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