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