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1/*
2 * VMware Balloon driver.
3 *
4 * Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; version 2 of the License and no later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
13 * NON INFRINGEMENT. See the GNU General Public License for more
14 * details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Maintained by: Dmitry Torokhov <dtor@vmware.com>
21 */
22
23/*
24 * This is VMware physical memory management driver for Linux. The driver
25 * acts like a "balloon" that can be inflated to reclaim physical pages by
26 * reserving them in the guest and invalidating them in the monitor,
27 * freeing up the underlying machine pages so they can be allocated to
28 * other guests. The balloon can also be deflated to allow the guest to
29 * use more physical memory. Higher level policies can control the sizes
30 * of balloons in VMs in order to manage physical memory resources.
31 */
32
33//#define DEBUG
34#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
36#include <linux/types.h>
37#include <linux/kernel.h>
38#include <linux/mm.h>
39#include <linux/sched.h>
40#include <linux/module.h>
41#include <linux/workqueue.h>
42#include <linux/debugfs.h>
43#include <linux/seq_file.h>
44#include <asm/hypervisor.h>
45
46MODULE_AUTHOR("VMware, Inc.");
47MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
48MODULE_VERSION("1.2.1.3-k");
49MODULE_ALIAS("dmi:*:svnVMware*:*");
50MODULE_ALIAS("vmware_vmmemctl");
51MODULE_LICENSE("GPL");
52
53/*
54 * Various constants controlling rate of inflaint/deflating balloon,
55 * measured in pages.
56 */
57
58/*
59 * Rate of allocating memory when there is no memory pressure
60 * (driver performs non-sleeping allocations).
61 */
62#define VMW_BALLOON_NOSLEEP_ALLOC_MAX 16384U
63
64/*
65 * Rates of memory allocaton when guest experiences memory pressure
66 * (driver performs sleeping allocations).
67 */
68#define VMW_BALLOON_RATE_ALLOC_MIN 512U
69#define VMW_BALLOON_RATE_ALLOC_MAX 2048U
70#define VMW_BALLOON_RATE_ALLOC_INC 16U
71
72/*
73 * Rates for releasing pages while deflating balloon.
74 */
75#define VMW_BALLOON_RATE_FREE_MIN 512U
76#define VMW_BALLOON_RATE_FREE_MAX 16384U
77#define VMW_BALLOON_RATE_FREE_INC 16U
78
79/*
80 * When guest is under memory pressure, use a reduced page allocation
81 * rate for next several cycles.
82 */
83#define VMW_BALLOON_SLOW_CYCLES 4
84
85/*
86 * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't
87 * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use
88 * __GFP_NOWARN, to suppress page allocation failure warnings.
89 */
90#define VMW_PAGE_ALLOC_NOSLEEP (__GFP_HIGHMEM|__GFP_NOWARN)
91
92/*
93 * Use GFP_HIGHUSER when executing in a separate kernel thread
94 * context and allocation can sleep. This is less stressful to
95 * the guest memory system, since it allows the thread to block
96 * while memory is reclaimed, and won't take pages from emergency
97 * low-memory pools.
98 */
99#define VMW_PAGE_ALLOC_CANSLEEP (GFP_HIGHUSER)
100
101/* Maximum number of page allocations without yielding processor */
102#define VMW_BALLOON_YIELD_THRESHOLD 1024
103
104/* Maximum number of refused pages we accumulate during inflation cycle */
105#define VMW_BALLOON_MAX_REFUSED 16
106
107/*
108 * Hypervisor communication port definitions.
109 */
110#define VMW_BALLOON_HV_PORT 0x5670
111#define VMW_BALLOON_HV_MAGIC 0x456c6d6f
112#define VMW_BALLOON_PROTOCOL_VERSION 2
113#define VMW_BALLOON_GUEST_ID 1 /* Linux */
114
115#define VMW_BALLOON_CMD_START 0
116#define VMW_BALLOON_CMD_GET_TARGET 1
117#define VMW_BALLOON_CMD_LOCK 2
118#define VMW_BALLOON_CMD_UNLOCK 3
119#define VMW_BALLOON_CMD_GUEST_ID 4
120
121/* error codes */
122#define VMW_BALLOON_SUCCESS 0
123#define VMW_BALLOON_FAILURE -1
124#define VMW_BALLOON_ERROR_CMD_INVALID 1
125#define VMW_BALLOON_ERROR_PPN_INVALID 2
126#define VMW_BALLOON_ERROR_PPN_LOCKED 3
127#define VMW_BALLOON_ERROR_PPN_UNLOCKED 4
128#define VMW_BALLOON_ERROR_PPN_PINNED 5
129#define VMW_BALLOON_ERROR_PPN_NOTNEEDED 6
130#define VMW_BALLOON_ERROR_RESET 7
131#define VMW_BALLOON_ERROR_BUSY 8
132
133#define VMWARE_BALLOON_CMD(cmd, data, result) \
134({ \
135 unsigned long __stat, __dummy1, __dummy2; \
136 __asm__ __volatile__ ("inl (%%dx)" : \
137 "=a"(__stat), \
138 "=c"(__dummy1), \
139 "=d"(__dummy2), \
140 "=b"(result) : \
141 "0"(VMW_BALLOON_HV_MAGIC), \
142 "1"(VMW_BALLOON_CMD_##cmd), \
143 "2"(VMW_BALLOON_HV_PORT), \
144 "3"(data) : \
145 "memory"); \
146 result &= -1UL; \
147 __stat & -1UL; \
148})
149
150#ifdef CONFIG_DEBUG_FS
151struct vmballoon_stats {
152 unsigned int timer;
153
154 /* allocation statistics */
155 unsigned int alloc;
156 unsigned int alloc_fail;
157 unsigned int sleep_alloc;
158 unsigned int sleep_alloc_fail;
159 unsigned int refused_alloc;
160 unsigned int refused_free;
161 unsigned int free;
162
163 /* monitor operations */
164 unsigned int lock;
165 unsigned int lock_fail;
166 unsigned int unlock;
167 unsigned int unlock_fail;
168 unsigned int target;
169 unsigned int target_fail;
170 unsigned int start;
171 unsigned int start_fail;
172 unsigned int guest_type;
173 unsigned int guest_type_fail;
174};
175
176#define STATS_INC(stat) (stat)++
177#else
178#define STATS_INC(stat)
179#endif
180
181struct vmballoon {
182
183 /* list of reserved physical pages */
184 struct list_head pages;
185
186 /* transient list of non-balloonable pages */
187 struct list_head refused_pages;
188 unsigned int n_refused_pages;
189
190 /* balloon size in pages */
191 unsigned int size;
192 unsigned int target;
193
194 /* reset flag */
195 bool reset_required;
196
197 /* adjustment rates (pages per second) */
198 unsigned int rate_alloc;
199 unsigned int rate_free;
200
201 /* slowdown page allocations for next few cycles */
202 unsigned int slow_allocation_cycles;
203
204#ifdef CONFIG_DEBUG_FS
205 /* statistics */
206 struct vmballoon_stats stats;
207
208 /* debugfs file exporting statistics */
209 struct dentry *dbg_entry;
210#endif
211
212 struct sysinfo sysinfo;
213
214 struct delayed_work dwork;
215};
216
217static struct vmballoon balloon;
218
219/*
220 * Send "start" command to the host, communicating supported version
221 * of the protocol.
222 */
223static bool vmballoon_send_start(struct vmballoon *b)
224{
225 unsigned long status, dummy;
226
227 STATS_INC(b->stats.start);
228
229 status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy);
230 if (status == VMW_BALLOON_SUCCESS)
231 return true;
232
233 pr_debug("%s - failed, hv returns %ld\n", __func__, status);
234 STATS_INC(b->stats.start_fail);
235 return false;
236}
237
238static bool vmballoon_check_status(struct vmballoon *b, unsigned long status)
239{
240 switch (status) {
241 case VMW_BALLOON_SUCCESS:
242 return true;
243
244 case VMW_BALLOON_ERROR_RESET:
245 b->reset_required = true;
246 /* fall through */
247
248 default:
249 return false;
250 }
251}
252
253/*
254 * Communicate guest type to the host so that it can adjust ballooning
255 * algorithm to the one most appropriate for the guest. This command
256 * is normally issued after sending "start" command and is part of
257 * standard reset sequence.
258 */
259static bool vmballoon_send_guest_id(struct vmballoon *b)
260{
261 unsigned long status, dummy;
262
263 status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy);
264
265 STATS_INC(b->stats.guest_type);
266
267 if (vmballoon_check_status(b, status))
268 return true;
269
270 pr_debug("%s - failed, hv returns %ld\n", __func__, status);
271 STATS_INC(b->stats.guest_type_fail);
272 return false;
273}
274
275/*
276 * Retrieve desired balloon size from the host.
277 */
278static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
279{
280 unsigned long status;
281 unsigned long target;
282 unsigned long limit;
283 u32 limit32;
284
285 /*
286 * si_meminfo() is cheap. Moreover, we want to provide dynamic
287 * max balloon size later. So let us call si_meminfo() every
288 * iteration.
289 */
290 si_meminfo(&b->sysinfo);
291 limit = b->sysinfo.totalram;
292
293 /* Ensure limit fits in 32-bits */
294 limit32 = (u32)limit;
295 if (limit != limit32)
296 return false;
297
298 /* update stats */
299 STATS_INC(b->stats.target);
300
301 status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target);
302 if (vmballoon_check_status(b, status)) {
303 *new_target = target;
304 return true;
305 }
306
307 pr_debug("%s - failed, hv returns %ld\n", __func__, status);
308 STATS_INC(b->stats.target_fail);
309 return false;
310}
311
312/*
313 * Notify the host about allocated page so that host can use it without
314 * fear that guest will need it. Host may reject some pages, we need to
315 * check the return value and maybe submit a different page.
316 */
317static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn,
318 unsigned int *hv_status)
319{
320 unsigned long status, dummy;
321 u32 pfn32;
322
323 pfn32 = (u32)pfn;
324 if (pfn32 != pfn)
325 return -1;
326
327 STATS_INC(b->stats.lock);
328
329 *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy);
330 if (vmballoon_check_status(b, status))
331 return 0;
332
333 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
334 STATS_INC(b->stats.lock_fail);
335 return 1;
336}
337
338/*
339 * Notify the host that guest intends to release given page back into
340 * the pool of available (to the guest) pages.
341 */
342static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
343{
344 unsigned long status, dummy;
345 u32 pfn32;
346
347 pfn32 = (u32)pfn;
348 if (pfn32 != pfn)
349 return false;
350
351 STATS_INC(b->stats.unlock);
352
353 status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy);
354 if (vmballoon_check_status(b, status))
355 return true;
356
357 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
358 STATS_INC(b->stats.unlock_fail);
359 return false;
360}
361
362/*
363 * Quickly release all pages allocated for the balloon. This function is
364 * called when host decides to "reset" balloon for one reason or another.
365 * Unlike normal "deflate" we do not (shall not) notify host of the pages
366 * being released.
367 */
368static void vmballoon_pop(struct vmballoon *b)
369{
370 struct page *page, *next;
371 unsigned int count = 0;
372
373 list_for_each_entry_safe(page, next, &b->pages, lru) {
374 list_del(&page->lru);
375 __free_page(page);
376 STATS_INC(b->stats.free);
377 b->size--;
378
379 if (++count >= b->rate_free) {
380 count = 0;
381 cond_resched();
382 }
383 }
384}
385
386/*
387 * Perform standard reset sequence by popping the balloon (in case it
388 * is not empty) and then restarting protocol. This operation normally
389 * happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
390 */
391static void vmballoon_reset(struct vmballoon *b)
392{
393 /* free all pages, skipping monitor unlock */
394 vmballoon_pop(b);
395
396 if (vmballoon_send_start(b)) {
397 b->reset_required = false;
398 if (!vmballoon_send_guest_id(b))
399 pr_err("failed to send guest ID to the host\n");
400 }
401}
402
403/*
404 * Allocate (or reserve) a page for the balloon and notify the host. If host
405 * refuses the page put it on "refuse" list and allocate another one until host
406 * is satisfied. "Refused" pages are released at the end of inflation cycle
407 * (when we allocate b->rate_alloc pages).
408 */
409static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep)
410{
411 struct page *page;
412 gfp_t flags;
413 unsigned int hv_status;
414 int locked;
415 flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP;
416
417 do {
418 if (!can_sleep)
419 STATS_INC(b->stats.alloc);
420 else
421 STATS_INC(b->stats.sleep_alloc);
422
423 page = alloc_page(flags);
424 if (!page) {
425 if (!can_sleep)
426 STATS_INC(b->stats.alloc_fail);
427 else
428 STATS_INC(b->stats.sleep_alloc_fail);
429 return -ENOMEM;
430 }
431
432 /* inform monitor */
433 locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status);
434 if (locked > 0) {
435 STATS_INC(b->stats.refused_alloc);
436
437 if (hv_status == VMW_BALLOON_ERROR_RESET ||
438 hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) {
439 __free_page(page);
440 return -EIO;
441 }
442
443 /*
444 * Place page on the list of non-balloonable pages
445 * and retry allocation, unless we already accumulated
446 * too many of them, in which case take a breather.
447 */
448 list_add(&page->lru, &b->refused_pages);
449 if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED)
450 return -EIO;
451 }
452 } while (locked != 0);
453
454 /* track allocated page */
455 list_add(&page->lru, &b->pages);
456
457 /* update balloon size */
458 b->size++;
459
460 return 0;
461}
462
463/*
464 * Release the page allocated for the balloon. Note that we first notify
465 * the host so it can make sure the page will be available for the guest
466 * to use, if needed.
467 */
468static int vmballoon_release_page(struct vmballoon *b, struct page *page)
469{
470 if (!vmballoon_send_unlock_page(b, page_to_pfn(page)))
471 return -EIO;
472
473 list_del(&page->lru);
474
475 /* deallocate page */
476 __free_page(page);
477 STATS_INC(b->stats.free);
478
479 /* update balloon size */
480 b->size--;
481
482 return 0;
483}
484
485/*
486 * Release pages that were allocated while attempting to inflate the
487 * balloon but were refused by the host for one reason or another.
488 */
489static void vmballoon_release_refused_pages(struct vmballoon *b)
490{
491 struct page *page, *next;
492
493 list_for_each_entry_safe(page, next, &b->refused_pages, lru) {
494 list_del(&page->lru);
495 __free_page(page);
496 STATS_INC(b->stats.refused_free);
497 }
498
499 b->n_refused_pages = 0;
500}
501
502/*
503 * Inflate the balloon towards its target size. Note that we try to limit
504 * the rate of allocation to make sure we are not choking the rest of the
505 * system.
506 */
507static void vmballoon_inflate(struct vmballoon *b)
508{
509 unsigned int goal;
510 unsigned int rate;
511 unsigned int i;
512 unsigned int allocations = 0;
513 int error = 0;
514 bool alloc_can_sleep = false;
515
516 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
517
518 /*
519 * First try NOSLEEP page allocations to inflate balloon.
520 *
521 * If we do not throttle nosleep allocations, we can drain all
522 * free pages in the guest quickly (if the balloon target is high).
523 * As a side-effect, draining free pages helps to inform (force)
524 * the guest to start swapping if balloon target is not met yet,
525 * which is a desired behavior. However, balloon driver can consume
526 * all available CPU cycles if too many pages are allocated in a
527 * second. Therefore, we throttle nosleep allocations even when
528 * the guest is not under memory pressure. OTOH, if we have already
529 * predicted that the guest is under memory pressure, then we
530 * slowdown page allocations considerably.
531 */
532
533 goal = b->target - b->size;
534 /*
535 * Start with no sleep allocation rate which may be higher
536 * than sleeping allocation rate.
537 */
538 rate = b->slow_allocation_cycles ?
539 b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX;
540
541 pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n",
542 __func__, goal, rate, b->rate_alloc);
543
544 for (i = 0; i < goal; i++) {
545
546 error = vmballoon_reserve_page(b, alloc_can_sleep);
547 if (error) {
548 if (error != -ENOMEM) {
549 /*
550 * Not a page allocation failure, stop this
551 * cycle. Maybe we'll get new target from
552 * the host soon.
553 */
554 break;
555 }
556
557 if (alloc_can_sleep) {
558 /*
559 * CANSLEEP page allocation failed, so guest
560 * is under severe memory pressure. Quickly
561 * decrease allocation rate.
562 */
563 b->rate_alloc = max(b->rate_alloc / 2,
564 VMW_BALLOON_RATE_ALLOC_MIN);
565 break;
566 }
567
568 /*
569 * NOSLEEP page allocation failed, so the guest is
570 * under memory pressure. Let us slow down page
571 * allocations for next few cycles so that the guest
572 * gets out of memory pressure. Also, if we already
573 * allocated b->rate_alloc pages, let's pause,
574 * otherwise switch to sleeping allocations.
575 */
576 b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES;
577
578 if (i >= b->rate_alloc)
579 break;
580
581 alloc_can_sleep = true;
582 /* Lower rate for sleeping allocations. */
583 rate = b->rate_alloc;
584 }
585
586 if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) {
587 cond_resched();
588 allocations = 0;
589 }
590
591 if (i >= rate) {
592 /* We allocated enough pages, let's take a break. */
593 break;
594 }
595 }
596
597 /*
598 * We reached our goal without failures so try increasing
599 * allocation rate.
600 */
601 if (error == 0 && i >= b->rate_alloc) {
602 unsigned int mult = i / b->rate_alloc;
603
604 b->rate_alloc =
605 min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC,
606 VMW_BALLOON_RATE_ALLOC_MAX);
607 }
608
609 vmballoon_release_refused_pages(b);
610}
611
612/*
613 * Decrease the size of the balloon allowing guest to use more memory.
614 */
615static void vmballoon_deflate(struct vmballoon *b)
616{
617 struct page *page, *next;
618 unsigned int i = 0;
619 unsigned int goal;
620 int error;
621
622 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
623
624 /* limit deallocation rate */
625 goal = min(b->size - b->target, b->rate_free);
626
627 pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free);
628
629 /* free pages to reach target */
630 list_for_each_entry_safe(page, next, &b->pages, lru) {
631 error = vmballoon_release_page(b, page);
632 if (error) {
633 /* quickly decrease rate in case of error */
634 b->rate_free = max(b->rate_free / 2,
635 VMW_BALLOON_RATE_FREE_MIN);
636 return;
637 }
638
639 if (++i >= goal)
640 break;
641 }
642
643 /* slowly increase rate if there were no errors */
644 b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC,
645 VMW_BALLOON_RATE_FREE_MAX);
646}
647
648/*
649 * Balloon work function: reset protocol, if needed, get the new size and
650 * adjust balloon as needed. Repeat in 1 sec.
651 */
652static void vmballoon_work(struct work_struct *work)
653{
654 struct delayed_work *dwork = to_delayed_work(work);
655 struct vmballoon *b = container_of(dwork, struct vmballoon, dwork);
656 unsigned int target;
657
658 STATS_INC(b->stats.timer);
659
660 if (b->reset_required)
661 vmballoon_reset(b);
662
663 if (b->slow_allocation_cycles > 0)
664 b->slow_allocation_cycles--;
665
666 if (vmballoon_send_get_target(b, &target)) {
667 /* update target, adjust size */
668 b->target = target;
669
670 if (b->size < target)
671 vmballoon_inflate(b);
672 else if (b->size > target)
673 vmballoon_deflate(b);
674 }
675
676 /*
677 * We are using a freezable workqueue so that balloon operations are
678 * stopped while the system transitions to/from sleep/hibernation.
679 */
680 queue_delayed_work(system_freezable_wq,
681 dwork, round_jiffies_relative(HZ));
682}
683
684/*
685 * DEBUGFS Interface
686 */
687#ifdef CONFIG_DEBUG_FS
688
689static int vmballoon_debug_show(struct seq_file *f, void *offset)
690{
691 struct vmballoon *b = f->private;
692 struct vmballoon_stats *stats = &b->stats;
693
694 /* format size info */
695 seq_printf(f,
696 "target: %8d pages\n"
697 "current: %8d pages\n",
698 b->target, b->size);
699
700 /* format rate info */
701 seq_printf(f,
702 "rateNoSleepAlloc: %8d pages/sec\n"
703 "rateSleepAlloc: %8d pages/sec\n"
704 "rateFree: %8d pages/sec\n",
705 VMW_BALLOON_NOSLEEP_ALLOC_MAX,
706 b->rate_alloc, b->rate_free);
707
708 seq_printf(f,
709 "\n"
710 "timer: %8u\n"
711 "start: %8u (%4u failed)\n"
712 "guestType: %8u (%4u failed)\n"
713 "lock: %8u (%4u failed)\n"
714 "unlock: %8u (%4u failed)\n"
715 "target: %8u (%4u failed)\n"
716 "primNoSleepAlloc: %8u (%4u failed)\n"
717 "primCanSleepAlloc: %8u (%4u failed)\n"
718 "primFree: %8u\n"
719 "errAlloc: %8u\n"
720 "errFree: %8u\n",
721 stats->timer,
722 stats->start, stats->start_fail,
723 stats->guest_type, stats->guest_type_fail,
724 stats->lock, stats->lock_fail,
725 stats->unlock, stats->unlock_fail,
726 stats->target, stats->target_fail,
727 stats->alloc, stats->alloc_fail,
728 stats->sleep_alloc, stats->sleep_alloc_fail,
729 stats->free,
730 stats->refused_alloc, stats->refused_free);
731
732 return 0;
733}
734
735static int vmballoon_debug_open(struct inode *inode, struct file *file)
736{
737 return single_open(file, vmballoon_debug_show, inode->i_private);
738}
739
740static const struct file_operations vmballoon_debug_fops = {
741 .owner = THIS_MODULE,
742 .open = vmballoon_debug_open,
743 .read = seq_read,
744 .llseek = seq_lseek,
745 .release = single_release,
746};
747
748static int __init vmballoon_debugfs_init(struct vmballoon *b)
749{
750 int error;
751
752 b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b,
753 &vmballoon_debug_fops);
754 if (IS_ERR(b->dbg_entry)) {
755 error = PTR_ERR(b->dbg_entry);
756 pr_err("failed to create debugfs entry, error: %d\n", error);
757 return error;
758 }
759
760 return 0;
761}
762
763static void __exit vmballoon_debugfs_exit(struct vmballoon *b)
764{
765 debugfs_remove(b->dbg_entry);
766}
767
768#else
769
770static inline int vmballoon_debugfs_init(struct vmballoon *b)
771{
772 return 0;
773}
774
775static inline void vmballoon_debugfs_exit(struct vmballoon *b)
776{
777}
778
779#endif /* CONFIG_DEBUG_FS */
780
781static int __init vmballoon_init(void)
782{
783 int error;
784
785 /*
786 * Check if we are running on VMware's hypervisor and bail out
787 * if we are not.
788 */
789 if (x86_hyper != &x86_hyper_vmware)
790 return -ENODEV;
791
792 INIT_LIST_HEAD(&balloon.pages);
793 INIT_LIST_HEAD(&balloon.refused_pages);
794
795 /* initialize rates */
796 balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX;
797 balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX;
798
799 INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work);
800
801 /*
802 * Start balloon.
803 */
804 if (!vmballoon_send_start(&balloon)) {
805 pr_err("failed to send start command to the host\n");
806 return -EIO;
807 }
808
809 if (!vmballoon_send_guest_id(&balloon)) {
810 pr_err("failed to send guest ID to the host\n");
811 return -EIO;
812 }
813
814 error = vmballoon_debugfs_init(&balloon);
815 if (error)
816 return error;
817
818 queue_delayed_work(system_freezable_wq, &balloon.dwork, 0);
819
820 return 0;
821}
822module_init(vmballoon_init);
823
824static void __exit vmballoon_exit(void)
825{
826 cancel_delayed_work_sync(&balloon.dwork);
827
828 vmballoon_debugfs_exit(&balloon);
829
830 /*
831 * Deallocate all reserved memory, and reset connection with monitor.
832 * Reset connection before deallocating memory to avoid potential for
833 * additional spurious resets from guest touching deallocated pages.
834 */
835 vmballoon_send_start(&balloon);
836 vmballoon_pop(&balloon);
837}
838module_exit(vmballoon_exit);