1 /* 2 * vm86 linux syscall support 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program 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 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 #include "qemu/osdep.h" 20 21 #include "qemu.h" 22 #include "user-internals.h" 23 24 //#define DEBUG_VM86 25 26 #ifdef DEBUG_VM86 27 # define LOG_VM86(...) qemu_log(__VA_ARGS__); 28 #else 29 # define LOG_VM86(...) do { } while (0) 30 #endif 31 32 33 #define set_flags(X,new,mask) \ 34 ((X) = ((X) & ~(mask)) | ((new) & (mask))) 35 36 #define SAFE_MASK (0xDD5) 37 #define RETURN_MASK (0xDFF) 38 39 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap) 40 { 41 return (((uint8_t *)bitmap)[nr >> 3] >> (nr & 7)) & 1; 42 } 43 44 static inline void vm_putw(CPUX86State *env, uint32_t segptr, 45 unsigned int reg16, unsigned int val) 46 { 47 cpu_stw_data(env, segptr + (reg16 & 0xffff), val); 48 } 49 50 static inline void vm_putl(CPUX86State *env, uint32_t segptr, 51 unsigned int reg16, unsigned int val) 52 { 53 cpu_stl_data(env, segptr + (reg16 & 0xffff), val); 54 } 55 56 static inline unsigned int vm_getb(CPUX86State *env, 57 uint32_t segptr, unsigned int reg16) 58 { 59 return cpu_ldub_data(env, segptr + (reg16 & 0xffff)); 60 } 61 62 static inline unsigned int vm_getw(CPUX86State *env, 63 uint32_t segptr, unsigned int reg16) 64 { 65 return cpu_lduw_data(env, segptr + (reg16 & 0xffff)); 66 } 67 68 static inline unsigned int vm_getl(CPUX86State *env, 69 uint32_t segptr, unsigned int reg16) 70 { 71 return cpu_ldl_data(env, segptr + (reg16 & 0xffff)); 72 } 73 74 void save_v86_state(CPUX86State *env) 75 { 76 CPUState *cs = env_cpu(env); 77 TaskState *ts = get_task_state(cs); 78 struct target_vm86plus_struct * target_v86; 79 80 if (!lock_user_struct(VERIFY_WRITE, target_v86, ts->target_v86, 0)) 81 /* FIXME - should return an error */ 82 return; 83 /* put the VM86 registers in the userspace register structure */ 84 target_v86->regs.eax = tswap32(env->regs[R_EAX]); 85 target_v86->regs.ebx = tswap32(env->regs[R_EBX]); 86 target_v86->regs.ecx = tswap32(env->regs[R_ECX]); 87 target_v86->regs.edx = tswap32(env->regs[R_EDX]); 88 target_v86->regs.esi = tswap32(env->regs[R_ESI]); 89 target_v86->regs.edi = tswap32(env->regs[R_EDI]); 90 target_v86->regs.ebp = tswap32(env->regs[R_EBP]); 91 target_v86->regs.esp = tswap32(env->regs[R_ESP]); 92 target_v86->regs.eip = tswap32(env->eip); 93 target_v86->regs.cs = tswap16(env->segs[R_CS].selector); 94 target_v86->regs.ss = tswap16(env->segs[R_SS].selector); 95 target_v86->regs.ds = tswap16(env->segs[R_DS].selector); 96 target_v86->regs.es = tswap16(env->segs[R_ES].selector); 97 target_v86->regs.fs = tswap16(env->segs[R_FS].selector); 98 target_v86->regs.gs = tswap16(env->segs[R_GS].selector); 99 set_flags(env->eflags, ts->v86flags, VIF_MASK | ts->v86mask); 100 target_v86->regs.eflags = tswap32(env->eflags); 101 unlock_user_struct(target_v86, ts->target_v86, 1); 102 LOG_VM86("save_v86_state: eflags=%08x cs:ip=%04x:%04x\n", 103 env->eflags, env->segs[R_CS].selector, env->eip); 104 105 /* restore 32 bit registers */ 106 env->regs[R_EAX] = ts->vm86_saved_regs.eax; 107 env->regs[R_EBX] = ts->vm86_saved_regs.ebx; 108 env->regs[R_ECX] = ts->vm86_saved_regs.ecx; 109 env->regs[R_EDX] = ts->vm86_saved_regs.edx; 110 env->regs[R_ESI] = ts->vm86_saved_regs.esi; 111 env->regs[R_EDI] = ts->vm86_saved_regs.edi; 112 env->regs[R_EBP] = ts->vm86_saved_regs.ebp; 113 env->regs[R_ESP] = ts->vm86_saved_regs.esp; 114 env->eflags = ts->vm86_saved_regs.eflags; 115 env->eip = ts->vm86_saved_regs.eip; 116 117 cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs); 118 cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss); 119 cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds); 120 cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es); 121 cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs); 122 cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs); 123 } 124 125 /* return from vm86 mode to 32 bit. The vm86() syscall will return 126 'retval' */ 127 static inline void return_to_32bit(CPUX86State *env, int retval) 128 { 129 LOG_VM86("return_to_32bit: ret=0x%x\n", retval); 130 save_v86_state(env); 131 env->regs[R_EAX] = retval; 132 } 133 134 static inline int set_IF(CPUX86State *env) 135 { 136 CPUState *cs = env_cpu(env); 137 TaskState *ts = get_task_state(cs); 138 139 ts->v86flags |= VIF_MASK; 140 if (ts->v86flags & VIP_MASK) { 141 return_to_32bit(env, TARGET_VM86_STI); 142 return 1; 143 } 144 return 0; 145 } 146 147 static inline void clear_IF(CPUX86State *env) 148 { 149 CPUState *cs = env_cpu(env); 150 TaskState *ts = get_task_state(cs); 151 152 ts->v86flags &= ~VIF_MASK; 153 } 154 155 static inline void clear_TF(CPUX86State *env) 156 { 157 env->eflags &= ~TF_MASK; 158 } 159 160 static inline void clear_AC(CPUX86State *env) 161 { 162 env->eflags &= ~AC_MASK; 163 } 164 165 static inline int set_vflags_long(unsigned long eflags, CPUX86State *env) 166 { 167 CPUState *cs = env_cpu(env); 168 TaskState *ts = get_task_state(cs); 169 170 set_flags(ts->v86flags, eflags, ts->v86mask); 171 set_flags(env->eflags, eflags, SAFE_MASK); 172 if (eflags & IF_MASK) 173 return set_IF(env); 174 else 175 clear_IF(env); 176 return 0; 177 } 178 179 static inline int set_vflags_short(unsigned short flags, CPUX86State *env) 180 { 181 CPUState *cs = env_cpu(env); 182 TaskState *ts = get_task_state(cs); 183 184 set_flags(ts->v86flags, flags, ts->v86mask & 0xffff); 185 set_flags(env->eflags, flags, SAFE_MASK); 186 if (flags & IF_MASK) 187 return set_IF(env); 188 else 189 clear_IF(env); 190 return 0; 191 } 192 193 static inline unsigned int get_vflags(CPUX86State *env) 194 { 195 CPUState *cs = env_cpu(env); 196 TaskState *ts = get_task_state(cs); 197 unsigned int flags; 198 199 flags = env->eflags & RETURN_MASK; 200 if (ts->v86flags & VIF_MASK) 201 flags |= IF_MASK; 202 flags |= IOPL_MASK; 203 return flags | (ts->v86flags & ts->v86mask); 204 } 205 206 #define ADD16(reg, val) reg = (reg & ~0xffff) | ((reg + (val)) & 0xffff) 207 208 /* handle VM86 interrupt (NOTE: the CPU core currently does not 209 support TSS interrupt revectoring, so this code is always executed) */ 210 static void do_int(CPUX86State *env, int intno) 211 { 212 CPUState *cs = env_cpu(env); 213 TaskState *ts = get_task_state(cs); 214 uint32_t int_addr, segoffs, ssp; 215 unsigned int sp; 216 217 if (env->segs[R_CS].selector == TARGET_BIOSSEG) 218 goto cannot_handle; 219 if (is_revectored(intno, &ts->vm86plus.int_revectored)) 220 goto cannot_handle; 221 if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff, 222 &ts->vm86plus.int21_revectored)) 223 goto cannot_handle; 224 int_addr = (intno << 2); 225 segoffs = cpu_ldl_data(env, int_addr); 226 if ((segoffs >> 16) == TARGET_BIOSSEG) 227 goto cannot_handle; 228 LOG_VM86("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n", 229 intno, segoffs >> 16, segoffs & 0xffff); 230 /* save old state */ 231 ssp = env->segs[R_SS].selector << 4; 232 sp = env->regs[R_ESP] & 0xffff; 233 vm_putw(env, ssp, sp - 2, get_vflags(env)); 234 vm_putw(env, ssp, sp - 4, env->segs[R_CS].selector); 235 vm_putw(env, ssp, sp - 6, env->eip); 236 ADD16(env->regs[R_ESP], -6); 237 /* goto interrupt handler */ 238 env->eip = segoffs & 0xffff; 239 cpu_x86_load_seg(env, R_CS, segoffs >> 16); 240 clear_TF(env); 241 clear_IF(env); 242 clear_AC(env); 243 return; 244 cannot_handle: 245 LOG_VM86("VM86: return to 32 bits int 0x%x\n", intno); 246 return_to_32bit(env, TARGET_VM86_INTx | (intno << 8)); 247 } 248 249 void handle_vm86_trap(CPUX86State *env, int trapno) 250 { 251 if (trapno == 1 || trapno == 3) { 252 return_to_32bit(env, TARGET_VM86_TRAP + (trapno << 8)); 253 } else { 254 do_int(env, trapno); 255 } 256 } 257 258 #define CHECK_IF_IN_TRAP() \ 259 if ((ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) && \ 260 (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_TFpendig)) \ 261 newflags |= TF_MASK 262 263 #define VM86_FAULT_RETURN \ 264 if ((ts->vm86plus.vm86plus.flags & TARGET_force_return_for_pic) && \ 265 (ts->v86flags & (IF_MASK | VIF_MASK))) \ 266 return_to_32bit(env, TARGET_VM86_PICRETURN); \ 267 return 268 269 void handle_vm86_fault(CPUX86State *env) 270 { 271 CPUState *cs = env_cpu(env); 272 TaskState *ts = get_task_state(cs); 273 uint32_t csp, ssp; 274 unsigned int ip, sp, newflags, newip, newcs, opcode, intno; 275 int data32, pref_done; 276 277 csp = env->segs[R_CS].selector << 4; 278 ip = env->eip & 0xffff; 279 280 ssp = env->segs[R_SS].selector << 4; 281 sp = env->regs[R_ESP] & 0xffff; 282 283 LOG_VM86("VM86 exception %04x:%08x\n", 284 env->segs[R_CS].selector, env->eip); 285 286 data32 = 0; 287 pref_done = 0; 288 do { 289 opcode = vm_getb(env, csp, ip); 290 ADD16(ip, 1); 291 switch (opcode) { 292 case 0x66: /* 32-bit data */ data32=1; break; 293 case 0x67: /* 32-bit address */ break; 294 case 0x2e: /* CS */ break; 295 case 0x3e: /* DS */ break; 296 case 0x26: /* ES */ break; 297 case 0x36: /* SS */ break; 298 case 0x65: /* GS */ break; 299 case 0x64: /* FS */ break; 300 case 0xf2: /* repnz */ break; 301 case 0xf3: /* rep */ break; 302 default: pref_done = 1; 303 } 304 } while (!pref_done); 305 306 /* VM86 mode */ 307 switch(opcode) { 308 case 0x9c: /* pushf */ 309 if (data32) { 310 vm_putl(env, ssp, sp - 4, get_vflags(env)); 311 ADD16(env->regs[R_ESP], -4); 312 } else { 313 vm_putw(env, ssp, sp - 2, get_vflags(env)); 314 ADD16(env->regs[R_ESP], -2); 315 } 316 env->eip = ip; 317 VM86_FAULT_RETURN; 318 319 case 0x9d: /* popf */ 320 if (data32) { 321 newflags = vm_getl(env, ssp, sp); 322 ADD16(env->regs[R_ESP], 4); 323 } else { 324 newflags = vm_getw(env, ssp, sp); 325 ADD16(env->regs[R_ESP], 2); 326 } 327 env->eip = ip; 328 CHECK_IF_IN_TRAP(); 329 if (data32) { 330 if (set_vflags_long(newflags, env)) 331 return; 332 } else { 333 if (set_vflags_short(newflags, env)) 334 return; 335 } 336 VM86_FAULT_RETURN; 337 338 case 0xcd: /* int */ 339 intno = vm_getb(env, csp, ip); 340 ADD16(ip, 1); 341 env->eip = ip; 342 if (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) { 343 if ( (ts->vm86plus.vm86plus.vm86dbg_intxxtab[intno >> 3] >> 344 (intno &7)) & 1) { 345 return_to_32bit(env, TARGET_VM86_INTx + (intno << 8)); 346 return; 347 } 348 } 349 do_int(env, intno); 350 break; 351 352 case 0xcf: /* iret */ 353 if (data32) { 354 newip = vm_getl(env, ssp, sp) & 0xffff; 355 newcs = vm_getl(env, ssp, sp + 4) & 0xffff; 356 newflags = vm_getl(env, ssp, sp + 8); 357 ADD16(env->regs[R_ESP], 12); 358 } else { 359 newip = vm_getw(env, ssp, sp); 360 newcs = vm_getw(env, ssp, sp + 2); 361 newflags = vm_getw(env, ssp, sp + 4); 362 ADD16(env->regs[R_ESP], 6); 363 } 364 env->eip = newip; 365 cpu_x86_load_seg(env, R_CS, newcs); 366 CHECK_IF_IN_TRAP(); 367 if (data32) { 368 if (set_vflags_long(newflags, env)) 369 return; 370 } else { 371 if (set_vflags_short(newflags, env)) 372 return; 373 } 374 VM86_FAULT_RETURN; 375 376 case 0xfa: /* cli */ 377 env->eip = ip; 378 clear_IF(env); 379 VM86_FAULT_RETURN; 380 381 case 0xfb: /* sti */ 382 env->eip = ip; 383 if (set_IF(env)) 384 return; 385 VM86_FAULT_RETURN; 386 387 default: 388 /* real VM86 GPF exception */ 389 return_to_32bit(env, TARGET_VM86_UNKNOWN); 390 break; 391 } 392 } 393 394 int do_vm86(CPUX86State *env, long subfunction, abi_ulong vm86_addr) 395 { 396 CPUState *cs = env_cpu(env); 397 TaskState *ts = get_task_state(cs); 398 struct target_vm86plus_struct * target_v86; 399 int ret; 400 401 switch (subfunction) { 402 case TARGET_VM86_REQUEST_IRQ: 403 case TARGET_VM86_FREE_IRQ: 404 case TARGET_VM86_GET_IRQ_BITS: 405 case TARGET_VM86_GET_AND_RESET_IRQ: 406 qemu_log_mask(LOG_UNIMP, "qemu: unsupported vm86 subfunction (%ld)\n", 407 subfunction); 408 ret = -TARGET_EINVAL; 409 goto out; 410 case TARGET_VM86_PLUS_INSTALL_CHECK: 411 /* NOTE: on old vm86 stuff this will return the error 412 from verify_area(), because the subfunction is 413 interpreted as (invalid) address to vm86_struct. 414 So the installation check works. 415 */ 416 ret = 0; 417 goto out; 418 } 419 420 /* save current CPU regs */ 421 ts->vm86_saved_regs.eax = 0; /* default vm86 syscall return code */ 422 ts->vm86_saved_regs.ebx = env->regs[R_EBX]; 423 ts->vm86_saved_regs.ecx = env->regs[R_ECX]; 424 ts->vm86_saved_regs.edx = env->regs[R_EDX]; 425 ts->vm86_saved_regs.esi = env->regs[R_ESI]; 426 ts->vm86_saved_regs.edi = env->regs[R_EDI]; 427 ts->vm86_saved_regs.ebp = env->regs[R_EBP]; 428 ts->vm86_saved_regs.esp = env->regs[R_ESP]; 429 ts->vm86_saved_regs.eflags = env->eflags; 430 ts->vm86_saved_regs.eip = env->eip; 431 ts->vm86_saved_regs.cs = env->segs[R_CS].selector; 432 ts->vm86_saved_regs.ss = env->segs[R_SS].selector; 433 ts->vm86_saved_regs.ds = env->segs[R_DS].selector; 434 ts->vm86_saved_regs.es = env->segs[R_ES].selector; 435 ts->vm86_saved_regs.fs = env->segs[R_FS].selector; 436 ts->vm86_saved_regs.gs = env->segs[R_GS].selector; 437 438 ts->target_v86 = vm86_addr; 439 if (!lock_user_struct(VERIFY_READ, target_v86, vm86_addr, 1)) 440 return -TARGET_EFAULT; 441 /* build vm86 CPU state */ 442 ts->v86flags = tswap32(target_v86->regs.eflags); 443 env->eflags = (env->eflags & ~SAFE_MASK) | 444 (tswap32(target_v86->regs.eflags) & SAFE_MASK) | VM_MASK; 445 446 ts->vm86plus.cpu_type = tswapal(target_v86->cpu_type); 447 switch (ts->vm86plus.cpu_type) { 448 case TARGET_CPU_286: 449 ts->v86mask = 0; 450 break; 451 case TARGET_CPU_386: 452 ts->v86mask = NT_MASK | IOPL_MASK; 453 break; 454 case TARGET_CPU_486: 455 ts->v86mask = AC_MASK | NT_MASK | IOPL_MASK; 456 break; 457 default: 458 ts->v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK; 459 break; 460 } 461 462 env->regs[R_EBX] = tswap32(target_v86->regs.ebx); 463 env->regs[R_ECX] = tswap32(target_v86->regs.ecx); 464 env->regs[R_EDX] = tswap32(target_v86->regs.edx); 465 env->regs[R_ESI] = tswap32(target_v86->regs.esi); 466 env->regs[R_EDI] = tswap32(target_v86->regs.edi); 467 env->regs[R_EBP] = tswap32(target_v86->regs.ebp); 468 env->regs[R_ESP] = tswap32(target_v86->regs.esp); 469 env->eip = tswap32(target_v86->regs.eip); 470 cpu_x86_load_seg(env, R_CS, tswap16(target_v86->regs.cs)); 471 cpu_x86_load_seg(env, R_SS, tswap16(target_v86->regs.ss)); 472 cpu_x86_load_seg(env, R_DS, tswap16(target_v86->regs.ds)); 473 cpu_x86_load_seg(env, R_ES, tswap16(target_v86->regs.es)); 474 cpu_x86_load_seg(env, R_FS, tswap16(target_v86->regs.fs)); 475 cpu_x86_load_seg(env, R_GS, tswap16(target_v86->regs.gs)); 476 ret = tswap32(target_v86->regs.eax); /* eax will be restored at 477 the end of the syscall */ 478 memcpy(&ts->vm86plus.int_revectored, 479 &target_v86->int_revectored, 32); 480 memcpy(&ts->vm86plus.int21_revectored, 481 &target_v86->int21_revectored, 32); 482 ts->vm86plus.vm86plus.flags = tswapal(target_v86->vm86plus.flags); 483 memcpy(&ts->vm86plus.vm86plus.vm86dbg_intxxtab, 484 target_v86->vm86plus.vm86dbg_intxxtab, 32); 485 unlock_user_struct(target_v86, vm86_addr, 0); 486 487 LOG_VM86("do_vm86: cs:ip=%04x:%04x\n", 488 env->segs[R_CS].selector, env->eip); 489 /* now the virtual CPU is ready for vm86 execution ! */ 490 out: 491 return ret; 492 } 493