target-s390x/mmu_helper.c

   1 /*
   2  * S390x MMU related functions
   3  *
   4  * Copyright (c) 2011 Alexander Graf
   5  * Copyright (c) 2015 Thomas Huth, IBM Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include "qemu/osdep.h"
  19 #include "qemu/error-report.h"
  20 #include "exec/address-spaces.h"
  21 #include "cpu.h"
  22 #include "sysemu/kvm.h"
  23 #include "trace.h"
  24 #include "hw/s390x/storage-keys.h"
  25
  26 /* #define DEBUG_S390 */
  27 /* #define DEBUG_S390_PTE */
  28 /* #define DEBUG_S390_STDOUT */
  29
  30 #ifdef DEBUG_S390
  31 #ifdef DEBUG_S390_STDOUT
  32 #define DPRINTF(fmt, ...) \
  33     do { fprintf(stderr, fmt, ## __VA_ARGS__); \
  34          if (qemu_log_separate()) qemu_log(fmt, ##__VA_ARGS__); } while (0)
  35 #else
  36 #define DPRINTF(fmt, ...) \
  37     do { qemu_log(fmt, ## __VA_ARGS__); } while (0)
  38 #endif
  39 #else
  40 #define DPRINTF(fmt, ...) \
  41     do { } while (0)
  42 #endif
  43
  44 #ifdef DEBUG_S390_PTE
  45 #define PTE_DPRINTF DPRINTF
  46 #else
  47 #define PTE_DPRINTF(fmt, ...) \
  48     do { } while (0)
  49 #endif
  50
  51 /* Fetch/store bits in the translation exception code: */
  52 #define FS_READ  0x800
  53 #define FS_WRITE 0x400
  54
  55 static void trigger_access_exception(CPUS390XState *env, uint32_t type,
  56                                      uint32_t ilen, uint64_t tec)
  57 {
  58     S390CPU *cpu = s390_env_get_cpu(env);
  59
  60     if (kvm_enabled()) {
  61         kvm_s390_access_exception(cpu, type, tec);
  62     } else {
  63         CPUState *cs = CPU(cpu);
  64         stq_phys(cs->as, env->psa + offsetof(LowCore, trans_exc_code), tec);
  65         trigger_pgm_exception(env, type, ilen);
  66     }
  67 }
  68
  69 static void trigger_prot_fault(CPUS390XState *env, target_ulong vaddr,
  70                                uint64_t asc, int rw, bool exc)
  71 {
  72     uint64_t tec;
  73
  74     tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | 4 | asc >> 46;
  75
  76     DPRINTF("%s: trans_exc_code=%016" PRIx64 "\n", __func__, tec);
  77
  78     if (!exc) {
  79         return;
  80     }
  81
  82     trigger_access_exception(env, PGM_PROTECTION, ILEN_LATER_INC, tec);
  83 }
  84
  85 static void trigger_page_fault(CPUS390XState *env, target_ulong vaddr,
  86                                uint32_t type, uint64_t asc, int rw, bool exc)
  87 {
  88     int ilen = ILEN_LATER;
  89     uint64_t tec;
  90
  91     tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | asc >> 46;
  92
  93     DPRINTF("%s: trans_exc_code=%016" PRIx64 "\n", __func__, tec);
  94
  95     if (!exc) {
  96         return;
  97     }
  98
  99     /* Code accesses have an undefined ilc.  */
 100     if (rw == MMU_INST_FETCH) {
 101         ilen = 2;
 102     }
 103
 104     trigger_access_exception(env, type, ilen, tec);
 105 }
 106
 107 /**
 108  * Translate real address to absolute (= physical)
 109  * address by taking care of the prefix mapping.
 110  */
 111 static target_ulong mmu_real2abs(CPUS390XState *env, target_ulong raddr)
 112 {
 113     if (raddr < 0x2000) {
 114         return raddr + env->psa;    /* Map the lowcore. */
 115     } else if (raddr >= env->psa && raddr < env->psa + 0x2000) {
 116         return raddr - env->psa;    /* Map the 0 page. */
 117     }
 118     return raddr;
 119 }
 120
 121 /* Decode page table entry (normal 4KB page) */
 122 static int mmu_translate_pte(CPUS390XState *env, target_ulong vaddr,
 123                              uint64_t asc, uint64_t pt_entry,
 124                              target_ulong *raddr, int *flags, int rw, bool exc)
 125 {
 126     if (pt_entry & _PAGE_INVALID) {
 127         DPRINTF("%s: PTE=0x%" PRIx64 " invalid\n", __func__, pt_entry);
 128         trigger_page_fault(env, vaddr, PGM_PAGE_TRANS, asc, rw, exc);
 129         return -1;
 130     }
 131     if (pt_entry & _PAGE_RES0) {
 132         trigger_page_fault(env, vaddr, PGM_TRANS_SPEC, asc, rw, exc);
 133         return -1;
 134     }
 135     if (pt_entry & _PAGE_RO) {
 136         *flags &= ~PAGE_WRITE;
 137     }
 138
 139     *raddr = pt_entry & _ASCE_ORIGIN;
 140
 141     PTE_DPRINTF("%s: PTE=0x%" PRIx64 "\n", __func__, pt_entry);
 142
 143     return 0;
 144 }
 145
 146 #define VADDR_PX    0xff000         /* Page index bits */
 147
 148 /* Decode segment table entry */
 149 static int mmu_translate_segment(CPUS390XState *env, target_ulong vaddr,
 150                                  uint64_t asc, uint64_t st_entry,
 151                                  target_ulong *raddr, int *flags, int rw,
 152                                  bool exc)
 153 {
 154     CPUState *cs = CPU(s390_env_get_cpu(env));
 155     uint64_t origin, offs, pt_entry;
 156
 157     if (st_entry & _SEGMENT_ENTRY_RO) {
 158         *flags &= ~PAGE_WRITE;
 159     }
 160
 161     if ((st_entry & _SEGMENT_ENTRY_FC) && (env->cregs[0] & CR0_EDAT)) {
 162         /* Decode EDAT1 segment frame absolute address (1MB page) */
 163         *raddr = (st_entry & 0xfffffffffff00000ULL) | (vaddr & 0xfffff);
 164         PTE_DPRINTF("%s: SEG=0x%" PRIx64 "\n", __func__, st_entry);
 165         return 0;
 166     }
 167
 168     /* Look up 4KB page entry */
 169     origin = st_entry & _SEGMENT_ENTRY_ORIGIN;
 170     offs  = (vaddr & VADDR_PX) >> 9;
 171     pt_entry = ldq_phys(cs->as, origin + offs);
 172     PTE_DPRINTF("%s: 0x%" PRIx64 " + 0x%" PRIx64 " => 0x%016" PRIx64 "\n",
 173                 __func__, origin, offs, pt_entry);
 174     return mmu_translate_pte(env, vaddr, asc, pt_entry, raddr, flags, rw, exc);
 175 }
 176
 177 /* Decode region table entries */
 178 static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
 179                                 uint64_t asc, uint64_t entry, int level,
 180                                 target_ulong *raddr, int *flags, int rw,
 181                                 bool exc)
 182 {
 183     CPUState *cs = CPU(s390_env_get_cpu(env));
 184     uint64_t origin, offs, new_entry;
 185     const int pchks[4] = {
 186         PGM_SEGMENT_TRANS, PGM_REG_THIRD_TRANS,
 187         PGM_REG_SEC_TRANS, PGM_REG_FIRST_TRANS
 188     };
 189
 190     PTE_DPRINTF("%s: 0x%" PRIx64 "\n", __func__, entry);
 191
 192     origin = entry & _REGION_ENTRY_ORIGIN;
 193     offs = (vaddr >> (17 + 11 * level / 4)) & 0x3ff8;
 194
 195     new_entry = ldq_phys(cs->as, origin + offs);
 196     PTE_DPRINTF("%s: 0x%" PRIx64 " + 0x%" PRIx64 " => 0x%016" PRIx64 "\n",
 197                 __func__, origin, offs, new_entry);
 198
 199     if ((new_entry & _REGION_ENTRY_INV) != 0) {
 200         DPRINTF("%s: invalid region\n", __func__);
 201         trigger_page_fault(env, vaddr, pchks[level / 4], asc, rw, exc);
 202         return -1;
 203     }
 204
 205     if ((new_entry & _REGION_ENTRY_TYPE_MASK) != level) {
 206         trigger_page_fault(env, vaddr, PGM_TRANS_SPEC, asc, rw, exc);
 207         return -1;
 208     }
 209
 210     if (level == _ASCE_TYPE_SEGMENT) {
 211         return mmu_translate_segment(env, vaddr, asc, new_entry, raddr, flags,
 212                                      rw, exc);
 213     }
 214
 215     /* Check region table offset and length */
 216     offs = (vaddr >> (28 + 11 * (level - 4) / 4)) & 3;
 217     if (offs < ((new_entry & _REGION_ENTRY_TF) >> 6)
 218         || offs > (new_entry & _REGION_ENTRY_LENGTH)) {
 219         DPRINTF("%s: invalid offset or len (%lx)\n", __func__, new_entry);
 220         trigger_page_fault(env, vaddr, pchks[level / 4 - 1], asc, rw, exc);
 221         return -1;
 222     }
 223
 224     if ((env->cregs[0] & CR0_EDAT) && (new_entry & _REGION_ENTRY_RO)) {
 225         *flags &= ~PAGE_WRITE;
 226     }
 227
 228     /* yet another region */
 229     return mmu_translate_region(env, vaddr, asc, new_entry, level - 4,
 230                                 raddr, flags, rw, exc);
 231 }
 232
 233 static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
 234                               uint64_t asc, uint64_t asce, target_ulong *raddr,
 235                               int *flags, int rw, bool exc)
 236 {
 237     int level;
 238     int r;
 239
 240     if (asce & _ASCE_REAL_SPACE) {
 241         /* direct mapping */
 242         *raddr = vaddr;
 243         return 0;
 244     }
 245
 246     level = asce & _ASCE_TYPE_MASK;
 247     switch (level) {
 248     case _ASCE_TYPE_REGION1:
 249         if ((vaddr >> 62) > (asce & _ASCE_TABLE_LENGTH)) {
 250             trigger_page_fault(env, vaddr, PGM_REG_FIRST_TRANS, asc, rw, exc);
 251             return -1;
 252         }
 253         break;
 254     case _ASCE_TYPE_REGION2:
 255         if (vaddr & 0xffe0000000000000ULL) {
 256             DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
 257                     " 0xffe0000000000000ULL\n", __func__, vaddr);
 258             trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
 259             return -1;
 260         }
 261         if ((vaddr >> 51 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
 262             trigger_page_fault(env, vaddr, PGM_REG_SEC_TRANS, asc, rw, exc);
 263             return -1;
 264         }
 265         break;
 266     case _ASCE_TYPE_REGION3:
 267         if (vaddr & 0xfffffc0000000000ULL) {
 268             DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
 269                     " 0xfffffc0000000000ULL\n", __func__, vaddr);
 270             trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
 271             return -1;
 272         }
 273         if ((vaddr >> 40 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
 274             trigger_page_fault(env, vaddr, PGM_REG_THIRD_TRANS, asc, rw, exc);
 275             return -1;
 276         }
 277         break;
 278     case _ASCE_TYPE_SEGMENT:
 279         if (vaddr & 0xffffffff80000000ULL) {
 280             DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
 281                     " 0xffffffff80000000ULL\n", __func__, vaddr);
 282             trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
 283             return -1;
 284         }
 285         if ((vaddr >> 29 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
 286             trigger_page_fault(env, vaddr, PGM_SEGMENT_TRANS, asc, rw, exc);
 287             return -1;
 288         }
 289         break;
 290     }
 291
 292     r = mmu_translate_region(env, vaddr, asc, asce, level, raddr, flags, rw,
 293                              exc);
 294     if (rw == MMU_DATA_STORE && !(*flags & PAGE_WRITE)) {
 295         trigger_prot_fault(env, vaddr, asc, rw, exc);
 296         return -1;
 297     }
 298
 299     return r;
 300 }
 301
 302 /**
 303  * Translate a virtual (logical) address into a physical (absolute) address.
 304  * @param vaddr  the virtual address
 305  * @param rw     0 = read, 1 = write, 2 = code fetch
 306  * @param asc    address space control (one of the PSW_ASC_* modes)
 307  * @param raddr  the translated address is stored to this pointer
 308  * @param flags  the PAGE_READ/WRITE/EXEC flags are stored to this pointer
 309  * @param exc    true = inject a program check if a fault occurred
 310  * @return       0 if the translation was successful, -1 if a fault occurred
 311  */
 312 int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
 313                   target_ulong *raddr, int *flags, bool exc)
 314 {
 315     static S390SKeysState *ss;
 316     static S390SKeysClass *skeyclass;
 317     int r = -1;
 318     uint8_t key;
 319
 320     if (unlikely(!ss)) {
 321         ss = s390_get_skeys_device();
 322         skeyclass = S390_SKEYS_GET_CLASS(ss);
 323     }
 324
 325     *flags = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
 326     vaddr &= TARGET_PAGE_MASK;
 327
 328     if (!(env->psw.mask & PSW_MASK_DAT)) {
 329         *raddr = vaddr;
 330         r = 0;
 331         goto out;
 332     }
 333
 334     switch (asc) {
 335     case PSW_ASC_PRIMARY:
 336         PTE_DPRINTF("%s: asc=primary\n", __func__);
 337         r = mmu_translate_asce(env, vaddr, asc, env->cregs[1], raddr, flags,
 338                                rw, exc);
 339         break;
 340     case PSW_ASC_HOME:
 341         PTE_DPRINTF("%s: asc=home\n", __func__);
 342         r = mmu_translate_asce(env, vaddr, asc, env->cregs[13], raddr, flags,
 343                                rw, exc);
 344         break;
 345     case PSW_ASC_SECONDARY:
 346         PTE_DPRINTF("%s: asc=secondary\n", __func__);
 347         /*
 348          * Instruction: Primary
 349          * Data: Secondary
 350          */
 351         if (rw == MMU_INST_FETCH) {
 352             r = mmu_translate_asce(env, vaddr, PSW_ASC_PRIMARY, env->cregs[1],
 353                                    raddr, flags, rw, exc);
 354             *flags &= ~(PAGE_READ | PAGE_WRITE);
 355         } else {
 356             r = mmu_translate_asce(env, vaddr, PSW_ASC_SECONDARY, env->cregs[7],
 357                                    raddr, flags, rw, exc);
 358             *flags &= ~(PAGE_EXEC);
 359         }
 360         break;
 361     case PSW_ASC_ACCREG:
 362     default:
 363         hw_error("guest switched to unknown asc mode\n");
 364         break;
 365     }
 366
 367  out:
 368     /* Convert real address -> absolute address */
 369     *raddr = mmu_real2abs(env, *raddr);
 370
 371     if (r == 0 && *raddr < ram_size) {
 372         if (skeyclass->get_skeys(ss, *raddr / TARGET_PAGE_SIZE, 1, &key)) {
 373             trace_get_skeys_nonzero(r);
 374             return 0;
 375         }
 376
 377         if (*flags & PAGE_READ) {
 378             key |= SK_R;
 379         }
 380
 381         if (*flags & PAGE_WRITE) {
 382             key |= SK_C;
 383         }
 384
 385         if (skeyclass->set_skeys(ss, *raddr / TARGET_PAGE_SIZE, 1, &key)) {
 386             trace_set_skeys_nonzero(r);
 387             return 0;
 388         }
 389     }
 390
 391     return r;
 392 }
 393
 394 /**
 395  * lowprot_enabled: Check whether low-address protection is enabled
 396  */
 397 static bool lowprot_enabled(const CPUS390XState *env)
 398 {
 399     if (!(env->cregs[0] & CR0_LOWPROT)) {
 400         return false;
 401     }
 402     if (!(env->psw.mask & PSW_MASK_DAT)) {
 403         return true;
 404     }
 405
 406     /* Check the private-space control bit */
 407     switch (env->psw.mask & PSW_MASK_ASC) {
 408     case PSW_ASC_PRIMARY:
 409         return !(env->cregs[1] & _ASCE_PRIVATE_SPACE);
 410     case PSW_ASC_SECONDARY:
 411         return !(env->cregs[7] & _ASCE_PRIVATE_SPACE);
 412     case PSW_ASC_HOME:
 413         return !(env->cregs[13] & _ASCE_PRIVATE_SPACE);
 414     default:
 415         /* We don't support access register mode */
 416         error_report("unsupported addressing mode");
 417         exit(1);
 418     }
 419 }
 420
 421 /**
 422  * translate_pages: Translate a set of consecutive logical page addresses
 423  * to absolute addresses
 424  */
 425 static int translate_pages(S390CPU *cpu, vaddr addr, int nr_pages,
 426                            target_ulong *pages, bool is_write)
 427 {
 428     bool lowprot = is_write && lowprot_enabled(&cpu->env);
 429     uint64_t asc = cpu->env.psw.mask & PSW_MASK_ASC;
 430     CPUS390XState *env = &cpu->env;
 431     int ret, i, pflags;
 432
 433     for (i = 0; i < nr_pages; i++) {
 434         /* Low-address protection? */
 435         if (lowprot && (addr < 512 || (addr >= 4096 && addr < 4096 + 512))) {
 436             trigger_access_exception(env, PGM_PROTECTION, ILEN_LATER_INC, 0);
 437             return -EACCES;
 438         }
 439         ret = mmu_translate(env, addr, is_write, asc, &pages[i], &pflags, true);
 440         if (ret) {
 441             return ret;
 442         }
 443         if (!address_space_access_valid(&address_space_memory, pages[i],
 444                                         TARGET_PAGE_SIZE, is_write)) {
 445             program_interrupt(env, PGM_ADDRESSING, 0);
 446             return -EFAULT;
 447         }
 448         addr += TARGET_PAGE_SIZE;
 449     }
 450
 451     return 0;
 452 }
 453
 454 /**
 455  * s390_cpu_virt_mem_rw:
 456  * @laddr:     the logical start address
 457  * @ar:        the access register number
 458  * @hostbuf:   buffer in host memory. NULL = do only checks w/o copying
 459  * @len:       length that should be transferred
 460  * @is_write:  true = write, false = read
 461  * Returns:    0 on success, non-zero if an exception occurred
 462  *
 463  * Copy from/to guest memory using logical addresses. Note that we inject a
 464  * program interrupt in case there is an error while accessing the memory.
 465  */
 466 int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, uint8_t ar, void *hostbuf,
 467                          int len, bool is_write)
 468 {
 469     int currlen, nr_pages, i;
 470     target_ulong *pages;
 471     int ret;
 472
 473     if (kvm_enabled()) {
 474         ret = kvm_s390_mem_op(cpu, laddr, ar, hostbuf, len, is_write);
 475         if (ret >= 0) {
 476             return ret;
 477         }
 478     }
 479
 480     nr_pages = (((laddr & ~TARGET_PAGE_MASK) + len - 1) >> TARGET_PAGE_BITS)
 481                + 1;
 482     pages = g_malloc(nr_pages * sizeof(*pages));
 483
 484     ret = translate_pages(cpu, laddr, nr_pages, pages, is_write);
 485     if (ret == 0 && hostbuf != NULL) {
 486         /* Copy data by stepping through the area page by page */
 487         for (i = 0; i < nr_pages; i++) {
 488             currlen = MIN(len, TARGET_PAGE_SIZE - (laddr % TARGET_PAGE_SIZE));
 489             cpu_physical_memory_rw(pages[i] | (laddr & ~TARGET_PAGE_MASK),
 490                                    hostbuf, currlen, is_write);
 491             laddr += currlen;
 492             hostbuf += currlen;
 493             len -= currlen;
 494         }
 495     }
 496
 497     g_free(pages);
 498     return ret;
 499 }