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