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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2012, Microsoft Corporation.
4 *
5 * Author:
6 * K. Y. Srinivasan <kys@microsoft.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/kernel.h>
12#include <linux/jiffies.h>
13#include <linux/mman.h>
14#include <linux/debugfs.h>
15#include <linux/delay.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/kthread.h>
20#include <linux/completion.h>
21#include <linux/count_zeros.h>
22#include <linux/memory_hotplug.h>
23#include <linux/memory.h>
24#include <linux/notifier.h>
25#include <linux/percpu_counter.h>
26#include <linux/page_reporting.h>
27
28#include <linux/hyperv.h>
29#include <asm/hyperv-tlfs.h>
30
31#include <asm/mshyperv.h>
32
33#define CREATE_TRACE_POINTS
34#include "hv_trace_balloon.h"
35
36/*
37 * We begin with definitions supporting the Dynamic Memory protocol
38 * with the host.
39 *
40 * Begin protocol definitions.
41 */
42
43
44
45/*
46 * Protocol versions. The low word is the minor version, the high word the major
47 * version.
48 *
49 * History:
50 * Initial version 1.0
51 * Changed to 0.1 on 2009/03/25
52 * Changes to 0.2 on 2009/05/14
53 * Changes to 0.3 on 2009/12/03
54 * Changed to 1.0 on 2011/04/05
55 */
56
57#define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
58#define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
59#define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
60
61enum {
62 DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3),
63 DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0),
64 DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0),
65
66 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,
67 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,
68 DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3,
69
70 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10
71};
72
73
74
75/*
76 * Message Types
77 */
78
79enum dm_message_type {
80 /*
81 * Version 0.3
82 */
83 DM_ERROR = 0,
84 DM_VERSION_REQUEST = 1,
85 DM_VERSION_RESPONSE = 2,
86 DM_CAPABILITIES_REPORT = 3,
87 DM_CAPABILITIES_RESPONSE = 4,
88 DM_STATUS_REPORT = 5,
89 DM_BALLOON_REQUEST = 6,
90 DM_BALLOON_RESPONSE = 7,
91 DM_UNBALLOON_REQUEST = 8,
92 DM_UNBALLOON_RESPONSE = 9,
93 DM_MEM_HOT_ADD_REQUEST = 10,
94 DM_MEM_HOT_ADD_RESPONSE = 11,
95 DM_VERSION_03_MAX = 11,
96 /*
97 * Version 1.0.
98 */
99 DM_INFO_MESSAGE = 12,
100 DM_VERSION_1_MAX = 12
101};
102
103
104/*
105 * Structures defining the dynamic memory management
106 * protocol.
107 */
108
109union dm_version {
110 struct {
111 __u16 minor_version;
112 __u16 major_version;
113 };
114 __u32 version;
115} __packed;
116
117
118union dm_caps {
119 struct {
120 __u64 balloon:1;
121 __u64 hot_add:1;
122 /*
123 * To support guests that may have alignment
124 * limitations on hot-add, the guest can specify
125 * its alignment requirements; a value of n
126 * represents an alignment of 2^n in mega bytes.
127 */
128 __u64 hot_add_alignment:4;
129 __u64 reservedz:58;
130 } cap_bits;
131 __u64 caps;
132} __packed;
133
134union dm_mem_page_range {
135 struct {
136 /*
137 * The PFN number of the first page in the range.
138 * 40 bits is the architectural limit of a PFN
139 * number for AMD64.
140 */
141 __u64 start_page:40;
142 /*
143 * The number of pages in the range.
144 */
145 __u64 page_cnt:24;
146 } finfo;
147 __u64 page_range;
148} __packed;
149
150
151
152/*
153 * The header for all dynamic memory messages:
154 *
155 * type: Type of the message.
156 * size: Size of the message in bytes; including the header.
157 * trans_id: The guest is responsible for manufacturing this ID.
158 */
159
160struct dm_header {
161 __u16 type;
162 __u16 size;
163 __u32 trans_id;
164} __packed;
165
166/*
167 * A generic message format for dynamic memory.
168 * Specific message formats are defined later in the file.
169 */
170
171struct dm_message {
172 struct dm_header hdr;
173 __u8 data[]; /* enclosed message */
174} __packed;
175
176
177/*
178 * Specific message types supporting the dynamic memory protocol.
179 */
180
181/*
182 * Version negotiation message. Sent from the guest to the host.
183 * The guest is free to try different versions until the host
184 * accepts the version.
185 *
186 * dm_version: The protocol version requested.
187 * is_last_attempt: If TRUE, this is the last version guest will request.
188 * reservedz: Reserved field, set to zero.
189 */
190
191struct dm_version_request {
192 struct dm_header hdr;
193 union dm_version version;
194 __u32 is_last_attempt:1;
195 __u32 reservedz:31;
196} __packed;
197
198/*
199 * Version response message; Host to Guest and indicates
200 * if the host has accepted the version sent by the guest.
201 *
202 * is_accepted: If TRUE, host has accepted the version and the guest
203 * should proceed to the next stage of the protocol. FALSE indicates that
204 * guest should re-try with a different version.
205 *
206 * reservedz: Reserved field, set to zero.
207 */
208
209struct dm_version_response {
210 struct dm_header hdr;
211 __u64 is_accepted:1;
212 __u64 reservedz:63;
213} __packed;
214
215/*
216 * Message reporting capabilities. This is sent from the guest to the
217 * host.
218 */
219
220struct dm_capabilities {
221 struct dm_header hdr;
222 union dm_caps caps;
223 __u64 min_page_cnt;
224 __u64 max_page_number;
225} __packed;
226
227/*
228 * Response to the capabilities message. This is sent from the host to the
229 * guest. This message notifies if the host has accepted the guest's
230 * capabilities. If the host has not accepted, the guest must shutdown
231 * the service.
232 *
233 * is_accepted: Indicates if the host has accepted guest's capabilities.
234 * reservedz: Must be 0.
235 */
236
237struct dm_capabilities_resp_msg {
238 struct dm_header hdr;
239 __u64 is_accepted:1;
240 __u64 reservedz:63;
241} __packed;
242
243/*
244 * This message is used to report memory pressure from the guest.
245 * This message is not part of any transaction and there is no
246 * response to this message.
247 *
248 * num_avail: Available memory in pages.
249 * num_committed: Committed memory in pages.
250 * page_file_size: The accumulated size of all page files
251 * in the system in pages.
252 * zero_free: The number of zero and free pages.
253 * page_file_writes: The writes to the page file in pages.
254 * io_diff: An indicator of file cache efficiency or page file activity,
255 * calculated as File Cache Page Fault Count - Page Read Count.
256 * This value is in pages.
257 *
258 * Some of these metrics are Windows specific and fortunately
259 * the algorithm on the host side that computes the guest memory
260 * pressure only uses num_committed value.
261 */
262
263struct dm_status {
264 struct dm_header hdr;
265 __u64 num_avail;
266 __u64 num_committed;
267 __u64 page_file_size;
268 __u64 zero_free;
269 __u32 page_file_writes;
270 __u32 io_diff;
271} __packed;
272
273
274/*
275 * Message to ask the guest to allocate memory - balloon up message.
276 * This message is sent from the host to the guest. The guest may not be
277 * able to allocate as much memory as requested.
278 *
279 * num_pages: number of pages to allocate.
280 */
281
282struct dm_balloon {
283 struct dm_header hdr;
284 __u32 num_pages;
285 __u32 reservedz;
286} __packed;
287
288
289/*
290 * Balloon response message; this message is sent from the guest
291 * to the host in response to the balloon message.
292 *
293 * reservedz: Reserved; must be set to zero.
294 * more_pages: If FALSE, this is the last message of the transaction.
295 * if TRUE there will atleast one more message from the guest.
296 *
297 * range_count: The number of ranges in the range array.
298 *
299 * range_array: An array of page ranges returned to the host.
300 *
301 */
302
303struct dm_balloon_response {
304 struct dm_header hdr;
305 __u32 reservedz;
306 __u32 more_pages:1;
307 __u32 range_count:31;
308 union dm_mem_page_range range_array[];
309} __packed;
310
311/*
312 * Un-balloon message; this message is sent from the host
313 * to the guest to give guest more memory.
314 *
315 * more_pages: If FALSE, this is the last message of the transaction.
316 * if TRUE there will atleast one more message from the guest.
317 *
318 * reservedz: Reserved; must be set to zero.
319 *
320 * range_count: The number of ranges in the range array.
321 *
322 * range_array: An array of page ranges returned to the host.
323 *
324 */
325
326struct dm_unballoon_request {
327 struct dm_header hdr;
328 __u32 more_pages:1;
329 __u32 reservedz:31;
330 __u32 range_count;
331 union dm_mem_page_range range_array[];
332} __packed;
333
334/*
335 * Un-balloon response message; this message is sent from the guest
336 * to the host in response to an unballoon request.
337 *
338 */
339
340struct dm_unballoon_response {
341 struct dm_header hdr;
342} __packed;
343
344
345/*
346 * Hot add request message. Message sent from the host to the guest.
347 *
348 * mem_range: Memory range to hot add.
349 *
350 */
351
352struct dm_hot_add {
353 struct dm_header hdr;
354 union dm_mem_page_range range;
355} __packed;
356
357/*
358 * Hot add response message.
359 * This message is sent by the guest to report the status of a hot add request.
360 * If page_count is less than the requested page count, then the host should
361 * assume all further hot add requests will fail, since this indicates that
362 * the guest has hit an upper physical memory barrier.
363 *
364 * Hot adds may also fail due to low resources; in this case, the guest must
365 * not complete this message until the hot add can succeed, and the host must
366 * not send a new hot add request until the response is sent.
367 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
368 * times it fails the request.
369 *
370 *
371 * page_count: number of pages that were successfully hot added.
372 *
373 * result: result of the operation 1: success, 0: failure.
374 *
375 */
376
377struct dm_hot_add_response {
378 struct dm_header hdr;
379 __u32 page_count;
380 __u32 result;
381} __packed;
382
383/*
384 * Types of information sent from host to the guest.
385 */
386
387enum dm_info_type {
388 INFO_TYPE_MAX_PAGE_CNT = 0,
389 MAX_INFO_TYPE
390};
391
392
393/*
394 * Header for the information message.
395 */
396
397struct dm_info_header {
398 enum dm_info_type type;
399 __u32 data_size;
400} __packed;
401
402/*
403 * This message is sent from the host to the guest to pass
404 * some relevant information (win8 addition).
405 *
406 * reserved: no used.
407 * info_size: size of the information blob.
408 * info: information blob.
409 */
410
411struct dm_info_msg {
412 struct dm_header hdr;
413 __u32 reserved;
414 __u32 info_size;
415 __u8 info[];
416};
417
418/*
419 * End protocol definitions.
420 */
421
422/*
423 * State to manage hot adding memory into the guest.
424 * The range start_pfn : end_pfn specifies the range
425 * that the host has asked us to hot add. The range
426 * start_pfn : ha_end_pfn specifies the range that we have
427 * currently hot added. We hot add in multiples of 128M
428 * chunks; it is possible that we may not be able to bring
429 * online all the pages in the region. The range
430 * covered_start_pfn:covered_end_pfn defines the pages that can
431 * be brough online.
432 */
433
434struct hv_hotadd_state {
435 struct list_head list;
436 unsigned long start_pfn;
437 unsigned long covered_start_pfn;
438 unsigned long covered_end_pfn;
439 unsigned long ha_end_pfn;
440 unsigned long end_pfn;
441 /*
442 * A list of gaps.
443 */
444 struct list_head gap_list;
445};
446
447struct hv_hotadd_gap {
448 struct list_head list;
449 unsigned long start_pfn;
450 unsigned long end_pfn;
451};
452
453struct balloon_state {
454 __u32 num_pages;
455 struct work_struct wrk;
456};
457
458struct hot_add_wrk {
459 union dm_mem_page_range ha_page_range;
460 union dm_mem_page_range ha_region_range;
461 struct work_struct wrk;
462};
463
464static bool allow_hibernation;
465static bool hot_add = true;
466static bool do_hot_add;
467/*
468 * Delay reporting memory pressure by
469 * the specified number of seconds.
470 */
471static uint pressure_report_delay = 45;
472extern unsigned int page_reporting_order;
473#define HV_MAX_FAILURES 2
474
475/*
476 * The last time we posted a pressure report to host.
477 */
478static unsigned long last_post_time;
479
480static int hv_hypercall_multi_failure;
481
482module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
483MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
484
485module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR));
486MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");
487static atomic_t trans_id = ATOMIC_INIT(0);
488
489static int dm_ring_size = VMBUS_RING_SIZE(16 * 1024);
490
491/*
492 * Driver specific state.
493 */
494
495enum hv_dm_state {
496 DM_INITIALIZING = 0,
497 DM_INITIALIZED,
498 DM_BALLOON_UP,
499 DM_BALLOON_DOWN,
500 DM_HOT_ADD,
501 DM_INIT_ERROR
502};
503
504
505static __u8 recv_buffer[HV_HYP_PAGE_SIZE];
506static __u8 balloon_up_send_buffer[HV_HYP_PAGE_SIZE];
507#define PAGES_IN_2M (2 * 1024 * 1024 / PAGE_SIZE)
508#define HA_CHUNK (128 * 1024 * 1024 / PAGE_SIZE)
509
510struct hv_dynmem_device {
511 struct hv_device *dev;
512 enum hv_dm_state state;
513 struct completion host_event;
514 struct completion config_event;
515
516 /*
517 * Number of pages we have currently ballooned out.
518 */
519 unsigned int num_pages_ballooned;
520 unsigned int num_pages_onlined;
521 unsigned int num_pages_added;
522
523 /*
524 * State to manage the ballooning (up) operation.
525 */
526 struct balloon_state balloon_wrk;
527
528 /*
529 * State to execute the "hot-add" operation.
530 */
531 struct hot_add_wrk ha_wrk;
532
533 /*
534 * This state tracks if the host has specified a hot-add
535 * region.
536 */
537 bool host_specified_ha_region;
538
539 /*
540 * State to synchronize hot-add.
541 */
542 struct completion ol_waitevent;
543 /*
544 * This thread handles hot-add
545 * requests from the host as well as notifying
546 * the host with regards to memory pressure in
547 * the guest.
548 */
549 struct task_struct *thread;
550
551 /*
552 * Protects ha_region_list, num_pages_onlined counter and individual
553 * regions from ha_region_list.
554 */
555 spinlock_t ha_lock;
556
557 /*
558 * A list of hot-add regions.
559 */
560 struct list_head ha_region_list;
561
562 /*
563 * We start with the highest version we can support
564 * and downgrade based on the host; we save here the
565 * next version to try.
566 */
567 __u32 next_version;
568
569 /*
570 * The negotiated version agreed by host.
571 */
572 __u32 version;
573
574 struct page_reporting_dev_info pr_dev_info;
575
576 /*
577 * Maximum number of pages that can be hot_add-ed
578 */
579 __u64 max_dynamic_page_count;
580};
581
582static struct hv_dynmem_device dm_device;
583
584static void post_status(struct hv_dynmem_device *dm);
585
586static void enable_page_reporting(void);
587
588static void disable_page_reporting(void);
589
590#ifdef CONFIG_MEMORY_HOTPLUG
591static inline bool has_pfn_is_backed(struct hv_hotadd_state *has,
592 unsigned long pfn)
593{
594 struct hv_hotadd_gap *gap;
595
596 /* The page is not backed. */
597 if ((pfn < has->covered_start_pfn) || (pfn >= has->covered_end_pfn))
598 return false;
599
600 /* Check for gaps. */
601 list_for_each_entry(gap, &has->gap_list, list) {
602 if ((pfn >= gap->start_pfn) && (pfn < gap->end_pfn))
603 return false;
604 }
605
606 return true;
607}
608
609static unsigned long hv_page_offline_check(unsigned long start_pfn,
610 unsigned long nr_pages)
611{
612 unsigned long pfn = start_pfn, count = 0;
613 struct hv_hotadd_state *has;
614 bool found;
615
616 while (pfn < start_pfn + nr_pages) {
617 /*
618 * Search for HAS which covers the pfn and when we find one
619 * count how many consequitive PFNs are covered.
620 */
621 found = false;
622 list_for_each_entry(has, &dm_device.ha_region_list, list) {
623 while ((pfn >= has->start_pfn) &&
624 (pfn < has->end_pfn) &&
625 (pfn < start_pfn + nr_pages)) {
626 found = true;
627 if (has_pfn_is_backed(has, pfn))
628 count++;
629 pfn++;
630 }
631 }
632
633 /*
634 * This PFN is not in any HAS (e.g. we're offlining a region
635 * which was present at boot), no need to account for it. Go
636 * to the next one.
637 */
638 if (!found)
639 pfn++;
640 }
641
642 return count;
643}
644
645static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
646 void *v)
647{
648 struct memory_notify *mem = (struct memory_notify *)v;
649 unsigned long flags, pfn_count;
650
651 switch (val) {
652 case MEM_ONLINE:
653 case MEM_CANCEL_ONLINE:
654 complete(&dm_device.ol_waitevent);
655 break;
656
657 case MEM_OFFLINE:
658 spin_lock_irqsave(&dm_device.ha_lock, flags);
659 pfn_count = hv_page_offline_check(mem->start_pfn,
660 mem->nr_pages);
661 if (pfn_count <= dm_device.num_pages_onlined) {
662 dm_device.num_pages_onlined -= pfn_count;
663 } else {
664 /*
665 * We're offlining more pages than we managed to online.
666 * This is unexpected. In any case don't let
667 * num_pages_onlined wrap around zero.
668 */
669 WARN_ON_ONCE(1);
670 dm_device.num_pages_onlined = 0;
671 }
672 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
673 break;
674 case MEM_GOING_ONLINE:
675 case MEM_GOING_OFFLINE:
676 case MEM_CANCEL_OFFLINE:
677 break;
678 }
679 return NOTIFY_OK;
680}
681
682static struct notifier_block hv_memory_nb = {
683 .notifier_call = hv_memory_notifier,
684 .priority = 0
685};
686
687/* Check if the particular page is backed and can be onlined and online it. */
688static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg)
689{
690 if (!has_pfn_is_backed(has, page_to_pfn(pg))) {
691 if (!PageOffline(pg))
692 __SetPageOffline(pg);
693 return;
694 }
695 if (PageOffline(pg))
696 __ClearPageOffline(pg);
697
698 /* This frame is currently backed; online the page. */
699 generic_online_page(pg, 0);
700
701 lockdep_assert_held(&dm_device.ha_lock);
702 dm_device.num_pages_onlined++;
703}
704
705static void hv_bring_pgs_online(struct hv_hotadd_state *has,
706 unsigned long start_pfn, unsigned long size)
707{
708 int i;
709
710 pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
711 for (i = 0; i < size; i++)
712 hv_page_online_one(has, pfn_to_page(start_pfn + i));
713}
714
715static void hv_mem_hot_add(unsigned long start, unsigned long size,
716 unsigned long pfn_count,
717 struct hv_hotadd_state *has)
718{
719 int ret = 0;
720 int i, nid;
721 unsigned long start_pfn;
722 unsigned long processed_pfn;
723 unsigned long total_pfn = pfn_count;
724 unsigned long flags;
725
726 for (i = 0; i < (size/HA_CHUNK); i++) {
727 start_pfn = start + (i * HA_CHUNK);
728
729 spin_lock_irqsave(&dm_device.ha_lock, flags);
730 has->ha_end_pfn += HA_CHUNK;
731
732 if (total_pfn > HA_CHUNK) {
733 processed_pfn = HA_CHUNK;
734 total_pfn -= HA_CHUNK;
735 } else {
736 processed_pfn = total_pfn;
737 total_pfn = 0;
738 }
739
740 has->covered_end_pfn += processed_pfn;
741 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
742
743 reinit_completion(&dm_device.ol_waitevent);
744
745 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
746 ret = add_memory(nid, PFN_PHYS((start_pfn)),
747 (HA_CHUNK << PAGE_SHIFT), MHP_MERGE_RESOURCE);
748
749 if (ret) {
750 pr_err("hot_add memory failed error is %d\n", ret);
751 if (ret == -EEXIST) {
752 /*
753 * This error indicates that the error
754 * is not a transient failure. This is the
755 * case where the guest's physical address map
756 * precludes hot adding memory. Stop all further
757 * memory hot-add.
758 */
759 do_hot_add = false;
760 }
761 spin_lock_irqsave(&dm_device.ha_lock, flags);
762 has->ha_end_pfn -= HA_CHUNK;
763 has->covered_end_pfn -= processed_pfn;
764 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
765 break;
766 }
767
768 /*
769 * Wait for memory to get onlined. If the kernel onlined the
770 * memory when adding it, this will return directly. Otherwise,
771 * it will wait for user space to online the memory. This helps
772 * to avoid adding memory faster than it is getting onlined. As
773 * adding succeeded, it is ok to proceed even if the memory was
774 * not onlined in time.
775 */
776 wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ);
777 post_status(&dm_device);
778 }
779}
780
781static void hv_online_page(struct page *pg, unsigned int order)
782{
783 struct hv_hotadd_state *has;
784 unsigned long flags;
785 unsigned long pfn = page_to_pfn(pg);
786
787 spin_lock_irqsave(&dm_device.ha_lock, flags);
788 list_for_each_entry(has, &dm_device.ha_region_list, list) {
789 /* The page belongs to a different HAS. */
790 if ((pfn < has->start_pfn) ||
791 (pfn + (1UL << order) > has->end_pfn))
792 continue;
793
794 hv_bring_pgs_online(has, pfn, 1UL << order);
795 break;
796 }
797 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
798}
799
800static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
801{
802 struct hv_hotadd_state *has;
803 struct hv_hotadd_gap *gap;
804 unsigned long residual, new_inc;
805 int ret = 0;
806 unsigned long flags;
807
808 spin_lock_irqsave(&dm_device.ha_lock, flags);
809 list_for_each_entry(has, &dm_device.ha_region_list, list) {
810 /*
811 * If the pfn range we are dealing with is not in the current
812 * "hot add block", move on.
813 */
814 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
815 continue;
816
817 /*
818 * If the current start pfn is not where the covered_end
819 * is, create a gap and update covered_end_pfn.
820 */
821 if (has->covered_end_pfn != start_pfn) {
822 gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC);
823 if (!gap) {
824 ret = -ENOMEM;
825 break;
826 }
827
828 INIT_LIST_HEAD(&gap->list);
829 gap->start_pfn = has->covered_end_pfn;
830 gap->end_pfn = start_pfn;
831 list_add_tail(&gap->list, &has->gap_list);
832
833 has->covered_end_pfn = start_pfn;
834 }
835
836 /*
837 * If the current hot add-request extends beyond
838 * our current limit; extend it.
839 */
840 if ((start_pfn + pfn_cnt) > has->end_pfn) {
841 residual = (start_pfn + pfn_cnt - has->end_pfn);
842 /*
843 * Extend the region by multiples of HA_CHUNK.
844 */
845 new_inc = (residual / HA_CHUNK) * HA_CHUNK;
846 if (residual % HA_CHUNK)
847 new_inc += HA_CHUNK;
848
849 has->end_pfn += new_inc;
850 }
851
852 ret = 1;
853 break;
854 }
855 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
856
857 return ret;
858}
859
860static unsigned long handle_pg_range(unsigned long pg_start,
861 unsigned long pg_count)
862{
863 unsigned long start_pfn = pg_start;
864 unsigned long pfn_cnt = pg_count;
865 unsigned long size;
866 struct hv_hotadd_state *has;
867 unsigned long pgs_ol = 0;
868 unsigned long old_covered_state;
869 unsigned long res = 0, flags;
870
871 pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count,
872 pg_start);
873
874 spin_lock_irqsave(&dm_device.ha_lock, flags);
875 list_for_each_entry(has, &dm_device.ha_region_list, list) {
876 /*
877 * If the pfn range we are dealing with is not in the current
878 * "hot add block", move on.
879 */
880 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
881 continue;
882
883 old_covered_state = has->covered_end_pfn;
884
885 if (start_pfn < has->ha_end_pfn) {
886 /*
887 * This is the case where we are backing pages
888 * in an already hot added region. Bring
889 * these pages online first.
890 */
891 pgs_ol = has->ha_end_pfn - start_pfn;
892 if (pgs_ol > pfn_cnt)
893 pgs_ol = pfn_cnt;
894
895 has->covered_end_pfn += pgs_ol;
896 pfn_cnt -= pgs_ol;
897 /*
898 * Check if the corresponding memory block is already
899 * online. It is possible to observe struct pages still
900 * being uninitialized here so check section instead.
901 * In case the section is online we need to bring the
902 * rest of pfns (which were not backed previously)
903 * online too.
904 */
905 if (start_pfn > has->start_pfn &&
906 online_section_nr(pfn_to_section_nr(start_pfn)))
907 hv_bring_pgs_online(has, start_pfn, pgs_ol);
908
909 }
910
911 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
912 /*
913 * We have some residual hot add range
914 * that needs to be hot added; hot add
915 * it now. Hot add a multiple of
916 * HA_CHUNK that fully covers the pages
917 * we have.
918 */
919 size = (has->end_pfn - has->ha_end_pfn);
920 if (pfn_cnt <= size) {
921 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
922 if (pfn_cnt % HA_CHUNK)
923 size += HA_CHUNK;
924 } else {
925 pfn_cnt = size;
926 }
927 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
928 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
929 spin_lock_irqsave(&dm_device.ha_lock, flags);
930 }
931 /*
932 * If we managed to online any pages that were given to us,
933 * we declare success.
934 */
935 res = has->covered_end_pfn - old_covered_state;
936 break;
937 }
938 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
939
940 return res;
941}
942
943static unsigned long process_hot_add(unsigned long pg_start,
944 unsigned long pfn_cnt,
945 unsigned long rg_start,
946 unsigned long rg_size)
947{
948 struct hv_hotadd_state *ha_region = NULL;
949 int covered;
950 unsigned long flags;
951
952 if (pfn_cnt == 0)
953 return 0;
954
955 if (!dm_device.host_specified_ha_region) {
956 covered = pfn_covered(pg_start, pfn_cnt);
957 if (covered < 0)
958 return 0;
959
960 if (covered)
961 goto do_pg_range;
962 }
963
964 /*
965 * If the host has specified a hot-add range; deal with it first.
966 */
967
968 if (rg_size != 0) {
969 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
970 if (!ha_region)
971 return 0;
972
973 INIT_LIST_HEAD(&ha_region->list);
974 INIT_LIST_HEAD(&ha_region->gap_list);
975
976 ha_region->start_pfn = rg_start;
977 ha_region->ha_end_pfn = rg_start;
978 ha_region->covered_start_pfn = pg_start;
979 ha_region->covered_end_pfn = pg_start;
980 ha_region->end_pfn = rg_start + rg_size;
981
982 spin_lock_irqsave(&dm_device.ha_lock, flags);
983 list_add_tail(&ha_region->list, &dm_device.ha_region_list);
984 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
985 }
986
987do_pg_range:
988 /*
989 * Process the page range specified; bringing them
990 * online if possible.
991 */
992 return handle_pg_range(pg_start, pfn_cnt);
993}
994
995#endif
996
997static void hot_add_req(struct work_struct *dummy)
998{
999 struct dm_hot_add_response resp;
1000#ifdef CONFIG_MEMORY_HOTPLUG
1001 unsigned long pg_start, pfn_cnt;
1002 unsigned long rg_start, rg_sz;
1003#endif
1004 struct hv_dynmem_device *dm = &dm_device;
1005
1006 memset(&resp, 0, sizeof(struct dm_hot_add_response));
1007 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
1008 resp.hdr.size = sizeof(struct dm_hot_add_response);
1009
1010#ifdef CONFIG_MEMORY_HOTPLUG
1011 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
1012 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
1013
1014 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
1015 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
1016
1017 if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
1018 unsigned long region_size;
1019 unsigned long region_start;
1020
1021 /*
1022 * The host has not specified the hot-add region.
1023 * Based on the hot-add page range being specified,
1024 * compute a hot-add region that can cover the pages
1025 * that need to be hot-added while ensuring the alignment
1026 * and size requirements of Linux as it relates to hot-add.
1027 */
1028 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
1029 if (pfn_cnt % HA_CHUNK)
1030 region_size += HA_CHUNK;
1031
1032 region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
1033
1034 rg_start = region_start;
1035 rg_sz = region_size;
1036 }
1037
1038 if (do_hot_add)
1039 resp.page_count = process_hot_add(pg_start, pfn_cnt,
1040 rg_start, rg_sz);
1041
1042 dm->num_pages_added += resp.page_count;
1043#endif
1044 /*
1045 * The result field of the response structure has the
1046 * following semantics:
1047 *
1048 * 1. If all or some pages hot-added: Guest should return success.
1049 *
1050 * 2. If no pages could be hot-added:
1051 *
1052 * If the guest returns success, then the host
1053 * will not attempt any further hot-add operations. This
1054 * signifies a permanent failure.
1055 *
1056 * If the guest returns failure, then this failure will be
1057 * treated as a transient failure and the host may retry the
1058 * hot-add operation after some delay.
1059 */
1060 if (resp.page_count > 0)
1061 resp.result = 1;
1062 else if (!do_hot_add)
1063 resp.result = 1;
1064 else
1065 resp.result = 0;
1066
1067 if (!do_hot_add || resp.page_count == 0) {
1068 if (!allow_hibernation)
1069 pr_err("Memory hot add failed\n");
1070 else
1071 pr_info("Ignore hot-add request!\n");
1072 }
1073
1074 dm->state = DM_INITIALIZED;
1075 resp.hdr.trans_id = atomic_inc_return(&trans_id);
1076 vmbus_sendpacket(dm->dev->channel, &resp,
1077 sizeof(struct dm_hot_add_response),
1078 (unsigned long)NULL,
1079 VM_PKT_DATA_INBAND, 0);
1080}
1081
1082static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
1083{
1084 struct dm_info_header *info_hdr;
1085
1086 info_hdr = (struct dm_info_header *)msg->info;
1087
1088 switch (info_hdr->type) {
1089 case INFO_TYPE_MAX_PAGE_CNT:
1090 if (info_hdr->data_size == sizeof(__u64)) {
1091 __u64 *max_page_count = (__u64 *)&info_hdr[1];
1092
1093 pr_info("Max. dynamic memory size: %llu MB\n",
1094 (*max_page_count) >> (20 - HV_HYP_PAGE_SHIFT));
1095 dm->max_dynamic_page_count = *max_page_count;
1096 }
1097
1098 break;
1099 default:
1100 pr_warn("Received Unknown type: %d\n", info_hdr->type);
1101 }
1102}
1103
1104static unsigned long compute_balloon_floor(void)
1105{
1106 unsigned long min_pages;
1107 unsigned long nr_pages = totalram_pages();
1108#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
1109 /* Simple continuous piecewiese linear function:
1110 * max MiB -> min MiB gradient
1111 * 0 0
1112 * 16 16
1113 * 32 24
1114 * 128 72 (1/2)
1115 * 512 168 (1/4)
1116 * 2048 360 (1/8)
1117 * 8192 744 (1/16)
1118 * 32768 1512 (1/32)
1119 */
1120 if (nr_pages < MB2PAGES(128))
1121 min_pages = MB2PAGES(8) + (nr_pages >> 1);
1122 else if (nr_pages < MB2PAGES(512))
1123 min_pages = MB2PAGES(40) + (nr_pages >> 2);
1124 else if (nr_pages < MB2PAGES(2048))
1125 min_pages = MB2PAGES(104) + (nr_pages >> 3);
1126 else if (nr_pages < MB2PAGES(8192))
1127 min_pages = MB2PAGES(232) + (nr_pages >> 4);
1128 else
1129 min_pages = MB2PAGES(488) + (nr_pages >> 5);
1130#undef MB2PAGES
1131 return min_pages;
1132}
1133
1134/*
1135 * Compute total committed memory pages
1136 */
1137
1138static unsigned long get_pages_committed(struct hv_dynmem_device *dm)
1139{
1140 return vm_memory_committed() +
1141 dm->num_pages_ballooned +
1142 (dm->num_pages_added > dm->num_pages_onlined ?
1143 dm->num_pages_added - dm->num_pages_onlined : 0) +
1144 compute_balloon_floor();
1145}
1146
1147/*
1148 * Post our status as it relates memory pressure to the
1149 * host. Host expects the guests to post this status
1150 * periodically at 1 second intervals.
1151 *
1152 * The metrics specified in this protocol are very Windows
1153 * specific and so we cook up numbers here to convey our memory
1154 * pressure.
1155 */
1156
1157static void post_status(struct hv_dynmem_device *dm)
1158{
1159 struct dm_status status;
1160 unsigned long now = jiffies;
1161 unsigned long last_post = last_post_time;
1162 unsigned long num_pages_avail, num_pages_committed;
1163
1164 if (pressure_report_delay > 0) {
1165 --pressure_report_delay;
1166 return;
1167 }
1168
1169 if (!time_after(now, (last_post_time + HZ)))
1170 return;
1171
1172 memset(&status, 0, sizeof(struct dm_status));
1173 status.hdr.type = DM_STATUS_REPORT;
1174 status.hdr.size = sizeof(struct dm_status);
1175 status.hdr.trans_id = atomic_inc_return(&trans_id);
1176
1177 /*
1178 * The host expects the guest to report free and committed memory.
1179 * Furthermore, the host expects the pressure information to include
1180 * the ballooned out pages. For a given amount of memory that we are
1181 * managing we need to compute a floor below which we should not
1182 * balloon. Compute this and add it to the pressure report.
1183 * We also need to report all offline pages (num_pages_added -
1184 * num_pages_onlined) as committed to the host, otherwise it can try
1185 * asking us to balloon them out.
1186 */
1187 num_pages_avail = si_mem_available();
1188 num_pages_committed = get_pages_committed(dm);
1189
1190 trace_balloon_status(num_pages_avail, num_pages_committed,
1191 vm_memory_committed(), dm->num_pages_ballooned,
1192 dm->num_pages_added, dm->num_pages_onlined);
1193
1194 /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */
1195 status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE;
1196 status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE;
1197
1198 /*
1199 * If our transaction ID is no longer current, just don't
1200 * send the status. This can happen if we were interrupted
1201 * after we picked our transaction ID.
1202 */
1203 if (status.hdr.trans_id != atomic_read(&trans_id))
1204 return;
1205
1206 /*
1207 * If the last post time that we sampled has changed,
1208 * we have raced, don't post the status.
1209 */
1210 if (last_post != last_post_time)
1211 return;
1212
1213 last_post_time = jiffies;
1214 vmbus_sendpacket(dm->dev->channel, &status,
1215 sizeof(struct dm_status),
1216 (unsigned long)NULL,
1217 VM_PKT_DATA_INBAND, 0);
1218
1219}
1220
1221static void free_balloon_pages(struct hv_dynmem_device *dm,
1222 union dm_mem_page_range *range_array)
1223{
1224 int num_pages = range_array->finfo.page_cnt;
1225 __u64 start_frame = range_array->finfo.start_page;
1226 struct page *pg;
1227 int i;
1228
1229 for (i = 0; i < num_pages; i++) {
1230 pg = pfn_to_page(i + start_frame);
1231 __ClearPageOffline(pg);
1232 __free_page(pg);
1233 dm->num_pages_ballooned--;
1234 adjust_managed_page_count(pg, 1);
1235 }
1236}
1237
1238
1239
1240static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
1241 unsigned int num_pages,
1242 struct dm_balloon_response *bl_resp,
1243 int alloc_unit)
1244{
1245 unsigned int i, j;
1246 struct page *pg;
1247
1248 for (i = 0; i < num_pages / alloc_unit; i++) {
1249 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
1250 HV_HYP_PAGE_SIZE)
1251 return i * alloc_unit;
1252
1253 /*
1254 * We execute this code in a thread context. Furthermore,
1255 * we don't want the kernel to try too hard.
1256 */
1257 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
1258 __GFP_NOMEMALLOC | __GFP_NOWARN,
1259 get_order(alloc_unit << PAGE_SHIFT));
1260
1261 if (!pg)
1262 return i * alloc_unit;
1263
1264 dm->num_pages_ballooned += alloc_unit;
1265
1266 /*
1267 * If we allocatted 2M pages; split them so we
1268 * can free them in any order we get.
1269 */
1270
1271 if (alloc_unit != 1)
1272 split_page(pg, get_order(alloc_unit << PAGE_SHIFT));
1273
1274 /* mark all pages offline */
1275 for (j = 0; j < alloc_unit; j++) {
1276 __SetPageOffline(pg + j);
1277 adjust_managed_page_count(pg + j, -1);
1278 }
1279
1280 bl_resp->range_count++;
1281 bl_resp->range_array[i].finfo.start_page =
1282 page_to_pfn(pg);
1283 bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
1284 bl_resp->hdr.size += sizeof(union dm_mem_page_range);
1285
1286 }
1287
1288 return i * alloc_unit;
1289}
1290
1291static void balloon_up(struct work_struct *dummy)
1292{
1293 unsigned int num_pages = dm_device.balloon_wrk.num_pages;
1294 unsigned int num_ballooned = 0;
1295 struct dm_balloon_response *bl_resp;
1296 int alloc_unit;
1297 int ret;
1298 bool done = false;
1299 int i;
1300 long avail_pages;
1301 unsigned long floor;
1302
1303 /*
1304 * We will attempt 2M allocations. However, if we fail to
1305 * allocate 2M chunks, we will go back to PAGE_SIZE allocations.
1306 */
1307 alloc_unit = PAGES_IN_2M;
1308
1309 avail_pages = si_mem_available();
1310 floor = compute_balloon_floor();
1311
1312 /* Refuse to balloon below the floor. */
1313 if (avail_pages < num_pages || avail_pages - num_pages < floor) {
1314 pr_info("Balloon request will be partially fulfilled. %s\n",
1315 avail_pages < num_pages ? "Not enough memory." :
1316 "Balloon floor reached.");
1317
1318 num_pages = avail_pages > floor ? (avail_pages - floor) : 0;
1319 }
1320
1321 while (!done) {
1322 memset(balloon_up_send_buffer, 0, HV_HYP_PAGE_SIZE);
1323 bl_resp = (struct dm_balloon_response *)balloon_up_send_buffer;
1324 bl_resp->hdr.type = DM_BALLOON_RESPONSE;
1325 bl_resp->hdr.size = sizeof(struct dm_balloon_response);
1326 bl_resp->more_pages = 1;
1327
1328 num_pages -= num_ballooned;
1329 num_ballooned = alloc_balloon_pages(&dm_device, num_pages,
1330 bl_resp, alloc_unit);
1331
1332 if (alloc_unit != 1 && num_ballooned == 0) {
1333 alloc_unit = 1;
1334 continue;
1335 }
1336
1337 if (num_ballooned == 0 || num_ballooned == num_pages) {
1338 pr_debug("Ballooned %u out of %u requested pages.\n",
1339 num_pages, dm_device.balloon_wrk.num_pages);
1340
1341 bl_resp->more_pages = 0;
1342 done = true;
1343 dm_device.state = DM_INITIALIZED;
1344 }
1345
1346 /*
1347 * We are pushing a lot of data through the channel;
1348 * deal with transient failures caused because of the
1349 * lack of space in the ring buffer.
1350 */
1351
1352 do {
1353 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
1354 ret = vmbus_sendpacket(dm_device.dev->channel,
1355 bl_resp,
1356 bl_resp->hdr.size,
1357 (unsigned long)NULL,
1358 VM_PKT_DATA_INBAND, 0);
1359
1360 if (ret == -EAGAIN)
1361 msleep(20);
1362 post_status(&dm_device);
1363 } while (ret == -EAGAIN);
1364
1365 if (ret) {
1366 /*
1367 * Free up the memory we allocatted.
1368 */
1369 pr_err("Balloon response failed\n");
1370
1371 for (i = 0; i < bl_resp->range_count; i++)
1372 free_balloon_pages(&dm_device,
1373 &bl_resp->range_array[i]);
1374
1375 done = true;
1376 }
1377 }
1378
1379}
1380
1381static void balloon_down(struct hv_dynmem_device *dm,
1382 struct dm_unballoon_request *req)
1383{
1384 union dm_mem_page_range *range_array = req->range_array;
1385 int range_count = req->range_count;
1386 struct dm_unballoon_response resp;
1387 int i;
1388 unsigned int prev_pages_ballooned = dm->num_pages_ballooned;
1389
1390 for (i = 0; i < range_count; i++) {
1391 free_balloon_pages(dm, &range_array[i]);
1392 complete(&dm_device.config_event);
1393 }
1394
1395 pr_debug("Freed %u ballooned pages.\n",
1396 prev_pages_ballooned - dm->num_pages_ballooned);
1397
1398 if (req->more_pages == 1)
1399 return;
1400
1401 memset(&resp, 0, sizeof(struct dm_unballoon_response));
1402 resp.hdr.type = DM_UNBALLOON_RESPONSE;
1403 resp.hdr.trans_id = atomic_inc_return(&trans_id);
1404 resp.hdr.size = sizeof(struct dm_unballoon_response);
1405
1406 vmbus_sendpacket(dm_device.dev->channel, &resp,
1407 sizeof(struct dm_unballoon_response),
1408 (unsigned long)NULL,
1409 VM_PKT_DATA_INBAND, 0);
1410
1411 dm->state = DM_INITIALIZED;
1412}
1413
1414static void balloon_onchannelcallback(void *context);
1415
1416static int dm_thread_func(void *dm_dev)
1417{
1418 struct hv_dynmem_device *dm = dm_dev;
1419
1420 while (!kthread_should_stop()) {
1421 wait_for_completion_interruptible_timeout(
1422 &dm_device.config_event, 1*HZ);
1423 /*
1424 * The host expects us to post information on the memory
1425 * pressure every second.
1426 */
1427 reinit_completion(&dm_device.config_event);
1428 post_status(dm);
1429 /*
1430 * disable free page reporting if multiple hypercall
1431 * failure flag set. It is not done in the page_reporting
1432 * callback context as that causes a deadlock between
1433 * page_reporting_process() and page_reporting_unregister()
1434 */
1435 if (hv_hypercall_multi_failure >= HV_MAX_FAILURES) {
1436 pr_err("Multiple failures in cold memory discard hypercall, disabling page reporting\n");
1437 disable_page_reporting();
1438 /* Reset the flag after disabling reporting */
1439 hv_hypercall_multi_failure = 0;
1440 }
1441 }
1442
1443 return 0;
1444}
1445
1446
1447static void version_resp(struct hv_dynmem_device *dm,
1448 struct dm_version_response *vresp)
1449{
1450 struct dm_version_request version_req;
1451 int ret;
1452
1453 if (vresp->is_accepted) {
1454 /*
1455 * We are done; wakeup the
1456 * context waiting for version
1457 * negotiation.
1458 */
1459 complete(&dm->host_event);
1460 return;
1461 }
1462 /*
1463 * If there are more versions to try, continue
1464 * with negotiations; if not
1465 * shutdown the service since we are not able
1466 * to negotiate a suitable version number
1467 * with the host.
1468 */
1469 if (dm->next_version == 0)
1470 goto version_error;
1471
1472 memset(&version_req, 0, sizeof(struct dm_version_request));
1473 version_req.hdr.type = DM_VERSION_REQUEST;
1474 version_req.hdr.size = sizeof(struct dm_version_request);
1475 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1476 version_req.version.version = dm->next_version;
1477 dm->version = version_req.version.version;
1478
1479 /*
1480 * Set the next version to try in case current version fails.
1481 * Win7 protocol ought to be the last one to try.
1482 */
1483 switch (version_req.version.version) {
1484 case DYNMEM_PROTOCOL_VERSION_WIN8:
1485 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
1486 version_req.is_last_attempt = 0;
1487 break;
1488 default:
1489 dm->next_version = 0;
1490 version_req.is_last_attempt = 1;
1491 }
1492
1493 ret = vmbus_sendpacket(dm->dev->channel, &version_req,
1494 sizeof(struct dm_version_request),
1495 (unsigned long)NULL,
1496 VM_PKT_DATA_INBAND, 0);
1497
1498 if (ret)
1499 goto version_error;
1500
1501 return;
1502
1503version_error:
1504 dm->state = DM_INIT_ERROR;
1505 complete(&dm->host_event);
1506}
1507
1508static void cap_resp(struct hv_dynmem_device *dm,
1509 struct dm_capabilities_resp_msg *cap_resp)
1510{
1511 if (!cap_resp->is_accepted) {
1512 pr_err("Capabilities not accepted by host\n");
1513 dm->state = DM_INIT_ERROR;
1514 }
1515 complete(&dm->host_event);
1516}
1517
1518static void balloon_onchannelcallback(void *context)
1519{
1520 struct hv_device *dev = context;
1521 u32 recvlen;
1522 u64 requestid;
1523 struct dm_message *dm_msg;
1524 struct dm_header *dm_hdr;
1525 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1526 struct dm_balloon *bal_msg;
1527 struct dm_hot_add *ha_msg;
1528 union dm_mem_page_range *ha_pg_range;
1529 union dm_mem_page_range *ha_region;
1530
1531 memset(recv_buffer, 0, sizeof(recv_buffer));
1532 vmbus_recvpacket(dev->channel, recv_buffer,
1533 HV_HYP_PAGE_SIZE, &recvlen, &requestid);
1534
1535 if (recvlen > 0) {
1536 dm_msg = (struct dm_message *)recv_buffer;
1537 dm_hdr = &dm_msg->hdr;
1538
1539 switch (dm_hdr->type) {
1540 case DM_VERSION_RESPONSE:
1541 version_resp(dm,
1542 (struct dm_version_response *)dm_msg);
1543 break;
1544
1545 case DM_CAPABILITIES_RESPONSE:
1546 cap_resp(dm,
1547 (struct dm_capabilities_resp_msg *)dm_msg);
1548 break;
1549
1550 case DM_BALLOON_REQUEST:
1551 if (allow_hibernation) {
1552 pr_info("Ignore balloon-up request!\n");
1553 break;
1554 }
1555
1556 if (dm->state == DM_BALLOON_UP)
1557 pr_warn("Currently ballooning\n");
1558 bal_msg = (struct dm_balloon *)recv_buffer;
1559 dm->state = DM_BALLOON_UP;
1560 dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
1561 schedule_work(&dm_device.balloon_wrk.wrk);
1562 break;
1563
1564 case DM_UNBALLOON_REQUEST:
1565 if (allow_hibernation) {
1566 pr_info("Ignore balloon-down request!\n");
1567 break;
1568 }
1569
1570 dm->state = DM_BALLOON_DOWN;
1571 balloon_down(dm,
1572 (struct dm_unballoon_request *)recv_buffer);
1573 break;
1574
1575 case DM_MEM_HOT_ADD_REQUEST:
1576 if (dm->state == DM_HOT_ADD)
1577 pr_warn("Currently hot-adding\n");
1578 dm->state = DM_HOT_ADD;
1579 ha_msg = (struct dm_hot_add *)recv_buffer;
1580 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
1581 /*
1582 * This is a normal hot-add request specifying
1583 * hot-add memory.
1584 */
1585 dm->host_specified_ha_region = false;
1586 ha_pg_range = &ha_msg->range;
1587 dm->ha_wrk.ha_page_range = *ha_pg_range;
1588 dm->ha_wrk.ha_region_range.page_range = 0;
1589 } else {
1590 /*
1591 * Host is specifying that we first hot-add
1592 * a region and then partially populate this
1593 * region.
1594 */
1595 dm->host_specified_ha_region = true;
1596 ha_pg_range = &ha_msg->range;
1597 ha_region = &ha_pg_range[1];
1598 dm->ha_wrk.ha_page_range = *ha_pg_range;
1599 dm->ha_wrk.ha_region_range = *ha_region;
1600 }
1601 schedule_work(&dm_device.ha_wrk.wrk);
1602 break;
1603
1604 case DM_INFO_MESSAGE:
1605 process_info(dm, (struct dm_info_msg *)dm_msg);
1606 break;
1607
1608 default:
1609 pr_warn_ratelimited("Unhandled message: type: %d\n", dm_hdr->type);
1610
1611 }
1612 }
1613
1614}
1615
1616#define HV_LARGE_REPORTING_ORDER 9
1617#define HV_LARGE_REPORTING_LEN (HV_HYP_PAGE_SIZE << \
1618 HV_LARGE_REPORTING_ORDER)
1619static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info,
1620 struct scatterlist *sgl, unsigned int nents)
1621{
1622 unsigned long flags;
1623 struct hv_memory_hint *hint;
1624 int i, order;
1625 u64 status;
1626 struct scatterlist *sg;
1627
1628 WARN_ON_ONCE(nents > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES);
1629 WARN_ON_ONCE(sgl->length < (HV_HYP_PAGE_SIZE << page_reporting_order));
1630 local_irq_save(flags);
1631 hint = *(struct hv_memory_hint **)this_cpu_ptr(hyperv_pcpu_input_arg);
1632 if (!hint) {
1633 local_irq_restore(flags);
1634 return -ENOSPC;
1635 }
1636
1637 hint->type = HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD;
1638 hint->reserved = 0;
1639 for_each_sg(sgl, sg, nents, i) {
1640 union hv_gpa_page_range *range;
1641
1642 range = &hint->ranges[i];
1643 range->address_space = 0;
1644 order = get_order(sg->length);
1645 /*
1646 * Hyper-V expects the additional_pages field in the units
1647 * of one of these 3 sizes, 4Kbytes, 2Mbytes or 1Gbytes.
1648 * This is dictated by the values of the fields page.largesize
1649 * and page_size.
1650 * This code however, only uses 4Kbytes and 2Mbytes units
1651 * and not 1Gbytes unit.
1652 */
1653
1654 /* page reporting for pages 2MB or higher */
1655 if (order >= HV_LARGE_REPORTING_ORDER ) {
1656 range->page.largepage = 1;
1657 range->page_size = HV_GPA_PAGE_RANGE_PAGE_SIZE_2MB;
1658 range->base_large_pfn = page_to_hvpfn(
1659 sg_page(sg)) >> HV_LARGE_REPORTING_ORDER;
1660 range->page.additional_pages =
1661 (sg->length / HV_LARGE_REPORTING_LEN) - 1;
1662 } else {
1663 /* Page reporting for pages below 2MB */
1664 range->page.basepfn = page_to_hvpfn(sg_page(sg));
1665 range->page.largepage = false;
1666 range->page.additional_pages =
1667 (sg->length / HV_HYP_PAGE_SIZE) - 1;
1668 }
1669
1670 }
1671
1672 status = hv_do_rep_hypercall(HV_EXT_CALL_MEMORY_HEAT_HINT, nents, 0,
1673 hint, NULL);
1674 local_irq_restore(flags);
1675 if (!hv_result_success(status)) {
1676
1677 pr_err("Cold memory discard hypercall failed with status %llx\n",
1678 status);
1679 if (hv_hypercall_multi_failure > 0)
1680 hv_hypercall_multi_failure++;
1681
1682 if (hv_result(status) == HV_STATUS_INVALID_PARAMETER) {
1683 pr_err("Underlying Hyper-V does not support order less than 9. Hypercall failed\n");
1684 pr_err("Defaulting to page_reporting_order %d\n",
1685 pageblock_order);
1686 page_reporting_order = pageblock_order;
1687 hv_hypercall_multi_failure++;
1688 return -EINVAL;
1689 }
1690
1691 return -EINVAL;
1692 }
1693
1694 return 0;
1695}
1696
1697static void enable_page_reporting(void)
1698{
1699 int ret;
1700
1701 if (!hv_query_ext_cap(HV_EXT_CAPABILITY_MEMORY_COLD_DISCARD_HINT)) {
1702 pr_debug("Cold memory discard hint not supported by Hyper-V\n");
1703 return;
1704 }
1705
1706 BUILD_BUG_ON(PAGE_REPORTING_CAPACITY > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES);
1707 dm_device.pr_dev_info.report = hv_free_page_report;
1708 /*
1709 * We let the page_reporting_order parameter decide the order
1710 * in the page_reporting code
1711 */
1712 dm_device.pr_dev_info.order = 0;
1713 ret = page_reporting_register(&dm_device.pr_dev_info);
1714 if (ret < 0) {
1715 dm_device.pr_dev_info.report = NULL;
1716 pr_err("Failed to enable cold memory discard: %d\n", ret);
1717 } else {
1718 pr_info("Cold memory discard hint enabled with order %d\n",
1719 page_reporting_order);
1720 }
1721}
1722
1723static void disable_page_reporting(void)
1724{
1725 if (dm_device.pr_dev_info.report) {
1726 page_reporting_unregister(&dm_device.pr_dev_info);
1727 dm_device.pr_dev_info.report = NULL;
1728 }
1729}
1730
1731static int ballooning_enabled(void)
1732{
1733 /*
1734 * Disable ballooning if the page size is not 4k (HV_HYP_PAGE_SIZE),
1735 * since currently it's unclear to us whether an unballoon request can
1736 * make sure all page ranges are guest page size aligned.
1737 */
1738 if (PAGE_SIZE != HV_HYP_PAGE_SIZE) {
1739 pr_info("Ballooning disabled because page size is not 4096 bytes\n");
1740 return 0;
1741 }
1742
1743 return 1;
1744}
1745
1746static int hot_add_enabled(void)
1747{
1748 /*
1749 * Disable hot add on ARM64, because we currently rely on
1750 * memory_add_physaddr_to_nid() to get a node id of a hot add range,
1751 * however ARM64's memory_add_physaddr_to_nid() always return 0 and
1752 * DM_MEM_HOT_ADD_REQUEST doesn't have the NUMA node information for
1753 * add_memory().
1754 */
1755 if (IS_ENABLED(CONFIG_ARM64)) {
1756 pr_info("Memory hot add disabled on ARM64\n");
1757 return 0;
1758 }
1759
1760 return 1;
1761}
1762
1763static int balloon_connect_vsp(struct hv_device *dev)
1764{
1765 struct dm_version_request version_req;
1766 struct dm_capabilities cap_msg;
1767 unsigned long t;
1768 int ret;
1769
1770 /*
1771 * max_pkt_size should be large enough for one vmbus packet header plus
1772 * our receive buffer size. Hyper-V sends messages up to
1773 * HV_HYP_PAGE_SIZE bytes long on balloon channel.
1774 */
1775 dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
1776
1777 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
1778 balloon_onchannelcallback, dev);
1779 if (ret)
1780 return ret;
1781
1782 /*
1783 * Initiate the hand shake with the host and negotiate
1784 * a version that the host can support. We start with the
1785 * highest version number and go down if the host cannot
1786 * support it.
1787 */
1788 memset(&version_req, 0, sizeof(struct dm_version_request));
1789 version_req.hdr.type = DM_VERSION_REQUEST;
1790 version_req.hdr.size = sizeof(struct dm_version_request);
1791 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1792 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;
1793 version_req.is_last_attempt = 0;
1794 dm_device.version = version_req.version.version;
1795
1796 ret = vmbus_sendpacket(dev->channel, &version_req,
1797 sizeof(struct dm_version_request),
1798 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);
1799 if (ret)
1800 goto out;
1801
1802 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1803 if (t == 0) {
1804 ret = -ETIMEDOUT;
1805 goto out;
1806 }
1807
1808 /*
1809 * If we could not negotiate a compatible version with the host
1810 * fail the probe function.
1811 */
1812 if (dm_device.state == DM_INIT_ERROR) {
1813 ret = -EPROTO;
1814 goto out;
1815 }
1816
1817 pr_info("Using Dynamic Memory protocol version %u.%u\n",
1818 DYNMEM_MAJOR_VERSION(dm_device.version),
1819 DYNMEM_MINOR_VERSION(dm_device.version));
1820
1821 /*
1822 * Now submit our capabilities to the host.
1823 */
1824 memset(&cap_msg, 0, sizeof(struct dm_capabilities));
1825 cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
1826 cap_msg.hdr.size = sizeof(struct dm_capabilities);
1827 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
1828
1829 /*
1830 * When hibernation (i.e. virtual ACPI S4 state) is enabled, the host
1831 * currently still requires the bits to be set, so we have to add code
1832 * to fail the host's hot-add and balloon up/down requests, if any.
1833 */
1834 cap_msg.caps.cap_bits.balloon = ballooning_enabled();
1835 cap_msg.caps.cap_bits.hot_add = hot_add_enabled();
1836
1837 /*
1838 * Specify our alignment requirements as it relates
1839 * memory hot-add. Specify 128MB alignment.
1840 */
1841 cap_msg.caps.cap_bits.hot_add_alignment = 7;
1842
1843 /*
1844 * Currently the host does not use these
1845 * values and we set them to what is done in the
1846 * Windows driver.
1847 */
1848 cap_msg.min_page_cnt = 0;
1849 cap_msg.max_page_number = -1;
1850
1851 ret = vmbus_sendpacket(dev->channel, &cap_msg,
1852 sizeof(struct dm_capabilities),
1853 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);
1854 if (ret)
1855 goto out;
1856
1857 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1858 if (t == 0) {
1859 ret = -ETIMEDOUT;
1860 goto out;
1861 }
1862
1863 /*
1864 * If the host does not like our capabilities,
1865 * fail the probe function.
1866 */
1867 if (dm_device.state == DM_INIT_ERROR) {
1868 ret = -EPROTO;
1869 goto out;
1870 }
1871
1872 return 0;
1873out:
1874 vmbus_close(dev->channel);
1875 return ret;
1876}
1877
1878/*
1879 * DEBUGFS Interface
1880 */
1881#ifdef CONFIG_DEBUG_FS
1882
1883/**
1884 * hv_balloon_debug_show - shows statistics of balloon operations.
1885 * @f: pointer to the &struct seq_file.
1886 * @offset: ignored.
1887 *
1888 * Provides the statistics that can be accessed in hv-balloon in the debugfs.
1889 *
1890 * Return: zero on success or an error code.
1891 */
1892static int hv_balloon_debug_show(struct seq_file *f, void *offset)
1893{
1894 struct hv_dynmem_device *dm = f->private;
1895 char *sname;
1896
1897 seq_printf(f, "%-22s: %u.%u\n", "host_version",
1898 DYNMEM_MAJOR_VERSION(dm->version),
1899 DYNMEM_MINOR_VERSION(dm->version));
1900
1901 seq_printf(f, "%-22s:", "capabilities");
1902 if (ballooning_enabled())
1903 seq_puts(f, " enabled");
1904
1905 if (hot_add_enabled())
1906 seq_puts(f, " hot_add");
1907
1908 seq_puts(f, "\n");
1909
1910 seq_printf(f, "%-22s: %u", "state", dm->state);
1911 switch (dm->state) {
1912 case DM_INITIALIZING:
1913 sname = "Initializing";
1914 break;
1915 case DM_INITIALIZED:
1916 sname = "Initialized";
1917 break;
1918 case DM_BALLOON_UP:
1919 sname = "Balloon Up";
1920 break;
1921 case DM_BALLOON_DOWN:
1922 sname = "Balloon Down";
1923 break;
1924 case DM_HOT_ADD:
1925 sname = "Hot Add";
1926 break;
1927 case DM_INIT_ERROR:
1928 sname = "Error";
1929 break;
1930 default:
1931 sname = "Unknown";
1932 }
1933 seq_printf(f, " (%s)\n", sname);
1934
1935 /* HV Page Size */
1936 seq_printf(f, "%-22s: %ld\n", "page_size", HV_HYP_PAGE_SIZE);
1937
1938 /* Pages added with hot_add */
1939 seq_printf(f, "%-22s: %u\n", "pages_added", dm->num_pages_added);
1940
1941 /* pages that are "onlined"/used from pages_added */
1942 seq_printf(f, "%-22s: %u\n", "pages_onlined", dm->num_pages_onlined);
1943
1944 /* pages we have given back to host */
1945 seq_printf(f, "%-22s: %u\n", "pages_ballooned", dm->num_pages_ballooned);
1946
1947 seq_printf(f, "%-22s: %lu\n", "total_pages_committed",
1948 get_pages_committed(dm));
1949
1950 seq_printf(f, "%-22s: %llu\n", "max_dynamic_page_count",
1951 dm->max_dynamic_page_count);
1952
1953 return 0;
1954}
1955
1956DEFINE_SHOW_ATTRIBUTE(hv_balloon_debug);
1957
1958static void hv_balloon_debugfs_init(struct hv_dynmem_device *b)
1959{
1960 debugfs_create_file("hv-balloon", 0444, NULL, b,
1961 &hv_balloon_debug_fops);
1962}
1963
1964static void hv_balloon_debugfs_exit(struct hv_dynmem_device *b)
1965{
1966 debugfs_lookup_and_remove("hv-balloon", NULL);
1967}
1968
1969#else
1970
1971static inline void hv_balloon_debugfs_init(struct hv_dynmem_device *b)
1972{
1973}
1974
1975static inline void hv_balloon_debugfs_exit(struct hv_dynmem_device *b)
1976{
1977}
1978
1979#endif /* CONFIG_DEBUG_FS */
1980
1981static int balloon_probe(struct hv_device *dev,
1982 const struct hv_vmbus_device_id *dev_id)
1983{
1984 int ret;
1985
1986 allow_hibernation = hv_is_hibernation_supported();
1987 if (allow_hibernation)
1988 hot_add = false;
1989
1990#ifdef CONFIG_MEMORY_HOTPLUG
1991 do_hot_add = hot_add;
1992#else
1993 do_hot_add = false;
1994#endif
1995 dm_device.dev = dev;
1996 dm_device.state = DM_INITIALIZING;
1997 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8;
1998 init_completion(&dm_device.host_event);
1999 init_completion(&dm_device.config_event);
2000 INIT_LIST_HEAD(&dm_device.ha_region_list);
2001 spin_lock_init(&dm_device.ha_lock);
2002 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
2003 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
2004 dm_device.host_specified_ha_region = false;
2005
2006#ifdef CONFIG_MEMORY_HOTPLUG
2007 set_online_page_callback(&hv_online_page);
2008 init_completion(&dm_device.ol_waitevent);
2009 register_memory_notifier(&hv_memory_nb);
2010#endif
2011
2012 hv_set_drvdata(dev, &dm_device);
2013
2014 ret = balloon_connect_vsp(dev);
2015 if (ret != 0)
2016 goto connect_error;
2017
2018 enable_page_reporting();
2019 dm_device.state = DM_INITIALIZED;
2020
2021 dm_device.thread =
2022 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
2023 if (IS_ERR(dm_device.thread)) {
2024 ret = PTR_ERR(dm_device.thread);
2025 goto probe_error;
2026 }
2027
2028 hv_balloon_debugfs_init(&dm_device);
2029
2030 return 0;
2031
2032probe_error:
2033 dm_device.state = DM_INIT_ERROR;
2034 dm_device.thread = NULL;
2035 disable_page_reporting();
2036 vmbus_close(dev->channel);
2037connect_error:
2038#ifdef CONFIG_MEMORY_HOTPLUG
2039 unregister_memory_notifier(&hv_memory_nb);
2040 restore_online_page_callback(&hv_online_page);
2041#endif
2042 return ret;
2043}
2044
2045static int balloon_remove(struct hv_device *dev)
2046{
2047 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
2048 struct hv_hotadd_state *has, *tmp;
2049 struct hv_hotadd_gap *gap, *tmp_gap;
2050 unsigned long flags;
2051
2052 if (dm->num_pages_ballooned != 0)
2053 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
2054
2055 hv_balloon_debugfs_exit(dm);
2056
2057 cancel_work_sync(&dm->balloon_wrk.wrk);
2058 cancel_work_sync(&dm->ha_wrk.wrk);
2059
2060 kthread_stop(dm->thread);
2061
2062 /*
2063 * This is to handle the case when balloon_resume()
2064 * call has failed and some cleanup has been done as
2065 * a part of the error handling.
2066 */
2067 if (dm_device.state != DM_INIT_ERROR) {
2068 disable_page_reporting();
2069 vmbus_close(dev->channel);
2070#ifdef CONFIG_MEMORY_HOTPLUG
2071 unregister_memory_notifier(&hv_memory_nb);
2072 restore_online_page_callback(&hv_online_page);
2073#endif
2074 }
2075
2076 spin_lock_irqsave(&dm_device.ha_lock, flags);
2077 list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
2078 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
2079 list_del(&gap->list);
2080 kfree(gap);
2081 }
2082 list_del(&has->list);
2083 kfree(has);
2084 }
2085 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
2086
2087 return 0;
2088}
2089
2090static int balloon_suspend(struct hv_device *hv_dev)
2091{
2092 struct hv_dynmem_device *dm = hv_get_drvdata(hv_dev);
2093
2094 tasklet_disable(&hv_dev->channel->callback_event);
2095
2096 cancel_work_sync(&dm->balloon_wrk.wrk);
2097 cancel_work_sync(&dm->ha_wrk.wrk);
2098
2099 if (dm->thread) {
2100 kthread_stop(dm->thread);
2101 dm->thread = NULL;
2102 vmbus_close(hv_dev->channel);
2103 }
2104
2105 tasklet_enable(&hv_dev->channel->callback_event);
2106
2107 return 0;
2108
2109}
2110
2111static int balloon_resume(struct hv_device *dev)
2112{
2113 int ret;
2114
2115 dm_device.state = DM_INITIALIZING;
2116
2117 ret = balloon_connect_vsp(dev);
2118
2119 if (ret != 0)
2120 goto out;
2121
2122 dm_device.thread =
2123 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
2124 if (IS_ERR(dm_device.thread)) {
2125 ret = PTR_ERR(dm_device.thread);
2126 dm_device.thread = NULL;
2127 goto close_channel;
2128 }
2129
2130 dm_device.state = DM_INITIALIZED;
2131 return 0;
2132close_channel:
2133 vmbus_close(dev->channel);
2134out:
2135 dm_device.state = DM_INIT_ERROR;
2136 disable_page_reporting();
2137#ifdef CONFIG_MEMORY_HOTPLUG
2138 unregister_memory_notifier(&hv_memory_nb);
2139 restore_online_page_callback(&hv_online_page);
2140#endif
2141 return ret;
2142}
2143
2144static const struct hv_vmbus_device_id id_table[] = {
2145 /* Dynamic Memory Class ID */
2146 /* 525074DC-8985-46e2-8057-A307DC18A502 */
2147 { HV_DM_GUID, },
2148 { },
2149};
2150
2151MODULE_DEVICE_TABLE(vmbus, id_table);
2152
2153static struct hv_driver balloon_drv = {
2154 .name = "hv_balloon",
2155 .id_table = id_table,
2156 .probe = balloon_probe,
2157 .remove = balloon_remove,
2158 .suspend = balloon_suspend,
2159 .resume = balloon_resume,
2160 .driver = {
2161 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
2162 },
2163};
2164
2165static int __init init_balloon_drv(void)
2166{
2167
2168 return vmbus_driver_register(&balloon_drv);
2169}
2170
2171module_init(init_balloon_drv);
2172
2173MODULE_DESCRIPTION("Hyper-V Balloon");
2174MODULE_LICENSE("GPL");