summaryrefslogtreecommitdiff
path: root/arch/s390/kvm/gaccess.c
blob: 0243b6e38d364cf005d99803742d55d4c73631b0 (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
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
// SPDX-License-Identifier: GPL-2.0
/*
 * guest access functions
 *
 * Copyright IBM Corp. 2014
 *
 */

#include <linux/vmalloc.h>
#include <linux/mm_types.h>
#include <linux/err.h>
#include <linux/pgtable.h>
#include <linux/bitfield.h>

#include <asm/gmap.h>
#include "kvm-s390.h"
#include "gaccess.h"
#include <asm/switch_to.h>

union asce {
	unsigned long val;
	struct {
		unsigned long origin : 52; /* Region- or Segment-Table Origin */
		unsigned long	 : 2;
		unsigned long g  : 1; /* Subspace Group Control */
		unsigned long p  : 1; /* Private Space Control */
		unsigned long s  : 1; /* Storage-Alteration-Event Control */
		unsigned long x  : 1; /* Space-Switch-Event Control */
		unsigned long r  : 1; /* Real-Space Control */
		unsigned long	 : 1;
		unsigned long dt : 2; /* Designation-Type Control */
		unsigned long tl : 2; /* Region- or Segment-Table Length */
	};
};

enum {
	ASCE_TYPE_SEGMENT = 0,
	ASCE_TYPE_REGION3 = 1,
	ASCE_TYPE_REGION2 = 2,
	ASCE_TYPE_REGION1 = 3
};

union region1_table_entry {
	unsigned long val;
	struct {
		unsigned long rto: 52;/* Region-Table Origin */
		unsigned long	 : 2;
		unsigned long p  : 1; /* DAT-Protection Bit */
		unsigned long	 : 1;
		unsigned long tf : 2; /* Region-Second-Table Offset */
		unsigned long i  : 1; /* Region-Invalid Bit */
		unsigned long	 : 1;
		unsigned long tt : 2; /* Table-Type Bits */
		unsigned long tl : 2; /* Region-Second-Table Length */
	};
};

union region2_table_entry {
	unsigned long val;
	struct {
		unsigned long rto: 52;/* Region-Table Origin */
		unsigned long	 : 2;
		unsigned long p  : 1; /* DAT-Protection Bit */
		unsigned long	 : 1;
		unsigned long tf : 2; /* Region-Third-Table Offset */
		unsigned long i  : 1; /* Region-Invalid Bit */
		unsigned long	 : 1;
		unsigned long tt : 2; /* Table-Type Bits */
		unsigned long tl : 2; /* Region-Third-Table Length */
	};
};

struct region3_table_entry_fc0 {
	unsigned long sto: 52;/* Segment-Table Origin */
	unsigned long	 : 1;
	unsigned long fc : 1; /* Format-Control */
	unsigned long p  : 1; /* DAT-Protection Bit */
	unsigned long	 : 1;
	unsigned long tf : 2; /* Segment-Table Offset */
	unsigned long i  : 1; /* Region-Invalid Bit */
	unsigned long cr : 1; /* Common-Region Bit */
	unsigned long tt : 2; /* Table-Type Bits */
	unsigned long tl : 2; /* Segment-Table Length */
};

struct region3_table_entry_fc1 {
	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
	unsigned long	 : 14;
	unsigned long av : 1; /* ACCF-Validity Control */
	unsigned long acc: 4; /* Access-Control Bits */
	unsigned long f  : 1; /* Fetch-Protection Bit */
	unsigned long fc : 1; /* Format-Control */
	unsigned long p  : 1; /* DAT-Protection Bit */
	unsigned long iep: 1; /* Instruction-Execution-Protection */
	unsigned long	 : 2;
	unsigned long i  : 1; /* Region-Invalid Bit */
	unsigned long cr : 1; /* Common-Region Bit */
	unsigned long tt : 2; /* Table-Type Bits */
	unsigned long	 : 2;
};

union region3_table_entry {
	unsigned long val;
	struct region3_table_entry_fc0 fc0;
	struct region3_table_entry_fc1 fc1;
	struct {
		unsigned long	 : 53;
		unsigned long fc : 1; /* Format-Control */
		unsigned long	 : 4;
		unsigned long i  : 1; /* Region-Invalid Bit */
		unsigned long cr : 1; /* Common-Region Bit */
		unsigned long tt : 2; /* Table-Type Bits */
		unsigned long	 : 2;
	};
};

struct segment_entry_fc0 {
	unsigned long pto: 53;/* Page-Table Origin */
	unsigned long fc : 1; /* Format-Control */
	unsigned long p  : 1; /* DAT-Protection Bit */
	unsigned long	 : 3;
	unsigned long i  : 1; /* Segment-Invalid Bit */
	unsigned long cs : 1; /* Common-Segment Bit */
	unsigned long tt : 2; /* Table-Type Bits */
	unsigned long	 : 2;
};

struct segment_entry_fc1 {
	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
	unsigned long	 : 3;
	unsigned long av : 1; /* ACCF-Validity Control */
	unsigned long acc: 4; /* Access-Control Bits */
	unsigned long f  : 1; /* Fetch-Protection Bit */
	unsigned long fc : 1; /* Format-Control */
	unsigned long p  : 1; /* DAT-Protection Bit */
	unsigned long iep: 1; /* Instruction-Execution-Protection */
	unsigned long	 : 2;
	unsigned long i  : 1; /* Segment-Invalid Bit */
	unsigned long cs : 1; /* Common-Segment Bit */
	unsigned long tt : 2; /* Table-Type Bits */
	unsigned long	 : 2;
};

union segment_table_entry {
	unsigned long val;
	struct segment_entry_fc0 fc0;
	struct segment_entry_fc1 fc1;
	struct {
		unsigned long	 : 53;
		unsigned long fc : 1; /* Format-Control */
		unsigned long	 : 4;
		unsigned long i  : 1; /* Segment-Invalid Bit */
		unsigned long cs : 1; /* Common-Segment Bit */
		unsigned long tt : 2; /* Table-Type Bits */
		unsigned long	 : 2;
	};
};

enum {
	TABLE_TYPE_SEGMENT = 0,
	TABLE_TYPE_REGION3 = 1,
	TABLE_TYPE_REGION2 = 2,
	TABLE_TYPE_REGION1 = 3
};

union page_table_entry {
	unsigned long val;
	struct {
		unsigned long pfra : 52; /* Page-Frame Real Address */
		unsigned long z  : 1; /* Zero Bit */
		unsigned long i  : 1; /* Page-Invalid Bit */
		unsigned long p  : 1; /* DAT-Protection Bit */
		unsigned long iep: 1; /* Instruction-Execution-Protection */
		unsigned long	 : 8;
	};
};

/*
 * vaddress union in order to easily decode a virtual address into its
 * region first index, region second index etc. parts.
 */
union vaddress {
	unsigned long addr;
	struct {
		unsigned long rfx : 11;
		unsigned long rsx : 11;
		unsigned long rtx : 11;
		unsigned long sx  : 11;
		unsigned long px  : 8;
		unsigned long bx  : 12;
	};
	struct {
		unsigned long rfx01 : 2;
		unsigned long	    : 9;
		unsigned long rsx01 : 2;
		unsigned long	    : 9;
		unsigned long rtx01 : 2;
		unsigned long	    : 9;
		unsigned long sx01  : 2;
		unsigned long	    : 29;
	};
};

/*
 * raddress union which will contain the result (real or absolute address)
 * after a page table walk. The rfaa, sfaa and pfra members are used to
 * simply assign them the value of a region, segment or page table entry.
 */
union raddress {
	unsigned long addr;
	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
	unsigned long pfra : 52; /* Page-Frame Real Address */
};

union alet {
	u32 val;
	struct {
		u32 reserved : 7;
		u32 p        : 1;
		u32 alesn    : 8;
		u32 alen     : 16;
	};
};

union ald {
	u32 val;
	struct {
		u32     : 1;
		u32 alo : 24;
		u32 all : 7;
	};
};

struct ale {
	unsigned long i      : 1; /* ALEN-Invalid Bit */
	unsigned long        : 5;
	unsigned long fo     : 1; /* Fetch-Only Bit */
	unsigned long p      : 1; /* Private Bit */
	unsigned long alesn  : 8; /* Access-List-Entry Sequence Number */
	unsigned long aleax  : 16; /* Access-List-Entry Authorization Index */
	unsigned long        : 32;
	unsigned long        : 1;
	unsigned long asteo  : 25; /* ASN-Second-Table-Entry Origin */
	unsigned long        : 6;
	unsigned long astesn : 32; /* ASTE Sequence Number */
};

struct aste {
	unsigned long i      : 1; /* ASX-Invalid Bit */
	unsigned long ato    : 29; /* Authority-Table Origin */
	unsigned long        : 1;
	unsigned long b      : 1; /* Base-Space Bit */
	unsigned long ax     : 16; /* Authorization Index */
	unsigned long atl    : 12; /* Authority-Table Length */
	unsigned long        : 2;
	unsigned long ca     : 1; /* Controlled-ASN Bit */
	unsigned long ra     : 1; /* Reusable-ASN Bit */
	unsigned long asce   : 64; /* Address-Space-Control Element */
	unsigned long ald    : 32;
	unsigned long astesn : 32;
	/* .. more fields there */
};

int ipte_lock_held(struct kvm *kvm)
{
	if (sclp.has_siif) {
		int rc;

		read_lock(&kvm->arch.sca_lock);
		rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
		read_unlock(&kvm->arch.sca_lock);
		return rc;
	}
	return kvm->arch.ipte_lock_count != 0;
}

static void ipte_lock_simple(struct kvm *kvm)
{
	union ipte_control old, new, *ic;

	mutex_lock(&kvm->arch.ipte_mutex);
	kvm->arch.ipte_lock_count++;
	if (kvm->arch.ipte_lock_count > 1)
		goto out;
retry:
	read_lock(&kvm->arch.sca_lock);
	ic = kvm_s390_get_ipte_control(kvm);
	do {
		old = READ_ONCE(*ic);
		if (old.k) {
			read_unlock(&kvm->arch.sca_lock);
			cond_resched();
			goto retry;
		}
		new = old;
		new.k = 1;
	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
	read_unlock(&kvm->arch.sca_lock);
out:
	mutex_unlock(&kvm->arch.ipte_mutex);
}

static void ipte_unlock_simple(struct kvm *kvm)
{
	union ipte_control old, new, *ic;

	mutex_lock(&kvm->arch.ipte_mutex);
	kvm->arch.ipte_lock_count--;
	if (kvm->arch.ipte_lock_count)
		goto out;
	read_lock(&kvm->arch.sca_lock);
	ic = kvm_s390_get_ipte_control(kvm);
	do {
		old = READ_ONCE(*ic);
		new = old;
		new.k = 0;
	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
	read_unlock(&kvm->arch.sca_lock);
	wake_up(&kvm->arch.ipte_wq);
out:
	mutex_unlock(&kvm->arch.ipte_mutex);
}

static void ipte_lock_siif(struct kvm *kvm)
{
	union ipte_control old, new, *ic;

retry:
	read_lock(&kvm->arch.sca_lock);
	ic = kvm_s390_get_ipte_control(kvm);
	do {
		old = READ_ONCE(*ic);
		if (old.kg) {
			read_unlock(&kvm->arch.sca_lock);
			cond_resched();
			goto retry;
		}
		new = old;
		new.k = 1;
		new.kh++;
	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
	read_unlock(&kvm->arch.sca_lock);
}

static void ipte_unlock_siif(struct kvm *kvm)
{
	union ipte_control old, new, *ic;

	read_lock(&kvm->arch.sca_lock);
	ic = kvm_s390_get_ipte_control(kvm);
	do {
		old = READ_ONCE(*ic);
		new = old;
		new.kh--;
		if (!new.kh)
			new.k = 0;
	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
	read_unlock(&kvm->arch.sca_lock);
	if (!new.kh)
		wake_up(&kvm->arch.ipte_wq);
}

void ipte_lock(struct kvm *kvm)
{
	if (sclp.has_siif)
		ipte_lock_siif(kvm);
	else
		ipte_lock_simple(kvm);
}

void ipte_unlock(struct kvm *kvm)
{
	if (sclp.has_siif)
		ipte_unlock_siif(kvm);
	else
		ipte_unlock_simple(kvm);
}

static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
			  enum gacc_mode mode)
{
	union alet alet;
	struct ale ale;
	struct aste aste;
	unsigned long ald_addr, authority_table_addr;
	union ald ald;
	int eax, rc;
	u8 authority_table;

	if (ar >= NUM_ACRS)
		return -EINVAL;

	save_access_regs(vcpu->run->s.regs.acrs);
	alet.val = vcpu->run->s.regs.acrs[ar];

	if (ar == 0 || alet.val == 0) {
		asce->val = vcpu->arch.sie_block->gcr[1];
		return 0;
	} else if (alet.val == 1) {
		asce->val = vcpu->arch.sie_block->gcr[7];
		return 0;
	}

	if (alet.reserved)
		return PGM_ALET_SPECIFICATION;

	if (alet.p)
		ald_addr = vcpu->arch.sie_block->gcr[5];
	else
		ald_addr = vcpu->arch.sie_block->gcr[2];
	ald_addr &= 0x7fffffc0;

	rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald));
	if (rc)
		return rc;

	if (alet.alen / 8 > ald.all)
		return PGM_ALEN_TRANSLATION;

	if (0x7fffffff - ald.alo * 128 < alet.alen * 16)
		return PGM_ADDRESSING;

	rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale,
			     sizeof(struct ale));
	if (rc)
		return rc;

	if (ale.i == 1)
		return PGM_ALEN_TRANSLATION;
	if (ale.alesn != alet.alesn)
		return PGM_ALE_SEQUENCE;

	rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste));
	if (rc)
		return rc;

	if (aste.i)
		return PGM_ASTE_VALIDITY;
	if (aste.astesn != ale.astesn)
		return PGM_ASTE_SEQUENCE;

	if (ale.p == 1) {
		eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff;
		if (ale.aleax != eax) {
			if (eax / 16 > aste.atl)
				return PGM_EXTENDED_AUTHORITY;

			authority_table_addr = aste.ato * 4 + eax / 4;

			rc = read_guest_real(vcpu, authority_table_addr,
					     &authority_table,
					     sizeof(u8));
			if (rc)
				return rc;

			if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0)
				return PGM_EXTENDED_AUTHORITY;
		}
	}

	if (ale.fo == 1 && mode == GACC_STORE)
		return PGM_PROTECTION;

	asce->val = aste.asce;
	return 0;
}

struct trans_exc_code_bits {
	unsigned long addr : 52; /* Translation-exception Address */
	unsigned long fsi  : 2;  /* Access Exception Fetch/Store Indication */
	unsigned long	   : 2;
	unsigned long b56  : 1;
	unsigned long	   : 3;
	unsigned long b60  : 1;
	unsigned long b61  : 1;
	unsigned long as   : 2;  /* ASCE Identifier */
};

enum {
	FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
	FSI_STORE   = 1, /* Exception was due to store operation */
	FSI_FETCH   = 2  /* Exception was due to fetch operation */
};

enum prot_type {
	PROT_TYPE_LA   = 0,
	PROT_TYPE_KEYC = 1,
	PROT_TYPE_ALC  = 2,
	PROT_TYPE_DAT  = 3,
	PROT_TYPE_IEP  = 4,
	/* Dummy value for passing an initialized value when code != PGM_PROTECTION */
	PROT_NONE,
};

static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
			    enum gacc_mode mode, enum prot_type prot, bool terminate)
{
	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
	struct trans_exc_code_bits *tec;

	memset(pgm, 0, sizeof(*pgm));
	pgm->code = code;
	tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;

	switch (code) {
	case PGM_PROTECTION:
		switch (prot) {
		case PROT_NONE:
			/* We should never get here, acts like termination */
			WARN_ON_ONCE(1);
			break;
		case PROT_TYPE_IEP:
			tec->b61 = 1;
			fallthrough;
		case PROT_TYPE_LA:
			tec->b56 = 1;
			break;
		case PROT_TYPE_KEYC:
			tec->b60 = 1;
			break;
		case PROT_TYPE_ALC:
			tec->b60 = 1;
			fallthrough;
		case PROT_TYPE_DAT:
			tec->b61 = 1;
			break;
		}
		if (terminate) {
			tec->b56 = 0;
			tec->b60 = 0;
			tec->b61 = 0;
		}
		fallthrough;
	case PGM_ASCE_TYPE:
	case PGM_PAGE_TRANSLATION:
	case PGM_REGION_FIRST_TRANS:
	case PGM_REGION_SECOND_TRANS:
	case PGM_REGION_THIRD_TRANS:
	case PGM_SEGMENT_TRANSLATION:
		/*
		 * op_access_id only applies to MOVE_PAGE -> set bit 61
		 * exc_access_id has to be set to 0 for some instructions. Both
		 * cases have to be handled by the caller.
		 */
		tec->addr = gva >> PAGE_SHIFT;
		tec->fsi = mode == GACC_STORE ? FSI_STORE : FSI_FETCH;
		tec->as = psw_bits(vcpu->arch.sie_block->gpsw).as;
		fallthrough;
	case PGM_ALEN_TRANSLATION:
	case PGM_ALE_SEQUENCE:
	case PGM_ASTE_VALIDITY:
	case PGM_ASTE_SEQUENCE:
	case PGM_EXTENDED_AUTHORITY:
		/*
		 * We can always store exc_access_id, as it is
		 * undefined for non-ar cases. It is undefined for
		 * most DAT protection exceptions.
		 */
		pgm->exc_access_id = ar;
		break;
	}
	return code;
}

static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
		     enum gacc_mode mode, enum prot_type prot)
{
	return trans_exc_ending(vcpu, code, gva, ar, mode, prot, false);
}

static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce,
			 unsigned long ga, u8 ar, enum gacc_mode mode)
{
	int rc;
	struct psw_bits psw = psw_bits(vcpu->arch.sie_block->gpsw);

	if (!psw.dat) {
		asce->val = 0;
		asce->r = 1;
		return 0;
	}

	if ((mode == GACC_IFETCH) && (psw.as != PSW_BITS_AS_HOME))
		psw.as = PSW_BITS_AS_PRIMARY;

	switch (psw.as) {
	case PSW_BITS_AS_PRIMARY:
		asce->val = vcpu->arch.sie_block->gcr[1];
		return 0;
	case PSW_BITS_AS_SECONDARY:
		asce->val = vcpu->arch.sie_block->gcr[7];
		return 0;
	case PSW_BITS_AS_HOME:
		asce->val = vcpu->arch.sie_block->gcr[13];
		return 0;
	case PSW_BITS_AS_ACCREG:
		rc = ar_translation(vcpu, asce, ar, mode);
		if (rc > 0)
			return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_ALC);
		return rc;
	}
	return 0;
}

static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
{
	return kvm_read_guest(kvm, gpa, val, sizeof(*val));
}

/**
 * guest_translate - translate a guest virtual into a guest absolute address
 * @vcpu: virtual cpu
 * @gva: guest virtual address
 * @gpa: points to where guest physical (absolute) address should be stored
 * @asce: effective asce
 * @mode: indicates the access mode to be used
 * @prot: returns the type for protection exceptions
 *
 * Translate a guest virtual address into a guest absolute address by means
 * of dynamic address translation as specified by the architecture.
 * If the resulting absolute address is not available in the configuration
 * an addressing exception is indicated and @gpa will not be changed.
 *
 * Returns: - zero on success; @gpa contains the resulting absolute address
 *	    - a negative value if guest access failed due to e.g. broken
 *	      guest mapping
 *	    - a positve value if an access exception happened. In this case
 *	      the returned value is the program interruption code as defined
 *	      by the architecture
 */
static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
				     unsigned long *gpa, const union asce asce,
				     enum gacc_mode mode, enum prot_type *prot)
{
	union vaddress vaddr = {.addr = gva};
	union raddress raddr = {.addr = gva};
	union page_table_entry pte;
	int dat_protection = 0;
	int iep_protection = 0;
	union ctlreg0 ctlreg0;
	unsigned long ptr;
	int edat1, edat2, iep;

	ctlreg0.val = vcpu->arch.sie_block->gcr[0];
	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
	iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130);
	if (asce.r)
		goto real_address;
	ptr = asce.origin * PAGE_SIZE;
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:
		if (vaddr.rfx01 > asce.tl)
			return PGM_REGION_FIRST_TRANS;
		ptr += vaddr.rfx * 8;
		break;
	case ASCE_TYPE_REGION2:
		if (vaddr.rfx)
			return PGM_ASCE_TYPE;
		if (vaddr.rsx01 > asce.tl)
			return PGM_REGION_SECOND_TRANS;
		ptr += vaddr.rsx * 8;
		break;
	case ASCE_TYPE_REGION3:
		if (vaddr.rfx || vaddr.rsx)
			return PGM_ASCE_TYPE;
		if (vaddr.rtx01 > asce.tl)
			return PGM_REGION_THIRD_TRANS;
		ptr += vaddr.rtx * 8;
		break;
	case ASCE_TYPE_SEGMENT:
		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
			return PGM_ASCE_TYPE;
		if (vaddr.sx01 > asce.tl)
			return PGM_SEGMENT_TRANSLATION;
		ptr += vaddr.sx * 8;
		break;
	}
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:	{
		union region1_table_entry rfte;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rfte.val))
			return -EFAULT;
		if (rfte.i)
			return PGM_REGION_FIRST_TRANS;
		if (rfte.tt != TABLE_TYPE_REGION1)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
			return PGM_REGION_SECOND_TRANS;
		if (edat1)
			dat_protection |= rfte.p;
		ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8;
	}
		fallthrough;
	case ASCE_TYPE_REGION2: {
		union region2_table_entry rste;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rste.val))
			return -EFAULT;
		if (rste.i)
			return PGM_REGION_SECOND_TRANS;
		if (rste.tt != TABLE_TYPE_REGION2)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
			return PGM_REGION_THIRD_TRANS;
		if (edat1)
			dat_protection |= rste.p;
		ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8;
	}
		fallthrough;
	case ASCE_TYPE_REGION3: {
		union region3_table_entry rtte;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rtte.val))
			return -EFAULT;
		if (rtte.i)
			return PGM_REGION_THIRD_TRANS;
		if (rtte.tt != TABLE_TYPE_REGION3)
			return PGM_TRANSLATION_SPEC;
		if (rtte.cr && asce.p && edat2)
			return PGM_TRANSLATION_SPEC;
		if (rtte.fc && edat2) {
			dat_protection |= rtte.fc1.p;
			iep_protection = rtte.fc1.iep;
			raddr.rfaa = rtte.fc1.rfaa;
			goto absolute_address;
		}
		if (vaddr.sx01 < rtte.fc0.tf)
			return PGM_SEGMENT_TRANSLATION;
		if (vaddr.sx01 > rtte.fc0.tl)
			return PGM_SEGMENT_TRANSLATION;
		if (edat1)
			dat_protection |= rtte.fc0.p;
		ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8;
	}
		fallthrough;
	case ASCE_TYPE_SEGMENT: {
		union segment_table_entry ste;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &ste.val))
			return -EFAULT;
		if (ste.i)
			return PGM_SEGMENT_TRANSLATION;
		if (ste.tt != TABLE_TYPE_SEGMENT)
			return PGM_TRANSLATION_SPEC;
		if (ste.cs && asce.p)
			return PGM_TRANSLATION_SPEC;
		if (ste.fc && edat1) {
			dat_protection |= ste.fc1.p;
			iep_protection = ste.fc1.iep;
			raddr.sfaa = ste.fc1.sfaa;
			goto absolute_address;
		}
		dat_protection |= ste.fc0.p;
		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
	}
	}
	if (kvm_is_error_gpa(vcpu->kvm, ptr))
		return PGM_ADDRESSING;
	if (deref_table(vcpu->kvm, ptr, &pte.val))
		return -EFAULT;
	if (pte.i)
		return PGM_PAGE_TRANSLATION;
	if (pte.z)
		return PGM_TRANSLATION_SPEC;
	dat_protection |= pte.p;
	iep_protection = pte.iep;
	raddr.pfra = pte.pfra;
real_address:
	raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
absolute_address:
	if (mode == GACC_STORE && dat_protection) {
		*prot = PROT_TYPE_DAT;
		return PGM_PROTECTION;
	}
	if (mode == GACC_IFETCH && iep_protection && iep) {
		*prot = PROT_TYPE_IEP;
		return PGM_PROTECTION;
	}
	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
		return PGM_ADDRESSING;
	*gpa = raddr.addr;
	return 0;
}

static inline int is_low_address(unsigned long ga)
{
	/* Check for address ranges 0..511 and 4096..4607 */
	return (ga & ~0x11fful) == 0;
}

static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
					  const union asce asce)
{
	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
	psw_t *psw = &vcpu->arch.sie_block->gpsw;

	if (!ctlreg0.lap)
		return 0;
	if (psw_bits(*psw).dat && asce.p)
		return 0;
	return 1;
}

static int vm_check_access_key(struct kvm *kvm, u8 access_key,
			       enum gacc_mode mode, gpa_t gpa)
{
	u8 storage_key, access_control;
	bool fetch_protected;
	unsigned long hva;
	int r;

	if (access_key == 0)
		return 0;

	hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
	if (kvm_is_error_hva(hva))
		return PGM_ADDRESSING;

	mmap_read_lock(current->mm);
	r = get_guest_storage_key(current->mm, hva, &storage_key);
	mmap_read_unlock(current->mm);
	if (r)
		return r;
	access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key);
	if (access_control == access_key)
		return 0;
	fetch_protected = storage_key & _PAGE_FP_BIT;
	if ((mode == GACC_FETCH || mode == GACC_IFETCH) && !fetch_protected)
		return 0;
	return PGM_PROTECTION;
}

static bool fetch_prot_override_applicable(struct kvm_vcpu *vcpu, enum gacc_mode mode,
					   union asce asce)
{
	psw_t *psw = &vcpu->arch.sie_block->gpsw;
	unsigned long override;

	if (mode == GACC_FETCH || mode == GACC_IFETCH) {
		/* check if fetch protection override enabled */
		override = vcpu->arch.sie_block->gcr[0];
		override &= CR0_FETCH_PROTECTION_OVERRIDE;
		/* not applicable if subject to DAT && private space */
		override = override && !(psw_bits(*psw).dat && asce.p);
		return override;
	}
	return false;
}

static bool fetch_prot_override_applies(unsigned long ga, unsigned int len)
{
	return ga < 2048 && ga + len <= 2048;
}

static bool storage_prot_override_applicable(struct kvm_vcpu *vcpu)
{
	/* check if storage protection override enabled */
	return vcpu->arch.sie_block->gcr[0] & CR0_STORAGE_PROTECTION_OVERRIDE;
}

static bool storage_prot_override_applies(u8 access_control)
{
	/* matches special storage protection override key (9) -> allow */
	return access_control == PAGE_SPO_ACC;
}

static int vcpu_check_access_key(struct kvm_vcpu *vcpu, u8 access_key,
				 enum gacc_mode mode, union asce asce, gpa_t gpa,
				 unsigned long ga, unsigned int len)
{
	u8 storage_key, access_control;
	unsigned long hva;
	int r;

	/* access key 0 matches any storage key -> allow */
	if (access_key == 0)
		return 0;
	/*
	 * caller needs to ensure that gfn is accessible, so we can
	 * assume that this cannot fail
	 */
	hva = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gpa));
	mmap_read_lock(current->mm);
	r = get_guest_storage_key(current->mm, hva, &storage_key);
	mmap_read_unlock(current->mm);
	if (r)
		return r;
	access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key);
	/* access key matches storage key -> allow */
	if (access_control == access_key)
		return 0;
	if (mode == GACC_FETCH || mode == GACC_IFETCH) {
		/* it is a fetch and fetch protection is off -> allow */
		if (!(storage_key & _PAGE_FP_BIT))
			return 0;
		if (fetch_prot_override_applicable(vcpu, mode, asce) &&
		    fetch_prot_override_applies(ga, len))
			return 0;
	}
	if (storage_prot_override_applicable(vcpu) &&
	    storage_prot_override_applies(access_control))
		return 0;
	return PGM_PROTECTION;
}

/**
 * guest_range_to_gpas() - Calculate guest physical addresses of page fragments
 * covering a logical range
 * @vcpu: virtual cpu
 * @ga: guest address, start of range
 * @ar: access register
 * @gpas: output argument, may be NULL
 * @len: length of range in bytes
 * @asce: address-space-control element to use for translation
 * @mode: access mode
 * @access_key: access key to mach the range's storage keys against
 *
 * Translate a logical range to a series of guest absolute addresses,
 * such that the concatenation of page fragments starting at each gpa make up
 * the whole range.
 * The translation is performed as if done by the cpu for the given @asce, @ar,
 * @mode and state of the @vcpu.
 * If the translation causes an exception, its program interruption code is
 * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified
 * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject
 * a correct exception into the guest.
 * The resulting gpas are stored into @gpas, unless it is NULL.
 *
 * Note: All fragments except the first one start at the beginning of a page.
 *	 When deriving the boundaries of a fragment from a gpa, all but the last
 *	 fragment end at the end of the page.
 *
 * Return:
 * * 0		- success
 * * <0		- translation could not be performed, for example if  guest
 *		  memory could not be accessed
 * * >0		- an access exception occurred. In this case the returned value
 *		  is the program interruption code and the contents of pgm may
 *		  be used to inject an exception into the guest.
 */
static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
			       unsigned long *gpas, unsigned long len,
			       const union asce asce, enum gacc_mode mode,
			       u8 access_key)
{
	psw_t *psw = &vcpu->arch.sie_block->gpsw;
	unsigned int offset = offset_in_page(ga);
	unsigned int fragment_len;
	int lap_enabled, rc = 0;
	enum prot_type prot;
	unsigned long gpa;

	lap_enabled = low_address_protection_enabled(vcpu, asce);
	while (min(PAGE_SIZE - offset, len) > 0) {
		fragment_len = min(PAGE_SIZE - offset, len);
		ga = kvm_s390_logical_to_effective(vcpu, ga);
		if (mode == GACC_STORE && lap_enabled && is_low_address(ga))
			return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode,
					 PROT_TYPE_LA);
		if (psw_bits(*psw).dat) {
			rc = guest_translate(vcpu, ga, &gpa, asce, mode, &prot);
			if (rc < 0)
				return rc;
		} else {
			gpa = kvm_s390_real_to_abs(vcpu, ga);
			if (kvm_is_error_gpa(vcpu->kvm, gpa)) {
				rc = PGM_ADDRESSING;
				prot = PROT_NONE;
			}
		}
		if (rc)
			return trans_exc(vcpu, rc, ga, ar, mode, prot);
		rc = vcpu_check_access_key(vcpu, access_key, mode, asce, gpa, ga,
					   fragment_len);
		if (rc)
			return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_KEYC);
		if (gpas)
			*gpas++ = gpa;
		offset = 0;
		ga += fragment_len;
		len -= fragment_len;
	}
	return 0;
}

static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
			     void *data, unsigned int len)
{
	const unsigned int offset = offset_in_page(gpa);
	const gfn_t gfn = gpa_to_gfn(gpa);
	int rc;

	if (mode == GACC_STORE)
		rc = kvm_write_guest_page(kvm, gfn, data, offset, len);
	else
		rc = kvm_read_guest_page(kvm, gfn, data, offset, len);
	return rc;
}

static int
access_guest_page_with_key(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
			   void *data, unsigned int len, u8 access_key)
{
	struct kvm_memory_slot *slot;
	bool writable;
	gfn_t gfn;
	hva_t hva;
	int rc;

	gfn = gpa >> PAGE_SHIFT;
	slot = gfn_to_memslot(kvm, gfn);
	hva = gfn_to_hva_memslot_prot(slot, gfn, &writable);

	if (kvm_is_error_hva(hva))
		return PGM_ADDRESSING;
	/*
	 * Check if it's a ro memslot, even tho that can't occur (they're unsupported).
	 * Don't try to actually handle that case.
	 */
	if (!writable && mode == GACC_STORE)
		return -EOPNOTSUPP;
	hva += offset_in_page(gpa);
	if (mode == GACC_STORE)
		rc = copy_to_user_key((void __user *)hva, data, len, access_key);
	else
		rc = copy_from_user_key(data, (void __user *)hva, len, access_key);
	if (rc)
		return PGM_PROTECTION;
	if (mode == GACC_STORE)
		mark_page_dirty_in_slot(kvm, slot, gfn);
	return 0;
}

int access_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, void *data,
			      unsigned long len, enum gacc_mode mode, u8 access_key)
{
	int offset = offset_in_page(gpa);
	int fragment_len;
	int rc;

	while (min(PAGE_SIZE - offset, len) > 0) {
		fragment_len = min(PAGE_SIZE - offset, len);
		rc = access_guest_page_with_key(kvm, mode, gpa, data, fragment_len, access_key);
		if (rc)
			return rc;
		offset = 0;
		len -= fragment_len;
		data += fragment_len;
		gpa += fragment_len;
	}
	return 0;
}

int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
			  void *data, unsigned long len, enum gacc_mode mode,
			  u8 access_key)
{
	psw_t *psw = &vcpu->arch.sie_block->gpsw;
	unsigned long nr_pages, idx;
	unsigned long gpa_array[2];
	unsigned int fragment_len;
	unsigned long *gpas;
	enum prot_type prot;
	int need_ipte_lock;
	union asce asce;
	bool try_storage_prot_override;
	bool try_fetch_prot_override;
	int rc;

	if (!len)
		return 0;
	ga = kvm_s390_logical_to_effective(vcpu, ga);
	rc = get_vcpu_asce(vcpu, &asce, ga, ar, mode);
	if (rc)
		return rc;
	nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
	gpas = gpa_array;
	if (nr_pages > ARRAY_SIZE(gpa_array))
		gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long)));
	if (!gpas)
		return -ENOMEM;
	try_fetch_prot_override = fetch_prot_override_applicable(vcpu, mode, asce);
	try_storage_prot_override = storage_prot_override_applicable(vcpu);
	need_ipte_lock = psw_bits(*psw).dat && !asce.r;
	if (need_ipte_lock)
		ipte_lock(vcpu->kvm);
	/*
	 * Since we do the access further down ultimately via a move instruction
	 * that does key checking and returns an error in case of a protection
	 * violation, we don't need to do the check during address translation.
	 * Skip it by passing access key 0, which matches any storage key,
	 * obviating the need for any further checks. As a result the check is
	 * handled entirely in hardware on access, we only need to take care to
	 * forego key protection checking if fetch protection override applies or
	 * retry with the special key 9 in case of storage protection override.
	 */
	rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode, 0);
	if (rc)
		goto out_unlock;
	for (idx = 0; idx < nr_pages; idx++) {
		fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len);
		if (try_fetch_prot_override && fetch_prot_override_applies(ga, fragment_len)) {
			rc = access_guest_page(vcpu->kvm, mode, gpas[idx],
					       data, fragment_len);
		} else {
			rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx],
							data, fragment_len, access_key);
		}
		if (rc == PGM_PROTECTION && try_storage_prot_override)
			rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx],
							data, fragment_len, PAGE_SPO_ACC);
		if (rc)
			break;
		len -= fragment_len;
		data += fragment_len;
		ga = kvm_s390_logical_to_effective(vcpu, ga + fragment_len);
	}
	if (rc > 0) {
		bool terminate = (mode == GACC_STORE) && (idx > 0);

		if (rc == PGM_PROTECTION)
			prot = PROT_TYPE_KEYC;
		else
			prot = PROT_NONE;
		rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
	}
out_unlock:
	if (need_ipte_lock)
		ipte_unlock(vcpu->kvm);
	if (nr_pages > ARRAY_SIZE(gpa_array))
		vfree(gpas);
	return rc;
}

int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
		      void *data, unsigned long len, enum gacc_mode mode)
{
	unsigned int fragment_len;
	unsigned long gpa;
	int rc = 0;

	while (len && !rc) {
		gpa = kvm_s390_real_to_abs(vcpu, gra);
		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
		rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len);
		len -= fragment_len;
		gra += fragment_len;
		data += fragment_len;
	}
	return rc;
}

/**
 * guest_translate_address_with_key - translate guest logical into guest absolute address
 * @vcpu: virtual cpu
 * @gva: Guest virtual address
 * @ar: Access register
 * @gpa: Guest physical address
 * @mode: Translation access mode
 * @access_key: access key to mach the storage key with
 *
 * Parameter semantics are the same as the ones from guest_translate.
 * The memory contents at the guest address are not changed.
 *
 * Note: The IPTE lock is not taken during this function, so the caller
 * has to take care of this.
 */
int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
				     unsigned long *gpa, enum gacc_mode mode,
				     u8 access_key)
{
	union asce asce;
	int rc;

	gva = kvm_s390_logical_to_effective(vcpu, gva);
	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
	if (rc)
		return rc;
	return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode,
				   access_key);
}

/**
 * check_gva_range - test a range of guest virtual addresses for accessibility
 * @vcpu: virtual cpu
 * @gva: Guest virtual address
 * @ar: Access register
 * @length: Length of test range
 * @mode: Translation access mode
 * @access_key: access key to mach the storage keys with
 */
int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
		    unsigned long length, enum gacc_mode mode, u8 access_key)
{
	union asce asce;
	int rc = 0;

	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
	if (rc)
		return rc;
	ipte_lock(vcpu->kvm);
	rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
				 access_key);
	ipte_unlock(vcpu->kvm);

	return rc;
}

/**
 * check_gpa_range - test a range of guest physical addresses for accessibility
 * @kvm: virtual machine instance
 * @gpa: guest physical address
 * @length: length of test range
 * @mode: access mode to test, relevant for storage keys
 * @access_key: access key to mach the storage keys with
 */
int check_gpa_range(struct kvm *kvm, unsigned long gpa, unsigned long length,
		    enum gacc_mode mode, u8 access_key)
{
	unsigned int fragment_len;
	int rc = 0;

	while (length && !rc) {
		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), length);
		rc = vm_check_access_key(kvm, access_key, mode, gpa);
		length -= fragment_len;
		gpa += fragment_len;
	}
	return rc;
}

/**
 * kvm_s390_check_low_addr_prot_real - check for low-address protection
 * @vcpu: virtual cpu
 * @gra: Guest real address
 *
 * Checks whether an address is subject to low-address protection and set
 * up vcpu->arch.pgm accordingly if necessary.
 *
 * Return: 0 if no protection exception, or PGM_PROTECTION if protected.
 */
int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
{
	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};

	if (!ctlreg0.lap || !is_low_address(gra))
		return 0;
	return trans_exc(vcpu, PGM_PROTECTION, gra, 0, GACC_STORE, PROT_TYPE_LA);
}

/**
 * kvm_s390_shadow_tables - walk the guest page table and create shadow tables
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @pgt: pointer to the beginning of the page table for the given address if
 *	 successful (return value 0), or to the first invalid DAT entry in
 *	 case of exceptions (return value > 0)
 * @dat_protection: referenced memory is write protected
 * @fake: pgt references contiguous guest memory block, not a pgtable
 */
static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
				  unsigned long *pgt, int *dat_protection,
				  int *fake)
{
	struct gmap *parent;
	union asce asce;
	union vaddress vaddr;
	unsigned long ptr;
	int rc;

	*fake = 0;
	*dat_protection = 0;
	parent = sg->parent;
	vaddr.addr = saddr;
	asce.val = sg->orig_asce;
	ptr = asce.origin * PAGE_SIZE;
	if (asce.r) {
		*fake = 1;
		ptr = 0;
		asce.dt = ASCE_TYPE_REGION1;
	}
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:
		if (vaddr.rfx01 > asce.tl && !*fake)
			return PGM_REGION_FIRST_TRANS;
		break;
	case ASCE_TYPE_REGION2:
		if (vaddr.rfx)
			return PGM_ASCE_TYPE;
		if (vaddr.rsx01 > asce.tl)
			return PGM_REGION_SECOND_TRANS;
		break;
	case ASCE_TYPE_REGION3:
		if (vaddr.rfx || vaddr.rsx)
			return PGM_ASCE_TYPE;
		if (vaddr.rtx01 > asce.tl)
			return PGM_REGION_THIRD_TRANS;
		break;
	case ASCE_TYPE_SEGMENT:
		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
			return PGM_ASCE_TYPE;
		if (vaddr.sx01 > asce.tl)
			return PGM_SEGMENT_TRANSLATION;
		break;
	}

	switch (asce.dt) {
	case ASCE_TYPE_REGION1: {
		union region1_table_entry rfte;

		if (*fake) {
			ptr += vaddr.rfx * _REGION1_SIZE;
			rfte.val = ptr;
			goto shadow_r2t;
		}
		*pgt = ptr + vaddr.rfx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
		if (rc)
			return rc;
		if (rfte.i)
			return PGM_REGION_FIRST_TRANS;
		if (rfte.tt != TABLE_TYPE_REGION1)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
			return PGM_REGION_SECOND_TRANS;
		if (sg->edat_level >= 1)
			*dat_protection |= rfte.p;
		ptr = rfte.rto * PAGE_SIZE;
shadow_r2t:
		rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_REGION2: {
		union region2_table_entry rste;

		if (*fake) {
			ptr += vaddr.rsx * _REGION2_SIZE;
			rste.val = ptr;
			goto shadow_r3t;
		}
		*pgt = ptr + vaddr.rsx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
		if (rc)
			return rc;
		if (rste.i)
			return PGM_REGION_SECOND_TRANS;
		if (rste.tt != TABLE_TYPE_REGION2)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
			return PGM_REGION_THIRD_TRANS;
		if (sg->edat_level >= 1)
			*dat_protection |= rste.p;
		ptr = rste.rto * PAGE_SIZE;
shadow_r3t:
		rste.p |= *dat_protection;
		rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_REGION3: {
		union region3_table_entry rtte;

		if (*fake) {
			ptr += vaddr.rtx * _REGION3_SIZE;
			rtte.val = ptr;
			goto shadow_sgt;
		}
		*pgt = ptr + vaddr.rtx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
		if (rc)
			return rc;
		if (rtte.i)
			return PGM_REGION_THIRD_TRANS;
		if (rtte.tt != TABLE_TYPE_REGION3)
			return PGM_TRANSLATION_SPEC;
		if (rtte.cr && asce.p && sg->edat_level >= 2)
			return PGM_TRANSLATION_SPEC;
		if (rtte.fc && sg->edat_level >= 2) {
			*dat_protection |= rtte.fc0.p;
			*fake = 1;
			ptr = rtte.fc1.rfaa * _REGION3_SIZE;
			rtte.val = ptr;
			goto shadow_sgt;
		}
		if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl)
			return PGM_SEGMENT_TRANSLATION;
		if (sg->edat_level >= 1)
			*dat_protection |= rtte.fc0.p;
		ptr = rtte.fc0.sto * PAGE_SIZE;
shadow_sgt:
		rtte.fc0.p |= *dat_protection;
		rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_SEGMENT: {
		union segment_table_entry ste;

		if (*fake) {
			ptr += vaddr.sx * _SEGMENT_SIZE;
			ste.val = ptr;
			goto shadow_pgt;
		}
		*pgt = ptr + vaddr.sx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
		if (rc)
			return rc;
		if (ste.i)
			return PGM_SEGMENT_TRANSLATION;
		if (ste.tt != TABLE_TYPE_SEGMENT)
			return PGM_TRANSLATION_SPEC;
		if (ste.cs && asce.p)
			return PGM_TRANSLATION_SPEC;
		*dat_protection |= ste.fc0.p;
		if (ste.fc && sg->edat_level >= 1) {
			*fake = 1;
			ptr = ste.fc1.sfaa * _SEGMENT_SIZE;
			ste.val = ptr;
			goto shadow_pgt;
		}
		ptr = ste.fc0.pto * (PAGE_SIZE / 2);
shadow_pgt:
		ste.fc0.p |= *dat_protection;
		rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake);
		if (rc)
			return rc;
	}
	}
	/* Return the parent address of the page table */
	*pgt = ptr;
	return 0;
}

/**
 * kvm_s390_shadow_fault - handle fault on a shadow page table
 * @vcpu: virtual cpu
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @datptr: will contain the address of the faulting DAT table entry, or of
 *	    the valid leaf, plus some flags
 *
 * Returns: - 0 if the shadow fault was successfully resolved
 *	    - > 0 (pgm exception code) on exceptions while faulting
 *	    - -EAGAIN if the caller can retry immediately
 *	    - -EFAULT when accessing invalid guest addresses
 *	    - -ENOMEM if out of memory
 */
int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
			  unsigned long saddr, unsigned long *datptr)
{
	union vaddress vaddr;
	union page_table_entry pte;
	unsigned long pgt = 0;
	int dat_protection, fake;
	int rc;

	mmap_read_lock(sg->mm);
	/*
	 * We don't want any guest-2 tables to change - so the parent
	 * tables/pointers we read stay valid - unshadowing is however
	 * always possible - only guest_table_lock protects us.
	 */
	ipte_lock(vcpu->kvm);

	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
	if (rc)
		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
					    &fake);

	vaddr.addr = saddr;
	if (fake) {
		pte.val = pgt + vaddr.px * PAGE_SIZE;
		goto shadow_page;
	}

	switch (rc) {
	case PGM_SEGMENT_TRANSLATION:
	case PGM_REGION_THIRD_TRANS:
	case PGM_REGION_SECOND_TRANS:
	case PGM_REGION_FIRST_TRANS:
		pgt |= PEI_NOT_PTE;
		break;
	case 0:
		pgt += vaddr.px * 8;
		rc = gmap_read_table(sg->parent, pgt, &pte.val);
	}
	if (datptr)
		*datptr = pgt | dat_protection * PEI_DAT_PROT;
	if (!rc && pte.i)
		rc = PGM_PAGE_TRANSLATION;
	if (!rc && pte.z)
		rc = PGM_TRANSLATION_SPEC;
shadow_page:
	pte.p |= dat_protection;
	if (!rc)
		rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
	ipte_unlock(vcpu->kvm);
	mmap_read_unlock(sg->mm);
	return rc;
}