
e2250429 RA |
784 | /* balloon's page migration 1st step -- inflate "newpage" */ |
785 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); | |
9d1ba805 | 786 | balloon_page_insert(vb_dev_info, newpage); |
e2250429 | 787 | vb_dev_info->isolated_pages--; |
09316c09 | 788 | __count_vm_event(BALLOON_MIGRATE); |
e2250429 RA |
789 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
790 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
87c9403b | 791 | set_page_pfns(vb, vb->pfns, newpage); |
e2250429 RA |
792 | tell_host(vb, vb->inflate_vq); |
793 | ||
d6d86c0a | 794 | /* balloon's page migration 2nd step -- deflate "page" */ |
89da619b | 795 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); |
e2250429 | 796 | balloon_page_delete(page); |
89da619b | 797 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
e2250429 | 798 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; |
87c9403b | 799 | set_page_pfns(vb, vb->pfns, page); |
e2250429 RA |
800 | tell_host(vb, vb->deflate_vq); |
801 | ||
802 | mutex_unlock(&vb->balloon_lock); | |
803 | ||
d6d86c0a KK |
804 | put_page(page); /* balloon reference */ |
805 | ||
dd4123f3 | 806 | return MIGRATEPAGE_SUCCESS; |
e2250429 | 807 | } |
b1123ea6 | 808 | |
99558d20 | 809 | static int balloon_init_fs_context(struct fs_context *fc) |
b1123ea6 | 810 | { |
99558d20 | 811 | return init_pseudo(fc, BALLOON_KVM_MAGIC) ? 0 : -ENOMEM; |
b1123ea6 MK |
812 | } |
813 | ||
814 | static struct file_system_type balloon_fs = { | |
815 | .name = "balloon-kvm", | |
99558d20 | 816 | .init_fs_context = balloon_init_fs_context, |
b1123ea6 MK |
817 | .kill_sb = kill_anon_super, |
818 | }; | |
819 | ||
e2250429 RA |
820 | #endif /* CONFIG_BALLOON_COMPACTION */ |
821 | ||
86a55978 WW |
822 | static unsigned long shrink_free_pages(struct virtio_balloon *vb, |
823 | unsigned long pages_to_free) | |
71994620 | 824 | { |
86a55978 | 825 | unsigned long blocks_to_free, blocks_freed; |
71994620 | 826 | |
86a55978 | 827 | pages_to_free = round_up(pages_to_free, |
63b9b80e MT |
828 | VIRTIO_BALLOON_HINT_BLOCK_PAGES); |
829 | blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES; | |
86a55978 WW |
830 | blocks_freed = return_free_pages_to_mm(vb, blocks_to_free); |
831 | ||
63b9b80e | 832 | return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES; |
86a55978 WW |
833 | } |
834 | ||
86a55978 WW |
835 | static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker, |
836 | struct shrink_control *sc) | |
837 | { | |
86a55978 WW |
838 | struct virtio_balloon *vb = container_of(shrinker, |
839 | struct virtio_balloon, shrinker); | |
840 | ||
da10329c | 841 | return shrink_free_pages(vb, sc->nr_to_scan); |
71994620 WW |
842 | } |
843 | ||
844 | static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker, | |
845 | struct shrink_control *sc) | |
846 | { | |
847 | struct virtio_balloon *vb = container_of(shrinker, | |
848 | struct virtio_balloon, shrinker); | |
849 | ||
da10329c DH |
850 | return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES; |
851 | } | |
852 | ||
853 | static int virtio_balloon_oom_notify(struct notifier_block *nb, | |
854 | unsigned long dummy, void *parm) | |
855 | { | |
856 | struct virtio_balloon *vb = container_of(nb, | |
857 | struct virtio_balloon, oom_nb); | |
858 | unsigned long *freed = parm; | |
859 | ||
860 | *freed += leak_balloon(vb, VIRTIO_BALLOON_OOM_NR_PAGES) / | |
861 | VIRTIO_BALLOON_PAGES_PER_PAGE; | |
862 | update_balloon_size(vb); | |
86a55978 | 863 | |
da10329c | 864 | return NOTIFY_OK; |
71994620 WW |
865 | } |
866 | ||
867 | static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb) | |
868 | { | |
869 | unregister_shrinker(&vb->shrinker); | |
870 | } | |
871 | ||
872 | static int virtio_balloon_register_shrinker(struct virtio_balloon *vb) | |
873 | { | |
874 | vb->shrinker.scan_objects = virtio_balloon_shrinker_scan; | |
875 | vb->shrinker.count_objects = virtio_balloon_shrinker_count; | |
876 | vb->shrinker.seeks = DEFAULT_SEEKS; | |
877 | ||
878 | return register_shrinker(&vb->shrinker); | |
879 | } | |
880 | ||
be91c33d AS |
881 | static int virtballoon_probe(struct virtio_device *vdev) |
882 | { | |
883 | struct virtio_balloon *vb; | |
884 | int err; | |
885 | ||
2d9becc1 MT |
886 | if (!vdev->config->get) { |
887 | dev_err(&vdev->dev, "%s failure: config access disabled\n", | |
888 | __func__); | |
889 | return -EINVAL; | |
890 | } | |
891 | ||
c51d8fca | 892 | vdev->priv = vb = kzalloc(sizeof(*vb), GFP_KERNEL); |
be91c33d AS |
893 | if (!vb) { |
894 | err = -ENOMEM; | |
895 | goto out; | |
896 | } | |
897 | ||
fd0e21c3 PM |
898 | INIT_WORK(&vb->update_balloon_stats_work, update_balloon_stats_func); |
899 | INIT_WORK(&vb->update_balloon_size_work, update_balloon_size_func); | |
fad7b7b2 | 900 | spin_lock_init(&vb->stop_update_lock); |
e2250429 | 901 | mutex_init(&vb->balloon_lock); |
9c378abc | 902 | init_waitqueue_head(&vb->acked); |
be91c33d | 903 | vb->vdev = vdev; |
be91c33d | 904 | |
9d1ba805 | 905 | balloon_devinfo_init(&vb->vb_dev_info); |
e2250429 | 906 | |
be91c33d AS |
907 | err = init_vqs(vb); |
908 | if (err) | |
9d1ba805 | 909 | goto out_free_vb; |
6b35e407 | 910 | |
b1123ea6 MK |
911 | #ifdef CONFIG_BALLOON_COMPACTION |
912 | balloon_mnt = kern_mount(&balloon_fs); | |
913 | if (IS_ERR(balloon_mnt)) { | |
914 | err = PTR_ERR(balloon_mnt); | |
b1123ea6 MK |
915 | goto out_del_vqs; |
916 | } | |
917 | ||
918 | vb->vb_dev_info.migratepage = virtballoon_migratepage; | |
919 | vb->vb_dev_info.inode = alloc_anon_inode(balloon_mnt->mnt_sb); | |
920 | if (IS_ERR(vb->vb_dev_info.inode)) { | |
921 | err = PTR_ERR(vb->vb_dev_info.inode); | |
1ad6f58e | 922 | goto out_kern_unmount; |
b1123ea6 MK |
923 | } |
924 | vb->vb_dev_info.inode->i_mapping->a_ops = &balloon_aops; | |
925 | #endif | |
86a55978 WW |
926 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { |
927 | /* | |
928 | * There is always one entry reserved for cmd id, so the ring | |
929 | * size needs to be at least two to report free page hints. | |
930 | */ | |
931 | if (virtqueue_get_vring_size(vb->free_page_vq) < 2) { | |
932 | err = -ENOSPC; | |
1ad6f58e | 933 | goto out_iput; |
86a55978 WW |
934 | } |
935 | vb->balloon_wq = alloc_workqueue("balloon-wq", | |
936 | WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0); | |
937 | if (!vb->balloon_wq) { | |
938 | err = -ENOMEM; | |
1ad6f58e | 939 | goto out_iput; |
86a55978 WW |
940 | } |
941 | INIT_WORK(&vb->report_free_page_work, report_free_page_func); | |
bf4dc0b2 | 942 | vb->cmd_id_received_cache = VIRTIO_BALLOON_CMD_ID_STOP; |
86a55978 WW |
943 | vb->cmd_id_active = cpu_to_virtio32(vb->vdev, |
944 | VIRTIO_BALLOON_CMD_ID_STOP); | |
945 | vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, | |
946 | VIRTIO_BALLOON_CMD_ID_STOP); | |
86a55978 WW |
947 | spin_lock_init(&vb->free_page_list_lock); |
948 | INIT_LIST_HEAD(&vb->free_page_list); | |
da10329c DH |
949 | /* |
950 | * We're allowed to reuse any free pages, even if they are | |
951 | * still to be processed by the host. | |
952 | */ | |
953 | err = virtio_balloon_register_shrinker(vb); | |
954 | if (err) | |
955 | goto out_del_balloon_wq; | |
956 | } | |
957 | ||
958 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) { | |
959 | vb->oom_nb.notifier_call = virtio_balloon_oom_notify; | |
960 | vb->oom_nb.priority = VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY; | |
961 | err = register_oom_notifier(&vb->oom_nb); | |
962 | if (err < 0) | |
963 | goto out_unregister_shrinker; | |
d74b78fa | 964 | } |
da10329c | 965 | |
d74b78fa AD |
966 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { |
967 | /* Start with poison val of 0 representing general init */ | |
968 | __u32 poison_val = 0; | |
969 | ||
970 | /* | |
971 | * Let the hypervisor know that we are expecting a | |
972 | * specific value to be written back in balloon pages. | |
ca72cc34 AD |
973 | * |
974 | * If the PAGE_POISON value was larger than a byte we would | |
975 | * need to byte swap poison_val here to guarantee it is | |
976 | * little-endian. However for now it is a single byte so we | |
977 | * can pass it as-is. | |
d74b78fa AD |
978 | */ |
979 | if (!want_init_on_free()) | |
2e991629 | 980 | memset(&poison_val, PAGE_POISON, sizeof(poison_val)); |
d74b78fa | 981 | |
805769d7 MT |
982 | virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, |
983 | poison_val, &poison_val); | |
86a55978 | 984 | } |
b0c504f1 AD |
985 | |
986 | vb->pr_dev_info.report = virtballoon_free_page_report; | |
987 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { | |
988 | unsigned int capacity; | |
989 | ||
990 | capacity = virtqueue_get_vring_size(vb->reporting_vq); | |
991 | if (capacity < PAGE_REPORTING_CAPACITY) { | |
992 | err = -ENOSPC; | |
da10329c | 993 | goto out_unregister_oom; |
b0c504f1 AD |
994 | } |
995 | ||
f8af4d08 GS |
996 | /* |
997 | * The default page reporting order is @pageblock_order, which | |
998 | * corresponds to 512MB in size on ARM64 when 64KB base page | |
999 | * size is used. The page reporting won't be triggered if the | |
1000 | * freeing page can't come up with a free area like that huge. | |
1001 | * So we specify the page reporting order to 5, corresponding | |
1002 | * to 2MB. It helps to avoid THP splitting if 4KB base page | |
1003 | * size is used by host. | |
1004 | * | |
1005 | * Ideally, the page reporting order is selected based on the | |
1006 | * host's base page size. However, it needs more work to report | |
1007 | * that value. The hard-coded order would be fine currently. | |
1008 | */ | |
1009 | #if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES) | |
1010 | vb->pr_dev_info.order = 5; | |
1011 | #endif | |
1012 | ||
b0c504f1 AD |
1013 | err = page_reporting_register(&vb->pr_dev_info); |
1014 | if (err) | |
da10329c | 1015 | goto out_unregister_oom; |
b0c504f1 AD |
1016 | } |
1017 | ||
88660f7f MT |
1018 | virtio_device_ready(vdev); |
1019 | ||
8424af53 KN |
1020 | if (towards_target(vb)) |
1021 | virtballoon_changed(vdev); | |
6b35e407 RR |
1022 | return 0; |
1023 | ||
da10329c | 1024 | out_unregister_oom: |
b0c504f1 | 1025 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) |
da10329c DH |
1026 | unregister_oom_notifier(&vb->oom_nb); |
1027 | out_unregister_shrinker: | |
1028 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
b0c504f1 | 1029 | virtio_balloon_unregister_shrinker(vb); |
86a55978 WW |
1030 | out_del_balloon_wq: |
1031 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
1032 | destroy_workqueue(vb->balloon_wq); | |
1ad6f58e DH |
1033 | out_iput: |
1034 | #ifdef CONFIG_BALLOON_COMPACTION | |
1035 | iput(vb->vb_dev_info.inode); | |
1036 | out_kern_unmount: | |
1037 | kern_unmount(balloon_mnt); | |
b1123ea6 | 1038 | out_del_vqs: |
6ae4edab | 1039 | #endif |
d2a7ddda | 1040 | vdev->config->del_vqs(vdev); |
6b35e407 RR |
1041 | out_free_vb: |
1042 | kfree(vb); | |
1043 | out: | |
1044 | return err; | |
1045 | } | |
1046 | ||
c877bab5 | 1047 | static void remove_common(struct virtio_balloon *vb) |
6b35e407 | 1048 | { |
6b35e407 RR |
1049 | /* There might be pages left in the balloon: free them. */ |
1050 | while (vb->num_pages) | |
1051 | leak_balloon(vb, vb->num_pages); | |
b8ae0eb3 | 1052 | update_balloon_size(vb); |
6b35e407 | 1053 | |
6c22dc61 DH |
1054 | /* There might be free pages that are being reported: release them. */ |
1055 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
1056 | return_free_pages_to_mm(vb, ULONG_MAX); | |
1057 | ||
6b35e407 | 1058 | /* Now we reset the device so we can clean up the queues. */ |
c877bab5 | 1059 | vb->vdev->config->reset(vb->vdev); |
6b35e407 | 1060 | |
c877bab5 AS |
1061 | vb->vdev->config->del_vqs(vb->vdev); |
1062 | } | |
1063 | ||
8590dbc7 | 1064 | static void virtballoon_remove(struct virtio_device *vdev) |
c877bab5 AS |
1065 | { |
1066 | struct virtio_balloon *vb = vdev->priv; | |
1067 | ||
b0c504f1 AD |
1068 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) |
1069 | page_reporting_unregister(&vb->pr_dev_info); | |
71994620 | 1070 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) |
da10329c DH |
1071 | unregister_oom_notifier(&vb->oom_nb); |
1072 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) | |
71994620 | 1073 | virtio_balloon_unregister_shrinker(vb); |
fad7b7b2 PM |
1074 | spin_lock_irq(&vb->stop_update_lock); |
1075 | vb->stop_update = true; | |
1076 | spin_unlock_irq(&vb->stop_update_lock); | |
fd0e21c3 PM |
1077 | cancel_work_sync(&vb->update_balloon_size_work); |
1078 | cancel_work_sync(&vb->update_balloon_stats_work); | |
fad7b7b2 | 1079 | |
86a55978 WW |
1080 | if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { |
1081 | cancel_work_sync(&vb->report_free_page_work); | |
1082 | destroy_workqueue(vb->balloon_wq); | |
1083 | } | |
1084 | ||
c877bab5 | 1085 | remove_common(vb); |
9c57b580 | 1086 | #ifdef CONFIG_BALLOON_COMPACTION |
b1123ea6 MK |
1087 | if (vb->vb_dev_info.inode) |
1088 | iput(vb->vb_dev_info.inode); | |
9c57b580 YX |
1089 | |
1090 | kern_unmount(balloon_mnt); | |
1091 | #endif | |
6b35e407 RR |
1092 | kfree(vb); |
1093 | } | |
1094 | ||
89107000 | 1095 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
1096 | static int virtballoon_freeze(struct virtio_device *vdev) |
1097 | { | |
4eb05d56 AS |
1098 | struct virtio_balloon *vb = vdev->priv; |
1099 | ||
e562966d | 1100 | /* |
fad7b7b2 | 1101 | * The workqueue is already frozen by the PM core before this |
e562966d AS |
1102 | * function is called. |
1103 | */ | |
c877bab5 | 1104 | remove_common(vb); |
e562966d AS |
1105 | return 0; |
1106 | } | |
1107 | ||
c45b4166 | 1108 | static int virtballoon_restore(struct virtio_device *vdev) |
4eb05d56 AS |
1109 | { |
1110 | struct virtio_balloon *vb = vdev->priv; | |
1111 | int ret; | |
1112 | ||
1113 | ret = init_vqs(vdev->priv); | |
1114 | if (ret) | |
1115 | return ret; | |
1116 | ||
486d2e63 MT |
1117 | virtio_device_ready(vdev); |
1118 | ||
fad7b7b2 PM |
1119 | if (towards_target(vb)) |
1120 | virtballoon_changed(vdev); | |
4eb05d56 AS |
1121 | update_balloon_size(vb); |
1122 | return 0; | |
1123 | } | |
e562966d AS |
1124 | #endif |
1125 | ||
e41b1355 MT |
1126 | static int virtballoon_validate(struct virtio_device *vdev) |
1127 | { | |
fb69c2c8 AD |
1128 | /* |
1129 | * Inform the hypervisor that our pages are poisoned or | |
1130 | * initialized. If we cannot do that then we should disable | |
1131 | * page reporting as it could potentially change the contents | |
1132 | * of our free pages. | |
1133 | */ | |
8f424750 | 1134 | if (!want_init_on_free() && !page_poisoning_enabled_static()) |
2e991629 | 1135 | __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON); |
fb69c2c8 AD |
1136 | else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) |
1137 | __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING); | |
2e991629 | 1138 | |
321bd212 | 1139 | __virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM); |
e41b1355 MT |
1140 | return 0; |
1141 | } | |
1142 | ||
9564e138 AL |
1143 | static unsigned int features[] = { |
1144 | VIRTIO_BALLOON_F_MUST_TELL_HOST, | |
1145 | VIRTIO_BALLOON_F_STATS_VQ, | |
5a10b7db | 1146 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM, |
86a55978 | 1147 | VIRTIO_BALLOON_F_FREE_PAGE_HINT, |
2e991629 | 1148 | VIRTIO_BALLOON_F_PAGE_POISON, |
b0c504f1 | 1149 | VIRTIO_BALLOON_F_REPORTING, |
9564e138 | 1150 | }; |
c45a6816 | 1151 | |
d817cd52 | 1152 | static struct virtio_driver virtio_balloon_driver = { |
c45a6816 RR |
1153 | .feature_table = features, |
1154 | .feature_table_size = ARRAY_SIZE(features), | |
6b35e407 RR |
1155 | .driver.name = KBUILD_MODNAME, |
1156 | .driver.owner = THIS_MODULE, | |
1157 | .id_table = id_table, | |
e41b1355 | 1158 | .validate = virtballoon_validate, |
6b35e407 | 1159 | .probe = virtballoon_probe, |
8590dbc7 | 1160 | .remove = virtballoon_remove, |
6b35e407 | 1161 | .config_changed = virtballoon_changed, |
89107000 | 1162 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
1163 | .freeze = virtballoon_freeze, |
1164 | .restore = virtballoon_restore, | |
e562966d | 1165 | #endif |
6b35e407 RR |
1166 | }; |
1167 | ||
b2a17029 | 1168 | module_virtio_driver(virtio_balloon_driver); |
6b35e407 RR |
1169 | MODULE_DEVICE_TABLE(virtio, id_table); |
1170 | MODULE_DESCRIPTION("Virtio balloon driver"); | |
1171 | MODULE_LICENSE("GPL"); |