1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * guest access functions 4 * 5 * Copyright IBM Corp. 2014 6 * 7 */ 8 9 #include <linux/vmalloc.h> 10 #include <linux/mm_types.h> 11 #include <linux/err.h> 12 #include <linux/pgtable.h> 13 #include <linux/bitfield.h> 14 #include <asm/access-regs.h> 15 #include <asm/fault.h> 16 #include <asm/gmap.h> 17 #include <asm/dat-bits.h> 18 #include "kvm-s390.h" 19 #include "gaccess.h" 20 21 /* 22 * vaddress union in order to easily decode a virtual address into its 23 * region first index, region second index etc. parts. 24 */ 25 union vaddress { 26 unsigned long addr; 27 struct { 28 unsigned long rfx : 11; 29 unsigned long rsx : 11; 30 unsigned long rtx : 11; 31 unsigned long sx : 11; 32 unsigned long px : 8; 33 unsigned long bx : 12; 34 }; 35 struct { 36 unsigned long rfx01 : 2; 37 unsigned long : 9; 38 unsigned long rsx01 : 2; 39 unsigned long : 9; 40 unsigned long rtx01 : 2; 41 unsigned long : 9; 42 unsigned long sx01 : 2; 43 unsigned long : 29; 44 }; 45 }; 46 47 /* 48 * raddress union which will contain the result (real or absolute address) 49 * after a page table walk. The rfaa, sfaa and pfra members are used to 50 * simply assign them the value of a region, segment or page table entry. 51 */ 52 union raddress { 53 unsigned long addr; 54 unsigned long rfaa : 33; /* Region-Frame Absolute Address */ 55 unsigned long sfaa : 44; /* Segment-Frame Absolute Address */ 56 unsigned long pfra : 52; /* Page-Frame Real Address */ 57 }; 58 59 union alet { 60 u32 val; 61 struct { 62 u32 reserved : 7; 63 u32 p : 1; 64 u32 alesn : 8; 65 u32 alen : 16; 66 }; 67 }; 68 69 union ald { 70 u32 val; 71 struct { 72 u32 : 1; 73 u32 alo : 24; 74 u32 all : 7; 75 }; 76 }; 77 78 struct ale { 79 unsigned long i : 1; /* ALEN-Invalid Bit */ 80 unsigned long : 5; 81 unsigned long fo : 1; /* Fetch-Only Bit */ 82 unsigned long p : 1; /* Private Bit */ 83 unsigned long alesn : 8; /* Access-List-Entry Sequence Number */ 84 unsigned long aleax : 16; /* Access-List-Entry Authorization Index */ 85 unsigned long : 32; 86 unsigned long : 1; 87 unsigned long asteo : 25; /* ASN-Second-Table-Entry Origin */ 88 unsigned long : 6; 89 unsigned long astesn : 32; /* ASTE Sequence Number */ 90 }; 91 92 struct aste { 93 unsigned long i : 1; /* ASX-Invalid Bit */ 94 unsigned long ato : 29; /* Authority-Table Origin */ 95 unsigned long : 1; 96 unsigned long b : 1; /* Base-Space Bit */ 97 unsigned long ax : 16; /* Authorization Index */ 98 unsigned long atl : 12; /* Authority-Table Length */ 99 unsigned long : 2; 100 unsigned long ca : 1; /* Controlled-ASN Bit */ 101 unsigned long ra : 1; /* Reusable-ASN Bit */ 102 unsigned long asce : 64; /* Address-Space-Control Element */ 103 unsigned long ald : 32; 104 unsigned long astesn : 32; 105 /* .. more fields there */ 106 }; 107 108 int ipte_lock_held(struct kvm *kvm) 109 { 110 if (sclp.has_siif) { 111 int rc; 112 113 read_lock(&kvm->arch.sca_lock); 114 rc = kvm_s390_get_ipte_control(kvm)->kh != 0; 115 read_unlock(&kvm->arch.sca_lock); 116 return rc; 117 } 118 return kvm->arch.ipte_lock_count != 0; 119 } 120 121 static void ipte_lock_simple(struct kvm *kvm) 122 { 123 union ipte_control old, new, *ic; 124 125 mutex_lock(&kvm->arch.ipte_mutex); 126 kvm->arch.ipte_lock_count++; 127 if (kvm->arch.ipte_lock_count > 1) 128 goto out; 129 retry: 130 read_lock(&kvm->arch.sca_lock); 131 ic = kvm_s390_get_ipte_control(kvm); 132 do { 133 old = READ_ONCE(*ic); 134 if (old.k) { 135 read_unlock(&kvm->arch.sca_lock); 136 cond_resched(); 137 goto retry; 138 } 139 new = old; 140 new.k = 1; 141 } while (cmpxchg(&ic->val, old.val, new.val) != old.val); 142 read_unlock(&kvm->arch.sca_lock); 143 out: 144 mutex_unlock(&kvm->arch.ipte_mutex); 145 } 146 147 static void ipte_unlock_simple(struct kvm *kvm) 148 { 149 union ipte_control old, new, *ic; 150 151 mutex_lock(&kvm->arch.ipte_mutex); 152 kvm->arch.ipte_lock_count--; 153 if (kvm->arch.ipte_lock_count) 154 goto out; 155 read_lock(&kvm->arch.sca_lock); 156 ic = kvm_s390_get_ipte_control(kvm); 157 do { 158 old = READ_ONCE(*ic); 159 new = old; 160 new.k = 0; 161 } while (cmpxchg(&ic->val, old.val, new.val) != old.val); 162 read_unlock(&kvm->arch.sca_lock); 163 wake_up(&kvm->arch.ipte_wq); 164 out: 165 mutex_unlock(&kvm->arch.ipte_mutex); 166 } 167 168 static void ipte_lock_siif(struct kvm *kvm) 169 { 170 union ipte_control old, new, *ic; 171 172 retry: 173 read_lock(&kvm->arch.sca_lock); 174 ic = kvm_s390_get_ipte_control(kvm); 175 do { 176 old = READ_ONCE(*ic); 177 if (old.kg) { 178 read_unlock(&kvm->arch.sca_lock); 179 cond_resched(); 180 goto retry; 181 } 182 new = old; 183 new.k = 1; 184 new.kh++; 185 } while (cmpxchg(&ic->val, old.val, new.val) != old.val); 186 read_unlock(&kvm->arch.sca_lock); 187 } 188 189 static void ipte_unlock_siif(struct kvm *kvm) 190 { 191 union ipte_control old, new, *ic; 192 193 read_lock(&kvm->arch.sca_lock); 194 ic = kvm_s390_get_ipte_control(kvm); 195 do { 196 old = READ_ONCE(*ic); 197 new = old; 198 new.kh--; 199 if (!new.kh) 200 new.k = 0; 201 } while (cmpxchg(&ic->val, old.val, new.val) != old.val); 202 read_unlock(&kvm->arch.sca_lock); 203 if (!new.kh) 204 wake_up(&kvm->arch.ipte_wq); 205 } 206 207 void ipte_lock(struct kvm *kvm) 208 { 209 if (sclp.has_siif) 210 ipte_lock_siif(kvm); 211 else 212 ipte_lock_simple(kvm); 213 } 214 215 void ipte_unlock(struct kvm *kvm) 216 { 217 if (sclp.has_siif) 218 ipte_unlock_siif(kvm); 219 else 220 ipte_unlock_simple(kvm); 221 } 222 223 static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar, 224 enum gacc_mode mode) 225 { 226 union alet alet; 227 struct ale ale; 228 struct aste aste; 229 unsigned long ald_addr, authority_table_addr; 230 union ald ald; 231 int eax, rc; 232 u8 authority_table; 233 234 if (ar >= NUM_ACRS) 235 return -EINVAL; 236 237 if (vcpu->arch.acrs_loaded) 238 save_access_regs(vcpu->run->s.regs.acrs); 239 alet.val = vcpu->run->s.regs.acrs[ar]; 240 241 if (ar == 0 || alet.val == 0) { 242 asce->val = vcpu->arch.sie_block->gcr[1]; 243 return 0; 244 } else if (alet.val == 1) { 245 asce->val = vcpu->arch.sie_block->gcr[7]; 246 return 0; 247 } 248 249 if (alet.reserved) 250 return PGM_ALET_SPECIFICATION; 251 252 if (alet.p) 253 ald_addr = vcpu->arch.sie_block->gcr[5]; 254 else 255 ald_addr = vcpu->arch.sie_block->gcr[2]; 256 ald_addr &= 0x7fffffc0; 257 258 rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald)); 259 if (rc) 260 return rc; 261 262 if (alet.alen / 8 > ald.all) 263 return PGM_ALEN_TRANSLATION; 264 265 if (0x7fffffff - ald.alo * 128 < alet.alen * 16) 266 return PGM_ADDRESSING; 267 268 rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale, 269 sizeof(struct ale)); 270 if (rc) 271 return rc; 272 273 if (ale.i == 1) 274 return PGM_ALEN_TRANSLATION; 275 if (ale.alesn != alet.alesn) 276 return PGM_ALE_SEQUENCE; 277 278 rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste)); 279 if (rc) 280 return rc; 281 282 if (aste.i) 283 return PGM_ASTE_VALIDITY; 284 if (aste.astesn != ale.astesn) 285 return PGM_ASTE_SEQUENCE; 286 287 if (ale.p == 1) { 288 eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff; 289 if (ale.aleax != eax) { 290 if (eax / 16 > aste.atl) 291 return PGM_EXTENDED_AUTHORITY; 292 293 authority_table_addr = aste.ato * 4 + eax / 4; 294 295 rc = read_guest_real(vcpu, authority_table_addr, 296 &authority_table, 297 sizeof(u8)); 298 if (rc) 299 return rc; 300 301 if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0) 302 return PGM_EXTENDED_AUTHORITY; 303 } 304 } 305 306 if (ale.fo == 1 && mode == GACC_STORE) 307 return PGM_PROTECTION; 308 309 asce->val = aste.asce; 310 return 0; 311 } 312 313 enum prot_type { 314 PROT_TYPE_LA = 0, 315 PROT_TYPE_KEYC = 1, 316 PROT_TYPE_ALC = 2, 317 PROT_TYPE_DAT = 3, 318 PROT_TYPE_IEP = 4, 319 /* Dummy value for passing an initialized value when code != PGM_PROTECTION */ 320 PROT_NONE, 321 }; 322 323 static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, 324 enum gacc_mode mode, enum prot_type prot, bool terminate) 325 { 326 struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm; 327 union teid *teid; 328 329 memset(pgm, 0, sizeof(*pgm)); 330 pgm->code = code; 331 teid = (union teid *)&pgm->trans_exc_code; 332 333 switch (code) { 334 case PGM_PROTECTION: 335 switch (prot) { 336 case PROT_NONE: 337 /* We should never get here, acts like termination */ 338 WARN_ON_ONCE(1); 339 break; 340 case PROT_TYPE_IEP: 341 teid->b61 = 1; 342 fallthrough; 343 case PROT_TYPE_LA: 344 teid->b56 = 1; 345 break; 346 case PROT_TYPE_KEYC: 347 teid->b60 = 1; 348 break; 349 case PROT_TYPE_ALC: 350 teid->b60 = 1; 351 fallthrough; 352 case PROT_TYPE_DAT: 353 teid->b61 = 1; 354 break; 355 } 356 if (terminate) { 357 teid->b56 = 0; 358 teid->b60 = 0; 359 teid->b61 = 0; 360 } 361 fallthrough; 362 case PGM_ASCE_TYPE: 363 case PGM_PAGE_TRANSLATION: 364 case PGM_REGION_FIRST_TRANS: 365 case PGM_REGION_SECOND_TRANS: 366 case PGM_REGION_THIRD_TRANS: 367 case PGM_SEGMENT_TRANSLATION: 368 /* 369 * op_access_id only applies to MOVE_PAGE -> set bit 61 370 * exc_access_id has to be set to 0 for some instructions. Both 371 * cases have to be handled by the caller. 372 */ 373 teid->addr = gva >> PAGE_SHIFT; 374 teid->fsi = mode == GACC_STORE ? TEID_FSI_STORE : TEID_FSI_FETCH; 375 teid->as = psw_bits(vcpu->arch.sie_block->gpsw).as; 376 fallthrough; 377 case PGM_ALEN_TRANSLATION: 378 case PGM_ALE_SEQUENCE: 379 case PGM_ASTE_VALIDITY: 380 case PGM_ASTE_SEQUENCE: 381 case PGM_EXTENDED_AUTHORITY: 382 /* 383 * We can always store exc_access_id, as it is 384 * undefined for non-ar cases. It is undefined for 385 * most DAT protection exceptions. 386 */ 387 pgm->exc_access_id = ar; 388 break; 389 } 390 return code; 391 } 392 393 static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, 394 enum gacc_mode mode, enum prot_type prot) 395 { 396 return trans_exc_ending(vcpu, code, gva, ar, mode, prot, false); 397 } 398 399 static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce, 400 unsigned long ga, u8 ar, enum gacc_mode mode) 401 { 402 int rc; 403 struct psw_bits psw = psw_bits(vcpu->arch.sie_block->gpsw); 404 405 if (!psw.dat) { 406 asce->val = 0; 407 asce->r = 1; 408 return 0; 409 } 410 411 if ((mode == GACC_IFETCH) && (psw.as != PSW_BITS_AS_HOME)) 412 psw.as = PSW_BITS_AS_PRIMARY; 413 414 switch (psw.as) { 415 case PSW_BITS_AS_PRIMARY: 416 asce->val = vcpu->arch.sie_block->gcr[1]; 417 return 0; 418 case PSW_BITS_AS_SECONDARY: 419 asce->val = vcpu->arch.sie_block->gcr[7]; 420 return 0; 421 case PSW_BITS_AS_HOME: 422 asce->val = vcpu->arch.sie_block->gcr[13]; 423 return 0; 424 case PSW_BITS_AS_ACCREG: 425 rc = ar_translation(vcpu, asce, ar, mode); 426 if (rc > 0) 427 return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_ALC); 428 return rc; 429 } 430 return 0; 431 } 432 433 static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val) 434 { 435 return kvm_read_guest(kvm, gpa, val, sizeof(*val)); 436 } 437 438 /** 439 * guest_translate - translate a guest virtual into a guest absolute address 440 * @vcpu: virtual cpu 441 * @gva: guest virtual address 442 * @gpa: points to where guest physical (absolute) address should be stored 443 * @asce: effective asce 444 * @mode: indicates the access mode to be used 445 * @prot: returns the type for protection exceptions 446 * 447 * Translate a guest virtual address into a guest absolute address by means 448 * of dynamic address translation as specified by the architecture. 449 * If the resulting absolute address is not available in the configuration 450 * an addressing exception is indicated and @gpa will not be changed. 451 * 452 * Returns: - zero on success; @gpa contains the resulting absolute address 453 * - a negative value if guest access failed due to e.g. broken 454 * guest mapping 455 * - a positive value if an access exception happened. In this case 456 * the returned value is the program interruption code as defined 457 * by the architecture 458 */ 459 static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva, 460 unsigned long *gpa, const union asce asce, 461 enum gacc_mode mode, enum prot_type *prot) 462 { 463 union vaddress vaddr = {.addr = gva}; 464 union raddress raddr = {.addr = gva}; 465 union page_table_entry pte; 466 int dat_protection = 0; 467 int iep_protection = 0; 468 union ctlreg0 ctlreg0; 469 unsigned long ptr; 470 int edat1, edat2, iep; 471 472 ctlreg0.val = vcpu->arch.sie_block->gcr[0]; 473 edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8); 474 edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78); 475 iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130); 476 if (asce.r) 477 goto real_address; 478 ptr = asce.rsto * PAGE_SIZE; 479 switch (asce.dt) { 480 case ASCE_TYPE_REGION1: 481 if (vaddr.rfx01 > asce.tl) 482 return PGM_REGION_FIRST_TRANS; 483 ptr += vaddr.rfx * 8; 484 break; 485 case ASCE_TYPE_REGION2: 486 if (vaddr.rfx) 487 return PGM_ASCE_TYPE; 488 if (vaddr.rsx01 > asce.tl) 489 return PGM_REGION_SECOND_TRANS; 490 ptr += vaddr.rsx * 8; 491 break; 492 case ASCE_TYPE_REGION3: 493 if (vaddr.rfx || vaddr.rsx) 494 return PGM_ASCE_TYPE; 495 if (vaddr.rtx01 > asce.tl) 496 return PGM_REGION_THIRD_TRANS; 497 ptr += vaddr.rtx * 8; 498 break; 499 case ASCE_TYPE_SEGMENT: 500 if (vaddr.rfx || vaddr.rsx || vaddr.rtx) 501 return PGM_ASCE_TYPE; 502 if (vaddr.sx01 > asce.tl) 503 return PGM_SEGMENT_TRANSLATION; 504 ptr += vaddr.sx * 8; 505 break; 506 } 507 switch (asce.dt) { 508 case ASCE_TYPE_REGION1: { 509 union region1_table_entry rfte; 510 511 if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) 512 return PGM_ADDRESSING; 513 if (deref_table(vcpu->kvm, ptr, &rfte.val)) 514 return -EFAULT; 515 if (rfte.i) 516 return PGM_REGION_FIRST_TRANS; 517 if (rfte.tt != TABLE_TYPE_REGION1) 518 return PGM_TRANSLATION_SPEC; 519 if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl) 520 return PGM_REGION_SECOND_TRANS; 521 if (edat1) 522 dat_protection |= rfte.p; 523 ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8; 524 } 525 fallthrough; 526 case ASCE_TYPE_REGION2: { 527 union region2_table_entry rste; 528 529 if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) 530 return PGM_ADDRESSING; 531 if (deref_table(vcpu->kvm, ptr, &rste.val)) 532 return -EFAULT; 533 if (rste.i) 534 return PGM_REGION_SECOND_TRANS; 535 if (rste.tt != TABLE_TYPE_REGION2) 536 return PGM_TRANSLATION_SPEC; 537 if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl) 538 return PGM_REGION_THIRD_TRANS; 539 if (edat1) 540 dat_protection |= rste.p; 541 ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8; 542 } 543 fallthrough; 544 case ASCE_TYPE_REGION3: { 545 union region3_table_entry rtte; 546 547 if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) 548 return PGM_ADDRESSING; 549 if (deref_table(vcpu->kvm, ptr, &rtte.val)) 550 return -EFAULT; 551 if (rtte.i) 552 return PGM_REGION_THIRD_TRANS; 553 if (rtte.tt != TABLE_TYPE_REGION3) 554 return PGM_TRANSLATION_SPEC; 555 if (rtte.cr && asce.p && edat2) 556 return PGM_TRANSLATION_SPEC; 557 if (rtte.fc && edat2) { 558 dat_protection |= rtte.fc1.p; 559 iep_protection = rtte.fc1.iep; 560 raddr.rfaa = rtte.fc1.rfaa; 561 goto absolute_address; 562 } 563 if (vaddr.sx01 < rtte.fc0.tf) 564 return PGM_SEGMENT_TRANSLATION; 565 if (vaddr.sx01 > rtte.fc0.tl) 566 return PGM_SEGMENT_TRANSLATION; 567 if (edat1) 568 dat_protection |= rtte.fc0.p; 569 ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8; 570 } 571 fallthrough; 572 case ASCE_TYPE_SEGMENT: { 573 union segment_table_entry ste; 574 575 if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) 576 return PGM_ADDRESSING; 577 if (deref_table(vcpu->kvm, ptr, &ste.val)) 578 return -EFAULT; 579 if (ste.i) 580 return PGM_SEGMENT_TRANSLATION; 581 if (ste.tt != TABLE_TYPE_SEGMENT) 582 return PGM_TRANSLATION_SPEC; 583 if (ste.cs && asce.p) 584 return PGM_TRANSLATION_SPEC; 585 if (ste.fc && edat1) { 586 dat_protection |= ste.fc1.p; 587 iep_protection = ste.fc1.iep; 588 raddr.sfaa = ste.fc1.sfaa; 589 goto absolute_address; 590 } 591 dat_protection |= ste.fc0.p; 592 ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8; 593 } 594 } 595 if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) 596 return PGM_ADDRESSING; 597 if (deref_table(vcpu->kvm, ptr, &pte.val)) 598 return -EFAULT; 599 if (pte.i) 600 return PGM_PAGE_TRANSLATION; 601 if (pte.z) 602 return PGM_TRANSLATION_SPEC; 603 dat_protection |= pte.p; 604 iep_protection = pte.iep; 605 raddr.pfra = pte.pfra; 606 real_address: 607 raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr); 608 absolute_address: 609 if (mode == GACC_STORE && dat_protection) { 610 *prot = PROT_TYPE_DAT; 611 return PGM_PROTECTION; 612 } 613 if (mode == GACC_IFETCH && iep_protection && iep) { 614 *prot = PROT_TYPE_IEP; 615 return PGM_PROTECTION; 616 } 617 if (!kvm_is_gpa_in_memslot(vcpu->kvm, raddr.addr)) 618 return PGM_ADDRESSING; 619 *gpa = raddr.addr; 620 return 0; 621 } 622 623 static inline int is_low_address(unsigned long ga) 624 { 625 /* Check for address ranges 0..511 and 4096..4607 */ 626 return (ga & ~0x11fful) == 0; 627 } 628 629 static int low_address_protection_enabled(struct kvm_vcpu *vcpu, 630 const union asce asce) 631 { 632 union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]}; 633 psw_t *psw = &vcpu->arch.sie_block->gpsw; 634 635 if (!ctlreg0.lap) 636 return 0; 637 if (psw_bits(*psw).dat && asce.p) 638 return 0; 639 return 1; 640 } 641 642 static int vm_check_access_key(struct kvm *kvm, u8 access_key, 643 enum gacc_mode mode, gpa_t gpa) 644 { 645 u8 storage_key, access_control; 646 bool fetch_protected; 647 unsigned long hva; 648 int r; 649 650 if (access_key == 0) 651 return 0; 652 653 hva = gfn_to_hva(kvm, gpa_to_gfn(gpa)); 654 if (kvm_is_error_hva(hva)) 655 return PGM_ADDRESSING; 656 657 mmap_read_lock(current->mm); 658 r = get_guest_storage_key(current->mm, hva, &storage_key); 659 mmap_read_unlock(current->mm); 660 if (r) 661 return r; 662 access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key); 663 if (access_control == access_key) 664 return 0; 665 fetch_protected = storage_key & _PAGE_FP_BIT; 666 if ((mode == GACC_FETCH || mode == GACC_IFETCH) && !fetch_protected) 667 return 0; 668 return PGM_PROTECTION; 669 } 670 671 static bool fetch_prot_override_applicable(struct kvm_vcpu *vcpu, enum gacc_mode mode, 672 union asce asce) 673 { 674 psw_t *psw = &vcpu->arch.sie_block->gpsw; 675 unsigned long override; 676 677 if (mode == GACC_FETCH || mode == GACC_IFETCH) { 678 /* check if fetch protection override enabled */ 679 override = vcpu->arch.sie_block->gcr[0]; 680 override &= CR0_FETCH_PROTECTION_OVERRIDE; 681 /* not applicable if subject to DAT && private space */ 682 override = override && !(psw_bits(*psw).dat && asce.p); 683 return override; 684 } 685 return false; 686 } 687 688 static bool fetch_prot_override_applies(unsigned long ga, unsigned int len) 689 { 690 return ga < 2048 && ga + len <= 2048; 691 } 692 693 static bool storage_prot_override_applicable(struct kvm_vcpu *vcpu) 694 { 695 /* check if storage protection override enabled */ 696 return vcpu->arch.sie_block->gcr[0] & CR0_STORAGE_PROTECTION_OVERRIDE; 697 } 698 699 static bool storage_prot_override_applies(u8 access_control) 700 { 701 /* matches special storage protection override key (9) -> allow */ 702 return access_control == PAGE_SPO_ACC; 703 } 704 705 static int vcpu_check_access_key(struct kvm_vcpu *vcpu, u8 access_key, 706 enum gacc_mode mode, union asce asce, gpa_t gpa, 707 unsigned long ga, unsigned int len) 708 { 709 u8 storage_key, access_control; 710 unsigned long hva; 711 int r; 712 713 /* access key 0 matches any storage key -> allow */ 714 if (access_key == 0) 715 return 0; 716 /* 717 * caller needs to ensure that gfn is accessible, so we can 718 * assume that this cannot fail 719 */ 720 hva = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gpa)); 721 mmap_read_lock(current->mm); 722 r = get_guest_storage_key(current->mm, hva, &storage_key); 723 mmap_read_unlock(current->mm); 724 if (r) 725 return r; 726 access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key); 727 /* access key matches storage key -> allow */ 728 if (access_control == access_key) 729 return 0; 730 if (mode == GACC_FETCH || mode == GACC_IFETCH) { 731 /* it is a fetch and fetch protection is off -> allow */ 732 if (!(storage_key & _PAGE_FP_BIT)) 733 return 0; 734 if (fetch_prot_override_applicable(vcpu, mode, asce) && 735 fetch_prot_override_applies(ga, len)) 736 return 0; 737 } 738 if (storage_prot_override_applicable(vcpu) && 739 storage_prot_override_applies(access_control)) 740 return 0; 741 return PGM_PROTECTION; 742 } 743 744 /** 745 * guest_range_to_gpas() - Calculate guest physical addresses of page fragments 746 * covering a logical range 747 * @vcpu: virtual cpu 748 * @ga: guest address, start of range 749 * @ar: access register 750 * @gpas: output argument, may be NULL 751 * @len: length of range in bytes 752 * @asce: address-space-control element to use for translation 753 * @mode: access mode 754 * @access_key: access key to mach the range's storage keys against 755 * 756 * Translate a logical range to a series of guest absolute addresses, 757 * such that the concatenation of page fragments starting at each gpa make up 758 * the whole range. 759 * The translation is performed as if done by the cpu for the given @asce, @ar, 760 * @mode and state of the @vcpu. 761 * If the translation causes an exception, its program interruption code is 762 * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified 763 * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject 764 * a correct exception into the guest. 765 * The resulting gpas are stored into @gpas, unless it is NULL. 766 * 767 * Note: All fragments except the first one start at the beginning of a page. 768 * When deriving the boundaries of a fragment from a gpa, all but the last 769 * fragment end at the end of the page. 770 * 771 * Return: 772 * * 0 - success 773 * * <0 - translation could not be performed, for example if guest 774 * memory could not be accessed 775 * * >0 - an access exception occurred. In this case the returned value 776 * is the program interruption code and the contents of pgm may 777 * be used to inject an exception into the guest. 778 */ 779 static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, 780 unsigned long *gpas, unsigned long len, 781 const union asce asce, enum gacc_mode mode, 782 u8 access_key) 783 { 784 psw_t *psw = &vcpu->arch.sie_block->gpsw; 785 unsigned int offset = offset_in_page(ga); 786 unsigned int fragment_len; 787 int lap_enabled, rc = 0; 788 enum prot_type prot; 789 unsigned long gpa; 790 791 lap_enabled = low_address_protection_enabled(vcpu, asce); 792 while (min(PAGE_SIZE - offset, len) > 0) { 793 fragment_len = min(PAGE_SIZE - offset, len); 794 ga = kvm_s390_logical_to_effective(vcpu, ga); 795 if (mode == GACC_STORE && lap_enabled && is_low_address(ga)) 796 return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode, 797 PROT_TYPE_LA); 798 if (psw_bits(*psw).dat) { 799 rc = guest_translate(vcpu, ga, &gpa, asce, mode, &prot); 800 if (rc < 0) 801 return rc; 802 } else { 803 gpa = kvm_s390_real_to_abs(vcpu, ga); 804 if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) { 805 rc = PGM_ADDRESSING; 806 prot = PROT_NONE; 807 } 808 } 809 if (rc) 810 return trans_exc(vcpu, rc, ga, ar, mode, prot); 811 rc = vcpu_check_access_key(vcpu, access_key, mode, asce, gpa, ga, 812 fragment_len); 813 if (rc) 814 return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_KEYC); 815 if (gpas) 816 *gpas++ = gpa; 817 offset = 0; 818 ga += fragment_len; 819 len -= fragment_len; 820 } 821 return 0; 822 } 823 824 static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, 825 void *data, unsigned int len) 826 { 827 const unsigned int offset = offset_in_page(gpa); 828 const gfn_t gfn = gpa_to_gfn(gpa); 829 int rc; 830 831 if (mode == GACC_STORE) 832 rc = kvm_write_guest_page(kvm, gfn, data, offset, len); 833 else 834 rc = kvm_read_guest_page(kvm, gfn, data, offset, len); 835 return rc; 836 } 837 838 static int 839 access_guest_page_with_key(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, 840 void *data, unsigned int len, u8 access_key) 841 { 842 struct kvm_memory_slot *slot; 843 bool writable; 844 gfn_t gfn; 845 hva_t hva; 846 int rc; 847 848 gfn = gpa >> PAGE_SHIFT; 849 slot = gfn_to_memslot(kvm, gfn); 850 hva = gfn_to_hva_memslot_prot(slot, gfn, &writable); 851 852 if (kvm_is_error_hva(hva)) 853 return PGM_ADDRESSING; 854 /* 855 * Check if it's a ro memslot, even tho that can't occur (they're unsupported). 856 * Don't try to actually handle that case. 857 */ 858 if (!writable && mode == GACC_STORE) 859 return -EOPNOTSUPP; 860 hva += offset_in_page(gpa); 861 if (mode == GACC_STORE) 862 rc = copy_to_user_key((void __user *)hva, data, len, access_key); 863 else 864 rc = copy_from_user_key(data, (void __user *)hva, len, access_key); 865 if (rc) 866 return PGM_PROTECTION; 867 if (mode == GACC_STORE) 868 mark_page_dirty_in_slot(kvm, slot, gfn); 869 return 0; 870 } 871 872 int access_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, void *data, 873 unsigned long len, enum gacc_mode mode, u8 access_key) 874 { 875 int offset = offset_in_page(gpa); 876 int fragment_len; 877 int rc; 878 879 while (min(PAGE_SIZE - offset, len) > 0) { 880 fragment_len = min(PAGE_SIZE - offset, len); 881 rc = access_guest_page_with_key(kvm, mode, gpa, data, fragment_len, access_key); 882 if (rc) 883 return rc; 884 offset = 0; 885 len -= fragment_len; 886 data += fragment_len; 887 gpa += fragment_len; 888 } 889 return 0; 890 } 891 892 int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, 893 void *data, unsigned long len, enum gacc_mode mode, 894 u8 access_key) 895 { 896 psw_t *psw = &vcpu->arch.sie_block->gpsw; 897 unsigned long nr_pages, idx; 898 unsigned long gpa_array[2]; 899 unsigned int fragment_len; 900 unsigned long *gpas; 901 enum prot_type prot; 902 int need_ipte_lock; 903 union asce asce; 904 bool try_storage_prot_override; 905 bool try_fetch_prot_override; 906 int rc; 907 908 if (!len) 909 return 0; 910 ga = kvm_s390_logical_to_effective(vcpu, ga); 911 rc = get_vcpu_asce(vcpu, &asce, ga, ar, mode); 912 if (rc) 913 return rc; 914 nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1; 915 gpas = gpa_array; 916 if (nr_pages > ARRAY_SIZE(gpa_array)) 917 gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long))); 918 if (!gpas) 919 return -ENOMEM; 920 try_fetch_prot_override = fetch_prot_override_applicable(vcpu, mode, asce); 921 try_storage_prot_override = storage_prot_override_applicable(vcpu); 922 need_ipte_lock = psw_bits(*psw).dat && !asce.r; 923 if (need_ipte_lock) 924 ipte_lock(vcpu->kvm); 925 /* 926 * Since we do the access further down ultimately via a move instruction 927 * that does key checking and returns an error in case of a protection 928 * violation, we don't need to do the check during address translation. 929 * Skip it by passing access key 0, which matches any storage key, 930 * obviating the need for any further checks. As a result the check is 931 * handled entirely in hardware on access, we only need to take care to 932 * forego key protection checking if fetch protection override applies or 933 * retry with the special key 9 in case of storage protection override. 934 */ 935 rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode, 0); 936 if (rc) 937 goto out_unlock; 938 for (idx = 0; idx < nr_pages; idx++) { 939 fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len); 940 if (try_fetch_prot_override && fetch_prot_override_applies(ga, fragment_len)) { 941 rc = access_guest_page(vcpu->kvm, mode, gpas[idx], 942 data, fragment_len); 943 } else { 944 rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx], 945 data, fragment_len, access_key); 946 } 947 if (rc == PGM_PROTECTION && try_storage_prot_override) 948 rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx], 949 data, fragment_len, PAGE_SPO_ACC); 950 if (rc) 951 break; 952 len -= fragment_len; 953 data += fragment_len; 954 ga = kvm_s390_logical_to_effective(vcpu, ga + fragment_len); 955 } 956 if (rc > 0) { 957 bool terminate = (mode == GACC_STORE) && (idx > 0); 958 959 if (rc == PGM_PROTECTION) 960 prot = PROT_TYPE_KEYC; 961 else 962 prot = PROT_NONE; 963 rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate); 964 } 965 out_unlock: 966 if (need_ipte_lock) 967 ipte_unlock(vcpu->kvm); 968 if (nr_pages > ARRAY_SIZE(gpa_array)) 969 vfree(gpas); 970 return rc; 971 } 972 973 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, 974 void *data, unsigned long len, enum gacc_mode mode) 975 { 976 unsigned int fragment_len; 977 unsigned long gpa; 978 int rc = 0; 979 980 while (len && !rc) { 981 gpa = kvm_s390_real_to_abs(vcpu, gra); 982 fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len); 983 rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len); 984 len -= fragment_len; 985 gra += fragment_len; 986 data += fragment_len; 987 } 988 return rc; 989 } 990 991 /** 992 * cmpxchg_guest_abs_with_key() - Perform cmpxchg on guest absolute address. 993 * @kvm: Virtual machine instance. 994 * @gpa: Absolute guest address of the location to be changed. 995 * @len: Operand length of the cmpxchg, required: 1 <= len <= 16. Providing a 996 * non power of two will result in failure. 997 * @old_addr: Pointer to old value. If the location at @gpa contains this value, 998 * the exchange will succeed. After calling cmpxchg_guest_abs_with_key() 999 * *@old_addr contains the value at @gpa before the attempt to 1000 * exchange the value. 1001 * @new: The value to place at @gpa. 1002 * @access_key: The access key to use for the guest access. 1003 * @success: output value indicating if an exchange occurred. 1004 * 1005 * Atomically exchange the value at @gpa by @new, if it contains *@old. 1006 * Honors storage keys. 1007 * 1008 * Return: * 0: successful exchange 1009 * * >0: a program interruption code indicating the reason cmpxchg could 1010 * not be attempted 1011 * * -EINVAL: address misaligned or len not power of two 1012 * * -EAGAIN: transient failure (len 1 or 2) 1013 * * -EOPNOTSUPP: read-only memslot (should never occur) 1014 */ 1015 int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, 1016 __uint128_t *old_addr, __uint128_t new, 1017 u8 access_key, bool *success) 1018 { 1019 gfn_t gfn = gpa_to_gfn(gpa); 1020 struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); 1021 bool writable; 1022 hva_t hva; 1023 int ret; 1024 1025 if (!IS_ALIGNED(gpa, len)) 1026 return -EINVAL; 1027 1028 hva = gfn_to_hva_memslot_prot(slot, gfn, &writable); 1029 if (kvm_is_error_hva(hva)) 1030 return PGM_ADDRESSING; 1031 /* 1032 * Check if it's a read-only memslot, even though that cannot occur 1033 * since those are unsupported. 1034 * Don't try to actually handle that case. 1035 */ 1036 if (!writable) 1037 return -EOPNOTSUPP; 1038 1039 hva += offset_in_page(gpa); 1040 /* 1041 * The cmpxchg_user_key macro depends on the type of "old", so we need 1042 * a case for each valid length and get some code duplication as long 1043 * as we don't introduce a new macro. 1044 */ 1045 switch (len) { 1046 case 1: { 1047 u8 old; 1048 1049 ret = cmpxchg_user_key((u8 __user *)hva, &old, *old_addr, new, access_key); 1050 *success = !ret && old == *old_addr; 1051 *old_addr = old; 1052 break; 1053 } 1054 case 2: { 1055 u16 old; 1056 1057 ret = cmpxchg_user_key((u16 __user *)hva, &old, *old_addr, new, access_key); 1058 *success = !ret && old == *old_addr; 1059 *old_addr = old; 1060 break; 1061 } 1062 case 4: { 1063 u32 old; 1064 1065 ret = cmpxchg_user_key((u32 __user *)hva, &old, *old_addr, new, access_key); 1066 *success = !ret && old == *old_addr; 1067 *old_addr = old; 1068 break; 1069 } 1070 case 8: { 1071 u64 old; 1072 1073 ret = cmpxchg_user_key((u64 __user *)hva, &old, *old_addr, new, access_key); 1074 *success = !ret && old == *old_addr; 1075 *old_addr = old; 1076 break; 1077 } 1078 case 16: { 1079 __uint128_t old; 1080 1081 ret = cmpxchg_user_key((__uint128_t __user *)hva, &old, *old_addr, new, access_key); 1082 *success = !ret && old == *old_addr; 1083 *old_addr = old; 1084 break; 1085 } 1086 default: 1087 return -EINVAL; 1088 } 1089 if (*success) 1090 mark_page_dirty_in_slot(kvm, slot, gfn); 1091 /* 1092 * Assume that the fault is caused by protection, either key protection 1093 * or user page write protection. 1094 */ 1095 if (ret == -EFAULT) 1096 ret = PGM_PROTECTION; 1097 return ret; 1098 } 1099 1100 /** 1101 * guest_translate_address_with_key - translate guest logical into guest absolute address 1102 * @vcpu: virtual cpu 1103 * @gva: Guest virtual address 1104 * @ar: Access register 1105 * @gpa: Guest physical address 1106 * @mode: Translation access mode 1107 * @access_key: access key to mach the storage key with 1108 * 1109 * Parameter semantics are the same as the ones from guest_translate. 1110 * The memory contents at the guest address are not changed. 1111 * 1112 * Note: The IPTE lock is not taken during this function, so the caller 1113 * has to take care of this. 1114 */ 1115 int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, 1116 unsigned long *gpa, enum gacc_mode mode, 1117 u8 access_key) 1118 { 1119 union asce asce; 1120 int rc; 1121 1122 gva = kvm_s390_logical_to_effective(vcpu, gva); 1123 rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); 1124 if (rc) 1125 return rc; 1126 return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode, 1127 access_key); 1128 } 1129 1130 /** 1131 * check_gva_range - test a range of guest virtual addresses for accessibility 1132 * @vcpu: virtual cpu 1133 * @gva: Guest virtual address 1134 * @ar: Access register 1135 * @length: Length of test range 1136 * @mode: Translation access mode 1137 * @access_key: access key to mach the storage keys with 1138 */ 1139 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, 1140 unsigned long length, enum gacc_mode mode, u8 access_key) 1141 { 1142 union asce asce; 1143 int rc = 0; 1144 1145 rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); 1146 if (rc) 1147 return rc; 1148 ipte_lock(vcpu->kvm); 1149 rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode, 1150 access_key); 1151 ipte_unlock(vcpu->kvm); 1152 1153 return rc; 1154 } 1155 1156 /** 1157 * check_gpa_range - test a range of guest physical addresses for accessibility 1158 * @kvm: virtual machine instance 1159 * @gpa: guest physical address 1160 * @length: length of test range 1161 * @mode: access mode to test, relevant for storage keys 1162 * @access_key: access key to mach the storage keys with 1163 */ 1164 int check_gpa_range(struct kvm *kvm, unsigned long gpa, unsigned long length, 1165 enum gacc_mode mode, u8 access_key) 1166 { 1167 unsigned int fragment_len; 1168 int rc = 0; 1169 1170 while (length && !rc) { 1171 fragment_len = min(PAGE_SIZE - offset_in_page(gpa), length); 1172 rc = vm_check_access_key(kvm, access_key, mode, gpa); 1173 length -= fragment_len; 1174 gpa += fragment_len; 1175 } 1176 return rc; 1177 } 1178 1179 /** 1180 * kvm_s390_check_low_addr_prot_real - check for low-address protection 1181 * @vcpu: virtual cpu 1182 * @gra: Guest real address 1183 * 1184 * Checks whether an address is subject to low-address protection and set 1185 * up vcpu->arch.pgm accordingly if necessary. 1186 * 1187 * Return: 0 if no protection exception, or PGM_PROTECTION if protected. 1188 */ 1189 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra) 1190 { 1191 union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]}; 1192 1193 if (!ctlreg0.lap || !is_low_address(gra)) 1194 return 0; 1195 return trans_exc(vcpu, PGM_PROTECTION, gra, 0, GACC_STORE, PROT_TYPE_LA); 1196 } 1197 1198 /** 1199 * kvm_s390_shadow_tables - walk the guest page table and create shadow tables 1200 * @sg: pointer to the shadow guest address space structure 1201 * @saddr: faulting address in the shadow gmap 1202 * @pgt: pointer to the beginning of the page table for the given address if 1203 * successful (return value 0), or to the first invalid DAT entry in 1204 * case of exceptions (return value > 0) 1205 * @dat_protection: referenced memory is write protected 1206 * @fake: pgt references contiguous guest memory block, not a pgtable 1207 */ 1208 static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 1209 unsigned long *pgt, int *dat_protection, 1210 int *fake) 1211 { 1212 struct kvm *kvm; 1213 struct gmap *parent; 1214 union asce asce; 1215 union vaddress vaddr; 1216 unsigned long ptr; 1217 int rc; 1218 1219 *fake = 0; 1220 *dat_protection = 0; 1221 kvm = sg->private; 1222 parent = sg->parent; 1223 vaddr.addr = saddr; 1224 asce.val = sg->orig_asce; 1225 ptr = asce.rsto * PAGE_SIZE; 1226 if (asce.r) { 1227 *fake = 1; 1228 ptr = 0; 1229 asce.dt = ASCE_TYPE_REGION1; 1230 } 1231 switch (asce.dt) { 1232 case ASCE_TYPE_REGION1: 1233 if (vaddr.rfx01 > asce.tl && !*fake) 1234 return PGM_REGION_FIRST_TRANS; 1235 break; 1236 case ASCE_TYPE_REGION2: 1237 if (vaddr.rfx) 1238 return PGM_ASCE_TYPE; 1239 if (vaddr.rsx01 > asce.tl) 1240 return PGM_REGION_SECOND_TRANS; 1241 break; 1242 case ASCE_TYPE_REGION3: 1243 if (vaddr.rfx || vaddr.rsx) 1244 return PGM_ASCE_TYPE; 1245 if (vaddr.rtx01 > asce.tl) 1246 return PGM_REGION_THIRD_TRANS; 1247 break; 1248 case ASCE_TYPE_SEGMENT: 1249 if (vaddr.rfx || vaddr.rsx || vaddr.rtx) 1250 return PGM_ASCE_TYPE; 1251 if (vaddr.sx01 > asce.tl) 1252 return PGM_SEGMENT_TRANSLATION; 1253 break; 1254 } 1255 1256 switch (asce.dt) { 1257 case ASCE_TYPE_REGION1: { 1258 union region1_table_entry rfte; 1259 1260 if (*fake) { 1261 ptr += vaddr.rfx * _REGION1_SIZE; 1262 rfte.val = ptr; 1263 goto shadow_r2t; 1264 } 1265 *pgt = ptr + vaddr.rfx * 8; 1266 rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val); 1267 if (rc) 1268 return rc; 1269 if (rfte.i) 1270 return PGM_REGION_FIRST_TRANS; 1271 if (rfte.tt != TABLE_TYPE_REGION1) 1272 return PGM_TRANSLATION_SPEC; 1273 if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl) 1274 return PGM_REGION_SECOND_TRANS; 1275 if (sg->edat_level >= 1) 1276 *dat_protection |= rfte.p; 1277 ptr = rfte.rto * PAGE_SIZE; 1278 shadow_r2t: 1279 rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake); 1280 if (rc) 1281 return rc; 1282 kvm->stat.gmap_shadow_r1_entry++; 1283 } 1284 fallthrough; 1285 case ASCE_TYPE_REGION2: { 1286 union region2_table_entry rste; 1287 1288 if (*fake) { 1289 ptr += vaddr.rsx * _REGION2_SIZE; 1290 rste.val = ptr; 1291 goto shadow_r3t; 1292 } 1293 *pgt = ptr + vaddr.rsx * 8; 1294 rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val); 1295 if (rc) 1296 return rc; 1297 if (rste.i) 1298 return PGM_REGION_SECOND_TRANS; 1299 if (rste.tt != TABLE_TYPE_REGION2) 1300 return PGM_TRANSLATION_SPEC; 1301 if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl) 1302 return PGM_REGION_THIRD_TRANS; 1303 if (sg->edat_level >= 1) 1304 *dat_protection |= rste.p; 1305 ptr = rste.rto * PAGE_SIZE; 1306 shadow_r3t: 1307 rste.p |= *dat_protection; 1308 rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake); 1309 if (rc) 1310 return rc; 1311 kvm->stat.gmap_shadow_r2_entry++; 1312 } 1313 fallthrough; 1314 case ASCE_TYPE_REGION3: { 1315 union region3_table_entry rtte; 1316 1317 if (*fake) { 1318 ptr += vaddr.rtx * _REGION3_SIZE; 1319 rtte.val = ptr; 1320 goto shadow_sgt; 1321 } 1322 *pgt = ptr + vaddr.rtx * 8; 1323 rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val); 1324 if (rc) 1325 return rc; 1326 if (rtte.i) 1327 return PGM_REGION_THIRD_TRANS; 1328 if (rtte.tt != TABLE_TYPE_REGION3) 1329 return PGM_TRANSLATION_SPEC; 1330 if (rtte.cr && asce.p && sg->edat_level >= 2) 1331 return PGM_TRANSLATION_SPEC; 1332 if (rtte.fc && sg->edat_level >= 2) { 1333 *dat_protection |= rtte.fc0.p; 1334 *fake = 1; 1335 ptr = rtte.fc1.rfaa * _REGION3_SIZE; 1336 rtte.val = ptr; 1337 goto shadow_sgt; 1338 } 1339 if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl) 1340 return PGM_SEGMENT_TRANSLATION; 1341 if (sg->edat_level >= 1) 1342 *dat_protection |= rtte.fc0.p; 1343 ptr = rtte.fc0.sto * PAGE_SIZE; 1344 shadow_sgt: 1345 rtte.fc0.p |= *dat_protection; 1346 rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake); 1347 if (rc) 1348 return rc; 1349 kvm->stat.gmap_shadow_r3_entry++; 1350 } 1351 fallthrough; 1352 case ASCE_TYPE_SEGMENT: { 1353 union segment_table_entry ste; 1354 1355 if (*fake) { 1356 ptr += vaddr.sx * _SEGMENT_SIZE; 1357 ste.val = ptr; 1358 goto shadow_pgt; 1359 } 1360 *pgt = ptr + vaddr.sx * 8; 1361 rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val); 1362 if (rc) 1363 return rc; 1364 if (ste.i) 1365 return PGM_SEGMENT_TRANSLATION; 1366 if (ste.tt != TABLE_TYPE_SEGMENT) 1367 return PGM_TRANSLATION_SPEC; 1368 if (ste.cs && asce.p) 1369 return PGM_TRANSLATION_SPEC; 1370 *dat_protection |= ste.fc0.p; 1371 if (ste.fc && sg->edat_level >= 1) { 1372 *fake = 1; 1373 ptr = ste.fc1.sfaa * _SEGMENT_SIZE; 1374 ste.val = ptr; 1375 goto shadow_pgt; 1376 } 1377 ptr = ste.fc0.pto * (PAGE_SIZE / 2); 1378 shadow_pgt: 1379 ste.fc0.p |= *dat_protection; 1380 rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake); 1381 if (rc) 1382 return rc; 1383 kvm->stat.gmap_shadow_sg_entry++; 1384 } 1385 } 1386 /* Return the parent address of the page table */ 1387 *pgt = ptr; 1388 return 0; 1389 } 1390 1391 /** 1392 * kvm_s390_shadow_fault - handle fault on a shadow page table 1393 * @vcpu: virtual cpu 1394 * @sg: pointer to the shadow guest address space structure 1395 * @saddr: faulting address in the shadow gmap 1396 * @datptr: will contain the address of the faulting DAT table entry, or of 1397 * the valid leaf, plus some flags 1398 * 1399 * Returns: - 0 if the shadow fault was successfully resolved 1400 * - > 0 (pgm exception code) on exceptions while faulting 1401 * - -EAGAIN if the caller can retry immediately 1402 * - -EFAULT when accessing invalid guest addresses 1403 * - -ENOMEM if out of memory 1404 */ 1405 int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, 1406 unsigned long saddr, unsigned long *datptr) 1407 { 1408 union vaddress vaddr; 1409 union page_table_entry pte; 1410 unsigned long pgt = 0; 1411 int dat_protection, fake; 1412 int rc; 1413 1414 mmap_read_lock(sg->mm); 1415 /* 1416 * We don't want any guest-2 tables to change - so the parent 1417 * tables/pointers we read stay valid - unshadowing is however 1418 * always possible - only guest_table_lock protects us. 1419 */ 1420 ipte_lock(vcpu->kvm); 1421 1422 rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake); 1423 if (rc) 1424 rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection, 1425 &fake); 1426 1427 vaddr.addr = saddr; 1428 if (fake) { 1429 pte.val = pgt + vaddr.px * PAGE_SIZE; 1430 goto shadow_page; 1431 } 1432 1433 switch (rc) { 1434 case PGM_SEGMENT_TRANSLATION: 1435 case PGM_REGION_THIRD_TRANS: 1436 case PGM_REGION_SECOND_TRANS: 1437 case PGM_REGION_FIRST_TRANS: 1438 pgt |= PEI_NOT_PTE; 1439 break; 1440 case 0: 1441 pgt += vaddr.px * 8; 1442 rc = gmap_read_table(sg->parent, pgt, &pte.val); 1443 } 1444 if (datptr) 1445 *datptr = pgt | dat_protection * PEI_DAT_PROT; 1446 if (!rc && pte.i) 1447 rc = PGM_PAGE_TRANSLATION; 1448 if (!rc && pte.z) 1449 rc = PGM_TRANSLATION_SPEC; 1450 shadow_page: 1451 pte.p |= dat_protection; 1452 if (!rc) 1453 rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); 1454 vcpu->kvm->stat.gmap_shadow_pg_entry++; 1455 ipte_unlock(vcpu->kvm); 1456 mmap_read_unlock(sg->mm); 1457 return rc; 1458 } 1459