1 /* 2 * x86 exception helpers - sysemu code 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "cpu.h" 22 #include "exec/exec-all.h" 23 #include "tcg/helper-tcg.h" 24 25 #define PG_ERROR_OK (-1) 26 27 typedef hwaddr (*MMUTranslateFunc)(CPUState *cs, hwaddr gphys, MMUAccessType access_type, 28 int *prot); 29 30 #define GET_HPHYS(cs, gpa, access_type, prot) \ 31 (get_hphys_func ? get_hphys_func(cs, gpa, access_type, prot) : gpa) 32 33 static int mmu_translate(CPUState *cs, hwaddr addr, MMUTranslateFunc get_hphys_func, 34 uint64_t cr3, int is_write1, int mmu_idx, int pg_mode, 35 hwaddr *xlat, int *page_size, int *prot) 36 { 37 X86CPU *cpu = X86_CPU(cs); 38 CPUX86State *env = &cpu->env; 39 uint64_t ptep, pte; 40 int32_t a20_mask; 41 target_ulong pde_addr, pte_addr; 42 int error_code = 0; 43 int is_dirty, is_write, is_user; 44 uint64_t rsvd_mask = PG_ADDRESS_MASK & ~MAKE_64BIT_MASK(0, cpu->phys_bits); 45 uint32_t page_offset; 46 uint32_t pkr; 47 48 is_user = (mmu_idx == MMU_USER_IDX); 49 is_write = is_write1 & 1; 50 a20_mask = x86_get_a20_mask(env); 51 52 if (!(pg_mode & PG_MODE_NXE)) { 53 rsvd_mask |= PG_NX_MASK; 54 } 55 56 if (pg_mode & PG_MODE_PAE) { 57 uint64_t pde, pdpe; 58 target_ulong pdpe_addr; 59 60 #ifdef TARGET_X86_64 61 if (pg_mode & PG_MODE_LMA) { 62 bool la57 = pg_mode & PG_MODE_LA57; 63 uint64_t pml5e_addr, pml5e; 64 uint64_t pml4e_addr, pml4e; 65 66 if (la57) { 67 pml5e_addr = ((cr3 & ~0xfff) + 68 (((addr >> 48) & 0x1ff) << 3)) & a20_mask; 69 pml5e_addr = GET_HPHYS(cs, pml5e_addr, MMU_DATA_STORE, NULL); 70 pml5e = x86_ldq_phys(cs, pml5e_addr); 71 if (!(pml5e & PG_PRESENT_MASK)) { 72 goto do_fault; 73 } 74 if (pml5e & (rsvd_mask | PG_PSE_MASK)) { 75 goto do_fault_rsvd; 76 } 77 if (!(pml5e & PG_ACCESSED_MASK)) { 78 pml5e |= PG_ACCESSED_MASK; 79 x86_stl_phys_notdirty(cs, pml5e_addr, pml5e); 80 } 81 ptep = pml5e ^ PG_NX_MASK; 82 } else { 83 pml5e = cr3; 84 ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK; 85 } 86 87 pml4e_addr = ((pml5e & PG_ADDRESS_MASK) + 88 (((addr >> 39) & 0x1ff) << 3)) & a20_mask; 89 pml4e_addr = GET_HPHYS(cs, pml4e_addr, MMU_DATA_STORE, NULL); 90 pml4e = x86_ldq_phys(cs, pml4e_addr); 91 if (!(pml4e & PG_PRESENT_MASK)) { 92 goto do_fault; 93 } 94 if (pml4e & (rsvd_mask | PG_PSE_MASK)) { 95 goto do_fault_rsvd; 96 } 97 if (!(pml4e & PG_ACCESSED_MASK)) { 98 pml4e |= PG_ACCESSED_MASK; 99 x86_stl_phys_notdirty(cs, pml4e_addr, pml4e); 100 } 101 ptep &= pml4e ^ PG_NX_MASK; 102 pdpe_addr = ((pml4e & PG_ADDRESS_MASK) + (((addr >> 30) & 0x1ff) << 3)) & 103 a20_mask; 104 pdpe_addr = GET_HPHYS(cs, pdpe_addr, MMU_DATA_STORE, NULL); 105 pdpe = x86_ldq_phys(cs, pdpe_addr); 106 if (!(pdpe & PG_PRESENT_MASK)) { 107 goto do_fault; 108 } 109 if (pdpe & rsvd_mask) { 110 goto do_fault_rsvd; 111 } 112 ptep &= pdpe ^ PG_NX_MASK; 113 if (!(pdpe & PG_ACCESSED_MASK)) { 114 pdpe |= PG_ACCESSED_MASK; 115 x86_stl_phys_notdirty(cs, pdpe_addr, pdpe); 116 } 117 if (pdpe & PG_PSE_MASK) { 118 /* 1 GB page */ 119 *page_size = 1024 * 1024 * 1024; 120 pte_addr = pdpe_addr; 121 pte = pdpe; 122 goto do_check_protect; 123 } 124 } else 125 #endif 126 { 127 /* XXX: load them when cr3 is loaded ? */ 128 pdpe_addr = ((cr3 & ~0x1f) + ((addr >> 27) & 0x18)) & 129 a20_mask; 130 pdpe_addr = GET_HPHYS(cs, pdpe_addr, MMU_DATA_STORE, NULL); 131 pdpe = x86_ldq_phys(cs, pdpe_addr); 132 if (!(pdpe & PG_PRESENT_MASK)) { 133 goto do_fault; 134 } 135 rsvd_mask |= PG_HI_USER_MASK; 136 if (pdpe & (rsvd_mask | PG_NX_MASK)) { 137 goto do_fault_rsvd; 138 } 139 ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK; 140 } 141 142 pde_addr = ((pdpe & PG_ADDRESS_MASK) + (((addr >> 21) & 0x1ff) << 3)) & 143 a20_mask; 144 pde_addr = GET_HPHYS(cs, pde_addr, MMU_DATA_STORE, NULL); 145 pde = x86_ldq_phys(cs, pde_addr); 146 if (!(pde & PG_PRESENT_MASK)) { 147 goto do_fault; 148 } 149 if (pde & rsvd_mask) { 150 goto do_fault_rsvd; 151 } 152 ptep &= pde ^ PG_NX_MASK; 153 if (pde & PG_PSE_MASK) { 154 /* 2 MB page */ 155 *page_size = 2048 * 1024; 156 pte_addr = pde_addr; 157 pte = pde; 158 goto do_check_protect; 159 } 160 /* 4 KB page */ 161 if (!(pde & PG_ACCESSED_MASK)) { 162 pde |= PG_ACCESSED_MASK; 163 x86_stl_phys_notdirty(cs, pde_addr, pde); 164 } 165 pte_addr = ((pde & PG_ADDRESS_MASK) + (((addr >> 12) & 0x1ff) << 3)) & 166 a20_mask; 167 pte_addr = GET_HPHYS(cs, pte_addr, MMU_DATA_STORE, NULL); 168 pte = x86_ldq_phys(cs, pte_addr); 169 if (!(pte & PG_PRESENT_MASK)) { 170 goto do_fault; 171 } 172 if (pte & rsvd_mask) { 173 goto do_fault_rsvd; 174 } 175 /* combine pde and pte nx, user and rw protections */ 176 ptep &= pte ^ PG_NX_MASK; 177 *page_size = 4096; 178 } else { 179 uint32_t pde; 180 181 /* page directory entry */ 182 pde_addr = ((cr3 & ~0xfff) + ((addr >> 20) & 0xffc)) & 183 a20_mask; 184 pde_addr = GET_HPHYS(cs, pde_addr, MMU_DATA_STORE, NULL); 185 pde = x86_ldl_phys(cs, pde_addr); 186 if (!(pde & PG_PRESENT_MASK)) { 187 goto do_fault; 188 } 189 ptep = pde | PG_NX_MASK; 190 191 /* if PSE bit is set, then we use a 4MB page */ 192 if ((pde & PG_PSE_MASK) && (pg_mode & PG_MODE_PSE)) { 193 *page_size = 4096 * 1024; 194 pte_addr = pde_addr; 195 196 /* Bits 20-13 provide bits 39-32 of the address, bit 21 is reserved. 197 * Leave bits 20-13 in place for setting accessed/dirty bits below. 198 */ 199 pte = pde | ((pde & 0x1fe000LL) << (32 - 13)); 200 rsvd_mask = 0x200000; 201 goto do_check_protect_pse36; 202 } 203 204 if (!(pde & PG_ACCESSED_MASK)) { 205 pde |= PG_ACCESSED_MASK; 206 x86_stl_phys_notdirty(cs, pde_addr, pde); 207 } 208 209 /* page directory entry */ 210 pte_addr = ((pde & ~0xfff) + ((addr >> 10) & 0xffc)) & 211 a20_mask; 212 pte_addr = GET_HPHYS(cs, pte_addr, MMU_DATA_STORE, NULL); 213 pte = x86_ldl_phys(cs, pte_addr); 214 if (!(pte & PG_PRESENT_MASK)) { 215 goto do_fault; 216 } 217 /* combine pde and pte user and rw protections */ 218 ptep &= pte | PG_NX_MASK; 219 *page_size = 4096; 220 rsvd_mask = 0; 221 } 222 223 do_check_protect: 224 rsvd_mask |= (*page_size - 1) & PG_ADDRESS_MASK & ~PG_PSE_PAT_MASK; 225 do_check_protect_pse36: 226 if (pte & rsvd_mask) { 227 goto do_fault_rsvd; 228 } 229 ptep ^= PG_NX_MASK; 230 231 /* can the page can be put in the TLB? prot will tell us */ 232 if (is_user && !(ptep & PG_USER_MASK)) { 233 goto do_fault_protect; 234 } 235 236 *prot = 0; 237 if (mmu_idx != MMU_KSMAP_IDX || !(ptep & PG_USER_MASK)) { 238 *prot |= PAGE_READ; 239 if ((ptep & PG_RW_MASK) || !(is_user || (pg_mode & PG_MODE_WP))) { 240 *prot |= PAGE_WRITE; 241 } 242 } 243 if (!(ptep & PG_NX_MASK) && 244 (mmu_idx == MMU_USER_IDX || 245 !((pg_mode & PG_MODE_SMEP) && (ptep & PG_USER_MASK)))) { 246 *prot |= PAGE_EXEC; 247 } 248 249 if (ptep & PG_USER_MASK) { 250 pkr = pg_mode & PG_MODE_PKE ? env->pkru : 0; 251 } else { 252 pkr = pg_mode & PG_MODE_PKS ? env->pkrs : 0; 253 } 254 if (pkr) { 255 uint32_t pk = (pte & PG_PKRU_MASK) >> PG_PKRU_BIT; 256 uint32_t pkr_ad = (pkr >> pk * 2) & 1; 257 uint32_t pkr_wd = (pkr >> pk * 2) & 2; 258 uint32_t pkr_prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; 259 260 if (pkr_ad) { 261 pkr_prot &= ~(PAGE_READ | PAGE_WRITE); 262 } else if (pkr_wd && (is_user || (pg_mode & PG_MODE_WP))) { 263 pkr_prot &= ~PAGE_WRITE; 264 } 265 266 *prot &= pkr_prot; 267 if ((pkr_prot & (1 << is_write1)) == 0) { 268 assert(is_write1 != 2); 269 error_code |= PG_ERROR_PK_MASK; 270 goto do_fault_protect; 271 } 272 } 273 274 if ((*prot & (1 << is_write1)) == 0) { 275 goto do_fault_protect; 276 } 277 278 /* yes, it can! */ 279 is_dirty = is_write && !(pte & PG_DIRTY_MASK); 280 if (!(pte & PG_ACCESSED_MASK) || is_dirty) { 281 pte |= PG_ACCESSED_MASK; 282 if (is_dirty) { 283 pte |= PG_DIRTY_MASK; 284 } 285 x86_stl_phys_notdirty(cs, pte_addr, pte); 286 } 287 288 if (!(pte & PG_DIRTY_MASK)) { 289 /* only set write access if already dirty... otherwise wait 290 for dirty access */ 291 assert(!is_write); 292 *prot &= ~PAGE_WRITE; 293 } 294 295 pte = pte & a20_mask; 296 297 /* align to page_size */ 298 pte &= PG_ADDRESS_MASK & ~(*page_size - 1); 299 page_offset = addr & (*page_size - 1); 300 *xlat = GET_HPHYS(cs, pte + page_offset, is_write1, prot); 301 return PG_ERROR_OK; 302 303 do_fault_rsvd: 304 error_code |= PG_ERROR_RSVD_MASK; 305 do_fault_protect: 306 error_code |= PG_ERROR_P_MASK; 307 do_fault: 308 error_code |= (is_write << PG_ERROR_W_BIT); 309 if (is_user) 310 error_code |= PG_ERROR_U_MASK; 311 if (is_write1 == 2 && 312 ((pg_mode & PG_MODE_NXE) || (pg_mode & PG_MODE_SMEP))) 313 error_code |= PG_ERROR_I_D_MASK; 314 return error_code; 315 } 316 317 hwaddr get_hphys(CPUState *cs, hwaddr gphys, MMUAccessType access_type, 318 int *prot) 319 { 320 CPUX86State *env = &X86_CPU(cs)->env; 321 uint64_t exit_info_1; 322 int page_size; 323 int next_prot; 324 hwaddr hphys; 325 326 if (likely(!(env->hflags2 & HF2_NPT_MASK))) { 327 return gphys; 328 } 329 330 exit_info_1 = mmu_translate(cs, gphys, NULL, env->nested_cr3, 331 access_type, MMU_USER_IDX, env->nested_pg_mode, 332 &hphys, &page_size, &next_prot); 333 if (exit_info_1 == PG_ERROR_OK) { 334 if (prot) { 335 *prot &= next_prot; 336 } 337 return hphys; 338 } 339 340 x86_stq_phys(cs, env->vm_vmcb + offsetof(struct vmcb, control.exit_info_2), 341 gphys); 342 if (prot) { 343 exit_info_1 |= SVM_NPTEXIT_GPA; 344 } else { /* page table access */ 345 exit_info_1 |= SVM_NPTEXIT_GPT; 346 } 347 cpu_vmexit(env, SVM_EXIT_NPF, exit_info_1, env->retaddr); 348 } 349 350 /* return value: 351 * -1 = cannot handle fault 352 * 0 = nothing more to do 353 * 1 = generate PF fault 354 */ 355 static int handle_mmu_fault(CPUState *cs, vaddr addr, int size, 356 int is_write1, int mmu_idx) 357 { 358 X86CPU *cpu = X86_CPU(cs); 359 CPUX86State *env = &cpu->env; 360 int error_code = PG_ERROR_OK; 361 int pg_mode, prot, page_size; 362 hwaddr paddr; 363 hwaddr vaddr; 364 365 #if defined(DEBUG_MMU) 366 printf("MMU fault: addr=%" VADDR_PRIx " w=%d mmu=%d eip=" TARGET_FMT_lx "\n", 367 addr, is_write1, mmu_idx, env->eip); 368 #endif 369 370 if (!(env->cr[0] & CR0_PG_MASK)) { 371 paddr = addr; 372 #ifdef TARGET_X86_64 373 if (!(env->hflags & HF_LMA_MASK)) { 374 /* Without long mode we can only address 32bits in real mode */ 375 paddr = (uint32_t)paddr; 376 } 377 #endif 378 prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; 379 page_size = 4096; 380 } else { 381 pg_mode = get_pg_mode(env); 382 if (pg_mode & PG_MODE_LMA) { 383 int32_t sext; 384 385 /* test virtual address sign extension */ 386 sext = (int64_t)addr >> (pg_mode & PG_MODE_LA57 ? 56 : 47); 387 if (sext != 0 && sext != -1) { 388 env->error_code = 0; 389 cs->exception_index = EXCP0D_GPF; 390 return 1; 391 } 392 } 393 394 error_code = mmu_translate(cs, addr, get_hphys, env->cr[3], is_write1, 395 mmu_idx, pg_mode, 396 &paddr, &page_size, &prot); 397 } 398 399 if (error_code == PG_ERROR_OK) { 400 /* Even if 4MB pages, we map only one 4KB page in the cache to 401 avoid filling it too fast */ 402 vaddr = addr & TARGET_PAGE_MASK; 403 paddr &= TARGET_PAGE_MASK; 404 405 assert(prot & (1 << is_write1)); 406 tlb_set_page_with_attrs(cs, vaddr, paddr, cpu_get_mem_attrs(env), 407 prot, mmu_idx, page_size); 408 return 0; 409 } else { 410 if (env->intercept_exceptions & (1 << EXCP0E_PAGE)) { 411 /* cr2 is not modified in case of exceptions */ 412 x86_stq_phys(cs, 413 env->vm_vmcb + offsetof(struct vmcb, control.exit_info_2), 414 addr); 415 } else { 416 env->cr[2] = addr; 417 } 418 env->error_code = error_code; 419 cs->exception_index = EXCP0E_PAGE; 420 return 1; 421 } 422 } 423 424 bool x86_cpu_tlb_fill(CPUState *cs, vaddr addr, int size, 425 MMUAccessType access_type, int mmu_idx, 426 bool probe, uintptr_t retaddr) 427 { 428 X86CPU *cpu = X86_CPU(cs); 429 CPUX86State *env = &cpu->env; 430 431 env->retaddr = retaddr; 432 if (handle_mmu_fault(cs, addr, size, access_type, mmu_idx)) { 433 /* FIXME: On error in get_hphys we have already jumped out. */ 434 g_assert(!probe); 435 raise_exception_err_ra(env, cs->exception_index, 436 env->error_code, retaddr); 437 } 438 return true; 439 } 440