1/*
2 * Copyright (c) 2012, Microsoft Corporation.
3 *
4 * Author:
5 * K. Y. Srinivasan <kys@microsoft.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
14 * NON INFRINGEMENT. See the GNU General Public License for more
15 * details.
16 *
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/kernel.h>
22#include <linux/jiffies.h>
23#include <linux/mman.h>
24#include <linux/delay.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/slab.h>
28#include <linux/kthread.h>
29#include <linux/completion.h>
30#include <linux/memory_hotplug.h>
31#include <linux/memory.h>
32#include <linux/notifier.h>
33#include <linux/percpu_counter.h>
34
35#include <linux/hyperv.h>
36
37#define CREATE_TRACE_POINTS
38#include "hv_trace_balloon.h"
39
40/*
41 * We begin with definitions supporting the Dynamic Memory protocol
42 * with the host.
43 *
44 * Begin protocol definitions.
45 */
46
47
48
49/*
50 * Protocol versions. The low word is the minor version, the high word the major
51 * version.
52 *
53 * History:
54 * Initial version 1.0
55 * Changed to 0.1 on 2009/03/25
56 * Changes to 0.2 on 2009/05/14
57 * Changes to 0.3 on 2009/12/03
58 * Changed to 1.0 on 2011/04/05
59 */
60
61#define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
62#define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
63#define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
64
65enum {
66 DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3),
67 DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0),
68 DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0),
69
70 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,
71 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,
72 DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3,
73
74 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10
75};
76
77
78
79/*
80 * Message Types
81 */
82
83enum dm_message_type {
84 /*
85 * Version 0.3
86 */
87 DM_ERROR = 0,
88 DM_VERSION_REQUEST = 1,
89 DM_VERSION_RESPONSE = 2,
90 DM_CAPABILITIES_REPORT = 3,
91 DM_CAPABILITIES_RESPONSE = 4,
92 DM_STATUS_REPORT = 5,
93 DM_BALLOON_REQUEST = 6,
94 DM_BALLOON_RESPONSE = 7,
95 DM_UNBALLOON_REQUEST = 8,
96 DM_UNBALLOON_RESPONSE = 9,
97 DM_MEM_HOT_ADD_REQUEST = 10,
98 DM_MEM_HOT_ADD_RESPONSE = 11,
99 DM_VERSION_03_MAX = 11,
100 /*
101 * Version 1.0.
102 */
103 DM_INFO_MESSAGE = 12,
104 DM_VERSION_1_MAX = 12
105};
106
107
108/*
109 * Structures defining the dynamic memory management
110 * protocol.
111 */
112
113union dm_version {
114 struct {
115 __u16 minor_version;
116 __u16 major_version;
117 };
118 __u32 version;
119} __packed;
120
121
122union dm_caps {
123 struct {
124 __u64 balloon:1;
125 __u64 hot_add:1;
126 /*
127 * To support guests that may have alignment
128 * limitations on hot-add, the guest can specify
129 * its alignment requirements; a value of n
130 * represents an alignment of 2^n in mega bytes.
131 */
132 __u64 hot_add_alignment:4;
133 __u64 reservedz:58;
134 } cap_bits;
135 __u64 caps;
136} __packed;
137
138union dm_mem_page_range {
139 struct {
140 /*
141 * The PFN number of the first page in the range.
142 * 40 bits is the architectural limit of a PFN
143 * number for AMD64.
144 */
145 __u64 start_page:40;
146 /*
147 * The number of pages in the range.
148 */
149 __u64 page_cnt:24;
150 } finfo;
151 __u64 page_range;
152} __packed;
153
154
155
156/*
157 * The header for all dynamic memory messages:
158 *
159 * type: Type of the message.
160 * size: Size of the message in bytes; including the header.
161 * trans_id: The guest is responsible for manufacturing this ID.
162 */
163
164struct dm_header {
165 __u16 type;
166 __u16 size;
167 __u32 trans_id;
168} __packed;
169
170/*
171 * A generic message format for dynamic memory.
172 * Specific message formats are defined later in the file.
173 */
174
175struct dm_message {
176 struct dm_header hdr;
177 __u8 data[]; /* enclosed message */
178} __packed;
179
180
181/*
182 * Specific message types supporting the dynamic memory protocol.
183 */
184
185/*
186 * Version negotiation message. Sent from the guest to the host.
187 * The guest is free to try different versions until the host
188 * accepts the version.
189 *
190 * dm_version: The protocol version requested.
191 * is_last_attempt: If TRUE, this is the last version guest will request.
192 * reservedz: Reserved field, set to zero.
193 */
194
195struct dm_version_request {
196 struct dm_header hdr;
197 union dm_version version;
198 __u32 is_last_attempt:1;
199 __u32 reservedz:31;
200} __packed;
201
202/*
203 * Version response message; Host to Guest and indicates
204 * if the host has accepted the version sent by the guest.
205 *
206 * is_accepted: If TRUE, host has accepted the version and the guest
207 * should proceed to the next stage of the protocol. FALSE indicates that
208 * guest should re-try with a different version.
209 *
210 * reservedz: Reserved field, set to zero.
211 */
212
213struct dm_version_response {
214 struct dm_header hdr;
215 __u64 is_accepted:1;
216 __u64 reservedz:63;
217} __packed;
218
219/*
220 * Message reporting capabilities. This is sent from the guest to the
221 * host.
222 */
223
224struct dm_capabilities {
225 struct dm_header hdr;
226 union dm_caps caps;
227 __u64 min_page_cnt;
228 __u64 max_page_number;
229} __packed;
230
231/*
232 * Response to the capabilities message. This is sent from the host to the
233 * guest. This message notifies if the host has accepted the guest's
234 * capabilities. If the host has not accepted, the guest must shutdown
235 * the service.
236 *
237 * is_accepted: Indicates if the host has accepted guest's capabilities.
238 * reservedz: Must be 0.
239 */
240
241struct dm_capabilities_resp_msg {
242 struct dm_header hdr;
243 __u64 is_accepted:1;
244 __u64 reservedz:63;
245} __packed;
246
247/*
248 * This message is used to report memory pressure from the guest.
249 * This message is not part of any transaction and there is no
250 * response to this message.
251 *
252 * num_avail: Available memory in pages.
253 * num_committed: Committed memory in pages.
254 * page_file_size: The accumulated size of all page files
255 * in the system in pages.
256 * zero_free: The nunber of zero and free pages.
257 * page_file_writes: The writes to the page file in pages.
258 * io_diff: An indicator of file cache efficiency or page file activity,
259 * calculated as File Cache Page Fault Count - Page Read Count.
260 * This value is in pages.
261 *
262 * Some of these metrics are Windows specific and fortunately
263 * the algorithm on the host side that computes the guest memory
264 * pressure only uses num_committed value.
265 */
266
267struct dm_status {
268 struct dm_header hdr;
269 __u64 num_avail;
270 __u64 num_committed;
271 __u64 page_file_size;
272 __u64 zero_free;
273 __u32 page_file_writes;
274 __u32 io_diff;
275} __packed;
276
277
278/*
279 * Message to ask the guest to allocate memory - balloon up message.
280 * This message is sent from the host to the guest. The guest may not be
281 * able to allocate as much memory as requested.
282 *
283 * num_pages: number of pages to allocate.
284 */
285
286struct dm_balloon {
287 struct dm_header hdr;
288 __u32 num_pages;
289 __u32 reservedz;
290} __packed;
291
292
293/*
294 * Balloon response message; this message is sent from the guest
295 * to the host in response to the balloon message.
296 *
297 * reservedz: Reserved; must be set to zero.
298 * more_pages: If FALSE, this is the last message of the transaction.
299 * if TRUE there will atleast one more message from the guest.
300 *
301 * range_count: The number of ranges in the range array.
302 *
303 * range_array: An array of page ranges returned to the host.
304 *
305 */
306
307struct dm_balloon_response {
308 struct dm_header hdr;
309 __u32 reservedz;
310 __u32 more_pages:1;
311 __u32 range_count:31;
312 union dm_mem_page_range range_array[];
313} __packed;
314
315/*
316 * Un-balloon message; this message is sent from the host
317 * to the guest to give guest more memory.
318 *
319 * more_pages: If FALSE, this is the last message of the transaction.
320 * if TRUE there will atleast one more message from the guest.
321 *
322 * reservedz: Reserved; must be set to zero.
323 *
324 * range_count: The number of ranges in the range array.
325 *
326 * range_array: An array of page ranges returned to the host.
327 *
328 */
329
330struct dm_unballoon_request {
331 struct dm_header hdr;
332 __u32 more_pages:1;
333 __u32 reservedz:31;
334 __u32 range_count;
335 union dm_mem_page_range range_array[];
336} __packed;
337
338/*
339 * Un-balloon response message; this message is sent from the guest
340 * to the host in response to an unballoon request.
341 *
342 */
343
344struct dm_unballoon_response {
345 struct dm_header hdr;
346} __packed;
347
348
349/*
350 * Hot add request message. Message sent from the host to the guest.
351 *
352 * mem_range: Memory range to hot add.
353 *
354 * On Linux we currently don't support this since we cannot hot add
355 * arbitrary granularity of memory.
356 */
357
358struct dm_hot_add {
359 struct dm_header hdr;
360 union dm_mem_page_range range;
361} __packed;
362
363/*
364 * Hot add response message.
365 * This message is sent by the guest to report the status of a hot add request.
366 * If page_count is less than the requested page count, then the host should
367 * assume all further hot add requests will fail, since this indicates that
368 * the guest has hit an upper physical memory barrier.
369 *
370 * Hot adds may also fail due to low resources; in this case, the guest must
371 * not complete this message until the hot add can succeed, and the host must
372 * not send a new hot add request until the response is sent.
373 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
374 * times it fails the request.
375 *
376 *
377 * page_count: number of pages that were successfully hot added.
378 *
379 * result: result of the operation 1: success, 0: failure.
380 *
381 */
382
383struct dm_hot_add_response {
384 struct dm_header hdr;
385 __u32 page_count;
386 __u32 result;
387} __packed;
388
389/*
390 * Types of information sent from host to the guest.
391 */
392
393enum dm_info_type {
394 INFO_TYPE_MAX_PAGE_CNT = 0,
395 MAX_INFO_TYPE
396};
397
398
399/*
400 * Header for the information message.
401 */
402
403struct dm_info_header {
404 enum dm_info_type type;
405 __u32 data_size;
406} __packed;
407
408/*
409 * This message is sent from the host to the guest to pass
410 * some relevant information (win8 addition).
411 *
412 * reserved: no used.
413 * info_size: size of the information blob.
414 * info: information blob.
415 */
416
417struct dm_info_msg {
418 struct dm_header hdr;
419 __u32 reserved;
420 __u32 info_size;
421 __u8 info[];
422};
423
424/*
425 * End protocol definitions.
426 */
427
428/*
429 * State to manage hot adding memory into the guest.
430 * The range start_pfn : end_pfn specifies the range
431 * that the host has asked us to hot add. The range
432 * start_pfn : ha_end_pfn specifies the range that we have
433 * currently hot added. We hot add in multiples of 128M
434 * chunks; it is possible that we may not be able to bring
435 * online all the pages in the region. The range
436 * covered_start_pfn:covered_end_pfn defines the pages that can
437 * be brough online.
438 */
439
440struct hv_hotadd_state {
441 struct list_head list;
442 unsigned long start_pfn;
443 unsigned long covered_start_pfn;
444 unsigned long covered_end_pfn;
445 unsigned long ha_end_pfn;
446 unsigned long end_pfn;
447 /*
448 * A list of gaps.
449 */
450 struct list_head gap_list;
451};
452
453struct hv_hotadd_gap {
454 struct list_head list;
455 unsigned long start_pfn;
456 unsigned long end_pfn;
457};
458
459struct balloon_state {
460 __u32 num_pages;
461 struct work_struct wrk;
462};
463
464struct hot_add_wrk {
465 union dm_mem_page_range ha_page_range;
466 union dm_mem_page_range ha_region_range;
467 struct work_struct wrk;
468};
469
470static bool hot_add = true;
471static bool do_hot_add;
472/*
473 * Delay reporting memory pressure by
474 * the specified number of seconds.
475 */
476static uint pressure_report_delay = 45;
477
478/*
479 * The last time we posted a pressure report to host.
480 */
481static unsigned long last_post_time;
482
483module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
484MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
485
486module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR));
487MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");
488static atomic_t trans_id = ATOMIC_INIT(0);
489
490static int dm_ring_size = (5 * PAGE_SIZE);
491
492/*
493 * Driver specific state.
494 */
495
496enum hv_dm_state {
497 DM_INITIALIZING = 0,
498 DM_INITIALIZED,
499 DM_BALLOON_UP,
500 DM_BALLOON_DOWN,
501 DM_HOT_ADD,
502 DM_INIT_ERROR
503};
504
505
506static __u8 recv_buffer[PAGE_SIZE];
507static __u8 *send_buffer;
508#define PAGES_IN_2M 512
509#define HA_CHUNK (32 * 1024)
510
511struct hv_dynmem_device {
512 struct hv_device *dev;
513 enum hv_dm_state state;
514 struct completion host_event;
515 struct completion config_event;
516
517 /*
518 * Number of pages we have currently ballooned out.
519 */
520 unsigned int num_pages_ballooned;
521 unsigned int num_pages_onlined;
522 unsigned int num_pages_added;
523
524 /*
525 * State to manage the ballooning (up) operation.
526 */
527 struct balloon_state balloon_wrk;
528
529 /*
530 * State to execute the "hot-add" operation.
531 */
532 struct hot_add_wrk ha_wrk;
533
534 /*
535 * This state tracks if the host has specified a hot-add
536 * region.
537 */
538 bool host_specified_ha_region;
539
540 /*
541 * State to synchronize hot-add.
542 */
543 struct completion ol_waitevent;
544 bool ha_waiting;
545 /*
546 * This thread handles hot-add
547 * requests from the host as well as notifying
548 * the host with regards to memory pressure in
549 * the guest.
550 */
551 struct task_struct *thread;
552
553 /*
554 * Protects ha_region_list, num_pages_onlined counter and individual
555 * regions from ha_region_list.
556 */
557 spinlock_t ha_lock;
558
559 /*
560 * A list of hot-add regions.
561 */
562 struct list_head ha_region_list;
563
564 /*
565 * We start with the highest version we can support
566 * and downgrade based on the host; we save here the
567 * next version to try.
568 */
569 __u32 next_version;
570
571 /*
572 * The negotiated version agreed by host.
573 */
574 __u32 version;
575};
576
577static struct hv_dynmem_device dm_device;
578
579static void post_status(struct hv_dynmem_device *dm);
580
581#ifdef CONFIG_MEMORY_HOTPLUG
582static inline bool has_pfn_is_backed(struct hv_hotadd_state *has,
583 unsigned long pfn)
584{
585 struct hv_hotadd_gap *gap;
586
587 /* The page is not backed. */
588 if ((pfn < has->covered_start_pfn) || (pfn >= has->covered_end_pfn))
589 return false;
590
591 /* Check for gaps. */
592 list_for_each_entry(gap, &has->gap_list, list) {
593 if ((pfn >= gap->start_pfn) && (pfn < gap->end_pfn))
594 return false;
595 }
596
597 return true;
598}
599
600static unsigned long hv_page_offline_check(unsigned long start_pfn,
601 unsigned long nr_pages)
602{
603 unsigned long pfn = start_pfn, count = 0;
604 struct hv_hotadd_state *has;
605 bool found;
606
607 while (pfn < start_pfn + nr_pages) {
608 /*
609 * Search for HAS which covers the pfn and when we find one
610 * count how many consequitive PFNs are covered.
611 */
612 found = false;
613 list_for_each_entry(has, &dm_device.ha_region_list, list) {
614 while ((pfn >= has->start_pfn) &&
615 (pfn < has->end_pfn) &&
616 (pfn < start_pfn + nr_pages)) {
617 found = true;
618 if (has_pfn_is_backed(has, pfn))
619 count++;
620 pfn++;
621 }
622 }
623
624 /*
625 * This PFN is not in any HAS (e.g. we're offlining a region
626 * which was present at boot), no need to account for it. Go
627 * to the next one.
628 */
629 if (!found)
630 pfn++;
631 }
632
633 return count;
634}
635
636static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
637 void *v)
638{
639 struct memory_notify *mem = (struct memory_notify *)v;
640 unsigned long flags, pfn_count;
641
642 switch (val) {
643 case MEM_ONLINE:
644 case MEM_CANCEL_ONLINE:
645 if (dm_device.ha_waiting) {
646 dm_device.ha_waiting = false;
647 complete(&dm_device.ol_waitevent);
648 }
649 break;
650
651 case MEM_OFFLINE:
652 spin_lock_irqsave(&dm_device.ha_lock, flags);
653 pfn_count = hv_page_offline_check(mem->start_pfn,
654 mem->nr_pages);
655 if (pfn_count <= dm_device.num_pages_onlined) {
656 dm_device.num_pages_onlined -= pfn_count;
657 } else {
658 /*
659 * We're offlining more pages than we managed to online.
660 * This is unexpected. In any case don't let
661 * num_pages_onlined wrap around zero.
662 */
663 WARN_ON_ONCE(1);
664 dm_device.num_pages_onlined = 0;
665 }
666 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
667 break;
668 case MEM_GOING_ONLINE:
669 case MEM_GOING_OFFLINE:
670 case MEM_CANCEL_OFFLINE:
671 break;
672 }
673 return NOTIFY_OK;
674}
675
676static struct notifier_block hv_memory_nb = {
677 .notifier_call = hv_memory_notifier,
678 .priority = 0
679};
680
681/* Check if the particular page is backed and can be onlined and online it. */
682static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg)
683{
684 if (!has_pfn_is_backed(has, page_to_pfn(pg))) {
685 if (!PageOffline(pg))
686 __SetPageOffline(pg);
687 return;
688 }
689 if (PageOffline(pg))
690 __ClearPageOffline(pg);
691
692 /* This frame is currently backed; online the page. */
693 __online_page_set_limits(pg);
694 __online_page_increment_counters(pg);
695 __online_page_free(pg);
696
697 lockdep_assert_held(&dm_device.ha_lock);
698 dm_device.num_pages_onlined++;
699}
700
701static void hv_bring_pgs_online(struct hv_hotadd_state *has,
702 unsigned long start_pfn, unsigned long size)
703{
704 int i;
705
706 pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
707 for (i = 0; i < size; i++)
708 hv_page_online_one(has, pfn_to_page(start_pfn + i));
709}
710
711static void hv_mem_hot_add(unsigned long start, unsigned long size,
712 unsigned long pfn_count,
713 struct hv_hotadd_state *has)
714{
715 int ret = 0;
716 int i, nid;
717 unsigned long start_pfn;
718 unsigned long processed_pfn;
719 unsigned long total_pfn = pfn_count;
720 unsigned long flags;
721
722 for (i = 0; i < (size/HA_CHUNK); i++) {
723 start_pfn = start + (i * HA_CHUNK);
724
725 spin_lock_irqsave(&dm_device.ha_lock, flags);
726 has->ha_end_pfn += HA_CHUNK;
727
728 if (total_pfn > HA_CHUNK) {
729 processed_pfn = HA_CHUNK;
730 total_pfn -= HA_CHUNK;
731 } else {
732 processed_pfn = total_pfn;
733 total_pfn = 0;
734 }
735
736 has->covered_end_pfn += processed_pfn;
737 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
738
739 init_completion(&dm_device.ol_waitevent);
740 dm_device.ha_waiting = !memhp_auto_online;
741
742 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
743 ret = add_memory(nid, PFN_PHYS((start_pfn)),
744 (HA_CHUNK << PAGE_SHIFT));
745
746 if (ret) {
747 pr_err("hot_add memory failed error is %d\n", ret);
748 if (ret == -EEXIST) {
749 /*
750 * This error indicates that the error
751 * is not a transient failure. This is the
752 * case where the guest's physical address map
753 * precludes hot adding memory. Stop all further
754 * memory hot-add.
755 */
756 do_hot_add = false;
757 }
758 spin_lock_irqsave(&dm_device.ha_lock, flags);
759 has->ha_end_pfn -= HA_CHUNK;
760 has->covered_end_pfn -= processed_pfn;
761 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
762 break;
763 }
764
765 /*
766 * Wait for the memory block to be onlined when memory onlining
767 * is done outside of kernel (memhp_auto_online). Since the hot
768 * add has succeeded, it is ok to proceed even if the pages in
769 * the hot added region have not been "onlined" within the
770 * allowed time.
771 */
772 if (dm_device.ha_waiting)
773 wait_for_completion_timeout(&dm_device.ol_waitevent,
774 5*HZ);
775 post_status(&dm_device);
776 }
777}
778
779static void hv_online_page(struct page *pg, unsigned int order)
780{
781 struct hv_hotadd_state *has;
782 unsigned long flags;
783 unsigned long pfn = page_to_pfn(pg);
784
785 spin_lock_irqsave(&dm_device.ha_lock, flags);
786 list_for_each_entry(has, &dm_device.ha_region_list, list) {
787 /* The page belongs to a different HAS. */
788 if ((pfn < has->start_pfn) ||
789 (pfn + (1UL << order) > has->end_pfn))
790 continue;
791
792 hv_bring_pgs_online(has, pfn, 1UL << order);
793 break;
794 }
795 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
796}
797
798static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
799{
800 struct hv_hotadd_state *has;
801 struct hv_hotadd_gap *gap;
802 unsigned long residual, new_inc;
803 int ret = 0;
804 unsigned long flags;
805
806 spin_lock_irqsave(&dm_device.ha_lock, flags);
807 list_for_each_entry(has, &dm_device.ha_region_list, list) {
808 /*
809 * If the pfn range we are dealing with is not in the current
810 * "hot add block", move on.
811 */
812 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
813 continue;
814
815 /*
816 * If the current start pfn is not where the covered_end
817 * is, create a gap and update covered_end_pfn.
818 */
819 if (has->covered_end_pfn != start_pfn) {
820 gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC);
821 if (!gap) {
822 ret = -ENOMEM;
823 break;
824 }
825
826 INIT_LIST_HEAD(&gap->list);
827 gap->start_pfn = has->covered_end_pfn;
828 gap->end_pfn = start_pfn;
829 list_add_tail(&gap->list, &has->gap_list);
830
831 has->covered_end_pfn = start_pfn;
832 }
833
834 /*
835 * If the current hot add-request extends beyond
836 * our current limit; extend it.
837 */
838 if ((start_pfn + pfn_cnt) > has->end_pfn) {
839 residual = (start_pfn + pfn_cnt - has->end_pfn);
840 /*
841 * Extend the region by multiples of HA_CHUNK.
842 */
843 new_inc = (residual / HA_CHUNK) * HA_CHUNK;
844 if (residual % HA_CHUNK)
845 new_inc += HA_CHUNK;
846
847 has->end_pfn += new_inc;
848 }
849
850 ret = 1;
851 break;
852 }
853 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
854
855 return ret;
856}
857
858static unsigned long handle_pg_range(unsigned long pg_start,
859 unsigned long pg_count)
860{
861 unsigned long start_pfn = pg_start;
862 unsigned long pfn_cnt = pg_count;
863 unsigned long size;
864 struct hv_hotadd_state *has;
865 unsigned long pgs_ol = 0;
866 unsigned long old_covered_state;
867 unsigned long res = 0, flags;
868
869 pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count,
870 pg_start);
871
872 spin_lock_irqsave(&dm_device.ha_lock, flags);
873 list_for_each_entry(has, &dm_device.ha_region_list, list) {
874 /*
875 * If the pfn range we are dealing with is not in the current
876 * "hot add block", move on.
877 */
878 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
879 continue;
880
881 old_covered_state = has->covered_end_pfn;
882
883 if (start_pfn < has->ha_end_pfn) {
884 /*
885 * This is the case where we are backing pages
886 * in an already hot added region. Bring
887 * these pages online first.
888 */
889 pgs_ol = has->ha_end_pfn - start_pfn;
890 if (pgs_ol > pfn_cnt)
891 pgs_ol = pfn_cnt;
892
893 has->covered_end_pfn += pgs_ol;
894 pfn_cnt -= pgs_ol;
895 /*
896 * Check if the corresponding memory block is already
897 * online. It is possible to observe struct pages still
898 * being uninitialized here so check section instead.
899 * In case the section is online we need to bring the
900 * rest of pfns (which were not backed previously)
901 * online too.
902 */
903 if (start_pfn > has->start_pfn &&
904 online_section_nr(pfn_to_section_nr(start_pfn)))
905 hv_bring_pgs_online(has, start_pfn, pgs_ol);
906
907 }
908
909 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
910 /*
911 * We have some residual hot add range
912 * that needs to be hot added; hot add
913 * it now. Hot add a multiple of
914 * of HA_CHUNK that fully covers the pages
915 * we have.
916 */
917 size = (has->end_pfn - has->ha_end_pfn);
918 if (pfn_cnt <= size) {
919 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
920 if (pfn_cnt % HA_CHUNK)
921 size += HA_CHUNK;
922 } else {
923 pfn_cnt = size;
924 }
925 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
926 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
927 spin_lock_irqsave(&dm_device.ha_lock, flags);
928 }
929 /*
930 * If we managed to online any pages that were given to us,
931 * we declare success.
932 */
933 res = has->covered_end_pfn - old_covered_state;
934 break;
935 }
936 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
937
938 return res;
939}
940
941static unsigned long process_hot_add(unsigned long pg_start,
942 unsigned long pfn_cnt,
943 unsigned long rg_start,
944 unsigned long rg_size)
945{
946 struct hv_hotadd_state *ha_region = NULL;
947 int covered;
948 unsigned long flags;
949
950 if (pfn_cnt == 0)
951 return 0;
952
953 if (!dm_device.host_specified_ha_region) {
954 covered = pfn_covered(pg_start, pfn_cnt);
955 if (covered < 0)
956 return 0;
957
958 if (covered)
959 goto do_pg_range;
960 }
961
962 /*
963 * If the host has specified a hot-add range; deal with it first.
964 */
965
966 if (rg_size != 0) {
967 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
968 if (!ha_region)
969 return 0;
970
971 INIT_LIST_HEAD(&ha_region->list);
972 INIT_LIST_HEAD(&ha_region->gap_list);
973
974 ha_region->start_pfn = rg_start;
975 ha_region->ha_end_pfn = rg_start;
976 ha_region->covered_start_pfn = pg_start;
977 ha_region->covered_end_pfn = pg_start;
978 ha_region->end_pfn = rg_start + rg_size;
979
980 spin_lock_irqsave(&dm_device.ha_lock, flags);
981 list_add_tail(&ha_region->list, &dm_device.ha_region_list);
982 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
983 }
984
985do_pg_range:
986 /*
987 * Process the page range specified; bringing them
988 * online if possible.
989 */
990 return handle_pg_range(pg_start, pfn_cnt);
991}
992
993#endif
994
995static void hot_add_req(struct work_struct *dummy)
996{
997 struct dm_hot_add_response resp;
998#ifdef CONFIG_MEMORY_HOTPLUG
999 unsigned long pg_start, pfn_cnt;
1000 unsigned long rg_start, rg_sz;
1001#endif
1002 struct hv_dynmem_device *dm = &dm_device;
1003
1004 memset(&resp, 0, sizeof(struct dm_hot_add_response));
1005 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
1006 resp.hdr.size = sizeof(struct dm_hot_add_response);
1007
1008#ifdef CONFIG_MEMORY_HOTPLUG
1009 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
1010 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
1011
1012 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
1013 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
1014
1015 if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
1016 unsigned long region_size;
1017 unsigned long region_start;
1018
1019 /*
1020 * The host has not specified the hot-add region.
1021 * Based on the hot-add page range being specified,
1022 * compute a hot-add region that can cover the pages
1023 * that need to be hot-added while ensuring the alignment
1024 * and size requirements of Linux as it relates to hot-add.
1025 */
1026 region_start = pg_start;
1027 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
1028 if (pfn_cnt % HA_CHUNK)
1029 region_size += HA_CHUNK;
1030
1031 region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
1032
1033 rg_start = region_start;
1034 rg_sz = region_size;
1035 }
1036
1037 if (do_hot_add)
1038 resp.page_count = process_hot_add(pg_start, pfn_cnt,
1039 rg_start, rg_sz);
1040
1041 dm->num_pages_added += resp.page_count;
1042#endif
1043 /*
1044 * The result field of the response structure has the
1045 * following semantics:
1046 *
1047 * 1. If all or some pages hot-added: Guest should return success.
1048 *
1049 * 2. If no pages could be hot-added:
1050 *
1051 * If the guest returns success, then the host
1052 * will not attempt any further hot-add operations. This
1053 * signifies a permanent failure.
1054 *
1055 * If the guest returns failure, then this failure will be
1056 * treated as a transient failure and the host may retry the
1057 * hot-add operation after some delay.
1058 */
1059 if (resp.page_count > 0)
1060 resp.result = 1;
1061 else if (!do_hot_add)
1062 resp.result = 1;
1063 else
1064 resp.result = 0;
1065
1066 if (!do_hot_add || (resp.page_count == 0))
1067 pr_err("Memory hot add failed\n");
1068
1069 dm->state = DM_INITIALIZED;
1070 resp.hdr.trans_id = atomic_inc_return(&trans_id);
1071 vmbus_sendpacket(dm->dev->channel, &resp,
1072 sizeof(struct dm_hot_add_response),
1073 (unsigned long)NULL,
1074 VM_PKT_DATA_INBAND, 0);
1075}
1076
1077static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
1078{
1079 struct dm_info_header *info_hdr;
1080
1081 info_hdr = (struct dm_info_header *)msg->info;
1082
1083 switch (info_hdr->type) {
1084 case INFO_TYPE_MAX_PAGE_CNT:
1085 if (info_hdr->data_size == sizeof(__u64)) {
1086 __u64 *max_page_count = (__u64 *)&info_hdr[1];
1087
1088 pr_info("Max. dynamic memory size: %llu MB\n",
1089 (*max_page_count) >> (20 - PAGE_SHIFT));
1090 }
1091
1092 break;
1093 default:
1094 pr_warn("Received Unknown type: %d\n", info_hdr->type);
1095 }
1096}
1097
1098static unsigned long compute_balloon_floor(void)
1099{
1100 unsigned long min_pages;
1101 unsigned long nr_pages = totalram_pages();
1102#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
1103 /* Simple continuous piecewiese linear function:
1104 * max MiB -> min MiB gradient
1105 * 0 0
1106 * 16 16
1107 * 32 24
1108 * 128 72 (1/2)
1109 * 512 168 (1/4)
1110 * 2048 360 (1/8)
1111 * 8192 744 (1/16)
1112 * 32768 1512 (1/32)
1113 */
1114 if (nr_pages < MB2PAGES(128))
1115 min_pages = MB2PAGES(8) + (nr_pages >> 1);
1116 else if (nr_pages < MB2PAGES(512))
1117 min_pages = MB2PAGES(40) + (nr_pages >> 2);
1118 else if (nr_pages < MB2PAGES(2048))
1119 min_pages = MB2PAGES(104) + (nr_pages >> 3);
1120 else if (nr_pages < MB2PAGES(8192))
1121 min_pages = MB2PAGES(232) + (nr_pages >> 4);
1122 else
1123 min_pages = MB2PAGES(488) + (nr_pages >> 5);
1124#undef MB2PAGES
1125 return min_pages;
1126}
1127
1128/*
1129 * Post our status as it relates memory pressure to the
1130 * host. Host expects the guests to post this status
1131 * periodically at 1 second intervals.
1132 *
1133 * The metrics specified in this protocol are very Windows
1134 * specific and so we cook up numbers here to convey our memory
1135 * pressure.
1136 */
1137
1138static void post_status(struct hv_dynmem_device *dm)
1139{
1140 struct dm_status status;
1141 unsigned long now = jiffies;
1142 unsigned long last_post = last_post_time;
1143
1144 if (pressure_report_delay > 0) {
1145 --pressure_report_delay;
1146 return;
1147 }
1148
1149 if (!time_after(now, (last_post_time + HZ)))
1150 return;
1151
1152 memset(&status, 0, sizeof(struct dm_status));
1153 status.hdr.type = DM_STATUS_REPORT;
1154 status.hdr.size = sizeof(struct dm_status);
1155 status.hdr.trans_id = atomic_inc_return(&trans_id);
1156
1157 /*
1158 * The host expects the guest to report free and committed memory.
1159 * Furthermore, the host expects the pressure information to include
1160 * the ballooned out pages. For a given amount of memory that we are
1161 * managing we need to compute a floor below which we should not
1162 * balloon. Compute this and add it to the pressure report.
1163 * We also need to report all offline pages (num_pages_added -
1164 * num_pages_onlined) as committed to the host, otherwise it can try
1165 * asking us to balloon them out.
1166 */
1167 status.num_avail = si_mem_available();
1168 status.num_committed = vm_memory_committed() +
1169 dm->num_pages_ballooned +
1170 (dm->num_pages_added > dm->num_pages_onlined ?
1171 dm->num_pages_added - dm->num_pages_onlined : 0) +
1172 compute_balloon_floor();
1173
1174 trace_balloon_status(status.num_avail, status.num_committed,
1175 vm_memory_committed(), dm->num_pages_ballooned,
1176 dm->num_pages_added, dm->num_pages_onlined);
1177 /*
1178 * If our transaction ID is no longer current, just don't
1179 * send the status. This can happen if we were interrupted
1180 * after we picked our transaction ID.
1181 */
1182 if (status.hdr.trans_id != atomic_read(&trans_id))
1183 return;
1184
1185 /*
1186 * If the last post time that we sampled has changed,
1187 * we have raced, don't post the status.
1188 */
1189 if (last_post != last_post_time)
1190 return;
1191
1192 last_post_time = jiffies;
1193 vmbus_sendpacket(dm->dev->channel, &status,
1194 sizeof(struct dm_status),
1195 (unsigned long)NULL,
1196 VM_PKT_DATA_INBAND, 0);
1197
1198}
1199
1200static void free_balloon_pages(struct hv_dynmem_device *dm,
1201 union dm_mem_page_range *range_array)
1202{
1203 int num_pages = range_array->finfo.page_cnt;
1204 __u64 start_frame = range_array->finfo.start_page;
1205 struct page *pg;
1206 int i;
1207
1208 for (i = 0; i < num_pages; i++) {
1209 pg = pfn_to_page(i + start_frame);
1210 __ClearPageOffline(pg);
1211 __free_page(pg);
1212 dm->num_pages_ballooned--;
1213 }
1214}
1215
1216
1217
1218static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
1219 unsigned int num_pages,
1220 struct dm_balloon_response *bl_resp,
1221 int alloc_unit)
1222{
1223 unsigned int i, j;
1224 struct page *pg;
1225
1226 if (num_pages < alloc_unit)
1227 return 0;
1228
1229 for (i = 0; (i * alloc_unit) < num_pages; i++) {
1230 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
1231 PAGE_SIZE)
1232 return i * alloc_unit;
1233
1234 /*
1235 * We execute this code in a thread context. Furthermore,
1236 * we don't want the kernel to try too hard.
1237 */
1238 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
1239 __GFP_NOMEMALLOC | __GFP_NOWARN,
1240 get_order(alloc_unit << PAGE_SHIFT));
1241
1242 if (!pg)
1243 return i * alloc_unit;
1244
1245 dm->num_pages_ballooned += alloc_unit;
1246
1247 /*
1248 * If we allocatted 2M pages; split them so we
1249 * can free them in any order we get.
1250 */
1251
1252 if (alloc_unit != 1)
1253 split_page(pg, get_order(alloc_unit << PAGE_SHIFT));
1254
1255 /* mark all pages offline */
1256 for (j = 0; j < (1 << get_order(alloc_unit << PAGE_SHIFT)); j++)
1257 __SetPageOffline(pg + j);
1258
1259 bl_resp->range_count++;
1260 bl_resp->range_array[i].finfo.start_page =
1261 page_to_pfn(pg);
1262 bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
1263 bl_resp->hdr.size += sizeof(union dm_mem_page_range);
1264
1265 }
1266
1267 return num_pages;
1268}
1269
1270static void balloon_up(struct work_struct *dummy)
1271{
1272 unsigned int num_pages = dm_device.balloon_wrk.num_pages;
1273 unsigned int num_ballooned = 0;
1274 struct dm_balloon_response *bl_resp;
1275 int alloc_unit;
1276 int ret;
1277 bool done = false;
1278 int i;
1279 long avail_pages;
1280 unsigned long floor;
1281
1282 /* The host balloons pages in 2M granularity. */
1283 WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0);
1284
1285 /*
1286 * We will attempt 2M allocations. However, if we fail to
1287 * allocate 2M chunks, we will go back to 4k allocations.
1288 */
1289 alloc_unit = 512;
1290
1291 avail_pages = si_mem_available();
1292 floor = compute_balloon_floor();
1293
1294 /* Refuse to balloon below the floor, keep the 2M granularity. */
1295 if (avail_pages < num_pages || avail_pages - num_pages < floor) {
1296 pr_warn("Balloon request will be partially fulfilled. %s\n",
1297 avail_pages < num_pages ? "Not enough memory." :
1298 "Balloon floor reached.");
1299
1300 num_pages = avail_pages > floor ? (avail_pages - floor) : 0;
1301 num_pages -= num_pages % PAGES_IN_2M;
1302 }
1303
1304 while (!done) {
1305 bl_resp = (struct dm_balloon_response *)send_buffer;
1306 memset(send_buffer, 0, PAGE_SIZE);
1307 bl_resp->hdr.type = DM_BALLOON_RESPONSE;
1308 bl_resp->hdr.size = sizeof(struct dm_balloon_response);
1309 bl_resp->more_pages = 1;
1310
1311 num_pages -= num_ballooned;
1312 num_ballooned = alloc_balloon_pages(&dm_device, num_pages,
1313 bl_resp, alloc_unit);
1314
1315 if (alloc_unit != 1 && num_ballooned == 0) {
1316 alloc_unit = 1;
1317 continue;
1318 }
1319
1320 if (num_ballooned == 0 || num_ballooned == num_pages) {
1321 pr_debug("Ballooned %u out of %u requested pages.\n",
1322 num_pages, dm_device.balloon_wrk.num_pages);
1323
1324 bl_resp->more_pages = 0;
1325 done = true;
1326 dm_device.state = DM_INITIALIZED;
1327 }
1328
1329 /*
1330 * We are pushing a lot of data through the channel;
1331 * deal with transient failures caused because of the
1332 * lack of space in the ring buffer.
1333 */
1334
1335 do {
1336 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
1337 ret = vmbus_sendpacket(dm_device.dev->channel,
1338 bl_resp,
1339 bl_resp->hdr.size,
1340 (unsigned long)NULL,
1341 VM_PKT_DATA_INBAND, 0);
1342
1343 if (ret == -EAGAIN)
1344 msleep(20);
1345 post_status(&dm_device);
1346 } while (ret == -EAGAIN);
1347
1348 if (ret) {
1349 /*
1350 * Free up the memory we allocatted.
1351 */
1352 pr_err("Balloon response failed\n");
1353
1354 for (i = 0; i < bl_resp->range_count; i++)
1355 free_balloon_pages(&dm_device,
1356 &bl_resp->range_array[i]);
1357
1358 done = true;
1359 }
1360 }
1361
1362}
1363
1364static void balloon_down(struct hv_dynmem_device *dm,
1365 struct dm_unballoon_request *req)
1366{
1367 union dm_mem_page_range *range_array = req->range_array;
1368 int range_count = req->range_count;
1369 struct dm_unballoon_response resp;
1370 int i;
1371 unsigned int prev_pages_ballooned = dm->num_pages_ballooned;
1372
1373 for (i = 0; i < range_count; i++) {
1374 free_balloon_pages(dm, &range_array[i]);
1375 complete(&dm_device.config_event);
1376 }
1377
1378 pr_debug("Freed %u ballooned pages.\n",
1379 prev_pages_ballooned - dm->num_pages_ballooned);
1380
1381 if (req->more_pages == 1)
1382 return;
1383
1384 memset(&resp, 0, sizeof(struct dm_unballoon_response));
1385 resp.hdr.type = DM_UNBALLOON_RESPONSE;
1386 resp.hdr.trans_id = atomic_inc_return(&trans_id);
1387 resp.hdr.size = sizeof(struct dm_unballoon_response);
1388
1389 vmbus_sendpacket(dm_device.dev->channel, &resp,
1390 sizeof(struct dm_unballoon_response),
1391 (unsigned long)NULL,
1392 VM_PKT_DATA_INBAND, 0);
1393
1394 dm->state = DM_INITIALIZED;
1395}
1396
1397static void balloon_onchannelcallback(void *context);
1398
1399static int dm_thread_func(void *dm_dev)
1400{
1401 struct hv_dynmem_device *dm = dm_dev;
1402
1403 while (!kthread_should_stop()) {
1404 wait_for_completion_interruptible_timeout(
1405 &dm_device.config_event, 1*HZ);
1406 /*
1407 * The host expects us to post information on the memory
1408 * pressure every second.
1409 */
1410 reinit_completion(&dm_device.config_event);
1411 post_status(dm);
1412 }
1413
1414 return 0;
1415}
1416
1417
1418static void version_resp(struct hv_dynmem_device *dm,
1419 struct dm_version_response *vresp)
1420{
1421 struct dm_version_request version_req;
1422 int ret;
1423
1424 if (vresp->is_accepted) {
1425 /*
1426 * We are done; wakeup the
1427 * context waiting for version
1428 * negotiation.
1429 */
1430 complete(&dm->host_event);
1431 return;
1432 }
1433 /*
1434 * If there are more versions to try, continue
1435 * with negotiations; if not
1436 * shutdown the service since we are not able
1437 * to negotiate a suitable version number
1438 * with the host.
1439 */
1440 if (dm->next_version == 0)
1441 goto version_error;
1442
1443 memset(&version_req, 0, sizeof(struct dm_version_request));
1444 version_req.hdr.type = DM_VERSION_REQUEST;
1445 version_req.hdr.size = sizeof(struct dm_version_request);
1446 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1447 version_req.version.version = dm->next_version;
1448 dm->version = version_req.version.version;
1449
1450 /*
1451 * Set the next version to try in case current version fails.
1452 * Win7 protocol ought to be the last one to try.
1453 */
1454 switch (version_req.version.version) {
1455 case DYNMEM_PROTOCOL_VERSION_WIN8:
1456 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
1457 version_req.is_last_attempt = 0;
1458 break;
1459 default:
1460 dm->next_version = 0;
1461 version_req.is_last_attempt = 1;
1462 }
1463
1464 ret = vmbus_sendpacket(dm->dev->channel, &version_req,
1465 sizeof(struct dm_version_request),
1466 (unsigned long)NULL,
1467 VM_PKT_DATA_INBAND, 0);
1468
1469 if (ret)
1470 goto version_error;
1471
1472 return;
1473
1474version_error:
1475 dm->state = DM_INIT_ERROR;
1476 complete(&dm->host_event);
1477}
1478
1479static void cap_resp(struct hv_dynmem_device *dm,
1480 struct dm_capabilities_resp_msg *cap_resp)
1481{
1482 if (!cap_resp->is_accepted) {
1483 pr_err("Capabilities not accepted by host\n");
1484 dm->state = DM_INIT_ERROR;
1485 }
1486 complete(&dm->host_event);
1487}
1488
1489static void balloon_onchannelcallback(void *context)
1490{
1491 struct hv_device *dev = context;
1492 u32 recvlen;
1493 u64 requestid;
1494 struct dm_message *dm_msg;
1495 struct dm_header *dm_hdr;
1496 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1497 struct dm_balloon *bal_msg;
1498 struct dm_hot_add *ha_msg;
1499 union dm_mem_page_range *ha_pg_range;
1500 union dm_mem_page_range *ha_region;
1501
1502 memset(recv_buffer, 0, sizeof(recv_buffer));
1503 vmbus_recvpacket(dev->channel, recv_buffer,
1504 PAGE_SIZE, &recvlen, &requestid);
1505
1506 if (recvlen > 0) {
1507 dm_msg = (struct dm_message *)recv_buffer;
1508 dm_hdr = &dm_msg->hdr;
1509
1510 switch (dm_hdr->type) {
1511 case DM_VERSION_RESPONSE:
1512 version_resp(dm,
1513 (struct dm_version_response *)dm_msg);
1514 break;
1515
1516 case DM_CAPABILITIES_RESPONSE:
1517 cap_resp(dm,
1518 (struct dm_capabilities_resp_msg *)dm_msg);
1519 break;
1520
1521 case DM_BALLOON_REQUEST:
1522 if (dm->state == DM_BALLOON_UP)
1523 pr_warn("Currently ballooning\n");
1524 bal_msg = (struct dm_balloon *)recv_buffer;
1525 dm->state = DM_BALLOON_UP;
1526 dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
1527 schedule_work(&dm_device.balloon_wrk.wrk);
1528 break;
1529
1530 case DM_UNBALLOON_REQUEST:
1531 dm->state = DM_BALLOON_DOWN;
1532 balloon_down(dm,
1533 (struct dm_unballoon_request *)recv_buffer);
1534 break;
1535
1536 case DM_MEM_HOT_ADD_REQUEST:
1537 if (dm->state == DM_HOT_ADD)
1538 pr_warn("Currently hot-adding\n");
1539 dm->state = DM_HOT_ADD;
1540 ha_msg = (struct dm_hot_add *)recv_buffer;
1541 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
1542 /*
1543 * This is a normal hot-add request specifying
1544 * hot-add memory.
1545 */
1546 dm->host_specified_ha_region = false;
1547 ha_pg_range = &ha_msg->range;
1548 dm->ha_wrk.ha_page_range = *ha_pg_range;
1549 dm->ha_wrk.ha_region_range.page_range = 0;
1550 } else {
1551 /*
1552 * Host is specifying that we first hot-add
1553 * a region and then partially populate this
1554 * region.
1555 */
1556 dm->host_specified_ha_region = true;
1557 ha_pg_range = &ha_msg->range;
1558 ha_region = &ha_pg_range[1];
1559 dm->ha_wrk.ha_page_range = *ha_pg_range;
1560 dm->ha_wrk.ha_region_range = *ha_region;
1561 }
1562 schedule_work(&dm_device.ha_wrk.wrk);
1563 break;
1564
1565 case DM_INFO_MESSAGE:
1566 process_info(dm, (struct dm_info_msg *)dm_msg);
1567 break;
1568
1569 default:
1570 pr_warn("Unhandled message: type: %d\n", dm_hdr->type);
1571
1572 }
1573 }
1574
1575}
1576
1577static int balloon_probe(struct hv_device *dev,
1578 const struct hv_vmbus_device_id *dev_id)
1579{
1580 int ret;
1581 unsigned long t;
1582 struct dm_version_request version_req;
1583 struct dm_capabilities cap_msg;
1584
1585#ifdef CONFIG_MEMORY_HOTPLUG
1586 do_hot_add = hot_add;
1587#else
1588 do_hot_add = false;
1589#endif
1590
1591 /*
1592 * First allocate a send buffer.
1593 */
1594
1595 send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
1596 if (!send_buffer)
1597 return -ENOMEM;
1598
1599 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
1600 balloon_onchannelcallback, dev);
1601
1602 if (ret)
1603 goto probe_error0;
1604
1605 dm_device.dev = dev;
1606 dm_device.state = DM_INITIALIZING;
1607 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8;
1608 init_completion(&dm_device.host_event);
1609 init_completion(&dm_device.config_event);
1610 INIT_LIST_HEAD(&dm_device.ha_region_list);
1611 spin_lock_init(&dm_device.ha_lock);
1612 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
1613 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
1614 dm_device.host_specified_ha_region = false;
1615
1616 dm_device.thread =
1617 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
1618 if (IS_ERR(dm_device.thread)) {
1619 ret = PTR_ERR(dm_device.thread);
1620 goto probe_error1;
1621 }
1622
1623#ifdef CONFIG_MEMORY_HOTPLUG
1624 set_online_page_callback(&hv_online_page);
1625 register_memory_notifier(&hv_memory_nb);
1626#endif
1627
1628 hv_set_drvdata(dev, &dm_device);
1629 /*
1630 * Initiate the hand shake with the host and negotiate
1631 * a version that the host can support. We start with the
1632 * highest version number and go down if the host cannot
1633 * support it.
1634 */
1635 memset(&version_req, 0, sizeof(struct dm_version_request));
1636 version_req.hdr.type = DM_VERSION_REQUEST;
1637 version_req.hdr.size = sizeof(struct dm_version_request);
1638 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1639 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;
1640 version_req.is_last_attempt = 0;
1641 dm_device.version = version_req.version.version;
1642
1643 ret = vmbus_sendpacket(dev->channel, &version_req,
1644 sizeof(struct dm_version_request),
1645 (unsigned long)NULL,
1646 VM_PKT_DATA_INBAND, 0);
1647 if (ret)
1648 goto probe_error2;
1649
1650 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1651 if (t == 0) {
1652 ret = -ETIMEDOUT;
1653 goto probe_error2;
1654 }
1655
1656 /*
1657 * If we could not negotiate a compatible version with the host
1658 * fail the probe function.
1659 */
1660 if (dm_device.state == DM_INIT_ERROR) {
1661 ret = -ETIMEDOUT;
1662 goto probe_error2;
1663 }
1664
1665 pr_info("Using Dynamic Memory protocol version %u.%u\n",
1666 DYNMEM_MAJOR_VERSION(dm_device.version),
1667 DYNMEM_MINOR_VERSION(dm_device.version));
1668
1669 /*
1670 * Now submit our capabilities to the host.
1671 */
1672 memset(&cap_msg, 0, sizeof(struct dm_capabilities));
1673 cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
1674 cap_msg.hdr.size = sizeof(struct dm_capabilities);
1675 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
1676
1677 cap_msg.caps.cap_bits.balloon = 1;
1678 cap_msg.caps.cap_bits.hot_add = 1;
1679
1680 /*
1681 * Specify our alignment requirements as it relates
1682 * memory hot-add. Specify 128MB alignment.
1683 */
1684 cap_msg.caps.cap_bits.hot_add_alignment = 7;
1685
1686 /*
1687 * Currently the host does not use these
1688 * values and we set them to what is done in the
1689 * Windows driver.
1690 */
1691 cap_msg.min_page_cnt = 0;
1692 cap_msg.max_page_number = -1;
1693
1694 ret = vmbus_sendpacket(dev->channel, &cap_msg,
1695 sizeof(struct dm_capabilities),
1696 (unsigned long)NULL,
1697 VM_PKT_DATA_INBAND, 0);
1698 if (ret)
1699 goto probe_error2;
1700
1701 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1702 if (t == 0) {
1703 ret = -ETIMEDOUT;
1704 goto probe_error2;
1705 }
1706
1707 /*
1708 * If the host does not like our capabilities,
1709 * fail the probe function.
1710 */
1711 if (dm_device.state == DM_INIT_ERROR) {
1712 ret = -ETIMEDOUT;
1713 goto probe_error2;
1714 }
1715
1716 dm_device.state = DM_INITIALIZED;
1717 last_post_time = jiffies;
1718
1719 return 0;
1720
1721probe_error2:
1722#ifdef CONFIG_MEMORY_HOTPLUG
1723 restore_online_page_callback(&hv_online_page);
1724#endif
1725 kthread_stop(dm_device.thread);
1726
1727probe_error1:
1728 vmbus_close(dev->channel);
1729probe_error0:
1730 kfree(send_buffer);
1731 return ret;
1732}
1733
1734static int balloon_remove(struct hv_device *dev)
1735{
1736 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1737 struct hv_hotadd_state *has, *tmp;
1738 struct hv_hotadd_gap *gap, *tmp_gap;
1739 unsigned long flags;
1740
1741 if (dm->num_pages_ballooned != 0)
1742 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
1743
1744 cancel_work_sync(&dm->balloon_wrk.wrk);
1745 cancel_work_sync(&dm->ha_wrk.wrk);
1746
1747 vmbus_close(dev->channel);
1748 kthread_stop(dm->thread);
1749 kfree(send_buffer);
1750#ifdef CONFIG_MEMORY_HOTPLUG
1751 restore_online_page_callback(&hv_online_page);
1752 unregister_memory_notifier(&hv_memory_nb);
1753#endif
1754 spin_lock_irqsave(&dm_device.ha_lock, flags);
1755 list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
1756 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
1757 list_del(&gap->list);
1758 kfree(gap);
1759 }
1760 list_del(&has->list);
1761 kfree(has);
1762 }
1763 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
1764
1765 return 0;
1766}
1767
1768static const struct hv_vmbus_device_id id_table[] = {
1769 /* Dynamic Memory Class ID */
1770 /* 525074DC-8985-46e2-8057-A307DC18A502 */
1771 { HV_DM_GUID, },
1772 { },
1773};
1774
1775MODULE_DEVICE_TABLE(vmbus, id_table);
1776
1777static struct hv_driver balloon_drv = {
1778 .name = "hv_balloon",
1779 .id_table = id_table,
1780 .probe = balloon_probe,
1781 .remove = balloon_remove,
1782 .driver = {
1783 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
1784 },
1785};
1786
1787static int __init init_balloon_drv(void)
1788{
1789
1790 return vmbus_driver_register(&balloon_drv);
1791}
1792
1793module_init(init_balloon_drv);
1794
1795MODULE_DESCRIPTION("Hyper-V Balloon");
1796MODULE_LICENSE("GPL");
1797