summaryrefslogtreecommitdiff
path: root/arch/x86/kvm/hyperv.c
blob: 5708e951a5c69664895a7b9a21ffe3c1bdc669bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
/*
 * KVM Microsoft Hyper-V emulation
 *
 * derived from arch/x86/kvm/x86.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 * Copyright (C) 2015 Andrey Smetanin <asmetanin@virtuozzo.com>
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 *   Andrey Smetanin <asmetanin@virtuozzo.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "x86.h"
#include "lapic.h"
#include "ioapic.h"
#include "hyperv.h"

#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/sched/cputime.h>
#include <linux/eventfd.h>

#include <asm/apicdef.h>
#include <trace/events/kvm.h>

#include "trace.h"

static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
{
	return atomic64_read(&synic->sint[sint]);
}

static inline int synic_get_sint_vector(u64 sint_value)
{
	if (sint_value & HV_SYNIC_SINT_MASKED)
		return -1;
	return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
}

static bool synic_has_vector_connected(struct kvm_vcpu_hv_synic *synic,
				      int vector)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
			return true;
	}
	return false;
}

static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
				     int vector)
{
	int i;
	u64 sint_value;

	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
		sint_value = synic_read_sint(synic, i);
		if (synic_get_sint_vector(sint_value) == vector &&
		    sint_value & HV_SYNIC_SINT_AUTO_EOI)
			return true;
	}
	return false;
}

static void synic_update_vector(struct kvm_vcpu_hv_synic *synic,
				int vector)
{
	if (vector < HV_SYNIC_FIRST_VALID_VECTOR)
		return;

	if (synic_has_vector_connected(synic, vector))
		__set_bit(vector, synic->vec_bitmap);
	else
		__clear_bit(vector, synic->vec_bitmap);

	if (synic_has_vector_auto_eoi(synic, vector))
		__set_bit(vector, synic->auto_eoi_bitmap);
	else
		__clear_bit(vector, synic->auto_eoi_bitmap);
}

static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
			  u64 data, bool host)
{
	int vector, old_vector;
	bool masked;

	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
	masked = data & HV_SYNIC_SINT_MASKED;

	/*
	 * Valid vectors are 16-255, however, nested Hyper-V attempts to write
	 * default '0x10000' value on boot and this should not #GP. We need to
	 * allow zero-initing the register from host as well.
	 */
	if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host && !masked)
		return 1;
	/*
	 * Guest may configure multiple SINTs to use the same vector, so
	 * we maintain a bitmap of vectors handled by synic, and a
	 * bitmap of vectors with auto-eoi behavior.  The bitmaps are
	 * updated here, and atomically queried on fast paths.
	 */
	old_vector = synic_read_sint(synic, sint) & HV_SYNIC_SINT_VECTOR_MASK;

	atomic64_set(&synic->sint[sint], data);

	synic_update_vector(synic, old_vector);

	synic_update_vector(synic, vector);

	/* Load SynIC vectors into EOI exit bitmap */
	kvm_make_request(KVM_REQ_SCAN_IOAPIC, synic_to_vcpu(synic));
	return 0;
}

static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
{
	struct kvm_vcpu *vcpu = NULL;
	int i;

	if (vpidx < KVM_MAX_VCPUS)
		vcpu = kvm_get_vcpu(kvm, vpidx);
	if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
		return vcpu;
	kvm_for_each_vcpu(i, vcpu, kvm)
		if (vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
			return vcpu;
	return NULL;
}

static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vpidx)
{
	struct kvm_vcpu *vcpu;
	struct kvm_vcpu_hv_synic *synic;

	vcpu = get_vcpu_by_vpidx(kvm, vpidx);
	if (!vcpu)
		return NULL;
	synic = vcpu_to_synic(vcpu);
	return (synic->active) ? synic : NULL;
}

static void synic_clear_sint_msg_pending(struct kvm_vcpu_hv_synic *synic,
					u32 sint)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	struct page *page;
	gpa_t gpa;
	struct hv_message *msg;
	struct hv_message_page *msg_page;

	gpa = synic->msg_page & PAGE_MASK;
	page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
	if (is_error_page(page)) {
		vcpu_err(vcpu, "Hyper-V SynIC can't get msg page, gpa 0x%llx\n",
			 gpa);
		return;
	}
	msg_page = kmap_atomic(page);

	msg = &msg_page->sint_message[sint];
	msg->header.message_flags.msg_pending = 0;

	kunmap_atomic(msg_page);
	kvm_release_page_dirty(page);
	kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
}

static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
{
	struct kvm *kvm = vcpu->kvm;
	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
	struct kvm_vcpu_hv_stimer *stimer;
	int gsi, idx, stimers_pending;

	trace_kvm_hv_notify_acked_sint(vcpu->vcpu_id, sint);

	if (synic->msg_page & HV_SYNIC_SIMP_ENABLE)
		synic_clear_sint_msg_pending(synic, sint);

	/* Try to deliver pending Hyper-V SynIC timers messages */
	stimers_pending = 0;
	for (idx = 0; idx < ARRAY_SIZE(hv_vcpu->stimer); idx++) {
		stimer = &hv_vcpu->stimer[idx];
		if (stimer->msg_pending &&
		    (stimer->config & HV_STIMER_ENABLE) &&
		    HV_STIMER_SINT(stimer->config) == sint) {
			set_bit(stimer->index,
				hv_vcpu->stimer_pending_bitmap);
			stimers_pending++;
		}
	}
	if (stimers_pending)
		kvm_make_request(KVM_REQ_HV_STIMER, vcpu);

	idx = srcu_read_lock(&kvm->irq_srcu);
	gsi = atomic_read(&synic->sint_to_gsi[sint]);
	if (gsi != -1)
		kvm_notify_acked_gsi(kvm, gsi);
	srcu_read_unlock(&kvm->irq_srcu, idx);
}

static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;

	hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;
	hv_vcpu->exit.u.synic.msr = msr;
	hv_vcpu->exit.u.synic.control = synic->control;
	hv_vcpu->exit.u.synic.evt_page = synic->evt_page;
	hv_vcpu->exit.u.synic.msg_page = synic->msg_page;

	kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
}

static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
			 u32 msr, u64 data, bool host)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	int ret;

	if (!synic->active)
		return 1;

	trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host);

	ret = 0;
	switch (msr) {
	case HV_X64_MSR_SCONTROL:
		synic->control = data;
		if (!host)
			synic_exit(synic, msr);
		break;
	case HV_X64_MSR_SVERSION:
		if (!host) {
			ret = 1;
			break;
		}
		synic->version = data;
		break;
	case HV_X64_MSR_SIEFP:
		if ((data & HV_SYNIC_SIEFP_ENABLE) && !host &&
		    !synic->dont_zero_synic_pages)
			if (kvm_clear_guest(vcpu->kvm,
					    data & PAGE_MASK, PAGE_SIZE)) {
				ret = 1;
				break;
			}
		synic->evt_page = data;
		if (!host)
			synic_exit(synic, msr);
		break;
	case HV_X64_MSR_SIMP:
		if ((data & HV_SYNIC_SIMP_ENABLE) && !host &&
		    !synic->dont_zero_synic_pages)
			if (kvm_clear_guest(vcpu->kvm,
					    data & PAGE_MASK, PAGE_SIZE)) {
				ret = 1;
				break;
			}
		synic->msg_page = data;
		if (!host)
			synic_exit(synic, msr);
		break;
	case HV_X64_MSR_EOM: {
		int i;

		for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
			kvm_hv_notify_acked_sint(vcpu, i);
		break;
	}
	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
		ret = synic_set_sint(synic, msr - HV_X64_MSR_SINT0, data, host);
		break;
	default:
		ret = 1;
		break;
	}
	return ret;
}

static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata)
{
	int ret;

	if (!synic->active)
		return 1;

	ret = 0;
	switch (msr) {
	case HV_X64_MSR_SCONTROL:
		*pdata = synic->control;
		break;
	case HV_X64_MSR_SVERSION:
		*pdata = synic->version;
		break;
	case HV_X64_MSR_SIEFP:
		*pdata = synic->evt_page;
		break;
	case HV_X64_MSR_SIMP:
		*pdata = synic->msg_page;
		break;
	case HV_X64_MSR_EOM:
		*pdata = 0;
		break;
	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
		*pdata = atomic64_read(&synic->sint[msr - HV_X64_MSR_SINT0]);
		break;
	default:
		ret = 1;
		break;
	}
	return ret;
}

static int synic_set_irq(struct kvm_vcpu_hv_synic *synic, u32 sint)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	struct kvm_lapic_irq irq;
	int ret, vector;

	if (sint >= ARRAY_SIZE(synic->sint))
		return -EINVAL;

	vector = synic_get_sint_vector(synic_read_sint(synic, sint));
	if (vector < 0)
		return -ENOENT;

	memset(&irq, 0, sizeof(irq));
	irq.shorthand = APIC_DEST_SELF;
	irq.dest_mode = APIC_DEST_PHYSICAL;
	irq.delivery_mode = APIC_DM_FIXED;
	irq.vector = vector;
	irq.level = 1;

	ret = kvm_irq_delivery_to_apic(vcpu->kvm, vcpu->arch.apic, &irq, NULL);
	trace_kvm_hv_synic_set_irq(vcpu->vcpu_id, sint, irq.vector, ret);
	return ret;
}

int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vpidx, u32 sint)
{
	struct kvm_vcpu_hv_synic *synic;

	synic = synic_get(kvm, vpidx);
	if (!synic)
		return -EINVAL;

	return synic_set_irq(synic, sint);
}

void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector)
{
	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
	int i;

	trace_kvm_hv_synic_send_eoi(vcpu->vcpu_id, vector);

	for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
			kvm_hv_notify_acked_sint(vcpu, i);
}

static int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vpidx, u32 sint, int gsi)
{
	struct kvm_vcpu_hv_synic *synic;

	synic = synic_get(kvm, vpidx);
	if (!synic)
		return -EINVAL;

	if (sint >= ARRAY_SIZE(synic->sint_to_gsi))
		return -EINVAL;

	atomic_set(&synic->sint_to_gsi[sint], gsi);
	return 0;
}

void kvm_hv_irq_routing_update(struct kvm *kvm)
{
	struct kvm_irq_routing_table *irq_rt;
	struct kvm_kernel_irq_routing_entry *e;
	u32 gsi;

	irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
					lockdep_is_held(&kvm->irq_lock));

	for (gsi = 0; gsi < irq_rt->nr_rt_entries; gsi++) {
		hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
			if (e->type == KVM_IRQ_ROUTING_HV_SINT)
				kvm_hv_set_sint_gsi(kvm, e->hv_sint.vcpu,
						    e->hv_sint.sint, gsi);
		}
	}
}

static void synic_init(struct kvm_vcpu_hv_synic *synic)
{
	int i;

	memset(synic, 0, sizeof(*synic));
	synic->version = HV_SYNIC_VERSION_1;
	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
		atomic64_set(&synic->sint[i], HV_SYNIC_SINT_MASKED);
		atomic_set(&synic->sint_to_gsi[i], -1);
	}
}

static u64 get_time_ref_counter(struct kvm *kvm)
{
	struct kvm_hv *hv = &kvm->arch.hyperv;
	struct kvm_vcpu *vcpu;
	u64 tsc;

	/*
	 * The guest has not set up the TSC page or the clock isn't
	 * stable, fall back to get_kvmclock_ns.
	 */
	if (!hv->tsc_ref.tsc_sequence)
		return div_u64(get_kvmclock_ns(kvm), 100);

	vcpu = kvm_get_vcpu(kvm, 0);
	tsc = kvm_read_l1_tsc(vcpu, rdtsc());
	return mul_u64_u64_shr(tsc, hv->tsc_ref.tsc_scale, 64)
		+ hv->tsc_ref.tsc_offset;
}

static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
				bool vcpu_kick)
{
	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);

	set_bit(stimer->index,
		vcpu_to_hv_vcpu(vcpu)->stimer_pending_bitmap);
	kvm_make_request(KVM_REQ_HV_STIMER, vcpu);
	if (vcpu_kick)
		kvm_vcpu_kick(vcpu);
}

static void stimer_cleanup(struct kvm_vcpu_hv_stimer *stimer)
{
	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);

	trace_kvm_hv_stimer_cleanup(stimer_to_vcpu(stimer)->vcpu_id,
				    stimer->index);

	hrtimer_cancel(&stimer->timer);
	clear_bit(stimer->index,
		  vcpu_to_hv_vcpu(vcpu)->stimer_pending_bitmap);
	stimer->msg_pending = false;
	stimer->exp_time = 0;
}

static enum hrtimer_restart stimer_timer_callback(struct hrtimer *timer)
{
	struct kvm_vcpu_hv_stimer *stimer;

	stimer = container_of(timer, struct kvm_vcpu_hv_stimer, timer);
	trace_kvm_hv_stimer_callback(stimer_to_vcpu(stimer)->vcpu_id,
				     stimer->index);
	stimer_mark_pending(stimer, true);

	return HRTIMER_NORESTART;
}

/*
 * stimer_start() assumptions:
 * a) stimer->count is not equal to 0
 * b) stimer->config has HV_STIMER_ENABLE flag
 */
static int stimer_start(struct kvm_vcpu_hv_stimer *stimer)
{
	u64 time_now;
	ktime_t ktime_now;

	time_now = get_time_ref_counter(stimer_to_vcpu(stimer)->kvm);
	ktime_now = ktime_get();

	if (stimer->config & HV_STIMER_PERIODIC) {
		if (stimer->exp_time) {
			if (time_now >= stimer->exp_time) {
				u64 remainder;

				div64_u64_rem(time_now - stimer->exp_time,
					      stimer->count, &remainder);
				stimer->exp_time =
					time_now + (stimer->count - remainder);
			}
		} else
			stimer->exp_time = time_now + stimer->count;

		trace_kvm_hv_stimer_start_periodic(
					stimer_to_vcpu(stimer)->vcpu_id,
					stimer->index,
					time_now, stimer->exp_time);

		hrtimer_start(&stimer->timer,
			      ktime_add_ns(ktime_now,
					   100 * (stimer->exp_time - time_now)),
			      HRTIMER_MODE_ABS);
		return 0;
	}
	stimer->exp_time = stimer->count;
	if (time_now >= stimer->count) {
		/*
		 * Expire timer according to Hypervisor Top-Level Functional
		 * specification v4(15.3.1):
		 * "If a one shot is enabled and the specified count is in
		 * the past, it will expire immediately."
		 */
		stimer_mark_pending(stimer, false);
		return 0;
	}

	trace_kvm_hv_stimer_start_one_shot(stimer_to_vcpu(stimer)->vcpu_id,
					   stimer->index,
					   time_now, stimer->count);

	hrtimer_start(&stimer->timer,
		      ktime_add_ns(ktime_now, 100 * (stimer->count - time_now)),
		      HRTIMER_MODE_ABS);
	return 0;
}

static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config,
			     bool host)
{
	trace_kvm_hv_stimer_set_config(stimer_to_vcpu(stimer)->vcpu_id,
				       stimer->index, config, host);

	stimer_cleanup(stimer);
	if ((stimer->config & HV_STIMER_ENABLE) && HV_STIMER_SINT(config) == 0)
		config &= ~HV_STIMER_ENABLE;
	stimer->config = config;
	stimer_mark_pending(stimer, false);
	return 0;
}

static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count,
			    bool host)
{
	trace_kvm_hv_stimer_set_count(stimer_to_vcpu(stimer)->vcpu_id,
				      stimer->index, count, host);

	stimer_cleanup(stimer);
	stimer->count = count;
	if (stimer->count == 0)
		stimer->config &= ~HV_STIMER_ENABLE;
	else if (stimer->config & HV_STIMER_AUTOENABLE)
		stimer->config |= HV_STIMER_ENABLE;
	stimer_mark_pending(stimer, false);
	return 0;
}

static int stimer_get_config(struct kvm_vcpu_hv_stimer *stimer, u64 *pconfig)
{
	*pconfig = stimer->config;
	return 0;
}

static int stimer_get_count(struct kvm_vcpu_hv_stimer *stimer, u64 *pcount)
{
	*pcount = stimer->count;
	return 0;
}

static int synic_deliver_msg(struct kvm_vcpu_hv_synic *synic, u32 sint,
			     struct hv_message *src_msg)
{
	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
	struct page *page;
	gpa_t gpa;
	struct hv_message *dst_msg;
	int r;
	struct hv_message_page *msg_page;

	if (!(synic->msg_page & HV_SYNIC_SIMP_ENABLE))
		return -ENOENT;

	gpa = synic->msg_page & PAGE_MASK;
	page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
	if (is_error_page(page))
		return -EFAULT;

	msg_page = kmap_atomic(page);
	dst_msg = &msg_page->sint_message[sint];
	if (sync_cmpxchg(&dst_msg->header.message_type, HVMSG_NONE,
			 src_msg->header.message_type) != HVMSG_NONE) {
		dst_msg->header.message_flags.msg_pending = 1;
		r = -EAGAIN;
	} else {
		memcpy(&dst_msg->u.payload, &src_msg->u.payload,
		       src_msg->header.payload_size);
		dst_msg->header.message_type = src_msg->header.message_type;
		dst_msg->header.payload_size = src_msg->header.payload_size;
		r = synic_set_irq(synic, sint);
		if (r >= 1)
			r = 0;
		else if (r == 0)
			r = -EFAULT;
	}
	kunmap_atomic(msg_page);
	kvm_release_page_dirty(page);
	kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
	return r;
}

static int stimer_send_msg(struct kvm_vcpu_hv_stimer *stimer)
{
	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
	struct hv_message *msg = &stimer->msg;
	struct hv_timer_message_payload *payload =
			(struct hv_timer_message_payload *)&msg->u.payload;

	payload->expiration_time = stimer->exp_time;
	payload->delivery_time = get_time_ref_counter(vcpu->kvm);
	return synic_deliver_msg(vcpu_to_synic(vcpu),
				 HV_STIMER_SINT(stimer->config), msg);
}

static void stimer_expiration(struct kvm_vcpu_hv_stimer *stimer)
{
	int r;

	stimer->msg_pending = true;
	r = stimer_send_msg(stimer);
	trace_kvm_hv_stimer_expiration(stimer_to_vcpu(stimer)->vcpu_id,
				       stimer->index, r);
	if (!r) {
		stimer->msg_pending = false;
		if (!(stimer->config & HV_STIMER_PERIODIC))
			stimer->config &= ~HV_STIMER_ENABLE;
	}
}

void kvm_hv_process_stimers(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
	struct kvm_vcpu_hv_stimer *stimer;
	u64 time_now, exp_time;
	int i;

	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
		if (test_and_clear_bit(i, hv_vcpu->stimer_pending_bitmap)) {
			stimer = &hv_vcpu->stimer[i];
			if (stimer->config & HV_STIMER_ENABLE) {
				exp_time = stimer->exp_time;

				if (exp_time) {
					time_now =
						get_time_ref_counter(vcpu->kvm);
					if (time_now >= exp_time)
						stimer_expiration(stimer);
				}

				if ((stimer->config & HV_STIMER_ENABLE) &&
				    stimer->count) {
					if (!stimer->msg_pending)
						stimer_start(stimer);
				} else
					stimer_cleanup(stimer);
			}
		}
}

void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
	int i;

	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
		stimer_cleanup(&hv_vcpu->stimer[i]);
}

static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
{
	struct hv_message *msg = &stimer->msg;
	struct hv_timer_message_payload *payload =
			(struct hv_timer_message_payload *)&msg->u.payload;

	memset(&msg->header, 0, sizeof(msg->header));
	msg->header.message_type = HVMSG_TIMER_EXPIRED;
	msg->header.payload_size = sizeof(*payload);

	payload->timer_index = stimer->index;
	payload->expiration_time = 0;
	payload->delivery_time = 0;
}

static void stimer_init(struct kvm_vcpu_hv_stimer *stimer, int timer_index)
{
	memset(stimer, 0, sizeof(*stimer));
	stimer->index = timer_index;
	hrtimer_init(&stimer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
	stimer->timer.function = stimer_timer_callback;
	stimer_prepare_msg(stimer);
}

void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
	int i;

	synic_init(&hv_vcpu->synic);

	bitmap_zero(hv_vcpu->stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT);
	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
		stimer_init(&hv_vcpu->stimer[i], i);
}

void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);

	hv_vcpu->vp_index = kvm_vcpu_get_idx(vcpu);
}

int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages)
{
	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);

	/*
	 * Hyper-V SynIC auto EOI SINT's are
	 * not compatible with APICV, so deactivate APICV
	 */
	kvm_vcpu_deactivate_apicv(vcpu);
	synic->active = true;
	synic->dont_zero_synic_pages = dont_zero_synic_pages;
	return 0;
}

static bool kvm_hv_msr_partition_wide(u32 msr)
{
	bool r = false;

	switch (msr) {
	case HV_X64_MSR_GUEST_OS_ID:
	case HV_X64_MSR_HYPERCALL:
	case HV_X64_MSR_REFERENCE_TSC:
	case HV_X64_MSR_TIME_REF_COUNT:
	case HV_X64_MSR_CRASH_CTL:
	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
	case HV_X64_MSR_RESET:
	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
	case HV_X64_MSR_TSC_EMULATION_CONTROL:
	case HV_X64_MSR_TSC_EMULATION_STATUS:
		r = true;
		break;
	}

	return r;
}

static int kvm_hv_msr_get_crash_data(struct kvm_vcpu *vcpu,
				     u32 index, u64 *pdata)
{
	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
		return -EINVAL;

	*pdata = hv->hv_crash_param[index];
	return 0;
}

static int kvm_hv_msr_get_crash_ctl(struct kvm_vcpu *vcpu, u64 *pdata)
{
	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	*pdata = hv->hv_crash_ctl;
	return 0;
}

static int kvm_hv_msr_set_crash_ctl(struct kvm_vcpu *vcpu, u64 data, bool host)
{
	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	if (host)
		hv->hv_crash_ctl = data & HV_X64_MSR_CRASH_CTL_NOTIFY;

	if (!host && (data & HV_X64_MSR_CRASH_CTL_NOTIFY)) {

		vcpu_debug(vcpu, "hv crash (0x%llx 0x%llx 0x%llx 0x%llx 0x%llx)\n",
			  hv->hv_crash_param[0],
			  hv->hv_crash_param[1],
			  hv->hv_crash_param[2],
			  hv->hv_crash_param[3],
			  hv->hv_crash_param[4]);

		/* Send notification about crash to user space */
		kvm_make_request(KVM_REQ_HV_CRASH, vcpu);
	}

	return 0;
}

static int kvm_hv_msr_set_crash_data(struct kvm_vcpu *vcpu,
				     u32 index, u64 data)
{
	struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

	if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
		return -EINVAL;

	hv->hv_crash_param[index] = data;
	return 0;
}

/*
 * The kvmclock and Hyper-V TSC page use similar formulas, and converting
 * between them is possible:
 *
 * kvmclock formula:
 *    nsec = (ticks - tsc_timestamp) * tsc_to_system_mul * 2^(tsc_shift-32)
 *           + system_time
 *
 * Hyper-V formula:
 *    nsec/100 = ticks * scale / 2^64 + offset
 *
 * When tsc_timestamp = system_time = 0, offset is zero in the Hyper-V formula.
 * By dividing the kvmclock formula by 100 and equating what's left we get:
 *    ticks * scale / 2^64 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *            scale / 2^64 =         tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *            scale        =         tsc_to_system_mul * 2^(32+tsc_shift) / 100
 *
 * Now expand the kvmclock formula and divide by 100:
 *    nsec = ticks * tsc_to_system_mul * 2^(tsc_shift-32)
 *           - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32)
 *           + system_time
 *    nsec/100 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *               - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *               + system_time / 100
 *
 * Replace tsc_to_system_mul * 2^(tsc_shift-32) / 100 by scale / 2^64:
 *    nsec/100 = ticks * scale / 2^64
 *               - tsc_timestamp * scale / 2^64
 *               + system_time / 100
 *
 * Equate with the Hyper-V formula so that ticks * scale / 2^64 cancels out:
 *    offset = system_time / 100 - tsc_timestamp * scale / 2^64
 *
 * These two equivalencies are implemented in this function.
 */
static bool compute_tsc_page_parameters(struct pvclock_vcpu_time_info *hv_clock,
					HV_REFERENCE_TSC_PAGE *tsc_ref)
{
	u64 max_mul;

	if (!(hv_clock->flags & PVCLOCK_TSC_STABLE_BIT))
		return false;

	/*
	 * check if scale would overflow, if so we use the time ref counter
	 *    tsc_to_system_mul * 2^(tsc_shift+32) / 100 >= 2^64
	 *    tsc_to_system_mul / 100 >= 2^(32-tsc_shift)
	 *    tsc_to_system_mul >= 100 * 2^(32-tsc_shift)
	 */
	max_mul = 100ull << (32 - hv_clock->tsc_shift);
	if (hv_clock->tsc_to_system_mul >= max_mul)
		return false;

	/*
	 * Otherwise compute the scale and offset according to the formulas
	 * derived above.
	 */
	tsc_ref->tsc_scale =
		mul_u64_u32_div(1ULL << (32 + hv_clock->tsc_shift),
				hv_clock->tsc_to_system_mul,
				100);

	tsc_ref->tsc_offset = hv_clock->system_time;
	do_div(tsc_ref->tsc_offset, 100);
	tsc_ref->tsc_offset -=
		mul_u64_u64_shr(hv_clock->tsc_timestamp, tsc_ref->tsc_scale, 64);
	return true;
}

void kvm_hv_setup_tsc_page(struct kvm *kvm,
			   struct pvclock_vcpu_time_info *hv_clock)
{
	struct kvm_hv *hv = &kvm->arch.hyperv;
	u32 tsc_seq;
	u64 gfn;

	BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence));
	BUILD_BUG_ON(offsetof(HV_REFERENCE_TSC_PAGE, tsc_sequence) != 0);

	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
		return;

	mutex_lock(&kvm->arch.hyperv.hv_lock);
	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
		goto out_unlock;

	gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
	/*
	 * Because the TSC parameters only vary when there is a
	 * change in the master clock, do not bother with caching.
	 */
	if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn),
				    &tsc_seq, sizeof(tsc_seq))))
		goto out_unlock;

	/*
	 * While we're computing and writing the parameters, force the
	 * guest to use the time reference count MSR.
	 */
	hv->tsc_ref.tsc_sequence = 0;
	if (kvm_write_guest(kvm, gfn_to_gpa(gfn),
			    &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)))
		goto out_unlock;

	if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref))
		goto out_unlock;

	/* Ensure sequence is zero before writing the rest of the struct.  */
	smp_wmb();
	if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref)))
		goto out_unlock;

	/*
	 * Now switch to the TSC page mechanism by writing the sequence.
	 */
	tsc_seq++;
	if (tsc_seq == 0xFFFFFFFF || tsc_seq == 0)
		tsc_seq = 1;

	/* Write the struct entirely before the non-zero sequence.  */
	smp_wmb();

	hv->tsc_ref.tsc_sequence = tsc_seq;
	kvm_write_guest(kvm, gfn_to_gpa(gfn),
			&hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence));
out_unlock:
	mutex_unlock(&kvm->arch.hyperv.hv_lock);
}

static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
			     bool host)
{
	struct kvm *kvm = vcpu->kvm;
	struct kvm_hv *hv = &kvm->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_GUEST_OS_ID:
		hv->hv_guest_os_id = data;
		/* setting guest os id to zero disables hypercall page */
		if (!hv->hv_guest_os_id)
			hv->hv_hypercall &= ~HV_X64_MSR_HYPERCALL_ENABLE;
		break;
	case HV_X64_MSR_HYPERCALL: {
		u64 gfn;
		unsigned long addr;
		u8 instructions[4];

		/* if guest os id is not set hypercall should remain disabled */
		if (!hv->hv_guest_os_id)
			break;
		if (!(data & HV_X64_MSR_HYPERCALL_ENABLE)) {
			hv->hv_hypercall = data;
			break;
		}
		gfn = data >> HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
		addr = gfn_to_hva(kvm, gfn);
		if (kvm_is_error_hva(addr))
			return 1;
		kvm_x86_ops->patch_hypercall(vcpu, instructions);
		((unsigned char *)instructions)[3] = 0xc3; /* ret */
		if (__copy_to_user((void __user *)addr, instructions, 4))
			return 1;
		hv->hv_hypercall = data;
		mark_page_dirty(kvm, gfn);
		break;
	}
	case HV_X64_MSR_REFERENCE_TSC:
		hv->hv_tsc_page = data;
		if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)
			kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
		break;
	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
		return kvm_hv_msr_set_crash_data(vcpu,
						 msr - HV_X64_MSR_CRASH_P0,
						 data);
	case HV_X64_MSR_CRASH_CTL:
		return kvm_hv_msr_set_crash_ctl(vcpu, data, host);
	case HV_X64_MSR_RESET:
		if (data == 1) {
			vcpu_debug(vcpu, "hyper-v reset requested\n");
			kvm_make_request(KVM_REQ_HV_RESET, vcpu);
		}
		break;
	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
		hv->hv_reenlightenment_control = data;
		break;
	case HV_X64_MSR_TSC_EMULATION_CONTROL:
		hv->hv_tsc_emulation_control = data;
		break;
	case HV_X64_MSR_TSC_EMULATION_STATUS:
		hv->hv_tsc_emulation_status = data;
		break;
	default:
		vcpu_unimpl(vcpu, "Hyper-V uhandled wrmsr: 0x%x data 0x%llx\n",
			    msr, data);
		return 1;
	}
	return 0;
}

/* Calculate cpu time spent by current task in 100ns units */
static u64 current_task_runtime_100ns(void)
{
	u64 utime, stime;

	task_cputime_adjusted(current, &utime, &stime);

	return div_u64(utime + stime, 100);
}

static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_VP_INDEX:
		if (!host)
			return 1;
		hv->vp_index = (u32)data;
		break;
	case HV_X64_MSR_VP_ASSIST_PAGE: {
		u64 gfn;
		unsigned long addr;

		if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
			hv->hv_vapic = data;
			if (kvm_lapic_enable_pv_eoi(vcpu, 0))
				return 1;
			break;
		}
		gfn = data >> HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT;
		addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
		if (kvm_is_error_hva(addr))
			return 1;
		if (__clear_user((void __user *)addr, PAGE_SIZE))
			return 1;
		hv->hv_vapic = data;
		kvm_vcpu_mark_page_dirty(vcpu, gfn);
		if (kvm_lapic_enable_pv_eoi(vcpu,
					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED))
			return 1;
		break;
	}
	case HV_X64_MSR_EOI:
		return kvm_hv_vapic_msr_write(vcpu, APIC_EOI, data);
	case HV_X64_MSR_ICR:
		return kvm_hv_vapic_msr_write(vcpu, APIC_ICR, data);
	case HV_X64_MSR_TPR:
		return kvm_hv_vapic_msr_write(vcpu, APIC_TASKPRI, data);
	case HV_X64_MSR_VP_RUNTIME:
		if (!host)
			return 1;
		hv->runtime_offset = data - current_task_runtime_100ns();
		break;
	case HV_X64_MSR_SCONTROL:
	case HV_X64_MSR_SVERSION:
	case HV_X64_MSR_SIEFP:
	case HV_X64_MSR_SIMP:
	case HV_X64_MSR_EOM:
	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
		return synic_set_msr(vcpu_to_synic(vcpu), msr, data, host);
	case HV_X64_MSR_STIMER0_CONFIG:
	case HV_X64_MSR_STIMER1_CONFIG:
	case HV_X64_MSR_STIMER2_CONFIG:
	case HV_X64_MSR_STIMER3_CONFIG: {
		int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;

		return stimer_set_config(vcpu_to_stimer(vcpu, timer_index),
					 data, host);
	}
	case HV_X64_MSR_STIMER0_COUNT:
	case HV_X64_MSR_STIMER1_COUNT:
	case HV_X64_MSR_STIMER2_COUNT:
	case HV_X64_MSR_STIMER3_COUNT: {
		int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;

		return stimer_set_count(vcpu_to_stimer(vcpu, timer_index),
					data, host);
	}
	default:
		vcpu_unimpl(vcpu, "Hyper-V uhandled wrmsr: 0x%x data 0x%llx\n",
			    msr, data);
		return 1;
	}

	return 0;
}

static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	u64 data = 0;
	struct kvm *kvm = vcpu->kvm;
	struct kvm_hv *hv = &kvm->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_GUEST_OS_ID:
		data = hv->hv_guest_os_id;
		break;
	case HV_X64_MSR_HYPERCALL:
		data = hv->hv_hypercall;
		break;
	case HV_X64_MSR_TIME_REF_COUNT:
		data = get_time_ref_counter(kvm);
		break;
	case HV_X64_MSR_REFERENCE_TSC:
		data = hv->hv_tsc_page;
		break;
	case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
		return kvm_hv_msr_get_crash_data(vcpu,
						 msr - HV_X64_MSR_CRASH_P0,
						 pdata);
	case HV_X64_MSR_CRASH_CTL:
		return kvm_hv_msr_get_crash_ctl(vcpu, pdata);
	case HV_X64_MSR_RESET:
		data = 0;
		break;
	case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
		data = hv->hv_reenlightenment_control;
		break;
	case HV_X64_MSR_TSC_EMULATION_CONTROL:
		data = hv->hv_tsc_emulation_control;
		break;
	case HV_X64_MSR_TSC_EMULATION_STATUS:
		data = hv->hv_tsc_emulation_status;
		break;
	default:
		vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
		return 1;
	}

	*pdata = data;
	return 0;
}

static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	u64 data = 0;
	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;

	switch (msr) {
	case HV_X64_MSR_VP_INDEX:
		data = hv->vp_index;
		break;
	case HV_X64_MSR_EOI:
		return kvm_hv_vapic_msr_read(vcpu, APIC_EOI, pdata);
	case HV_X64_MSR_ICR:
		return kvm_hv_vapic_msr_read(vcpu, APIC_ICR, pdata);
	case HV_X64_MSR_TPR:
		return kvm_hv_vapic_msr_read(vcpu, APIC_TASKPRI, pdata);
	case HV_X64_MSR_VP_ASSIST_PAGE:
		data = hv->hv_vapic;
		break;
	case HV_X64_MSR_VP_RUNTIME:
		data = current_task_runtime_100ns() + hv->runtime_offset;
		break;
	case HV_X64_MSR_SCONTROL:
	case HV_X64_MSR_SVERSION:
	case HV_X64_MSR_SIEFP:
	case HV_X64_MSR_SIMP:
	case HV_X64_MSR_EOM:
	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
		return synic_get_msr(vcpu_to_synic(vcpu), msr, pdata);
	case HV_X64_MSR_STIMER0_CONFIG:
	case HV_X64_MSR_STIMER1_CONFIG:
	case HV_X64_MSR_STIMER2_CONFIG:
	case HV_X64_MSR_STIMER3_CONFIG: {
		int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;

		return stimer_get_config(vcpu_to_stimer(vcpu, timer_index),
					 pdata);
	}
	case HV_X64_MSR_STIMER0_COUNT:
	case HV_X64_MSR_STIMER1_COUNT:
	case HV_X64_MSR_STIMER2_COUNT:
	case HV_X64_MSR_STIMER3_COUNT: {
		int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;

		return stimer_get_count(vcpu_to_stimer(vcpu, timer_index),
					pdata);
	}
	case HV_X64_MSR_TSC_FREQUENCY:
		data = (u64)vcpu->arch.virtual_tsc_khz * 1000;
		break;
	case HV_X64_MSR_APIC_FREQUENCY:
		data = APIC_BUS_FREQUENCY;
		break;
	default:
		vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
		return 1;
	}
	*pdata = data;
	return 0;
}

int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
	if (kvm_hv_msr_partition_wide(msr)) {
		int r;

		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
		r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
		return r;
	} else
		return kvm_hv_set_msr(vcpu, msr, data, host);
}

int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	if (kvm_hv_msr_partition_wide(msr)) {
		int r;

		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
		r = kvm_hv_get_msr_pw(vcpu, msr, pdata);
		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
		return r;
	} else
		return kvm_hv_get_msr(vcpu, msr, pdata);
}

bool kvm_hv_hypercall_enabled(struct kvm *kvm)
{
	return READ_ONCE(kvm->arch.hyperv.hv_hypercall) & HV_X64_MSR_HYPERCALL_ENABLE;
}

static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
{
	bool longmode;

	longmode = is_64_bit_mode(vcpu);
	if (longmode)
		kvm_register_write(vcpu, VCPU_REGS_RAX, result);
	else {
		kvm_register_write(vcpu, VCPU_REGS_RDX, result >> 32);
		kvm_register_write(vcpu, VCPU_REGS_RAX, result & 0xffffffff);
	}
}

static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;

	kvm_hv_hypercall_set_result(vcpu, run->hyperv.u.hcall.result);
	return kvm_skip_emulated_instruction(vcpu);
}

static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
{
	struct eventfd_ctx *eventfd;

	if (unlikely(!fast)) {
		int ret;
		gpa_t gpa = param;

		if ((gpa & (__alignof__(param) - 1)) ||
		    offset_in_page(gpa) + sizeof(param) > PAGE_SIZE)
			return HV_STATUS_INVALID_ALIGNMENT;

		ret = kvm_vcpu_read_guest(vcpu, gpa, &param, sizeof(param));
		if (ret < 0)
			return HV_STATUS_INVALID_ALIGNMENT;
	}

	/*
	 * Per spec, bits 32-47 contain the extra "flag number".  However, we
	 * have no use for it, and in all known usecases it is zero, so just
	 * report lookup failure if it isn't.
	 */
	if (param & 0xffff00000000ULL)
		return HV_STATUS_INVALID_PORT_ID;
	/* remaining bits are reserved-zero */
	if (param & ~KVM_HYPERV_CONN_ID_MASK)
		return HV_STATUS_INVALID_HYPERCALL_INPUT;

	/* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */
	rcu_read_lock();
	eventfd = idr_find(&vcpu->kvm->arch.hyperv.conn_to_evt, param);
	rcu_read_unlock();
	if (!eventfd)
		return HV_STATUS_INVALID_PORT_ID;

	eventfd_signal(eventfd, 1);
	return HV_STATUS_SUCCESS;
}

int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
{
	u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
	uint16_t code, rep_idx, rep_cnt;
	bool fast, longmode;

	/*
	 * hypercall generates UD from non zero cpl and real mode
	 * per HYPER-V spec
	 */
	if (kvm_x86_ops->get_cpl(vcpu) != 0 || !is_protmode(vcpu)) {
		kvm_queue_exception(vcpu, UD_VECTOR);
		return 1;
	}

	longmode = is_64_bit_mode(vcpu);

	if (!longmode) {
		param = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDX) << 32) |
			(kvm_register_read(vcpu, VCPU_REGS_RAX) & 0xffffffff);
		ingpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RBX) << 32) |
			(kvm_register_read(vcpu, VCPU_REGS_RCX) & 0xffffffff);
		outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) |
			(kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff);
	}
#ifdef CONFIG_X86_64
	else {
		param = kvm_register_read(vcpu, VCPU_REGS_RCX);
		ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX);
		outgpa = kvm_register_read(vcpu, VCPU_REGS_R8);
	}
#endif

	code = param & 0xffff;
	fast = (param >> 16) & 0x1;
	rep_cnt = (param >> 32) & 0xfff;
	rep_idx = (param >> 48) & 0xfff;

	trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);

	/* Hypercall continuation is not supported yet */
	if (rep_cnt || rep_idx) {
		ret = HV_STATUS_INVALID_HYPERCALL_CODE;
		goto set_result;
	}

	switch (code) {
	case HVCALL_NOTIFY_LONG_SPIN_WAIT:
		kvm_vcpu_on_spin(vcpu, true);
		break;
	case HVCALL_SIGNAL_EVENT:
		ret = kvm_hvcall_signal_event(vcpu, fast, ingpa);
		if (ret != HV_STATUS_INVALID_PORT_ID)
			break;
		/* maybe userspace knows this conn_id: fall through */
	case HVCALL_POST_MESSAGE:
		/* don't bother userspace if it has no way to handle it */
		if (!vcpu_to_synic(vcpu)->active) {
			ret = HV_STATUS_INVALID_HYPERCALL_CODE;
			break;
		}
		vcpu->run->exit_reason = KVM_EXIT_HYPERV;
		vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
		vcpu->run->hyperv.u.hcall.input = param;
		vcpu->run->hyperv.u.hcall.params[0] = ingpa;
		vcpu->run->hyperv.u.hcall.params[1] = outgpa;
		vcpu->arch.complete_userspace_io =
				kvm_hv_hypercall_complete_userspace;
		return 0;
	default:
		ret = HV_STATUS_INVALID_HYPERCALL_CODE;
		break;
	}

set_result:
	kvm_hv_hypercall_set_result(vcpu, ret);
	return 1;
}

void kvm_hv_init_vm(struct kvm *kvm)
{
	mutex_init(&kvm->arch.hyperv.hv_lock);
	idr_init(&kvm->arch.hyperv.conn_to_evt);
}

void kvm_hv_destroy_vm(struct kvm *kvm)
{
	struct eventfd_ctx *eventfd;
	int i;

	idr_for_each_entry(&kvm->arch.hyperv.conn_to_evt, eventfd, i)
		eventfd_ctx_put(eventfd);
	idr_destroy(&kvm->arch.hyperv.conn_to_evt);
}

static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd)
{
	struct kvm_hv *hv = &kvm->arch.hyperv;
	struct eventfd_ctx *eventfd;
	int ret;

	eventfd = eventfd_ctx_fdget(fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	mutex_lock(&hv->hv_lock);
	ret = idr_alloc(&hv->conn_to_evt, eventfd, conn_id, conn_id + 1,
			GFP_KERNEL);
	mutex_unlock(&hv->hv_lock);

	if (ret >= 0)
		return 0;

	if (ret == -ENOSPC)
		ret = -EEXIST;
	eventfd_ctx_put(eventfd);
	return ret;
}

static int kvm_hv_eventfd_deassign(struct kvm *kvm, u32 conn_id)
{
	struct kvm_hv *hv = &kvm->arch.hyperv;
	struct eventfd_ctx *eventfd;

	mutex_lock(&hv->hv_lock);
	eventfd = idr_remove(&hv->conn_to_evt, conn_id);
	mutex_unlock(&hv->hv_lock);

	if (!eventfd)
		return -ENOENT;

	synchronize_srcu(&kvm->srcu);
	eventfd_ctx_put(eventfd);
	return 0;
}

int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args)
{
	if ((args->flags & ~KVM_HYPERV_EVENTFD_DEASSIGN) ||
	    (args->conn_id & ~KVM_HYPERV_CONN_ID_MASK))
		return -EINVAL;

	if (args->flags == KVM_HYPERV_EVENTFD_DEASSIGN)
		return kvm_hv_eventfd_deassign(kvm, args->conn_id);
	return kvm_hv_eventfd_assign(kvm, args->conn_id, args->fd);
}