Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
   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
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * KVM/MIPS: Deliver/Emulate exceptions to the guest kernel
 *
 * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
 * Authors: Sanjay Lal <sanjayl@kymasys.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/log2.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>

#include "interrupt.h"

static gpa_t kvm_trap_emul_gva_to_gpa_cb(gva_t gva)
{
	gpa_t gpa;
	gva_t kseg = KSEGX(gva);
	gva_t gkseg = KVM_GUEST_KSEGX(gva);

	if ((kseg == CKSEG0) || (kseg == CKSEG1))
		gpa = CPHYSADDR(gva);
	else if (gkseg == KVM_GUEST_KSEG0)
		gpa = KVM_GUEST_CPHYSADDR(gva);
	else {
		kvm_err("%s: cannot find GPA for GVA: %#lx\n", __func__, gva);
		kvm_mips_dump_host_tlbs();
		gpa = KVM_INVALID_ADDR;
	}

	kvm_debug("%s: gva %#lx, gpa: %#llx\n", __func__, gva, gpa);

	return gpa;
}

static int kvm_trap_emul_no_handler(struct kvm_vcpu *vcpu)
{
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	u32 exccode = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
	u32 inst = 0;

	/*
	 *  Fetch the instruction.
	 */
	if (cause & CAUSEF_BD)
		opc += 1;
	kvm_get_badinstr(opc, vcpu, &inst);

	kvm_err("Exception Code: %d not handled @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#x\n",
		exccode, opc, inst, badvaddr,
		kvm_read_c0_guest_status(vcpu->arch.cop0));
	kvm_arch_vcpu_dump_regs(vcpu);
	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
	return RESUME_HOST;
}

static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 1) {
		/* FPU Unusable */
		if (!kvm_mips_guest_has_fpu(&vcpu->arch) ||
		    (kvm_read_c0_guest_status(cop0) & ST0_CU1) == 0) {
			/*
			 * Unusable/no FPU in guest:
			 * deliver guest COP1 Unusable Exception
			 */
			er = kvm_mips_emulate_fpu_exc(cause, opc, run, vcpu);
		} else {
			/* Restore FPU state */
			kvm_own_fpu(vcpu);
			er = EMULATE_DONE;
		}
	} else {
		er = kvm_mips_emulate_inst(cause, opc, run, vcpu);
	}

	switch (er) {
	case EMULATE_DONE:
		ret = RESUME_GUEST;
		break;

	case EMULATE_FAIL:
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
		break;

	case EMULATE_WAIT:
		run->exit_reason = KVM_EXIT_INTR;
		ret = RESUME_HOST;
		break;

	case EMULATE_HYPERCALL:
		ret = kvm_mips_handle_hypcall(vcpu);
		break;

	default:
		BUG();
	}
	return ret;
}

static int kvm_mips_bad_load(u32 cause, u32 *opc, struct kvm_run *run,
			     struct kvm_vcpu *vcpu)
{
	enum emulation_result er;
	union mips_instruction inst;
	int err;

	/* A code fetch fault doesn't count as an MMIO */
	if (kvm_is_ifetch_fault(&vcpu->arch)) {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		return RESUME_HOST;
	}

	/* Fetch the instruction. */
	if (cause & CAUSEF_BD)
		opc += 1;
	err = kvm_get_badinstr(opc, vcpu, &inst.word);
	if (err) {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		return RESUME_HOST;
	}

	/* Emulate the load */
	er = kvm_mips_emulate_load(inst, cause, run, vcpu);
	if (er == EMULATE_FAIL) {
		kvm_err("Emulate load from MMIO space failed\n");
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
	} else {
		run->exit_reason = KVM_EXIT_MMIO;
	}
	return RESUME_HOST;
}

static int kvm_mips_bad_store(u32 cause, u32 *opc, struct kvm_run *run,
			      struct kvm_vcpu *vcpu)
{
	enum emulation_result er;
	union mips_instruction inst;
	int err;

	/* Fetch the instruction. */
	if (cause & CAUSEF_BD)
		opc += 1;
	err = kvm_get_badinstr(opc, vcpu, &inst.word);
	if (err) {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		return RESUME_HOST;
	}

	/* Emulate the store */
	er = kvm_mips_emulate_store(inst, cause, run, vcpu);
	if (er == EMULATE_FAIL) {
		kvm_err("Emulate store to MMIO space failed\n");
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
	} else {
		run->exit_reason = KVM_EXIT_MMIO;
	}
	return RESUME_HOST;
}

static int kvm_mips_bad_access(u32 cause, u32 *opc, struct kvm_run *run,
			       struct kvm_vcpu *vcpu, bool store)
{
	if (store)
		return kvm_mips_bad_store(cause, opc, run, vcpu);
	else
		return kvm_mips_bad_load(cause, opc, run, vcpu);
}

static int kvm_trap_emul_handle_tlb_mod(struct kvm_vcpu *vcpu)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
	u32 cause = vcpu->arch.host_cp0_cause;
	struct kvm_mips_tlb *tlb;
	unsigned long entryhi;
	int index;

	if (KVM_GUEST_KSEGX(badvaddr) < KVM_GUEST_KSEG0
	    || KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG23) {
		/*
		 * First find the mapping in the guest TLB. If the failure to
		 * write was due to the guest TLB, it should be up to the guest
		 * to handle it.
		 */
		entryhi = (badvaddr & VPN2_MASK) |
			  (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
		index = kvm_mips_guest_tlb_lookup(vcpu, entryhi);

		/*
		 * These should never happen.
		 * They would indicate stale host TLB entries.
		 */
		if (unlikely(index < 0)) {
			run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
			return RESUME_HOST;
		}
		tlb = vcpu->arch.guest_tlb + index;
		if (unlikely(!TLB_IS_VALID(*tlb, badvaddr))) {
			run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
			return RESUME_HOST;
		}

		/*
		 * Guest entry not dirty? That would explain the TLB modified
		 * exception. Relay that on to the guest so it can handle it.
		 */
		if (!TLB_IS_DIRTY(*tlb, badvaddr)) {
			kvm_mips_emulate_tlbmod(cause, opc, run, vcpu);
			return RESUME_GUEST;
		}

		if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, badvaddr,
							 true))
			/* Not writable, needs handling as MMIO */
			return kvm_mips_bad_store(cause, opc, run, vcpu);
		return RESUME_GUEST;
	} else if (KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG0) {
		if (kvm_mips_handle_kseg0_tlb_fault(badvaddr, vcpu, true) < 0)
			/* Not writable, needs handling as MMIO */
			return kvm_mips_bad_store(cause, opc, run, vcpu);
		return RESUME_GUEST;
	} else {
		/* host kernel addresses are all handled as MMIO */
		return kvm_mips_bad_store(cause, opc, run, vcpu);
	}
}

static int kvm_trap_emul_handle_tlb_miss(struct kvm_vcpu *vcpu, bool store)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	if (((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR)
	    && KVM_GUEST_KERNEL_MODE(vcpu)) {
		if (kvm_mips_handle_commpage_tlb_fault(badvaddr, vcpu) < 0) {
			run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
			ret = RESUME_HOST;
		}
	} else if (KVM_GUEST_KSEGX(badvaddr) < KVM_GUEST_KSEG0
		   || KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG23) {
		kvm_debug("USER ADDR TLB %s fault: cause %#x, PC: %p, BadVaddr: %#lx\n",
			  store ? "ST" : "LD", cause, opc, badvaddr);

		/*
		 * User Address (UA) fault, this could happen if
		 * (1) TLB entry not present/valid in both Guest and shadow host
		 *     TLBs, in this case we pass on the fault to the guest
		 *     kernel and let it handle it.
		 * (2) TLB entry is present in the Guest TLB but not in the
		 *     shadow, in this case we inject the TLB from the Guest TLB
		 *     into the shadow host TLB
		 */

		er = kvm_mips_handle_tlbmiss(cause, opc, run, vcpu, store);
		if (er == EMULATE_DONE)
			ret = RESUME_GUEST;
		else {
			run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
			ret = RESUME_HOST;
		}
	} else if (KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG0) {
		/*
		 * All KSEG0 faults are handled by KVM, as the guest kernel does
		 * not expect to ever get them
		 */
		if (kvm_mips_handle_kseg0_tlb_fault(badvaddr, vcpu, store) < 0)
			ret = kvm_mips_bad_access(cause, opc, run, vcpu, store);
	} else if (KVM_GUEST_KERNEL_MODE(vcpu)
		   && (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) {
		/*
		 * With EVA we may get a TLB exception instead of an address
		 * error when the guest performs MMIO to KSeg1 addresses.
		 */
		ret = kvm_mips_bad_access(cause, opc, run, vcpu, store);
	} else {
		kvm_err("Illegal TLB %s fault address , cause %#x, PC: %p, BadVaddr: %#lx\n",
			store ? "ST" : "LD", cause, opc, badvaddr);
		kvm_mips_dump_host_tlbs();
		kvm_arch_vcpu_dump_regs(vcpu);
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_tlb_st_miss(struct kvm_vcpu *vcpu)
{
	return kvm_trap_emul_handle_tlb_miss(vcpu, true);
}

static int kvm_trap_emul_handle_tlb_ld_miss(struct kvm_vcpu *vcpu)
{
	return kvm_trap_emul_handle_tlb_miss(vcpu, false);
}

static int kvm_trap_emul_handle_addr_err_st(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
	u32 cause = vcpu->arch.host_cp0_cause;
	int ret = RESUME_GUEST;

	if (KVM_GUEST_KERNEL_MODE(vcpu)
	    && (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) {
		ret = kvm_mips_bad_store(cause, opc, run, vcpu);
	} else {
		kvm_err("Address Error (STORE): cause %#x, PC: %p, BadVaddr: %#lx\n",
			cause, opc, badvaddr);
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_addr_err_ld(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
	u32 cause = vcpu->arch.host_cp0_cause;
	int ret = RESUME_GUEST;

	if (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1) {
		ret = kvm_mips_bad_load(cause, opc, run, vcpu);
	} else {
		kvm_err("Address Error (LOAD): cause %#x, PC: %p, BadVaddr: %#lx\n",
			cause, opc, badvaddr);
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_syscall(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_emulate_syscall(cause, opc, run, vcpu);
	if (er == EMULATE_DONE)
		ret = RESUME_GUEST;
	else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_res_inst(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_handle_ri(cause, opc, run, vcpu);
	if (er == EMULATE_DONE)
		ret = RESUME_GUEST;
	else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_emulate_bp_exc(cause, opc, run, vcpu);
	if (er == EMULATE_DONE)
		ret = RESUME_GUEST;
	else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_trap(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *)vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_emulate_trap_exc(cause, opc, run, vcpu);
	if (er == EMULATE_DONE) {
		ret = RESUME_GUEST;
	} else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_msa_fpe(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *)vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_emulate_msafpe_exc(cause, opc, run, vcpu);
	if (er == EMULATE_DONE) {
		ret = RESUME_GUEST;
	} else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

static int kvm_trap_emul_handle_fpe(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *)vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	er = kvm_mips_emulate_fpe_exc(cause, opc, run, vcpu);
	if (er == EMULATE_DONE) {
		ret = RESUME_GUEST;
	} else {
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
	}
	return ret;
}

/**
 * kvm_trap_emul_handle_msa_disabled() - Guest used MSA while disabled in root.
 * @vcpu:	Virtual CPU context.
 *
 * Handle when the guest attempts to use MSA when it is disabled.
 */
static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	struct kvm_run *run = vcpu->run;
	u32 __user *opc = (u32 __user *) vcpu->arch.pc;
	u32 cause = vcpu->arch.host_cp0_cause;
	enum emulation_result er = EMULATE_DONE;
	int ret = RESUME_GUEST;

	if (!kvm_mips_guest_has_msa(&vcpu->arch) ||
	    (kvm_read_c0_guest_status(cop0) & (ST0_CU1 | ST0_FR)) == ST0_CU1) {
		/*
		 * No MSA in guest, or FPU enabled and not in FR=1 mode,
		 * guest reserved instruction exception
		 */
		er = kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
	} else if (!(kvm_read_c0_guest_config5(cop0) & MIPS_CONF5_MSAEN)) {
		/* MSA disabled by guest, guest MSA disabled exception */
		er = kvm_mips_emulate_msadis_exc(cause, opc, run, vcpu);
	} else {
		/* Restore MSA/FPU state */
		kvm_own_msa(vcpu);
		er = EMULATE_DONE;
	}

	switch (er) {
	case EMULATE_DONE:
		ret = RESUME_GUEST;
		break;

	case EMULATE_FAIL:
		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
		ret = RESUME_HOST;
		break;

	default:
		BUG();
	}
	return ret;
}

static int kvm_trap_emul_hardware_enable(void)
{
	return 0;
}

static void kvm_trap_emul_hardware_disable(void)
{
}

static int kvm_trap_emul_check_extension(struct kvm *kvm, long ext)
{
	int r;

	switch (ext) {
	case KVM_CAP_MIPS_TE:
		r = 1;
		break;
	default:
		r = 0;
		break;
	}

	return r;
}

static int kvm_trap_emul_vcpu_init(struct kvm_vcpu *vcpu)
{
	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;

	/*
	 * Allocate GVA -> HPA page tables.
	 * MIPS doesn't use the mm_struct pointer argument.
	 */
	kern_mm->pgd = pgd_alloc(kern_mm);
	if (!kern_mm->pgd)
		return -ENOMEM;

	user_mm->pgd = pgd_alloc(user_mm);
	if (!user_mm->pgd) {
		pgd_free(kern_mm, kern_mm->pgd);
		return -ENOMEM;
	}

	return 0;
}

static void kvm_mips_emul_free_gva_pt(pgd_t *pgd)
{
	/* Don't free host kernel page tables copied from init_mm.pgd */
	const unsigned long end = 0x80000000;
	unsigned long pgd_va, pud_va, pmd_va;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	int i, j, k;

	for (i = 0; i < USER_PTRS_PER_PGD; i++) {
		if (pgd_none(pgd[i]))
			continue;

		pgd_va = (unsigned long)i << PGDIR_SHIFT;
		if (pgd_va >= end)
			break;
		pud = pud_offset(pgd + i, 0);
		for (j = 0; j < PTRS_PER_PUD; j++) {
			if (pud_none(pud[j]))
				continue;

			pud_va = pgd_va | ((unsigned long)j << PUD_SHIFT);
			if (pud_va >= end)
				break;
			pmd = pmd_offset(pud + j, 0);
			for (k = 0; k < PTRS_PER_PMD; k++) {
				if (pmd_none(pmd[k]))
					continue;

				pmd_va = pud_va | (k << PMD_SHIFT);
				if (pmd_va >= end)
					break;
				pte = pte_offset(pmd + k, 0);
				pte_free_kernel(NULL, pte);
			}
			pmd_free(NULL, pmd);
		}
		pud_free(NULL, pud);
	}
	pgd_free(NULL, pgd);
}

static void kvm_trap_emul_vcpu_uninit(struct kvm_vcpu *vcpu)
{
	kvm_mips_emul_free_gva_pt(vcpu->arch.guest_kernel_mm.pgd);
	kvm_mips_emul_free_gva_pt(vcpu->arch.guest_user_mm.pgd);
}

static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	u32 config, config1;
	int vcpu_id = vcpu->vcpu_id;

	/* Start off the timer at 100 MHz */
	kvm_mips_init_count(vcpu, 100*1000*1000);

	/*
	 * Arch specific stuff, set up config registers properly so that the
	 * guest will come up as expected
	 */
#ifndef CONFIG_CPU_MIPSR6
	/* r2-r5, simulate a MIPS 24kc */
	kvm_write_c0_guest_prid(cop0, 0x00019300);
#else
	/* r6+, simulate a generic QEMU machine */
	kvm_write_c0_guest_prid(cop0, 0x00010000);
#endif
	/*
	 * Have config1, Cacheable, noncoherent, write-back, write allocate.
	 * Endianness, arch revision & virtually tagged icache should match
	 * host.
	 */
	config = read_c0_config() & MIPS_CONF_AR;
	config |= MIPS_CONF_M | CONF_CM_CACHABLE_NONCOHERENT | MIPS_CONF_MT_TLB;
#ifdef CONFIG_CPU_BIG_ENDIAN
	config |= CONF_BE;
#endif
	if (cpu_has_vtag_icache)
		config |= MIPS_CONF_VI;
	kvm_write_c0_guest_config(cop0, config);

	/* Read the cache characteristics from the host Config1 Register */
	config1 = (read_c0_config1() & ~0x7f);

	/* DCache line size not correctly reported in Config1 on Octeon CPUs */
	if (cpu_dcache_line_size()) {
		config1 &= ~MIPS_CONF1_DL;
		config1 |= ((ilog2(cpu_dcache_line_size()) - 1) <<
			    MIPS_CONF1_DL_SHF) & MIPS_CONF1_DL;
	}

	/* Set up MMU size */
	config1 &= ~(0x3f << 25);
	config1 |= ((KVM_MIPS_GUEST_TLB_SIZE - 1) << 25);

	/* We unset some bits that we aren't emulating */
	config1 &= ~(MIPS_CONF1_C2 | MIPS_CONF1_MD | MIPS_CONF1_PC |
		     MIPS_CONF1_WR | MIPS_CONF1_CA);
	kvm_write_c0_guest_config1(cop0, config1);

	/* Have config3, no tertiary/secondary caches implemented */
	kvm_write_c0_guest_config2(cop0, MIPS_CONF_M);
	/* MIPS_CONF_M | (read_c0_config2() & 0xfff) */

	/* Have config4, UserLocal */
	kvm_write_c0_guest_config3(cop0, MIPS_CONF_M | MIPS_CONF3_ULRI);

	/* Have config5 */
	kvm_write_c0_guest_config4(cop0, MIPS_CONF_M);

	/* No config6 */
	kvm_write_c0_guest_config5(cop0, 0);

	/* Set Wait IE/IXMT Ignore in Config7, IAR, AR */
	kvm_write_c0_guest_config7(cop0, (MIPS_CONF7_WII) | (1 << 10));

	/* Status */
	kvm_write_c0_guest_status(cop0, ST0_BEV | ST0_ERL);

	/*
	 * Setup IntCtl defaults, compatibility mode for timer interrupts (HW5)
	 */
	kvm_write_c0_guest_intctl(cop0, 0xFC000000);

	/* Put in vcpu id as CPUNum into Ebase Reg to handle SMP Guests */
	kvm_write_c0_guest_ebase(cop0, KVM_GUEST_KSEG0 |
				       (vcpu_id & MIPS_EBASE_CPUNUM));

	/* Put PC at guest reset vector */
	vcpu->arch.pc = KVM_GUEST_CKSEG1ADDR(0x1fc00000);

	return 0;
}

static void kvm_trap_emul_flush_shadow_all(struct kvm *kvm)
{
	/* Flush GVA page tables and invalidate GVA ASIDs on all VCPUs */
	kvm_flush_remote_tlbs(kvm);
}

static void kvm_trap_emul_flush_shadow_memslot(struct kvm *kvm,
					const struct kvm_memory_slot *slot)
{
	kvm_trap_emul_flush_shadow_all(kvm);
}

static u64 kvm_trap_emul_get_one_regs[] = {
	KVM_REG_MIPS_CP0_INDEX,
	KVM_REG_MIPS_CP0_ENTRYLO0,
	KVM_REG_MIPS_CP0_ENTRYLO1,
	KVM_REG_MIPS_CP0_CONTEXT,
	KVM_REG_MIPS_CP0_USERLOCAL,
	KVM_REG_MIPS_CP0_PAGEMASK,
	KVM_REG_MIPS_CP0_WIRED,
	KVM_REG_MIPS_CP0_HWRENA,
	KVM_REG_MIPS_CP0_BADVADDR,
	KVM_REG_MIPS_CP0_COUNT,
	KVM_REG_MIPS_CP0_ENTRYHI,
	KVM_REG_MIPS_CP0_COMPARE,
	KVM_REG_MIPS_CP0_STATUS,
	KVM_REG_MIPS_CP0_INTCTL,
	KVM_REG_MIPS_CP0_CAUSE,
	KVM_REG_MIPS_CP0_EPC,
	KVM_REG_MIPS_CP0_PRID,
	KVM_REG_MIPS_CP0_EBASE,
	KVM_REG_MIPS_CP0_CONFIG,
	KVM_REG_MIPS_CP0_CONFIG1,
	KVM_REG_MIPS_CP0_CONFIG2,
	KVM_REG_MIPS_CP0_CONFIG3,
	KVM_REG_MIPS_CP0_CONFIG4,
	KVM_REG_MIPS_CP0_CONFIG5,
	KVM_REG_MIPS_CP0_CONFIG7,
	KVM_REG_MIPS_CP0_ERROREPC,
	KVM_REG_MIPS_CP0_KSCRATCH1,
	KVM_REG_MIPS_CP0_KSCRATCH2,
	KVM_REG_MIPS_CP0_KSCRATCH3,
	KVM_REG_MIPS_CP0_KSCRATCH4,
	KVM_REG_MIPS_CP0_KSCRATCH5,
	KVM_REG_MIPS_CP0_KSCRATCH6,

	KVM_REG_MIPS_COUNT_CTL,
	KVM_REG_MIPS_COUNT_RESUME,
	KVM_REG_MIPS_COUNT_HZ,
};

static unsigned long kvm_trap_emul_num_regs(struct kvm_vcpu *vcpu)
{
	return ARRAY_SIZE(kvm_trap_emul_get_one_regs);
}

static int kvm_trap_emul_copy_reg_indices(struct kvm_vcpu *vcpu,
					  u64 __user *indices)
{
	if (copy_to_user(indices, kvm_trap_emul_get_one_regs,
			 sizeof(kvm_trap_emul_get_one_regs)))
		return -EFAULT;
	indices += ARRAY_SIZE(kvm_trap_emul_get_one_regs);

	return 0;
}

static int kvm_trap_emul_get_one_reg(struct kvm_vcpu *vcpu,
				     const struct kvm_one_reg *reg,
				     s64 *v)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;

	switch (reg->id) {
	case KVM_REG_MIPS_CP0_INDEX:
		*v = (long)kvm_read_c0_guest_index(cop0);
		break;
	case KVM_REG_MIPS_CP0_ENTRYLO0:
		*v = kvm_read_c0_guest_entrylo0(cop0);
		break;
	case KVM_REG_MIPS_CP0_ENTRYLO1:
		*v = kvm_read_c0_guest_entrylo1(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONTEXT:
		*v = (long)kvm_read_c0_guest_context(cop0);
		break;
	case KVM_REG_MIPS_CP0_USERLOCAL:
		*v = (long)kvm_read_c0_guest_userlocal(cop0);
		break;
	case KVM_REG_MIPS_CP0_PAGEMASK:
		*v = (long)kvm_read_c0_guest_pagemask(cop0);
		break;
	case KVM_REG_MIPS_CP0_WIRED:
		*v = (long)kvm_read_c0_guest_wired(cop0);
		break;
	case KVM_REG_MIPS_CP0_HWRENA:
		*v = (long)kvm_read_c0_guest_hwrena(cop0);
		break;
	case KVM_REG_MIPS_CP0_BADVADDR:
		*v = (long)kvm_read_c0_guest_badvaddr(cop0);
		break;
	case KVM_REG_MIPS_CP0_ENTRYHI:
		*v = (long)kvm_read_c0_guest_entryhi(cop0);
		break;
	case KVM_REG_MIPS_CP0_COMPARE:
		*v = (long)kvm_read_c0_guest_compare(cop0);
		break;
	case KVM_REG_MIPS_CP0_STATUS:
		*v = (long)kvm_read_c0_guest_status(cop0);
		break;
	case KVM_REG_MIPS_CP0_INTCTL:
		*v = (long)kvm_read_c0_guest_intctl(cop0);
		break;
	case KVM_REG_MIPS_CP0_CAUSE:
		*v = (long)kvm_read_c0_guest_cause(cop0);
		break;
	case KVM_REG_MIPS_CP0_EPC:
		*v = (long)kvm_read_c0_guest_epc(cop0);
		break;
	case KVM_REG_MIPS_CP0_PRID:
		*v = (long)kvm_read_c0_guest_prid(cop0);
		break;
	case KVM_REG_MIPS_CP0_EBASE:
		*v = (long)kvm_read_c0_guest_ebase(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG:
		*v = (long)kvm_read_c0_guest_config(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG1:
		*v = (long)kvm_read_c0_guest_config1(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG2:
		*v = (long)kvm_read_c0_guest_config2(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG3:
		*v = (long)kvm_read_c0_guest_config3(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG4:
		*v = (long)kvm_read_c0_guest_config4(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG5:
		*v = (long)kvm_read_c0_guest_config5(cop0);
		break;
	case KVM_REG_MIPS_CP0_CONFIG7:
		*v = (long)kvm_read_c0_guest_config7(cop0);
		break;
	case KVM_REG_MIPS_CP0_COUNT:
		*v = kvm_mips_read_count(vcpu);
		break;
	case KVM_REG_MIPS_COUNT_CTL:
		*v = vcpu->arch.count_ctl;
		break;
	case KVM_REG_MIPS_COUNT_RESUME:
		*v = ktime_to_ns(vcpu->arch.count_resume);
		break;
	case KVM_REG_MIPS_COUNT_HZ:
		*v = vcpu->arch.count_hz;
		break;
	case KVM_REG_MIPS_CP0_ERROREPC:
		*v = (long)kvm_read_c0_guest_errorepc(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH1:
		*v = (long)kvm_read_c0_guest_kscratch1(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH2:
		*v = (long)kvm_read_c0_guest_kscratch2(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH3:
		*v = (long)kvm_read_c0_guest_kscratch3(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH4:
		*v = (long)kvm_read_c0_guest_kscratch4(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH5:
		*v = (long)kvm_read_c0_guest_kscratch5(cop0);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH6:
		*v = (long)kvm_read_c0_guest_kscratch6(cop0);
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
				     const struct kvm_one_reg *reg,
				     s64 v)
{
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	int ret = 0;
	unsigned int cur, change;

	switch (reg->id) {
	case KVM_REG_MIPS_CP0_INDEX:
		kvm_write_c0_guest_index(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_ENTRYLO0:
		kvm_write_c0_guest_entrylo0(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_ENTRYLO1:
		kvm_write_c0_guest_entrylo1(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_CONTEXT:
		kvm_write_c0_guest_context(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_USERLOCAL:
		kvm_write_c0_guest_userlocal(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_PAGEMASK:
		kvm_write_c0_guest_pagemask(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_WIRED:
		kvm_write_c0_guest_wired(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_HWRENA:
		kvm_write_c0_guest_hwrena(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_BADVADDR:
		kvm_write_c0_guest_badvaddr(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_ENTRYHI:
		kvm_write_c0_guest_entryhi(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_STATUS:
		kvm_write_c0_guest_status(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_INTCTL:
		/* No VInt, so no VS, read-only for now */
		break;
	case KVM_REG_MIPS_CP0_EPC:
		kvm_write_c0_guest_epc(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_PRID:
		kvm_write_c0_guest_prid(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_EBASE:
		/*
		 * Allow core number to be written, but the exception base must
		 * remain in guest KSeg0.
		 */
		kvm_change_c0_guest_ebase(cop0, 0x1ffff000 | MIPS_EBASE_CPUNUM,
					  v);
		break;
	case KVM_REG_MIPS_CP0_COUNT:
		kvm_mips_write_count(vcpu, v);
		break;
	case KVM_REG_MIPS_CP0_COMPARE:
		kvm_mips_write_compare(vcpu, v, false);
		break;
	case KVM_REG_MIPS_CP0_CAUSE:
		/*
		 * If the timer is stopped or started (DC bit) it must look
		 * atomic with changes to the interrupt pending bits (TI, IRQ5).
		 * A timer interrupt should not happen in between.
		 */
		if ((kvm_read_c0_guest_cause(cop0) ^ v) & CAUSEF_DC) {
			if (v & CAUSEF_DC) {
				/* disable timer first */
				kvm_mips_count_disable_cause(vcpu);
				kvm_change_c0_guest_cause(cop0, (u32)~CAUSEF_DC,
							  v);
			} else {
				/* enable timer last */
				kvm_change_c0_guest_cause(cop0, (u32)~CAUSEF_DC,
							  v);
				kvm_mips_count_enable_cause(vcpu);
			}
		} else {
			kvm_write_c0_guest_cause(cop0, v);
		}
		break;
	case KVM_REG_MIPS_CP0_CONFIG:
		/* read-only for now */
		break;
	case KVM_REG_MIPS_CP0_CONFIG1:
		cur = kvm_read_c0_guest_config1(cop0);
		change = (cur ^ v) & kvm_mips_config1_wrmask(vcpu);
		if (change) {
			v = cur ^ change;
			kvm_write_c0_guest_config1(cop0, v);
		}
		break;
	case KVM_REG_MIPS_CP0_CONFIG2:
		/* read-only for now */
		break;
	case KVM_REG_MIPS_CP0_CONFIG3:
		cur = kvm_read_c0_guest_config3(cop0);
		change = (cur ^ v) & kvm_mips_config3_wrmask(vcpu);
		if (change) {
			v = cur ^ change;
			kvm_write_c0_guest_config3(cop0, v);
		}
		break;
	case KVM_REG_MIPS_CP0_CONFIG4:
		cur = kvm_read_c0_guest_config4(cop0);
		change = (cur ^ v) & kvm_mips_config4_wrmask(vcpu);
		if (change) {
			v = cur ^ change;
			kvm_write_c0_guest_config4(cop0, v);
		}
		break;
	case KVM_REG_MIPS_CP0_CONFIG5:
		cur = kvm_read_c0_guest_config5(cop0);
		change = (cur ^ v) & kvm_mips_config5_wrmask(vcpu);
		if (change) {
			v = cur ^ change;
			kvm_write_c0_guest_config5(cop0, v);
		}
		break;
	case KVM_REG_MIPS_CP0_CONFIG7:
		/* writes ignored */
		break;
	case KVM_REG_MIPS_COUNT_CTL:
		ret = kvm_mips_set_count_ctl(vcpu, v);
		break;
	case KVM_REG_MIPS_COUNT_RESUME:
		ret = kvm_mips_set_count_resume(vcpu, v);
		break;
	case KVM_REG_MIPS_COUNT_HZ:
		ret = kvm_mips_set_count_hz(vcpu, v);
		break;
	case KVM_REG_MIPS_CP0_ERROREPC:
		kvm_write_c0_guest_errorepc(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH1:
		kvm_write_c0_guest_kscratch1(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH2:
		kvm_write_c0_guest_kscratch2(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH3:
		kvm_write_c0_guest_kscratch3(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH4:
		kvm_write_c0_guest_kscratch4(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH5:
		kvm_write_c0_guest_kscratch5(cop0, v);
		break;
	case KVM_REG_MIPS_CP0_KSCRATCH6:
		kvm_write_c0_guest_kscratch6(cop0, v);
		break;
	default:
		return -EINVAL;
	}
	return ret;
}

static int kvm_trap_emul_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
	struct mm_struct *mm;

	/*
	 * Were we in guest context? If so, restore the appropriate ASID based
	 * on the mode of the Guest (Kernel/User).
	 */
	if (current->flags & PF_VCPU) {
		mm = KVM_GUEST_KERNEL_MODE(vcpu) ? kern_mm : user_mm;
		check_switch_mmu_context(mm);
		kvm_mips_suspend_mm(cpu);
		ehb();
	}

	return 0;
}

static int kvm_trap_emul_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
{
	kvm_lose_fpu(vcpu);

	if (current->flags & PF_VCPU) {
		/* Restore normal Linux process memory map */
		check_switch_mmu_context(current->mm);
		kvm_mips_resume_mm(cpu);
		ehb();
	}

	return 0;
}

static void kvm_trap_emul_check_requests(struct kvm_vcpu *vcpu, int cpu,
					 bool reload_asid)
{
	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
	struct mm_struct *mm;
	int i;

	if (likely(!kvm_request_pending(vcpu)))
		return;

	if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
		/*
		 * Both kernel & user GVA mappings must be invalidated. The
		 * caller is just about to check whether the ASID is stale
		 * anyway so no need to reload it here.
		 */
		kvm_mips_flush_gva_pt(kern_mm->pgd, KMF_GPA | KMF_KERN);
		kvm_mips_flush_gva_pt(user_mm->pgd, KMF_GPA | KMF_USER);
		for_each_possible_cpu(i) {
			set_cpu_context(i, kern_mm, 0);
			set_cpu_context(i, user_mm, 0);
		}

		/* Generate new ASID for current mode */
		if (reload_asid) {
			mm = KVM_GUEST_KERNEL_MODE(vcpu) ? kern_mm : user_mm;
			get_new_mmu_context(mm);
			htw_stop();
			write_c0_entryhi(cpu_asid(cpu, mm));
			TLBMISS_HANDLER_SETUP_PGD(mm->pgd);
			htw_start();
		}
	}
}

/**
 * kvm_trap_emul_gva_lockless_begin() - Begin lockless access to GVA space.
 * @vcpu:	VCPU pointer.
 *
 * Call before a GVA space access outside of guest mode, to ensure that
 * asynchronous TLB flush requests are handled or delayed until completion of
 * the GVA access (as indicated by a matching kvm_trap_emul_gva_lockless_end()).
 *
 * Should be called with IRQs already enabled.
 */
void kvm_trap_emul_gva_lockless_begin(struct kvm_vcpu *vcpu)
{
	/* We re-enable IRQs in kvm_trap_emul_gva_lockless_end() */
	WARN_ON_ONCE(irqs_disabled());

	/*
	 * The caller is about to access the GVA space, so we set the mode to
	 * force TLB flush requests to send an IPI, and also disable IRQs to
	 * delay IPI handling until kvm_trap_emul_gva_lockless_end().
	 */
	local_irq_disable();

	/*
	 * Make sure the read of VCPU requests is not reordered ahead of the
	 * write to vcpu->mode, or we could miss a TLB flush request while
	 * the requester sees the VCPU as outside of guest mode and not needing
	 * an IPI.
	 */
	smp_store_mb(vcpu->mode, READING_SHADOW_PAGE_TABLES);

	/*
	 * If a TLB flush has been requested (potentially while
	 * OUTSIDE_GUEST_MODE and assumed immediately effective), perform it
	 * before accessing the GVA space, and be sure to reload the ASID if
	 * necessary as it'll be immediately used.
	 *
	 * TLB flush requests after this check will trigger an IPI due to the
	 * mode change above, which will be delayed due to IRQs disabled.
	 */
	kvm_trap_emul_check_requests(vcpu, smp_processor_id(), true);
}

/**
 * kvm_trap_emul_gva_lockless_end() - End lockless access to GVA space.
 * @vcpu:	VCPU pointer.
 *
 * Called after a GVA space access outside of guest mode. Should have a matching
 * call to kvm_trap_emul_gva_lockless_begin().
 */
void kvm_trap_emul_gva_lockless_end(struct kvm_vcpu *vcpu)
{
	/*
	 * Make sure the write to vcpu->mode is not reordered in front of GVA
	 * accesses, or a TLB flush requester may not think it necessary to send
	 * an IPI.
	 */
	smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE);

	/*
	 * Now that the access to GVA space is complete, its safe for pending
	 * TLB flush request IPIs to be handled (which indicates completion).
	 */
	local_irq_enable();
}

static void kvm_trap_emul_vcpu_reenter(struct kvm_run *run,
				       struct kvm_vcpu *vcpu)
{
	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
	struct mm_struct *mm;
	struct mips_coproc *cop0 = vcpu->arch.cop0;
	int i, cpu = smp_processor_id();
	unsigned int gasid;

	/*
	 * No need to reload ASID, IRQs are disabled already so there's no rush,
	 * and we'll check if we need to regenerate below anyway before
	 * re-entering the guest.
	 */
	kvm_trap_emul_check_requests(vcpu, cpu, false);

	if (KVM_GUEST_KERNEL_MODE(vcpu)) {
		mm = kern_mm;
	} else {
		mm = user_mm;

		/*
		 * Lazy host ASID regeneration / PT flush for guest user mode.
		 * If the guest ASID has changed since the last guest usermode
		 * execution, invalidate the stale TLB entries and flush GVA PT
		 * entries too.
		 */
		gasid = kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID;
		if (gasid != vcpu->arch.last_user_gasid) {
			kvm_mips_flush_gva_pt(user_mm->pgd, KMF_USER);
			for_each_possible_cpu(i)
				set_cpu_context(i, user_mm, 0);
			vcpu->arch.last_user_gasid = gasid;
		}
	}

	/*
	 * Check if ASID is stale. This may happen due to a TLB flush request or
	 * a lazy user MM invalidation.
	 */
	check_mmu_context(mm);
}

static int kvm_trap_emul_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
	int cpu = smp_processor_id();
	int r;

	/* Check if we have any exceptions/interrupts pending */
	kvm_mips_deliver_interrupts(vcpu,
				    kvm_read_c0_guest_cause(vcpu->arch.cop0));

	kvm_trap_emul_vcpu_reenter(run, vcpu);

	/*
	 * We use user accessors to access guest memory, but we don't want to
	 * invoke Linux page faulting.
	 */
	pagefault_disable();

	/* Disable hardware page table walking while in guest */
	htw_stop();

	/*
	 * While in guest context we're in the guest's address space, not the
	 * host process address space, so we need to be careful not to confuse
	 * e.g. cache management IPIs.
	 */
	kvm_mips_suspend_mm(cpu);

	r = vcpu->arch.vcpu_run(run, vcpu);

	/* We may have migrated while handling guest exits */
	cpu = smp_processor_id();

	/* Restore normal Linux process memory map */
	check_switch_mmu_context(current->mm);
	kvm_mips_resume_mm(cpu);

	htw_start();

	pagefault_enable();

	return r;
}

static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
	/* exit handlers */
	.handle_cop_unusable = kvm_trap_emul_handle_cop_unusable,
	.handle_tlb_mod = kvm_trap_emul_handle_tlb_mod,
	.handle_tlb_st_miss = kvm_trap_emul_handle_tlb_st_miss,
	.handle_tlb_ld_miss = kvm_trap_emul_handle_tlb_ld_miss,
	.handle_addr_err_st = kvm_trap_emul_handle_addr_err_st,
	.handle_addr_err_ld = kvm_trap_emul_handle_addr_err_ld,
	.handle_syscall = kvm_trap_emul_handle_syscall,
	.handle_res_inst = kvm_trap_emul_handle_res_inst,
	.handle_break = kvm_trap_emul_handle_break,
	.handle_trap = kvm_trap_emul_handle_trap,
	.handle_msa_fpe = kvm_trap_emul_handle_msa_fpe,
	.handle_fpe = kvm_trap_emul_handle_fpe,
	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
	.handle_guest_exit = kvm_trap_emul_no_handler,

	.hardware_enable = kvm_trap_emul_hardware_enable,
	.hardware_disable = kvm_trap_emul_hardware_disable,
	.check_extension = kvm_trap_emul_check_extension,
	.vcpu_init = kvm_trap_emul_vcpu_init,
	.vcpu_uninit = kvm_trap_emul_vcpu_uninit,
	.vcpu_setup = kvm_trap_emul_vcpu_setup,
	.flush_shadow_all = kvm_trap_emul_flush_shadow_all,
	.flush_shadow_memslot = kvm_trap_emul_flush_shadow_memslot,
	.gva_to_gpa = kvm_trap_emul_gva_to_gpa_cb,
	.queue_timer_int = kvm_mips_queue_timer_int_cb,
	.dequeue_timer_int = kvm_mips_dequeue_timer_int_cb,
	.queue_io_int = kvm_mips_queue_io_int_cb,
	.dequeue_io_int = kvm_mips_dequeue_io_int_cb,
	.irq_deliver = kvm_mips_irq_deliver_cb,
	.irq_clear = kvm_mips_irq_clear_cb,
	.num_regs = kvm_trap_emul_num_regs,
	.copy_reg_indices = kvm_trap_emul_copy_reg_indices,
	.get_one_reg = kvm_trap_emul_get_one_reg,
	.set_one_reg = kvm_trap_emul_set_one_reg,
	.vcpu_load = kvm_trap_emul_vcpu_load,
	.vcpu_put = kvm_trap_emul_vcpu_put,
	.vcpu_run = kvm_trap_emul_vcpu_run,
	.vcpu_reenter = kvm_trap_emul_vcpu_reenter,
};

int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks)
{
	*install_callbacks = &kvm_trap_emul_callbacks;
	return 0;
}