1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2012 Sandvine, Inc. 5 * Copyright (c) 2012 NetApp, Inc. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #ifdef _KERNEL 36 #include <sys/param.h> 37 #include <sys/pcpu.h> 38 #include <sys/systm.h> 39 #include <sys/proc.h> 40 41 #include <vm/vm.h> 42 #include <vm/pmap.h> 43 44 #include <machine/vmparam.h> 45 #include <machine/vmm.h> 46 #else /* !_KERNEL */ 47 #include <sys/types.h> 48 #include <sys/errno.h> 49 #include <sys/_iovec.h> 50 51 #include <machine/vmm.h> 52 53 #include <err.h> 54 #include <assert.h> 55 #include <stdbool.h> 56 #include <stddef.h> 57 #include <stdio.h> 58 #include <string.h> 59 #include <strings.h> 60 #include <vmmapi.h> 61 #define KASSERT(exp,msg) assert((exp)) 62 #define panic(...) errx(4, __VA_ARGS__) 63 #endif /* _KERNEL */ 64 65 #include <machine/vmm_instruction_emul.h> 66 #include <x86/psl.h> 67 #include <x86/specialreg.h> 68 69 /* struct vie_op.op_type */ 70 enum { 71 VIE_OP_TYPE_NONE = 0, 72 VIE_OP_TYPE_MOV, 73 VIE_OP_TYPE_MOVSX, 74 VIE_OP_TYPE_MOVZX, 75 VIE_OP_TYPE_AND, 76 VIE_OP_TYPE_OR, 77 VIE_OP_TYPE_SUB, 78 VIE_OP_TYPE_TWO_BYTE, 79 VIE_OP_TYPE_PUSH, 80 VIE_OP_TYPE_CMP, 81 VIE_OP_TYPE_POP, 82 VIE_OP_TYPE_MOVS, 83 VIE_OP_TYPE_GROUP1, 84 VIE_OP_TYPE_STOS, 85 VIE_OP_TYPE_BITTEST, 86 VIE_OP_TYPE_TWOB_GRP15, 87 VIE_OP_TYPE_ADD, 88 VIE_OP_TYPE_TEST, 89 VIE_OP_TYPE_BEXTR, 90 VIE_OP_TYPE_LAST 91 }; 92 93 /* struct vie_op.op_flags */ 94 #define VIE_OP_F_IMM (1 << 0) /* 16/32-bit immediate operand */ 95 #define VIE_OP_F_IMM8 (1 << 1) /* 8-bit immediate operand */ 96 #define VIE_OP_F_MOFFSET (1 << 2) /* 16/32/64-bit immediate moffset */ 97 #define VIE_OP_F_NO_MODRM (1 << 3) 98 #define VIE_OP_F_NO_GLA_VERIFICATION (1 << 4) 99 100 static const struct vie_op three_byte_opcodes_0f38[256] = { 101 [0xF7] = { 102 .op_byte = 0xF7, 103 .op_type = VIE_OP_TYPE_BEXTR, 104 }, 105 }; 106 107 static const struct vie_op two_byte_opcodes[256] = { 108 [0xAE] = { 109 .op_byte = 0xAE, 110 .op_type = VIE_OP_TYPE_TWOB_GRP15, 111 }, 112 [0xB6] = { 113 .op_byte = 0xB6, 114 .op_type = VIE_OP_TYPE_MOVZX, 115 }, 116 [0xB7] = { 117 .op_byte = 0xB7, 118 .op_type = VIE_OP_TYPE_MOVZX, 119 }, 120 [0xBA] = { 121 .op_byte = 0xBA, 122 .op_type = VIE_OP_TYPE_BITTEST, 123 .op_flags = VIE_OP_F_IMM8, 124 }, 125 [0xBE] = { 126 .op_byte = 0xBE, 127 .op_type = VIE_OP_TYPE_MOVSX, 128 }, 129 }; 130 131 static const struct vie_op one_byte_opcodes[256] = { 132 [0x03] = { 133 .op_byte = 0x03, 134 .op_type = VIE_OP_TYPE_ADD, 135 }, 136 [0x0F] = { 137 .op_byte = 0x0F, 138 .op_type = VIE_OP_TYPE_TWO_BYTE 139 }, 140 [0x0B] = { 141 .op_byte = 0x0B, 142 .op_type = VIE_OP_TYPE_OR, 143 }, 144 [0x2B] = { 145 .op_byte = 0x2B, 146 .op_type = VIE_OP_TYPE_SUB, 147 }, 148 [0x39] = { 149 .op_byte = 0x39, 150 .op_type = VIE_OP_TYPE_CMP, 151 }, 152 [0x3B] = { 153 .op_byte = 0x3B, 154 .op_type = VIE_OP_TYPE_CMP, 155 }, 156 [0x88] = { 157 .op_byte = 0x88, 158 .op_type = VIE_OP_TYPE_MOV, 159 }, 160 [0x89] = { 161 .op_byte = 0x89, 162 .op_type = VIE_OP_TYPE_MOV, 163 }, 164 [0x8A] = { 165 .op_byte = 0x8A, 166 .op_type = VIE_OP_TYPE_MOV, 167 }, 168 [0x8B] = { 169 .op_byte = 0x8B, 170 .op_type = VIE_OP_TYPE_MOV, 171 }, 172 [0xA1] = { 173 .op_byte = 0xA1, 174 .op_type = VIE_OP_TYPE_MOV, 175 .op_flags = VIE_OP_F_MOFFSET | VIE_OP_F_NO_MODRM, 176 }, 177 [0xA3] = { 178 .op_byte = 0xA3, 179 .op_type = VIE_OP_TYPE_MOV, 180 .op_flags = VIE_OP_F_MOFFSET | VIE_OP_F_NO_MODRM, 181 }, 182 [0xA4] = { 183 .op_byte = 0xA4, 184 .op_type = VIE_OP_TYPE_MOVS, 185 .op_flags = VIE_OP_F_NO_MODRM | VIE_OP_F_NO_GLA_VERIFICATION 186 }, 187 [0xA5] = { 188 .op_byte = 0xA5, 189 .op_type = VIE_OP_TYPE_MOVS, 190 .op_flags = VIE_OP_F_NO_MODRM | VIE_OP_F_NO_GLA_VERIFICATION 191 }, 192 [0xAA] = { 193 .op_byte = 0xAA, 194 .op_type = VIE_OP_TYPE_STOS, 195 .op_flags = VIE_OP_F_NO_MODRM | VIE_OP_F_NO_GLA_VERIFICATION 196 }, 197 [0xAB] = { 198 .op_byte = 0xAB, 199 .op_type = VIE_OP_TYPE_STOS, 200 .op_flags = VIE_OP_F_NO_MODRM | VIE_OP_F_NO_GLA_VERIFICATION 201 }, 202 [0xC6] = { 203 /* XXX Group 11 extended opcode - not just MOV */ 204 .op_byte = 0xC6, 205 .op_type = VIE_OP_TYPE_MOV, 206 .op_flags = VIE_OP_F_IMM8, 207 }, 208 [0xC7] = { 209 .op_byte = 0xC7, 210 .op_type = VIE_OP_TYPE_MOV, 211 .op_flags = VIE_OP_F_IMM, 212 }, 213 [0x23] = { 214 .op_byte = 0x23, 215 .op_type = VIE_OP_TYPE_AND, 216 }, 217 [0x80] = { 218 /* Group 1 extended opcode */ 219 .op_byte = 0x80, 220 .op_type = VIE_OP_TYPE_GROUP1, 221 .op_flags = VIE_OP_F_IMM8, 222 }, 223 [0x81] = { 224 /* Group 1 extended opcode */ 225 .op_byte = 0x81, 226 .op_type = VIE_OP_TYPE_GROUP1, 227 .op_flags = VIE_OP_F_IMM, 228 }, 229 [0x83] = { 230 /* Group 1 extended opcode */ 231 .op_byte = 0x83, 232 .op_type = VIE_OP_TYPE_GROUP1, 233 .op_flags = VIE_OP_F_IMM8, 234 }, 235 [0x8F] = { 236 /* XXX Group 1A extended opcode - not just POP */ 237 .op_byte = 0x8F, 238 .op_type = VIE_OP_TYPE_POP, 239 }, 240 [0xF7] = { 241 /* XXX Group 3 extended opcode - not just TEST */ 242 .op_byte = 0xF7, 243 .op_type = VIE_OP_TYPE_TEST, 244 .op_flags = VIE_OP_F_IMM, 245 }, 246 [0xFF] = { 247 /* XXX Group 5 extended opcode - not just PUSH */ 248 .op_byte = 0xFF, 249 .op_type = VIE_OP_TYPE_PUSH, 250 } 251 }; 252 253 /* struct vie.mod */ 254 #define VIE_MOD_INDIRECT 0 255 #define VIE_MOD_INDIRECT_DISP8 1 256 #define VIE_MOD_INDIRECT_DISP32 2 257 #define VIE_MOD_DIRECT 3 258 259 /* struct vie.rm */ 260 #define VIE_RM_SIB 4 261 #define VIE_RM_DISP32 5 262 263 #define GB (1024 * 1024 * 1024) 264 265 static enum vm_reg_name gpr_map[16] = { 266 VM_REG_GUEST_RAX, 267 VM_REG_GUEST_RCX, 268 VM_REG_GUEST_RDX, 269 VM_REG_GUEST_RBX, 270 VM_REG_GUEST_RSP, 271 VM_REG_GUEST_RBP, 272 VM_REG_GUEST_RSI, 273 VM_REG_GUEST_RDI, 274 VM_REG_GUEST_R8, 275 VM_REG_GUEST_R9, 276 VM_REG_GUEST_R10, 277 VM_REG_GUEST_R11, 278 VM_REG_GUEST_R12, 279 VM_REG_GUEST_R13, 280 VM_REG_GUEST_R14, 281 VM_REG_GUEST_R15 282 }; 283 284 static uint64_t size2mask[] = { 285 [1] = 0xff, 286 [2] = 0xffff, 287 [4] = 0xffffffff, 288 [8] = 0xffffffffffffffff, 289 }; 290 291 static int 292 vie_read_register(void *vm, int vcpuid, enum vm_reg_name reg, uint64_t *rval) 293 { 294 int error; 295 296 error = vm_get_register(vm, vcpuid, reg, rval); 297 298 return (error); 299 } 300 301 static void 302 vie_calc_bytereg(struct vie *vie, enum vm_reg_name *reg, int *lhbr) 303 { 304 *lhbr = 0; 305 *reg = gpr_map[vie->reg]; 306 307 /* 308 * 64-bit mode imposes limitations on accessing legacy high byte 309 * registers (lhbr). 310 * 311 * The legacy high-byte registers cannot be addressed if the REX 312 * prefix is present. In this case the values 4, 5, 6 and 7 of the 313 * 'ModRM:reg' field address %spl, %bpl, %sil and %dil respectively. 314 * 315 * If the REX prefix is not present then the values 4, 5, 6 and 7 316 * of the 'ModRM:reg' field address the legacy high-byte registers, 317 * %ah, %ch, %dh and %bh respectively. 318 */ 319 if (!vie->rex_present) { 320 if (vie->reg & 0x4) { 321 *lhbr = 1; 322 *reg = gpr_map[vie->reg & 0x3]; 323 } 324 } 325 } 326 327 static int 328 vie_read_bytereg(void *vm, int vcpuid, struct vie *vie, uint8_t *rval) 329 { 330 uint64_t val; 331 int error, lhbr; 332 enum vm_reg_name reg; 333 334 vie_calc_bytereg(vie, ®, &lhbr); 335 error = vm_get_register(vm, vcpuid, reg, &val); 336 337 /* 338 * To obtain the value of a legacy high byte register shift the 339 * base register right by 8 bits (%ah = %rax >> 8). 340 */ 341 if (lhbr) 342 *rval = val >> 8; 343 else 344 *rval = val; 345 return (error); 346 } 347 348 static int 349 vie_write_bytereg(void *vm, int vcpuid, struct vie *vie, uint8_t byte) 350 { 351 uint64_t origval, val, mask; 352 int error, lhbr; 353 enum vm_reg_name reg; 354 355 vie_calc_bytereg(vie, ®, &lhbr); 356 error = vm_get_register(vm, vcpuid, reg, &origval); 357 if (error == 0) { 358 val = byte; 359 mask = 0xff; 360 if (lhbr) { 361 /* 362 * Shift left by 8 to store 'byte' in a legacy high 363 * byte register. 364 */ 365 val <<= 8; 366 mask <<= 8; 367 } 368 val |= origval & ~mask; 369 error = vm_set_register(vm, vcpuid, reg, val); 370 } 371 return (error); 372 } 373 374 int 375 vie_update_register(void *vm, int vcpuid, enum vm_reg_name reg, 376 uint64_t val, int size) 377 { 378 int error; 379 uint64_t origval; 380 381 switch (size) { 382 case 1: 383 case 2: 384 error = vie_read_register(vm, vcpuid, reg, &origval); 385 if (error) 386 return (error); 387 val &= size2mask[size]; 388 val |= origval & ~size2mask[size]; 389 break; 390 case 4: 391 val &= 0xffffffffUL; 392 break; 393 case 8: 394 break; 395 default: 396 return (EINVAL); 397 } 398 399 error = vm_set_register(vm, vcpuid, reg, val); 400 return (error); 401 } 402 403 #define RFLAGS_STATUS_BITS (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_V) 404 405 /* 406 * Return the status flags that would result from doing (x - y). 407 */ 408 #define GETCC(sz) \ 409 static u_long \ 410 getcc##sz(uint##sz##_t x, uint##sz##_t y) \ 411 { \ 412 u_long rflags; \ 413 \ 414 __asm __volatile("sub %2,%1; pushfq; popq %0" : \ 415 "=r" (rflags), "+r" (x) : "m" (y)); \ 416 return (rflags); \ 417 } struct __hack 418 419 GETCC(8); 420 GETCC(16); 421 GETCC(32); 422 GETCC(64); 423 424 static u_long 425 getcc(int opsize, uint64_t x, uint64_t y) 426 { 427 KASSERT(opsize == 1 || opsize == 2 || opsize == 4 || opsize == 8, 428 ("getcc: invalid operand size %d", opsize)); 429 430 if (opsize == 1) 431 return (getcc8(x, y)); 432 else if (opsize == 2) 433 return (getcc16(x, y)); 434 else if (opsize == 4) 435 return (getcc32(x, y)); 436 else 437 return (getcc64(x, y)); 438 } 439 440 /* 441 * Macro creation of functions getaddflags{8,16,32,64} 442 */ 443 #define GETADDFLAGS(sz) \ 444 static u_long \ 445 getaddflags##sz(uint##sz##_t x, uint##sz##_t y) \ 446 { \ 447 u_long rflags; \ 448 \ 449 __asm __volatile("add %2,%1; pushfq; popq %0" : \ 450 "=r" (rflags), "+r" (x) : "m" (y)); \ 451 return (rflags); \ 452 } struct __hack 453 454 GETADDFLAGS(8); 455 GETADDFLAGS(16); 456 GETADDFLAGS(32); 457 GETADDFLAGS(64); 458 459 static u_long 460 getaddflags(int opsize, uint64_t x, uint64_t y) 461 { 462 KASSERT(opsize == 1 || opsize == 2 || opsize == 4 || opsize == 8, 463 ("getaddflags: invalid operand size %d", opsize)); 464 465 if (opsize == 1) 466 return (getaddflags8(x, y)); 467 else if (opsize == 2) 468 return (getaddflags16(x, y)); 469 else if (opsize == 4) 470 return (getaddflags32(x, y)); 471 else 472 return (getaddflags64(x, y)); 473 } 474 475 /* 476 * Return the status flags that would result from doing (x & y). 477 */ 478 #define GETANDFLAGS(sz) \ 479 static u_long \ 480 getandflags##sz(uint##sz##_t x, uint##sz##_t y) \ 481 { \ 482 u_long rflags; \ 483 \ 484 __asm __volatile("and %2,%1; pushfq; popq %0" : \ 485 "=r" (rflags), "+r" (x) : "m" (y)); \ 486 return (rflags); \ 487 } struct __hack 488 489 GETANDFLAGS(8); 490 GETANDFLAGS(16); 491 GETANDFLAGS(32); 492 GETANDFLAGS(64); 493 494 static u_long 495 getandflags(int opsize, uint64_t x, uint64_t y) 496 { 497 KASSERT(opsize == 1 || opsize == 2 || opsize == 4 || opsize == 8, 498 ("getandflags: invalid operand size %d", opsize)); 499 500 if (opsize == 1) 501 return (getandflags8(x, y)); 502 else if (opsize == 2) 503 return (getandflags16(x, y)); 504 else if (opsize == 4) 505 return (getandflags32(x, y)); 506 else 507 return (getandflags64(x, y)); 508 } 509 510 static int 511 emulate_mov(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 512 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 513 { 514 int error, size; 515 enum vm_reg_name reg; 516 uint8_t byte; 517 uint64_t val; 518 519 size = vie->opsize; 520 error = EINVAL; 521 522 switch (vie->op.op_byte) { 523 case 0x88: 524 /* 525 * MOV byte from reg (ModRM:reg) to mem (ModRM:r/m) 526 * 88/r: mov r/m8, r8 527 * REX + 88/r: mov r/m8, r8 (%ah, %ch, %dh, %bh not available) 528 */ 529 size = 1; /* override for byte operation */ 530 error = vie_read_bytereg(vm, vcpuid, vie, &byte); 531 if (error == 0) 532 error = memwrite(vm, vcpuid, gpa, byte, size, arg); 533 break; 534 case 0x89: 535 /* 536 * MOV from reg (ModRM:reg) to mem (ModRM:r/m) 537 * 89/r: mov r/m16, r16 538 * 89/r: mov r/m32, r32 539 * REX.W + 89/r mov r/m64, r64 540 */ 541 reg = gpr_map[vie->reg]; 542 error = vie_read_register(vm, vcpuid, reg, &val); 543 if (error == 0) { 544 val &= size2mask[size]; 545 error = memwrite(vm, vcpuid, gpa, val, size, arg); 546 } 547 break; 548 case 0x8A: 549 /* 550 * MOV byte from mem (ModRM:r/m) to reg (ModRM:reg) 551 * 8A/r: mov r8, r/m8 552 * REX + 8A/r: mov r8, r/m8 553 */ 554 size = 1; /* override for byte operation */ 555 error = memread(vm, vcpuid, gpa, &val, size, arg); 556 if (error == 0) 557 error = vie_write_bytereg(vm, vcpuid, vie, val); 558 break; 559 case 0x8B: 560 /* 561 * MOV from mem (ModRM:r/m) to reg (ModRM:reg) 562 * 8B/r: mov r16, r/m16 563 * 8B/r: mov r32, r/m32 564 * REX.W 8B/r: mov r64, r/m64 565 */ 566 error = memread(vm, vcpuid, gpa, &val, size, arg); 567 if (error == 0) { 568 reg = gpr_map[vie->reg]; 569 error = vie_update_register(vm, vcpuid, reg, val, size); 570 } 571 break; 572 case 0xA1: 573 /* 574 * MOV from seg:moffset to AX/EAX/RAX 575 * A1: mov AX, moffs16 576 * A1: mov EAX, moffs32 577 * REX.W + A1: mov RAX, moffs64 578 */ 579 error = memread(vm, vcpuid, gpa, &val, size, arg); 580 if (error == 0) { 581 reg = VM_REG_GUEST_RAX; 582 error = vie_update_register(vm, vcpuid, reg, val, size); 583 } 584 break; 585 case 0xA3: 586 /* 587 * MOV from AX/EAX/RAX to seg:moffset 588 * A3: mov moffs16, AX 589 * A3: mov moffs32, EAX 590 * REX.W + A3: mov moffs64, RAX 591 */ 592 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RAX, &val); 593 if (error == 0) { 594 val &= size2mask[size]; 595 error = memwrite(vm, vcpuid, gpa, val, size, arg); 596 } 597 break; 598 case 0xC6: 599 /* 600 * MOV from imm8 to mem (ModRM:r/m) 601 * C6/0 mov r/m8, imm8 602 * REX + C6/0 mov r/m8, imm8 603 */ 604 size = 1; /* override for byte operation */ 605 error = memwrite(vm, vcpuid, gpa, vie->immediate, size, arg); 606 break; 607 case 0xC7: 608 /* 609 * MOV from imm16/imm32 to mem (ModRM:r/m) 610 * C7/0 mov r/m16, imm16 611 * C7/0 mov r/m32, imm32 612 * REX.W + C7/0 mov r/m64, imm32 (sign-extended to 64-bits) 613 */ 614 val = vie->immediate & size2mask[size]; 615 error = memwrite(vm, vcpuid, gpa, val, size, arg); 616 break; 617 default: 618 break; 619 } 620 621 return (error); 622 } 623 624 static int 625 emulate_movx(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 626 mem_region_read_t memread, mem_region_write_t memwrite, 627 void *arg) 628 { 629 int error, size; 630 enum vm_reg_name reg; 631 uint64_t val; 632 633 size = vie->opsize; 634 error = EINVAL; 635 636 switch (vie->op.op_byte) { 637 case 0xB6: 638 /* 639 * MOV and zero extend byte from mem (ModRM:r/m) to 640 * reg (ModRM:reg). 641 * 642 * 0F B6/r movzx r16, r/m8 643 * 0F B6/r movzx r32, r/m8 644 * REX.W + 0F B6/r movzx r64, r/m8 645 */ 646 647 /* get the first operand */ 648 error = memread(vm, vcpuid, gpa, &val, 1, arg); 649 if (error) 650 break; 651 652 /* get the second operand */ 653 reg = gpr_map[vie->reg]; 654 655 /* zero-extend byte */ 656 val = (uint8_t)val; 657 658 /* write the result */ 659 error = vie_update_register(vm, vcpuid, reg, val, size); 660 break; 661 case 0xB7: 662 /* 663 * MOV and zero extend word from mem (ModRM:r/m) to 664 * reg (ModRM:reg). 665 * 666 * 0F B7/r movzx r32, r/m16 667 * REX.W + 0F B7/r movzx r64, r/m16 668 */ 669 error = memread(vm, vcpuid, gpa, &val, 2, arg); 670 if (error) 671 return (error); 672 673 reg = gpr_map[vie->reg]; 674 675 /* zero-extend word */ 676 val = (uint16_t)val; 677 678 error = vie_update_register(vm, vcpuid, reg, val, size); 679 break; 680 case 0xBE: 681 /* 682 * MOV and sign extend byte from mem (ModRM:r/m) to 683 * reg (ModRM:reg). 684 * 685 * 0F BE/r movsx r16, r/m8 686 * 0F BE/r movsx r32, r/m8 687 * REX.W + 0F BE/r movsx r64, r/m8 688 */ 689 690 /* get the first operand */ 691 error = memread(vm, vcpuid, gpa, &val, 1, arg); 692 if (error) 693 break; 694 695 /* get the second operand */ 696 reg = gpr_map[vie->reg]; 697 698 /* sign extend byte */ 699 val = (int8_t)val; 700 701 /* write the result */ 702 error = vie_update_register(vm, vcpuid, reg, val, size); 703 break; 704 default: 705 break; 706 } 707 return (error); 708 } 709 710 /* 711 * Helper function to calculate and validate a linear address. 712 */ 713 static int 714 get_gla(void *vm, int vcpuid, struct vie *vie, struct vm_guest_paging *paging, 715 int opsize, int addrsize, int prot, enum vm_reg_name seg, 716 enum vm_reg_name gpr, uint64_t *gla, int *fault) 717 { 718 struct seg_desc desc; 719 uint64_t cr0, val, rflags; 720 int error; 721 722 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_CR0, &cr0); 723 KASSERT(error == 0, ("%s: error %d getting cr0", __func__, error)); 724 725 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 726 KASSERT(error == 0, ("%s: error %d getting rflags", __func__, error)); 727 728 error = vm_get_seg_desc(vm, vcpuid, seg, &desc); 729 KASSERT(error == 0, ("%s: error %d getting segment descriptor %d", 730 __func__, error, seg)); 731 732 error = vie_read_register(vm, vcpuid, gpr, &val); 733 KASSERT(error == 0, ("%s: error %d getting register %d", __func__, 734 error, gpr)); 735 736 if (vie_calculate_gla(paging->cpu_mode, seg, &desc, val, opsize, 737 addrsize, prot, gla)) { 738 if (seg == VM_REG_GUEST_SS) 739 vm_inject_ss(vm, vcpuid, 0); 740 else 741 vm_inject_gp(vm, vcpuid); 742 goto guest_fault; 743 } 744 745 if (vie_canonical_check(paging->cpu_mode, *gla)) { 746 if (seg == VM_REG_GUEST_SS) 747 vm_inject_ss(vm, vcpuid, 0); 748 else 749 vm_inject_gp(vm, vcpuid); 750 goto guest_fault; 751 } 752 753 if (vie_alignment_check(paging->cpl, opsize, cr0, rflags, *gla)) { 754 vm_inject_ac(vm, vcpuid, 0); 755 goto guest_fault; 756 } 757 758 *fault = 0; 759 return (0); 760 761 guest_fault: 762 *fault = 1; 763 return (0); 764 } 765 766 static int 767 emulate_movs(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 768 struct vm_guest_paging *paging, mem_region_read_t memread, 769 mem_region_write_t memwrite, void *arg) 770 { 771 #ifdef _KERNEL 772 struct vm_copyinfo copyinfo[2]; 773 #else 774 struct iovec copyinfo[2]; 775 #endif 776 uint64_t dstaddr, srcaddr, dstgpa, srcgpa, val; 777 uint64_t rcx, rdi, rsi, rflags; 778 int error, fault, opsize, seg, repeat; 779 780 opsize = (vie->op.op_byte == 0xA4) ? 1 : vie->opsize; 781 val = 0; 782 error = 0; 783 784 /* 785 * XXX although the MOVS instruction is only supposed to be used with 786 * the "rep" prefix some guests like FreeBSD will use "repnz" instead. 787 * 788 * Empirically the "repnz" prefix has identical behavior to "rep" 789 * and the zero flag does not make a difference. 790 */ 791 repeat = vie->repz_present | vie->repnz_present; 792 793 if (repeat) { 794 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RCX, &rcx); 795 KASSERT(!error, ("%s: error %d getting rcx", __func__, error)); 796 797 /* 798 * The count register is %rcx, %ecx or %cx depending on the 799 * address size of the instruction. 800 */ 801 if ((rcx & vie_size2mask(vie->addrsize)) == 0) { 802 error = 0; 803 goto done; 804 } 805 } 806 807 /* 808 * Source Destination Comments 809 * -------------------------------------------- 810 * (1) memory memory n/a 811 * (2) memory mmio emulated 812 * (3) mmio memory emulated 813 * (4) mmio mmio emulated 814 * 815 * At this point we don't have sufficient information to distinguish 816 * between (2), (3) and (4). We use 'vm_copy_setup()' to tease this 817 * out because it will succeed only when operating on regular memory. 818 * 819 * XXX the emulation doesn't properly handle the case where 'gpa' 820 * is straddling the boundary between the normal memory and MMIO. 821 */ 822 823 seg = vie->segment_override ? vie->segment_register : VM_REG_GUEST_DS; 824 error = get_gla(vm, vcpuid, vie, paging, opsize, vie->addrsize, 825 PROT_READ, seg, VM_REG_GUEST_RSI, &srcaddr, &fault); 826 if (error || fault) 827 goto done; 828 829 error = vm_copy_setup(vm, vcpuid, paging, srcaddr, opsize, PROT_READ, 830 copyinfo, nitems(copyinfo), &fault); 831 if (error == 0) { 832 if (fault) 833 goto done; /* Resume guest to handle fault */ 834 835 /* 836 * case (2): read from system memory and write to mmio. 837 */ 838 vm_copyin(vm, vcpuid, copyinfo, &val, opsize); 839 vm_copy_teardown(vm, vcpuid, copyinfo, nitems(copyinfo)); 840 error = memwrite(vm, vcpuid, gpa, val, opsize, arg); 841 if (error) 842 goto done; 843 } else { 844 /* 845 * 'vm_copy_setup()' is expected to fail for cases (3) and (4) 846 * if 'srcaddr' is in the mmio space. 847 */ 848 849 error = get_gla(vm, vcpuid, vie, paging, opsize, vie->addrsize, 850 PROT_WRITE, VM_REG_GUEST_ES, VM_REG_GUEST_RDI, &dstaddr, 851 &fault); 852 if (error || fault) 853 goto done; 854 855 error = vm_copy_setup(vm, vcpuid, paging, dstaddr, opsize, 856 PROT_WRITE, copyinfo, nitems(copyinfo), &fault); 857 if (error == 0) { 858 if (fault) 859 goto done; /* Resume guest to handle fault */ 860 861 /* 862 * case (3): read from MMIO and write to system memory. 863 * 864 * A MMIO read can have side-effects so we 865 * commit to it only after vm_copy_setup() is 866 * successful. If a page-fault needs to be 867 * injected into the guest then it will happen 868 * before the MMIO read is attempted. 869 */ 870 error = memread(vm, vcpuid, gpa, &val, opsize, arg); 871 if (error) 872 goto done; 873 874 vm_copyout(vm, vcpuid, &val, copyinfo, opsize); 875 vm_copy_teardown(vm, vcpuid, copyinfo, nitems(copyinfo)); 876 } else { 877 /* 878 * Case (4): read from and write to mmio. 879 * 880 * Commit to the MMIO read/write (with potential 881 * side-effects) only after we are sure that the 882 * instruction is not going to be restarted due 883 * to address translation faults. 884 */ 885 error = vm_gla2gpa(vm, vcpuid, paging, srcaddr, 886 PROT_READ, &srcgpa, &fault); 887 if (error || fault) 888 goto done; 889 890 error = vm_gla2gpa(vm, vcpuid, paging, dstaddr, 891 PROT_WRITE, &dstgpa, &fault); 892 if (error || fault) 893 goto done; 894 895 error = memread(vm, vcpuid, srcgpa, &val, opsize, arg); 896 if (error) 897 goto done; 898 899 error = memwrite(vm, vcpuid, dstgpa, val, opsize, arg); 900 if (error) 901 goto done; 902 } 903 } 904 905 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RSI, &rsi); 906 KASSERT(error == 0, ("%s: error %d getting rsi", __func__, error)); 907 908 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RDI, &rdi); 909 KASSERT(error == 0, ("%s: error %d getting rdi", __func__, error)); 910 911 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 912 KASSERT(error == 0, ("%s: error %d getting rflags", __func__, error)); 913 914 if (rflags & PSL_D) { 915 rsi -= opsize; 916 rdi -= opsize; 917 } else { 918 rsi += opsize; 919 rdi += opsize; 920 } 921 922 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RSI, rsi, 923 vie->addrsize); 924 KASSERT(error == 0, ("%s: error %d updating rsi", __func__, error)); 925 926 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RDI, rdi, 927 vie->addrsize); 928 KASSERT(error == 0, ("%s: error %d updating rdi", __func__, error)); 929 930 if (repeat) { 931 rcx = rcx - 1; 932 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RCX, 933 rcx, vie->addrsize); 934 KASSERT(!error, ("%s: error %d updating rcx", __func__, error)); 935 936 /* 937 * Repeat the instruction if the count register is not zero. 938 */ 939 if ((rcx & vie_size2mask(vie->addrsize)) != 0) 940 vm_restart_instruction(vm, vcpuid); 941 } 942 done: 943 KASSERT(error == 0 || error == EFAULT, ("%s: unexpected error %d", 944 __func__, error)); 945 return (error); 946 } 947 948 static int 949 emulate_stos(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 950 struct vm_guest_paging *paging, mem_region_read_t memread, 951 mem_region_write_t memwrite, void *arg) 952 { 953 int error, opsize, repeat; 954 uint64_t val; 955 uint64_t rcx, rdi, rflags; 956 957 opsize = (vie->op.op_byte == 0xAA) ? 1 : vie->opsize; 958 repeat = vie->repz_present | vie->repnz_present; 959 960 if (repeat) { 961 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RCX, &rcx); 962 KASSERT(!error, ("%s: error %d getting rcx", __func__, error)); 963 964 /* 965 * The count register is %rcx, %ecx or %cx depending on the 966 * address size of the instruction. 967 */ 968 if ((rcx & vie_size2mask(vie->addrsize)) == 0) 969 return (0); 970 } 971 972 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RAX, &val); 973 KASSERT(!error, ("%s: error %d getting rax", __func__, error)); 974 975 error = memwrite(vm, vcpuid, gpa, val, opsize, arg); 976 if (error) 977 return (error); 978 979 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RDI, &rdi); 980 KASSERT(error == 0, ("%s: error %d getting rdi", __func__, error)); 981 982 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 983 KASSERT(error == 0, ("%s: error %d getting rflags", __func__, error)); 984 985 if (rflags & PSL_D) 986 rdi -= opsize; 987 else 988 rdi += opsize; 989 990 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RDI, rdi, 991 vie->addrsize); 992 KASSERT(error == 0, ("%s: error %d updating rdi", __func__, error)); 993 994 if (repeat) { 995 rcx = rcx - 1; 996 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RCX, 997 rcx, vie->addrsize); 998 KASSERT(!error, ("%s: error %d updating rcx", __func__, error)); 999 1000 /* 1001 * Repeat the instruction if the count register is not zero. 1002 */ 1003 if ((rcx & vie_size2mask(vie->addrsize)) != 0) 1004 vm_restart_instruction(vm, vcpuid); 1005 } 1006 1007 return (0); 1008 } 1009 1010 static int 1011 emulate_and(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1012 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1013 { 1014 int error, size; 1015 enum vm_reg_name reg; 1016 uint64_t result, rflags, rflags2, val1, val2; 1017 1018 size = vie->opsize; 1019 error = EINVAL; 1020 1021 switch (vie->op.op_byte) { 1022 case 0x23: 1023 /* 1024 * AND reg (ModRM:reg) and mem (ModRM:r/m) and store the 1025 * result in reg. 1026 * 1027 * 23/r and r16, r/m16 1028 * 23/r and r32, r/m32 1029 * REX.W + 23/r and r64, r/m64 1030 */ 1031 1032 /* get the first operand */ 1033 reg = gpr_map[vie->reg]; 1034 error = vie_read_register(vm, vcpuid, reg, &val1); 1035 if (error) 1036 break; 1037 1038 /* get the second operand */ 1039 error = memread(vm, vcpuid, gpa, &val2, size, arg); 1040 if (error) 1041 break; 1042 1043 /* perform the operation and write the result */ 1044 result = val1 & val2; 1045 error = vie_update_register(vm, vcpuid, reg, result, size); 1046 break; 1047 case 0x81: 1048 case 0x83: 1049 /* 1050 * AND mem (ModRM:r/m) with immediate and store the 1051 * result in mem. 1052 * 1053 * 81 /4 and r/m16, imm16 1054 * 81 /4 and r/m32, imm32 1055 * REX.W + 81 /4 and r/m64, imm32 sign-extended to 64 1056 * 1057 * 83 /4 and r/m16, imm8 sign-extended to 16 1058 * 83 /4 and r/m32, imm8 sign-extended to 32 1059 * REX.W + 83/4 and r/m64, imm8 sign-extended to 64 1060 */ 1061 1062 /* get the first operand */ 1063 error = memread(vm, vcpuid, gpa, &val1, size, arg); 1064 if (error) 1065 break; 1066 1067 /* 1068 * perform the operation with the pre-fetched immediate 1069 * operand and write the result 1070 */ 1071 result = val1 & vie->immediate; 1072 error = memwrite(vm, vcpuid, gpa, result, size, arg); 1073 break; 1074 default: 1075 break; 1076 } 1077 if (error) 1078 return (error); 1079 1080 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1081 if (error) 1082 return (error); 1083 1084 /* 1085 * OF and CF are cleared; the SF, ZF and PF flags are set according 1086 * to the result; AF is undefined. 1087 * 1088 * The updated status flags are obtained by subtracting 0 from 'result'. 1089 */ 1090 rflags2 = getcc(size, result, 0); 1091 rflags &= ~RFLAGS_STATUS_BITS; 1092 rflags |= rflags2 & (PSL_PF | PSL_Z | PSL_N); 1093 1094 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 8); 1095 return (error); 1096 } 1097 1098 static int 1099 emulate_or(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1100 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1101 { 1102 int error, size; 1103 enum vm_reg_name reg; 1104 uint64_t result, rflags, rflags2, val1, val2; 1105 1106 size = vie->opsize; 1107 error = EINVAL; 1108 1109 switch (vie->op.op_byte) { 1110 case 0x0B: 1111 /* 1112 * OR reg (ModRM:reg) and mem (ModRM:r/m) and store the 1113 * result in reg. 1114 * 1115 * 0b/r or r16, r/m16 1116 * 0b/r or r32, r/m32 1117 * REX.W + 0b/r or r64, r/m64 1118 */ 1119 1120 /* get the first operand */ 1121 reg = gpr_map[vie->reg]; 1122 error = vie_read_register(vm, vcpuid, reg, &val1); 1123 if (error) 1124 break; 1125 1126 /* get the second operand */ 1127 error = memread(vm, vcpuid, gpa, &val2, size, arg); 1128 if (error) 1129 break; 1130 1131 /* perform the operation and write the result */ 1132 result = val1 | val2; 1133 error = vie_update_register(vm, vcpuid, reg, result, size); 1134 break; 1135 case 0x81: 1136 case 0x83: 1137 /* 1138 * OR mem (ModRM:r/m) with immediate and store the 1139 * result in mem. 1140 * 1141 * 81 /1 or r/m16, imm16 1142 * 81 /1 or r/m32, imm32 1143 * REX.W + 81 /1 or r/m64, imm32 sign-extended to 64 1144 * 1145 * 83 /1 or r/m16, imm8 sign-extended to 16 1146 * 83 /1 or r/m32, imm8 sign-extended to 32 1147 * REX.W + 83/1 or r/m64, imm8 sign-extended to 64 1148 */ 1149 1150 /* get the first operand */ 1151 error = memread(vm, vcpuid, gpa, &val1, size, arg); 1152 if (error) 1153 break; 1154 1155 /* 1156 * perform the operation with the pre-fetched immediate 1157 * operand and write the result 1158 */ 1159 result = val1 | vie->immediate; 1160 error = memwrite(vm, vcpuid, gpa, result, size, arg); 1161 break; 1162 default: 1163 break; 1164 } 1165 if (error) 1166 return (error); 1167 1168 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1169 if (error) 1170 return (error); 1171 1172 /* 1173 * OF and CF are cleared; the SF, ZF and PF flags are set according 1174 * to the result; AF is undefined. 1175 * 1176 * The updated status flags are obtained by subtracting 0 from 'result'. 1177 */ 1178 rflags2 = getcc(size, result, 0); 1179 rflags &= ~RFLAGS_STATUS_BITS; 1180 rflags |= rflags2 & (PSL_PF | PSL_Z | PSL_N); 1181 1182 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 8); 1183 return (error); 1184 } 1185 1186 static int 1187 emulate_cmp(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1188 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1189 { 1190 int error, size; 1191 uint64_t regop, memop, op1, op2, rflags, rflags2; 1192 enum vm_reg_name reg; 1193 1194 size = vie->opsize; 1195 switch (vie->op.op_byte) { 1196 case 0x39: 1197 case 0x3B: 1198 /* 1199 * 39/r CMP r/m16, r16 1200 * 39/r CMP r/m32, r32 1201 * REX.W 39/r CMP r/m64, r64 1202 * 1203 * 3B/r CMP r16, r/m16 1204 * 3B/r CMP r32, r/m32 1205 * REX.W + 3B/r CMP r64, r/m64 1206 * 1207 * Compare the first operand with the second operand and 1208 * set status flags in EFLAGS register. The comparison is 1209 * performed by subtracting the second operand from the first 1210 * operand and then setting the status flags. 1211 */ 1212 1213 /* Get the register operand */ 1214 reg = gpr_map[vie->reg]; 1215 error = vie_read_register(vm, vcpuid, reg, ®op); 1216 if (error) 1217 return (error); 1218 1219 /* Get the memory operand */ 1220 error = memread(vm, vcpuid, gpa, &memop, size, arg); 1221 if (error) 1222 return (error); 1223 1224 if (vie->op.op_byte == 0x3B) { 1225 op1 = regop; 1226 op2 = memop; 1227 } else { 1228 op1 = memop; 1229 op2 = regop; 1230 } 1231 rflags2 = getcc(size, op1, op2); 1232 break; 1233 case 0x80: 1234 case 0x81: 1235 case 0x83: 1236 /* 1237 * 80 /7 cmp r/m8, imm8 1238 * REX + 80 /7 cmp r/m8, imm8 1239 * 1240 * 81 /7 cmp r/m16, imm16 1241 * 81 /7 cmp r/m32, imm32 1242 * REX.W + 81 /7 cmp r/m64, imm32 sign-extended to 64 1243 * 1244 * 83 /7 cmp r/m16, imm8 sign-extended to 16 1245 * 83 /7 cmp r/m32, imm8 sign-extended to 32 1246 * REX.W + 83 /7 cmp r/m64, imm8 sign-extended to 64 1247 * 1248 * Compare mem (ModRM:r/m) with immediate and set 1249 * status flags according to the results. The 1250 * comparison is performed by subtracting the 1251 * immediate from the first operand and then setting 1252 * the status flags. 1253 * 1254 */ 1255 if (vie->op.op_byte == 0x80) 1256 size = 1; 1257 1258 /* get the first operand */ 1259 error = memread(vm, vcpuid, gpa, &op1, size, arg); 1260 if (error) 1261 return (error); 1262 1263 rflags2 = getcc(size, op1, vie->immediate); 1264 break; 1265 default: 1266 return (EINVAL); 1267 } 1268 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1269 if (error) 1270 return (error); 1271 rflags &= ~RFLAGS_STATUS_BITS; 1272 rflags |= rflags2 & RFLAGS_STATUS_BITS; 1273 1274 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 8); 1275 return (error); 1276 } 1277 1278 static int 1279 emulate_test(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1280 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1281 { 1282 int error, size; 1283 uint64_t op1, rflags, rflags2; 1284 1285 size = vie->opsize; 1286 error = EINVAL; 1287 1288 switch (vie->op.op_byte) { 1289 case 0xF7: 1290 /* 1291 * F7 /0 test r/m16, imm16 1292 * F7 /0 test r/m32, imm32 1293 * REX.W + F7 /0 test r/m64, imm32 sign-extended to 64 1294 * 1295 * Test mem (ModRM:r/m) with immediate and set status 1296 * flags according to the results. The comparison is 1297 * performed by anding the immediate from the first 1298 * operand and then setting the status flags. 1299 */ 1300 if ((vie->reg & 7) != 0) 1301 return (EINVAL); 1302 1303 error = memread(vm, vcpuid, gpa, &op1, size, arg); 1304 if (error) 1305 return (error); 1306 1307 rflags2 = getandflags(size, op1, vie->immediate); 1308 break; 1309 default: 1310 return (EINVAL); 1311 } 1312 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1313 if (error) 1314 return (error); 1315 1316 /* 1317 * OF and CF are cleared; the SF, ZF and PF flags are set according 1318 * to the result; AF is undefined. 1319 */ 1320 rflags &= ~RFLAGS_STATUS_BITS; 1321 rflags |= rflags2 & (PSL_PF | PSL_Z | PSL_N); 1322 1323 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 8); 1324 return (error); 1325 } 1326 1327 static int 1328 emulate_bextr(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1329 struct vm_guest_paging *paging, mem_region_read_t memread, 1330 mem_region_write_t memwrite, void *arg) 1331 { 1332 uint64_t src1, src2, dst, rflags; 1333 unsigned start, len; 1334 int error, size; 1335 1336 size = vie->opsize; 1337 error = EINVAL; 1338 1339 /* 1340 * VEX.LZ.0F38.W0 F7 /r BEXTR r32a, r/m32, r32b 1341 * VEX.LZ.0F38.W1 F7 /r BEXTR r64a, r/m64, r64b 1342 * 1343 * Destination operand is ModRM:reg. Source operands are ModRM:r/m and 1344 * Vex.vvvv. 1345 * 1346 * Operand size is always 32-bit if not in 64-bit mode (W1 is ignored). 1347 */ 1348 if (size != 4 && paging->cpu_mode != CPU_MODE_64BIT) 1349 size = 4; 1350 1351 /* 1352 * Extracts contiguous bits from the first /source/ operand (second 1353 * operand) using an index and length specified in the second /source/ 1354 * operand (third operand). 1355 */ 1356 error = memread(vm, vcpuid, gpa, &src1, size, arg); 1357 if (error) 1358 return (error); 1359 error = vie_read_register(vm, vcpuid, gpr_map[vie->vex_reg], &src2); 1360 if (error) 1361 return (error); 1362 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1363 if (error) 1364 return (error); 1365 1366 start = (src2 & 0xff); 1367 len = (src2 & 0xff00) >> 8; 1368 1369 /* If no bits are extracted, the destination register is cleared. */ 1370 dst = 0; 1371 1372 /* If START exceeds the operand size, no bits are extracted. */ 1373 if (start > size * 8) 1374 goto done; 1375 /* Length is bounded by both the destination size and start offset. */ 1376 if (start + len > size * 8) 1377 len = (size * 8) - start; 1378 if (len == 0) 1379 goto done; 1380 1381 if (start > 0) 1382 src1 = (src1 >> start); 1383 if (len < 64) 1384 src1 = src1 & ((1ull << len) - 1); 1385 dst = src1; 1386 1387 done: 1388 error = vie_update_register(vm, vcpuid, gpr_map[vie->reg], dst, size); 1389 if (error) 1390 return (error); 1391 1392 /* 1393 * AMD: OF, CF cleared; SF/AF/PF undefined; ZF set by result. 1394 * Intel: ZF is set by result; AF/SF/PF undefined; all others cleared. 1395 */ 1396 rflags &= ~RFLAGS_STATUS_BITS; 1397 if (dst == 0) 1398 rflags |= PSL_Z; 1399 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 1400 8); 1401 return (error); 1402 } 1403 1404 static int 1405 emulate_add(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1406 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1407 { 1408 int error, size; 1409 uint64_t nval, rflags, rflags2, val1, val2; 1410 enum vm_reg_name reg; 1411 1412 size = vie->opsize; 1413 error = EINVAL; 1414 1415 switch (vie->op.op_byte) { 1416 case 0x03: 1417 /* 1418 * ADD r/m to r and store the result in r 1419 * 1420 * 03/r ADD r16, r/m16 1421 * 03/r ADD r32, r/m32 1422 * REX.W + 03/r ADD r64, r/m64 1423 */ 1424 1425 /* get the first operand */ 1426 reg = gpr_map[vie->reg]; 1427 error = vie_read_register(vm, vcpuid, reg, &val1); 1428 if (error) 1429 break; 1430 1431 /* get the second operand */ 1432 error = memread(vm, vcpuid, gpa, &val2, size, arg); 1433 if (error) 1434 break; 1435 1436 /* perform the operation and write the result */ 1437 nval = val1 + val2; 1438 error = vie_update_register(vm, vcpuid, reg, nval, size); 1439 break; 1440 default: 1441 break; 1442 } 1443 1444 if (!error) { 1445 rflags2 = getaddflags(size, val1, val2); 1446 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, 1447 &rflags); 1448 if (error) 1449 return (error); 1450 1451 rflags &= ~RFLAGS_STATUS_BITS; 1452 rflags |= rflags2 & RFLAGS_STATUS_BITS; 1453 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, 1454 rflags, 8); 1455 } 1456 1457 return (error); 1458 } 1459 1460 static int 1461 emulate_sub(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1462 mem_region_read_t memread, mem_region_write_t memwrite, void *arg) 1463 { 1464 int error, size; 1465 uint64_t nval, rflags, rflags2, val1, val2; 1466 enum vm_reg_name reg; 1467 1468 size = vie->opsize; 1469 error = EINVAL; 1470 1471 switch (vie->op.op_byte) { 1472 case 0x2B: 1473 /* 1474 * SUB r/m from r and store the result in r 1475 * 1476 * 2B/r SUB r16, r/m16 1477 * 2B/r SUB r32, r/m32 1478 * REX.W + 2B/r SUB r64, r/m64 1479 */ 1480 1481 /* get the first operand */ 1482 reg = gpr_map[vie->reg]; 1483 error = vie_read_register(vm, vcpuid, reg, &val1); 1484 if (error) 1485 break; 1486 1487 /* get the second operand */ 1488 error = memread(vm, vcpuid, gpa, &val2, size, arg); 1489 if (error) 1490 break; 1491 1492 /* perform the operation and write the result */ 1493 nval = val1 - val2; 1494 error = vie_update_register(vm, vcpuid, reg, nval, size); 1495 break; 1496 default: 1497 break; 1498 } 1499 1500 if (!error) { 1501 rflags2 = getcc(size, val1, val2); 1502 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, 1503 &rflags); 1504 if (error) 1505 return (error); 1506 1507 rflags &= ~RFLAGS_STATUS_BITS; 1508 rflags |= rflags2 & RFLAGS_STATUS_BITS; 1509 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, 1510 rflags, 8); 1511 } 1512 1513 return (error); 1514 } 1515 1516 static int 1517 emulate_stack_op(void *vm, int vcpuid, uint64_t mmio_gpa, struct vie *vie, 1518 struct vm_guest_paging *paging, mem_region_read_t memread, 1519 mem_region_write_t memwrite, void *arg) 1520 { 1521 #ifdef _KERNEL 1522 struct vm_copyinfo copyinfo[2]; 1523 #else 1524 struct iovec copyinfo[2]; 1525 #endif 1526 struct seg_desc ss_desc; 1527 uint64_t cr0, rflags, rsp, stack_gla, val; 1528 int error, fault, size, stackaddrsize, pushop; 1529 1530 val = 0; 1531 size = vie->opsize; 1532 pushop = (vie->op.op_type == VIE_OP_TYPE_PUSH) ? 1 : 0; 1533 1534 /* 1535 * From "Address-Size Attributes for Stack Accesses", Intel SDL, Vol 1 1536 */ 1537 if (paging->cpu_mode == CPU_MODE_REAL) { 1538 stackaddrsize = 2; 1539 } else if (paging->cpu_mode == CPU_MODE_64BIT) { 1540 /* 1541 * "Stack Manipulation Instructions in 64-bit Mode", SDM, Vol 3 1542 * - Stack pointer size is always 64-bits. 1543 * - PUSH/POP of 32-bit values is not possible in 64-bit mode. 1544 * - 16-bit PUSH/POP is supported by using the operand size 1545 * override prefix (66H). 1546 */ 1547 stackaddrsize = 8; 1548 size = vie->opsize_override ? 2 : 8; 1549 } else { 1550 /* 1551 * In protected or compatibility mode the 'B' flag in the 1552 * stack-segment descriptor determines the size of the 1553 * stack pointer. 1554 */ 1555 error = vm_get_seg_desc(vm, vcpuid, VM_REG_GUEST_SS, &ss_desc); 1556 KASSERT(error == 0, ("%s: error %d getting SS descriptor", 1557 __func__, error)); 1558 if (SEG_DESC_DEF32(ss_desc.access)) 1559 stackaddrsize = 4; 1560 else 1561 stackaddrsize = 2; 1562 } 1563 1564 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_CR0, &cr0); 1565 KASSERT(error == 0, ("%s: error %d getting cr0", __func__, error)); 1566 1567 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1568 KASSERT(error == 0, ("%s: error %d getting rflags", __func__, error)); 1569 1570 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RSP, &rsp); 1571 KASSERT(error == 0, ("%s: error %d getting rsp", __func__, error)); 1572 if (pushop) { 1573 rsp -= size; 1574 } 1575 1576 if (vie_calculate_gla(paging->cpu_mode, VM_REG_GUEST_SS, &ss_desc, 1577 rsp, size, stackaddrsize, pushop ? PROT_WRITE : PROT_READ, 1578 &stack_gla)) { 1579 vm_inject_ss(vm, vcpuid, 0); 1580 return (0); 1581 } 1582 1583 if (vie_canonical_check(paging->cpu_mode, stack_gla)) { 1584 vm_inject_ss(vm, vcpuid, 0); 1585 return (0); 1586 } 1587 1588 if (vie_alignment_check(paging->cpl, size, cr0, rflags, stack_gla)) { 1589 vm_inject_ac(vm, vcpuid, 0); 1590 return (0); 1591 } 1592 1593 error = vm_copy_setup(vm, vcpuid, paging, stack_gla, size, 1594 pushop ? PROT_WRITE : PROT_READ, copyinfo, nitems(copyinfo), 1595 &fault); 1596 if (error || fault) 1597 return (error); 1598 1599 if (pushop) { 1600 error = memread(vm, vcpuid, mmio_gpa, &val, size, arg); 1601 if (error == 0) 1602 vm_copyout(vm, vcpuid, &val, copyinfo, size); 1603 } else { 1604 vm_copyin(vm, vcpuid, copyinfo, &val, size); 1605 error = memwrite(vm, vcpuid, mmio_gpa, val, size, arg); 1606 rsp += size; 1607 } 1608 vm_copy_teardown(vm, vcpuid, copyinfo, nitems(copyinfo)); 1609 1610 if (error == 0) { 1611 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RSP, rsp, 1612 stackaddrsize); 1613 KASSERT(error == 0, ("error %d updating rsp", error)); 1614 } 1615 return (error); 1616 } 1617 1618 static int 1619 emulate_push(void *vm, int vcpuid, uint64_t mmio_gpa, struct vie *vie, 1620 struct vm_guest_paging *paging, mem_region_read_t memread, 1621 mem_region_write_t memwrite, void *arg) 1622 { 1623 int error; 1624 1625 /* 1626 * Table A-6, "Opcode Extensions", Intel SDM, Vol 2. 1627 * 1628 * PUSH is part of the group 5 extended opcodes and is identified 1629 * by ModRM:reg = b110. 1630 */ 1631 if ((vie->reg & 7) != 6) 1632 return (EINVAL); 1633 1634 error = emulate_stack_op(vm, vcpuid, mmio_gpa, vie, paging, memread, 1635 memwrite, arg); 1636 return (error); 1637 } 1638 1639 static int 1640 emulate_pop(void *vm, int vcpuid, uint64_t mmio_gpa, struct vie *vie, 1641 struct vm_guest_paging *paging, mem_region_read_t memread, 1642 mem_region_write_t memwrite, void *arg) 1643 { 1644 int error; 1645 1646 /* 1647 * Table A-6, "Opcode Extensions", Intel SDM, Vol 2. 1648 * 1649 * POP is part of the group 1A extended opcodes and is identified 1650 * by ModRM:reg = b000. 1651 */ 1652 if ((vie->reg & 7) != 0) 1653 return (EINVAL); 1654 1655 error = emulate_stack_op(vm, vcpuid, mmio_gpa, vie, paging, memread, 1656 memwrite, arg); 1657 return (error); 1658 } 1659 1660 static int 1661 emulate_group1(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1662 struct vm_guest_paging *paging, mem_region_read_t memread, 1663 mem_region_write_t memwrite, void *memarg) 1664 { 1665 int error; 1666 1667 switch (vie->reg & 7) { 1668 case 0x1: /* OR */ 1669 error = emulate_or(vm, vcpuid, gpa, vie, 1670 memread, memwrite, memarg); 1671 break; 1672 case 0x4: /* AND */ 1673 error = emulate_and(vm, vcpuid, gpa, vie, 1674 memread, memwrite, memarg); 1675 break; 1676 case 0x7: /* CMP */ 1677 error = emulate_cmp(vm, vcpuid, gpa, vie, 1678 memread, memwrite, memarg); 1679 break; 1680 default: 1681 error = EINVAL; 1682 break; 1683 } 1684 1685 return (error); 1686 } 1687 1688 static int 1689 emulate_bittest(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1690 mem_region_read_t memread, mem_region_write_t memwrite, void *memarg) 1691 { 1692 uint64_t val, rflags; 1693 int error, bitmask, bitoff; 1694 1695 /* 1696 * 0F BA is a Group 8 extended opcode. 1697 * 1698 * Currently we only emulate the 'Bit Test' instruction which is 1699 * identified by a ModR/M:reg encoding of 100b. 1700 */ 1701 if ((vie->reg & 7) != 4) 1702 return (EINVAL); 1703 1704 error = vie_read_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, &rflags); 1705 KASSERT(error == 0, ("%s: error %d getting rflags", __func__, error)); 1706 1707 error = memread(vm, vcpuid, gpa, &val, vie->opsize, memarg); 1708 if (error) 1709 return (error); 1710 1711 /* 1712 * Intel SDM, Vol 2, Table 3-2: 1713 * "Range of Bit Positions Specified by Bit Offset Operands" 1714 */ 1715 bitmask = vie->opsize * 8 - 1; 1716 bitoff = vie->immediate & bitmask; 1717 1718 /* Copy the bit into the Carry flag in %rflags */ 1719 if (val & (1UL << bitoff)) 1720 rflags |= PSL_C; 1721 else 1722 rflags &= ~PSL_C; 1723 1724 error = vie_update_register(vm, vcpuid, VM_REG_GUEST_RFLAGS, rflags, 8); 1725 KASSERT(error == 0, ("%s: error %d updating rflags", __func__, error)); 1726 1727 return (0); 1728 } 1729 1730 static int 1731 emulate_twob_group15(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1732 mem_region_read_t memread, mem_region_write_t memwrite, void *memarg) 1733 { 1734 int error; 1735 uint64_t buf; 1736 1737 switch (vie->reg & 7) { 1738 case 0x7: /* CLFLUSH, CLFLUSHOPT, and SFENCE */ 1739 if (vie->mod == 0x3) { 1740 /* 1741 * SFENCE. Ignore it, VM exit provides enough 1742 * barriers on its own. 1743 */ 1744 error = 0; 1745 } else { 1746 /* 1747 * CLFLUSH, CLFLUSHOPT. Only check for access 1748 * rights. 1749 */ 1750 error = memread(vm, vcpuid, gpa, &buf, 1, memarg); 1751 } 1752 break; 1753 default: 1754 error = EINVAL; 1755 break; 1756 } 1757 1758 return (error); 1759 } 1760 1761 int 1762 vmm_emulate_instruction(void *vm, int vcpuid, uint64_t gpa, struct vie *vie, 1763 struct vm_guest_paging *paging, mem_region_read_t memread, 1764 mem_region_write_t memwrite, void *memarg) 1765 { 1766 int error; 1767 1768 if (!vie->decoded) 1769 return (EINVAL); 1770 1771 switch (vie->op.op_type) { 1772 case VIE_OP_TYPE_GROUP1: 1773 error = emulate_group1(vm, vcpuid, gpa, vie, paging, memread, 1774 memwrite, memarg); 1775 break; 1776 case VIE_OP_TYPE_POP: 1777 error = emulate_pop(vm, vcpuid, gpa, vie, paging, memread, 1778 memwrite, memarg); 1779 break; 1780 case VIE_OP_TYPE_PUSH: 1781 error = emulate_push(vm, vcpuid, gpa, vie, paging, memread, 1782 memwrite, memarg); 1783 break; 1784 case VIE_OP_TYPE_CMP: 1785 error = emulate_cmp(vm, vcpuid, gpa, vie, 1786 memread, memwrite, memarg); 1787 break; 1788 case VIE_OP_TYPE_MOV: 1789 error = emulate_mov(vm, vcpuid, gpa, vie, 1790 memread, memwrite, memarg); 1791 break; 1792 case VIE_OP_TYPE_MOVSX: 1793 case VIE_OP_TYPE_MOVZX: 1794 error = emulate_movx(vm, vcpuid, gpa, vie, 1795 memread, memwrite, memarg); 1796 break; 1797 case VIE_OP_TYPE_MOVS: 1798 error = emulate_movs(vm, vcpuid, gpa, vie, paging, memread, 1799 memwrite, memarg); 1800 break; 1801 case VIE_OP_TYPE_STOS: 1802 error = emulate_stos(vm, vcpuid, gpa, vie, paging, memread, 1803 memwrite, memarg); 1804 break; 1805 case VIE_OP_TYPE_AND: 1806 error = emulate_and(vm, vcpuid, gpa, vie, 1807 memread, memwrite, memarg); 1808 break; 1809 case VIE_OP_TYPE_OR: 1810 error = emulate_or(vm, vcpuid, gpa, vie, 1811 memread, memwrite, memarg); 1812 break; 1813 case VIE_OP_TYPE_SUB: 1814 error = emulate_sub(vm, vcpuid, gpa, vie, 1815 memread, memwrite, memarg); 1816 break; 1817 case VIE_OP_TYPE_BITTEST: 1818 error = emulate_bittest(vm, vcpuid, gpa, vie, 1819 memread, memwrite, memarg); 1820 break; 1821 case VIE_OP_TYPE_TWOB_GRP15: 1822 error = emulate_twob_group15(vm, vcpuid, gpa, vie, 1823 memread, memwrite, memarg); 1824 break; 1825 case VIE_OP_TYPE_ADD: 1826 error = emulate_add(vm, vcpuid, gpa, vie, memread, 1827 memwrite, memarg); 1828 break; 1829 case VIE_OP_TYPE_TEST: 1830 error = emulate_test(vm, vcpuid, gpa, vie, 1831 memread, memwrite, memarg); 1832 break; 1833 case VIE_OP_TYPE_BEXTR: 1834 error = emulate_bextr(vm, vcpuid, gpa, vie, paging, 1835 memread, memwrite, memarg); 1836 break; 1837 default: 1838 error = EINVAL; 1839 break; 1840 } 1841 1842 return (error); 1843 } 1844 1845 int 1846 vie_alignment_check(int cpl, int size, uint64_t cr0, uint64_t rf, uint64_t gla) 1847 { 1848 KASSERT(size == 1 || size == 2 || size == 4 || size == 8, 1849 ("%s: invalid size %d", __func__, size)); 1850 KASSERT(cpl >= 0 && cpl <= 3, ("%s: invalid cpl %d", __func__, cpl)); 1851 1852 if (cpl != 3 || (cr0 & CR0_AM) == 0 || (rf & PSL_AC) == 0) 1853 return (0); 1854 1855 return ((gla & (size - 1)) ? 1 : 0); 1856 } 1857 1858 int 1859 vie_canonical_check(enum vm_cpu_mode cpu_mode, uint64_t gla) 1860 { 1861 uint64_t mask; 1862 1863 if (cpu_mode != CPU_MODE_64BIT) 1864 return (0); 1865 1866 /* 1867 * The value of the bit 47 in the 'gla' should be replicated in the 1868 * most significant 16 bits. 1869 */ 1870 mask = ~((1UL << 48) - 1); 1871 if (gla & (1UL << 47)) 1872 return ((gla & mask) != mask); 1873 else 1874 return ((gla & mask) != 0); 1875 } 1876 1877 uint64_t 1878 vie_size2mask(int size) 1879 { 1880 KASSERT(size == 1 || size == 2 || size == 4 || size == 8, 1881 ("vie_size2mask: invalid size %d", size)); 1882 return (size2mask[size]); 1883 } 1884 1885 int 1886 vie_calculate_gla(enum vm_cpu_mode cpu_mode, enum vm_reg_name seg, 1887 struct seg_desc *desc, uint64_t offset, int length, int addrsize, 1888 int prot, uint64_t *gla) 1889 { 1890 uint64_t firstoff, low_limit, high_limit, segbase; 1891 int glasize, type; 1892 1893 KASSERT(seg >= VM_REG_GUEST_ES && seg <= VM_REG_GUEST_GS, 1894 ("%s: invalid segment %d", __func__, seg)); 1895 KASSERT(length == 1 || length == 2 || length == 4 || length == 8, 1896 ("%s: invalid operand size %d", __func__, length)); 1897 KASSERT((prot & ~(PROT_READ | PROT_WRITE)) == 0, 1898 ("%s: invalid prot %#x", __func__, prot)); 1899 1900 firstoff = offset; 1901 if (cpu_mode == CPU_MODE_64BIT) { 1902 KASSERT(addrsize == 4 || addrsize == 8, ("%s: invalid address " 1903 "size %d for cpu_mode %d", __func__, addrsize, cpu_mode)); 1904 glasize = 8; 1905 } else { 1906 KASSERT(addrsize == 2 || addrsize == 4, ("%s: invalid address " 1907 "size %d for cpu mode %d", __func__, addrsize, cpu_mode)); 1908 glasize = 4; 1909 /* 1910 * If the segment selector is loaded with a NULL selector 1911 * then the descriptor is unusable and attempting to use 1912 * it results in a #GP(0). 1913 */ 1914 if (SEG_DESC_UNUSABLE(desc->access)) 1915 return (-1); 1916 1917 /* 1918 * The processor generates a #NP exception when a segment 1919 * register is loaded with a selector that points to a 1920 * descriptor that is not present. If this was the case then 1921 * it would have been checked before the VM-exit. 1922 */ 1923 KASSERT(SEG_DESC_PRESENT(desc->access), 1924 ("segment %d not present: %#x", seg, desc->access)); 1925 1926 /* 1927 * The descriptor type must indicate a code/data segment. 1928 */ 1929 type = SEG_DESC_TYPE(desc->access); 1930 KASSERT(type >= 16 && type <= 31, ("segment %d has invalid " 1931 "descriptor type %#x", seg, type)); 1932 1933 if (prot & PROT_READ) { 1934 /* #GP on a read access to a exec-only code segment */ 1935 if ((type & 0xA) == 0x8) 1936 return (-1); 1937 } 1938 1939 if (prot & PROT_WRITE) { 1940 /* 1941 * #GP on a write access to a code segment or a 1942 * read-only data segment. 1943 */ 1944 if (type & 0x8) /* code segment */ 1945 return (-1); 1946 1947 if ((type & 0xA) == 0) /* read-only data seg */ 1948 return (-1); 1949 } 1950 1951 /* 1952 * 'desc->limit' is fully expanded taking granularity into 1953 * account. 1954 */ 1955 if ((type & 0xC) == 0x4) { 1956 /* expand-down data segment */ 1957 low_limit = desc->limit + 1; 1958 high_limit = SEG_DESC_DEF32(desc->access) ? 1959 0xffffffff : 0xffff; 1960 } else { 1961 /* code segment or expand-up data segment */ 1962 low_limit = 0; 1963 high_limit = desc->limit; 1964 } 1965 1966 while (length > 0) { 1967 offset &= vie_size2mask(addrsize); 1968 if (offset < low_limit || offset > high_limit) 1969 return (-1); 1970 offset++; 1971 length--; 1972 } 1973 } 1974 1975 /* 1976 * In 64-bit mode all segments except %fs and %gs have a segment 1977 * base address of 0. 1978 */ 1979 if (cpu_mode == CPU_MODE_64BIT && seg != VM_REG_GUEST_FS && 1980 seg != VM_REG_GUEST_GS) { 1981 segbase = 0; 1982 } else { 1983 segbase = desc->base; 1984 } 1985 1986 /* 1987 * Truncate 'firstoff' to the effective address size before adding 1988 * it to the segment base. 1989 */ 1990 firstoff &= vie_size2mask(addrsize); 1991 *gla = (segbase + firstoff) & vie_size2mask(glasize); 1992 return (0); 1993 } 1994 1995 /* 1996 * Prepare a partially decoded vie for a 2nd attempt. 1997 */ 1998 void 1999 vie_restart(struct vie *vie) 2000 { 2001 _Static_assert( 2002 offsetof(struct vie, inst) < offsetof(struct vie, vie_startzero) && 2003 offsetof(struct vie, num_valid) < offsetof(struct vie, vie_startzero), 2004 "restart should not erase instruction length or contents"); 2005 2006 memset((char *)vie + offsetof(struct vie, vie_startzero), 0, 2007 sizeof(*vie) - offsetof(struct vie, vie_startzero)); 2008 2009 vie->base_register = VM_REG_LAST; 2010 vie->index_register = VM_REG_LAST; 2011 vie->segment_register = VM_REG_LAST; 2012 } 2013 2014 void 2015 vie_init(struct vie *vie, const char *inst_bytes, int inst_length) 2016 { 2017 KASSERT(inst_length >= 0 && inst_length <= VIE_INST_SIZE, 2018 ("%s: invalid instruction length (%d)", __func__, inst_length)); 2019 2020 vie_restart(vie); 2021 memset(vie->inst, 0, sizeof(vie->inst)); 2022 if (inst_length != 0) 2023 memcpy(vie->inst, inst_bytes, inst_length); 2024 vie->num_valid = inst_length; 2025 } 2026 2027 #ifdef _KERNEL 2028 static int 2029 pf_error_code(int usermode, int prot, int rsvd, uint64_t pte) 2030 { 2031 int error_code = 0; 2032 2033 if (pte & PG_V) 2034 error_code |= PGEX_P; 2035 if (prot & VM_PROT_WRITE) 2036 error_code |= PGEX_W; 2037 if (usermode) 2038 error_code |= PGEX_U; 2039 if (rsvd) 2040 error_code |= PGEX_RSV; 2041 if (prot & VM_PROT_EXECUTE) 2042 error_code |= PGEX_I; 2043 2044 return (error_code); 2045 } 2046 2047 static void 2048 ptp_release(void **cookie) 2049 { 2050 if (*cookie != NULL) { 2051 vm_gpa_release(*cookie); 2052 *cookie = NULL; 2053 } 2054 } 2055 2056 static void * 2057 ptp_hold(struct vm *vm, int vcpu, vm_paddr_t ptpphys, size_t len, void **cookie) 2058 { 2059 void *ptr; 2060 2061 ptp_release(cookie); 2062 ptr = vm_gpa_hold(vm, vcpu, ptpphys, len, VM_PROT_RW, cookie); 2063 return (ptr); 2064 } 2065 2066 static int 2067 _vm_gla2gpa(struct vm *vm, int vcpuid, struct vm_guest_paging *paging, 2068 uint64_t gla, int prot, uint64_t *gpa, int *guest_fault, bool check_only) 2069 { 2070 int nlevels, pfcode, ptpshift, ptpindex, retval, usermode, writable; 2071 u_int retries; 2072 uint64_t *ptpbase, ptpphys, pte, pgsize; 2073 uint32_t *ptpbase32, pte32; 2074 void *cookie; 2075 2076 *guest_fault = 0; 2077 2078 usermode = (paging->cpl == 3 ? 1 : 0); 2079 writable = prot & VM_PROT_WRITE; 2080 cookie = NULL; 2081 retval = 0; 2082 retries = 0; 2083 restart: 2084 ptpphys = paging->cr3; /* root of the page tables */ 2085 ptp_release(&cookie); 2086 if (retries++ > 0) 2087 maybe_yield(); 2088 2089 if (vie_canonical_check(paging->cpu_mode, gla)) { 2090 /* 2091 * XXX assuming a non-stack reference otherwise a stack fault 2092 * should be generated. 2093 */ 2094 if (!check_only) 2095 vm_inject_gp(vm, vcpuid); 2096 goto fault; 2097 } 2098 2099 if (paging->paging_mode == PAGING_MODE_FLAT) { 2100 *gpa = gla; 2101 goto done; 2102 } 2103 2104 if (paging->paging_mode == PAGING_MODE_32) { 2105 nlevels = 2; 2106 while (--nlevels >= 0) { 2107 /* Zero out the lower 12 bits. */ 2108 ptpphys &= ~0xfff; 2109 2110 ptpbase32 = ptp_hold(vm, vcpuid, ptpphys, PAGE_SIZE, 2111 &cookie); 2112 2113 if (ptpbase32 == NULL) 2114 goto error; 2115 2116 ptpshift = PAGE_SHIFT + nlevels * 10; 2117 ptpindex = (gla >> ptpshift) & 0x3FF; 2118 pgsize = 1UL << ptpshift; 2119 2120 pte32 = ptpbase32[ptpindex]; 2121 2122 if ((pte32 & PG_V) == 0 || 2123 (usermode && (pte32 & PG_U) == 0) || 2124 (writable && (pte32 & PG_RW) == 0)) { 2125 if (!check_only) { 2126 pfcode = pf_error_code(usermode, prot, 0, 2127 pte32); 2128 vm_inject_pf(vm, vcpuid, pfcode, gla); 2129 } 2130 goto fault; 2131 } 2132 2133 /* 2134 * Emulate the x86 MMU's management of the accessed 2135 * and dirty flags. While the accessed flag is set 2136 * at every level of the page table, the dirty flag 2137 * is only set at the last level providing the guest 2138 * physical address. 2139 */ 2140 if (!check_only && (pte32 & PG_A) == 0) { 2141 if (atomic_cmpset_32(&ptpbase32[ptpindex], 2142 pte32, pte32 | PG_A) == 0) { 2143 goto restart; 2144 } 2145 } 2146 2147 /* XXX must be ignored if CR4.PSE=0 */ 2148 if (nlevels > 0 && (pte32 & PG_PS) != 0) 2149 break; 2150 2151 ptpphys = pte32; 2152 } 2153 2154 /* Set the dirty bit in the page table entry if necessary */ 2155 if (!check_only && writable && (pte32 & PG_M) == 0) { 2156 if (atomic_cmpset_32(&ptpbase32[ptpindex], 2157 pte32, pte32 | PG_M) == 0) { 2158 goto restart; 2159 } 2160 } 2161 2162 /* Zero out the lower 'ptpshift' bits */ 2163 pte32 >>= ptpshift; pte32 <<= ptpshift; 2164 *gpa = pte32 | (gla & (pgsize - 1)); 2165 goto done; 2166 } 2167 2168 if (paging->paging_mode == PAGING_MODE_PAE) { 2169 /* Zero out the lower 5 bits and the upper 32 bits */ 2170 ptpphys &= 0xffffffe0UL; 2171 2172 ptpbase = ptp_hold(vm, vcpuid, ptpphys, sizeof(*ptpbase) * 4, 2173 &cookie); 2174 if (ptpbase == NULL) 2175 goto error; 2176 2177 ptpindex = (gla >> 30) & 0x3; 2178 2179 pte = ptpbase[ptpindex]; 2180 2181 if ((pte & PG_V) == 0) { 2182 if (!check_only) { 2183 pfcode = pf_error_code(usermode, prot, 0, pte); 2184 vm_inject_pf(vm, vcpuid, pfcode, gla); 2185 } 2186 goto fault; 2187 } 2188 2189 ptpphys = pte; 2190 2191 nlevels = 2; 2192 } else 2193 nlevels = 4; 2194 while (--nlevels >= 0) { 2195 /* Zero out the lower 12 bits and the upper 12 bits */ 2196 ptpphys >>= 12; ptpphys <<= 24; ptpphys >>= 12; 2197 2198 ptpbase = ptp_hold(vm, vcpuid, ptpphys, PAGE_SIZE, &cookie); 2199 if (ptpbase == NULL) 2200 goto error; 2201 2202 ptpshift = PAGE_SHIFT + nlevels * 9; 2203 ptpindex = (gla >> ptpshift) & 0x1FF; 2204 pgsize = 1UL << ptpshift; 2205 2206 pte = ptpbase[ptpindex]; 2207 2208 if ((pte & PG_V) == 0 || 2209 (usermode && (pte & PG_U) == 0) || 2210 (writable && (pte & PG_RW) == 0)) { 2211 if (!check_only) { 2212 pfcode = pf_error_code(usermode, prot, 0, pte); 2213 vm_inject_pf(vm, vcpuid, pfcode, gla); 2214 } 2215 goto fault; 2216 } 2217 2218 /* Set the accessed bit in the page table entry */ 2219 if (!check_only && (pte & PG_A) == 0) { 2220 if (atomic_cmpset_64(&ptpbase[ptpindex], 2221 pte, pte | PG_A) == 0) { 2222 goto restart; 2223 } 2224 } 2225 2226 if (nlevels > 0 && (pte & PG_PS) != 0) { 2227 if (pgsize > 1 * GB) { 2228 if (!check_only) { 2229 pfcode = pf_error_code(usermode, prot, 1, 2230 pte); 2231 vm_inject_pf(vm, vcpuid, pfcode, gla); 2232 } 2233 goto fault; 2234 } 2235 break; 2236 } 2237 2238 ptpphys = pte; 2239 } 2240 2241 /* Set the dirty bit in the page table entry if necessary */ 2242 if (!check_only && writable && (pte & PG_M) == 0) { 2243 if (atomic_cmpset_64(&ptpbase[ptpindex], pte, pte | PG_M) == 0) 2244 goto restart; 2245 } 2246 2247 /* Zero out the lower 'ptpshift' bits and the upper 12 bits */ 2248 pte >>= ptpshift; pte <<= (ptpshift + 12); pte >>= 12; 2249 *gpa = pte | (gla & (pgsize - 1)); 2250 done: 2251 ptp_release(&cookie); 2252 KASSERT(retval == 0 || retval == EFAULT, ("%s: unexpected retval %d", 2253 __func__, retval)); 2254 return (retval); 2255 error: 2256 retval = EFAULT; 2257 goto done; 2258 fault: 2259 *guest_fault = 1; 2260 goto done; 2261 } 2262 2263 int 2264 vm_gla2gpa(struct vm *vm, int vcpuid, struct vm_guest_paging *paging, 2265 uint64_t gla, int prot, uint64_t *gpa, int *guest_fault) 2266 { 2267 2268 return (_vm_gla2gpa(vm, vcpuid, paging, gla, prot, gpa, guest_fault, 2269 false)); 2270 } 2271 2272 int 2273 vm_gla2gpa_nofault(struct vm *vm, int vcpuid, struct vm_guest_paging *paging, 2274 uint64_t gla, int prot, uint64_t *gpa, int *guest_fault) 2275 { 2276 2277 return (_vm_gla2gpa(vm, vcpuid, paging, gla, prot, gpa, guest_fault, 2278 true)); 2279 } 2280 2281 int 2282 vmm_fetch_instruction(struct vm *vm, int vcpuid, struct vm_guest_paging *paging, 2283 uint64_t rip, int inst_length, struct vie *vie, int *faultptr) 2284 { 2285 struct vm_copyinfo copyinfo[2]; 2286 int error, prot; 2287 2288 if (inst_length > VIE_INST_SIZE) 2289 panic("vmm_fetch_instruction: invalid length %d", inst_length); 2290 2291 prot = PROT_READ | PROT_EXEC; 2292 error = vm_copy_setup(vm, vcpuid, paging, rip, inst_length, prot, 2293 copyinfo, nitems(copyinfo), faultptr); 2294 if (error || *faultptr) 2295 return (error); 2296 2297 vm_copyin(vm, vcpuid, copyinfo, vie->inst, inst_length); 2298 vm_copy_teardown(vm, vcpuid, copyinfo, nitems(copyinfo)); 2299 vie->num_valid = inst_length; 2300 return (0); 2301 } 2302 #endif /* _KERNEL */ 2303 2304 static int 2305 vie_peek(struct vie *vie, uint8_t *x) 2306 { 2307 2308 if (vie->num_processed < vie->num_valid) { 2309 *x = vie->inst[vie->num_processed]; 2310 return (0); 2311 } else 2312 return (-1); 2313 } 2314 2315 static void 2316 vie_advance(struct vie *vie) 2317 { 2318 2319 vie->num_processed++; 2320 } 2321 2322 static bool 2323 segment_override(uint8_t x, int *seg) 2324 { 2325 2326 switch (x) { 2327 case 0x2E: 2328 *seg = VM_REG_GUEST_CS; 2329 break; 2330 case 0x36: 2331 *seg = VM_REG_GUEST_SS; 2332 break; 2333 case 0x3E: 2334 *seg = VM_REG_GUEST_DS; 2335 break; 2336 case 0x26: 2337 *seg = VM_REG_GUEST_ES; 2338 break; 2339 case 0x64: 2340 *seg = VM_REG_GUEST_FS; 2341 break; 2342 case 0x65: 2343 *seg = VM_REG_GUEST_GS; 2344 break; 2345 default: 2346 return (false); 2347 } 2348 return (true); 2349 } 2350 2351 static int 2352 decode_prefixes(struct vie *vie, enum vm_cpu_mode cpu_mode, int cs_d) 2353 { 2354 uint8_t x; 2355 2356 while (1) { 2357 if (vie_peek(vie, &x)) 2358 return (-1); 2359 2360 if (x == 0x66) 2361 vie->opsize_override = 1; 2362 else if (x == 0x67) 2363 vie->addrsize_override = 1; 2364 else if (x == 0xF3) 2365 vie->repz_present = 1; 2366 else if (x == 0xF2) 2367 vie->repnz_present = 1; 2368 else if (segment_override(x, &vie->segment_register)) 2369 vie->segment_override = 1; 2370 else 2371 break; 2372 2373 vie_advance(vie); 2374 } 2375 2376 /* 2377 * From section 2.2.1, "REX Prefixes", Intel SDM Vol 2: 2378 * - Only one REX prefix is allowed per instruction. 2379 * - The REX prefix must immediately precede the opcode byte or the 2380 * escape opcode byte. 2381 * - If an instruction has a mandatory prefix (0x66, 0xF2 or 0xF3) 2382 * the mandatory prefix must come before the REX prefix. 2383 */ 2384 if (cpu_mode == CPU_MODE_64BIT && x >= 0x40 && x <= 0x4F) { 2385 vie->rex_present = 1; 2386 vie->rex_w = x & 0x8 ? 1 : 0; 2387 vie->rex_r = x & 0x4 ? 1 : 0; 2388 vie->rex_x = x & 0x2 ? 1 : 0; 2389 vie->rex_b = x & 0x1 ? 1 : 0; 2390 vie_advance(vie); 2391 } 2392 2393 /* 2394 * § 2.3.5, "The VEX Prefix", SDM Vol 2. 2395 */ 2396 if ((cpu_mode == CPU_MODE_64BIT || cpu_mode == CPU_MODE_COMPATIBILITY) 2397 && x == 0xC4) { 2398 const struct vie_op *optab; 2399 2400 /* 3-byte VEX prefix. */ 2401 vie->vex_present = 1; 2402 2403 vie_advance(vie); 2404 if (vie_peek(vie, &x)) 2405 return (-1); 2406 2407 /* 2408 * 2nd byte: [R', X', B', mmmmm[4:0]]. Bits are inverted 2409 * relative to REX encoding. 2410 */ 2411 vie->rex_r = x & 0x80 ? 0 : 1; 2412 vie->rex_x = x & 0x40 ? 0 : 1; 2413 vie->rex_b = x & 0x20 ? 0 : 1; 2414 2415 switch (x & 0x1F) { 2416 case 0x2: 2417 /* 0F 38. */ 2418 optab = three_byte_opcodes_0f38; 2419 break; 2420 case 0x1: 2421 /* 0F class - nothing handled here yet. */ 2422 /* FALLTHROUGH */ 2423 case 0x3: 2424 /* 0F 3A class - nothing handled here yet. */ 2425 /* FALLTHROUGH */ 2426 default: 2427 /* Reserved (#UD). */ 2428 return (-1); 2429 } 2430 2431 vie_advance(vie); 2432 if (vie_peek(vie, &x)) 2433 return (-1); 2434 2435 /* 3rd byte: [W, vvvv[6:3], L, pp[1:0]]. */ 2436 vie->rex_w = x & 0x80 ? 1 : 0; 2437 2438 vie->vex_reg = ((~(unsigned)x & 0x78u) >> 3); 2439 vie->vex_l = !!(x & 0x4); 2440 vie->vex_pp = (x & 0x3); 2441 2442 /* PP: 1=66 2=F3 3=F2 prefixes. */ 2443 switch (vie->vex_pp) { 2444 case 0x1: 2445 vie->opsize_override = 1; 2446 break; 2447 case 0x2: 2448 vie->repz_present = 1; 2449 break; 2450 case 0x3: 2451 vie->repnz_present = 1; 2452 break; 2453 } 2454 2455 vie_advance(vie); 2456 2457 /* Opcode, sans literal prefix prefix. */ 2458 if (vie_peek(vie, &x)) 2459 return (-1); 2460 2461 vie->op = optab[x]; 2462 if (vie->op.op_type == VIE_OP_TYPE_NONE) 2463 return (-1); 2464 2465 vie_advance(vie); 2466 } 2467 2468 /* 2469 * Section "Operand-Size And Address-Size Attributes", Intel SDM, Vol 1 2470 */ 2471 if (cpu_mode == CPU_MODE_64BIT) { 2472 /* 2473 * Default address size is 64-bits and default operand size 2474 * is 32-bits. 2475 */ 2476 vie->addrsize = vie->addrsize_override ? 4 : 8; 2477 if (vie->rex_w) 2478 vie->opsize = 8; 2479 else if (vie->opsize_override) 2480 vie->opsize = 2; 2481 else 2482 vie->opsize = 4; 2483 } else if (cs_d) { 2484 /* Default address and operand sizes are 32-bits */ 2485 vie->addrsize = vie->addrsize_override ? 2 : 4; 2486 vie->opsize = vie->opsize_override ? 2 : 4; 2487 } else { 2488 /* Default address and operand sizes are 16-bits */ 2489 vie->addrsize = vie->addrsize_override ? 4 : 2; 2490 vie->opsize = vie->opsize_override ? 4 : 2; 2491 } 2492 return (0); 2493 } 2494 2495 static int 2496 decode_two_byte_opcode(struct vie *vie) 2497 { 2498 uint8_t x; 2499 2500 if (vie_peek(vie, &x)) 2501 return (-1); 2502 2503 vie->op = two_byte_opcodes[x]; 2504 2505 if (vie->op.op_type == VIE_OP_TYPE_NONE) 2506 return (-1); 2507 2508 vie_advance(vie); 2509 return (0); 2510 } 2511 2512 static int 2513 decode_opcode(struct vie *vie) 2514 { 2515 uint8_t x; 2516 2517 if (vie_peek(vie, &x)) 2518 return (-1); 2519 2520 /* Already did this via VEX prefix. */ 2521 if (vie->op.op_type != VIE_OP_TYPE_NONE) 2522 return (0); 2523 2524 vie->op = one_byte_opcodes[x]; 2525 2526 if (vie->op.op_type == VIE_OP_TYPE_NONE) 2527 return (-1); 2528 2529 vie_advance(vie); 2530 2531 if (vie->op.op_type == VIE_OP_TYPE_TWO_BYTE) 2532 return (decode_two_byte_opcode(vie)); 2533 2534 return (0); 2535 } 2536 2537 static int 2538 decode_modrm(struct vie *vie, enum vm_cpu_mode cpu_mode) 2539 { 2540 uint8_t x; 2541 2542 if (vie->op.op_flags & VIE_OP_F_NO_MODRM) 2543 return (0); 2544 2545 if (cpu_mode == CPU_MODE_REAL) 2546 return (-1); 2547 2548 if (vie_peek(vie, &x)) 2549 return (-1); 2550 2551 vie->mod = (x >> 6) & 0x3; 2552 vie->rm = (x >> 0) & 0x7; 2553 vie->reg = (x >> 3) & 0x7; 2554 2555 /* 2556 * A direct addressing mode makes no sense in the context of an EPT 2557 * fault. There has to be a memory access involved to cause the 2558 * EPT fault. 2559 */ 2560 if (vie->mod == VIE_MOD_DIRECT) 2561 return (-1); 2562 2563 if ((vie->mod == VIE_MOD_INDIRECT && vie->rm == VIE_RM_DISP32) || 2564 (vie->mod != VIE_MOD_DIRECT && vie->rm == VIE_RM_SIB)) { 2565 /* 2566 * Table 2-5: Special Cases of REX Encodings 2567 * 2568 * mod=0, r/m=5 is used in the compatibility mode to 2569 * indicate a disp32 without a base register. 2570 * 2571 * mod!=3, r/m=4 is used in the compatibility mode to 2572 * indicate that the SIB byte is present. 2573 * 2574 * The 'b' bit in the REX prefix is don't care in 2575 * this case. 2576 */ 2577 } else { 2578 vie->rm |= (vie->rex_b << 3); 2579 } 2580 2581 vie->reg |= (vie->rex_r << 3); 2582 2583 /* SIB */ 2584 if (vie->mod != VIE_MOD_DIRECT && vie->rm == VIE_RM_SIB) 2585 goto done; 2586 2587 vie->base_register = gpr_map[vie->rm]; 2588 2589 switch (vie->mod) { 2590 case VIE_MOD_INDIRECT_DISP8: 2591 vie->disp_bytes = 1; 2592 break; 2593 case VIE_MOD_INDIRECT_DISP32: 2594 vie->disp_bytes = 4; 2595 break; 2596 case VIE_MOD_INDIRECT: 2597 if (vie->rm == VIE_RM_DISP32) { 2598 vie->disp_bytes = 4; 2599 /* 2600 * Table 2-7. RIP-Relative Addressing 2601 * 2602 * In 64-bit mode mod=00 r/m=101 implies [rip] + disp32 2603 * whereas in compatibility mode it just implies disp32. 2604 */ 2605 2606 if (cpu_mode == CPU_MODE_64BIT) 2607 vie->base_register = VM_REG_GUEST_RIP; 2608 else 2609 vie->base_register = VM_REG_LAST; 2610 } 2611 break; 2612 } 2613 2614 done: 2615 vie_advance(vie); 2616 2617 return (0); 2618 } 2619 2620 static int 2621 decode_sib(struct vie *vie) 2622 { 2623 uint8_t x; 2624 2625 /* Proceed only if SIB byte is present */ 2626 if (vie->mod == VIE_MOD_DIRECT || vie->rm != VIE_RM_SIB) 2627 return (0); 2628 2629 if (vie_peek(vie, &x)) 2630 return (-1); 2631 2632 /* De-construct the SIB byte */ 2633 vie->ss = (x >> 6) & 0x3; 2634 vie->index = (x >> 3) & 0x7; 2635 vie->base = (x >> 0) & 0x7; 2636 2637 /* Apply the REX prefix modifiers */ 2638 vie->index |= vie->rex_x << 3; 2639 vie->base |= vie->rex_b << 3; 2640 2641 switch (vie->mod) { 2642 case VIE_MOD_INDIRECT_DISP8: 2643 vie->disp_bytes = 1; 2644 break; 2645 case VIE_MOD_INDIRECT_DISP32: 2646 vie->disp_bytes = 4; 2647 break; 2648 } 2649 2650 if (vie->mod == VIE_MOD_INDIRECT && 2651 (vie->base == 5 || vie->base == 13)) { 2652 /* 2653 * Special case when base register is unused if mod = 0 2654 * and base = %rbp or %r13. 2655 * 2656 * Documented in: 2657 * Table 2-3: 32-bit Addressing Forms with the SIB Byte 2658 * Table 2-5: Special Cases of REX Encodings 2659 */ 2660 vie->disp_bytes = 4; 2661 } else { 2662 vie->base_register = gpr_map[vie->base]; 2663 } 2664 2665 /* 2666 * All encodings of 'index' are valid except for %rsp (4). 2667 * 2668 * Documented in: 2669 * Table 2-3: 32-bit Addressing Forms with the SIB Byte 2670 * Table 2-5: Special Cases of REX Encodings 2671 */ 2672 if (vie->index != 4) 2673 vie->index_register = gpr_map[vie->index]; 2674 2675 /* 'scale' makes sense only in the context of an index register */ 2676 if (vie->index_register < VM_REG_LAST) 2677 vie->scale = 1 << vie->ss; 2678 2679 vie_advance(vie); 2680 2681 return (0); 2682 } 2683 2684 static int 2685 decode_displacement(struct vie *vie) 2686 { 2687 int n, i; 2688 uint8_t x; 2689 2690 union { 2691 char buf[4]; 2692 int8_t signed8; 2693 int32_t signed32; 2694 } u; 2695 2696 if ((n = vie->disp_bytes) == 0) 2697 return (0); 2698 2699 if (n != 1 && n != 4) 2700 panic("decode_displacement: invalid disp_bytes %d", n); 2701 2702 for (i = 0; i < n; i++) { 2703 if (vie_peek(vie, &x)) 2704 return (-1); 2705 2706 u.buf[i] = x; 2707 vie_advance(vie); 2708 } 2709 2710 if (n == 1) 2711 vie->displacement = u.signed8; /* sign-extended */ 2712 else 2713 vie->displacement = u.signed32; /* sign-extended */ 2714 2715 return (0); 2716 } 2717 2718 static int 2719 decode_immediate(struct vie *vie) 2720 { 2721 int i, n; 2722 uint8_t x; 2723 union { 2724 char buf[4]; 2725 int8_t signed8; 2726 int16_t signed16; 2727 int32_t signed32; 2728 } u; 2729 2730 /* Figure out immediate operand size (if any) */ 2731 if (vie->op.op_flags & VIE_OP_F_IMM) { 2732 /* 2733 * Section 2.2.1.5 "Immediates", Intel SDM: 2734 * In 64-bit mode the typical size of immediate operands 2735 * remains 32-bits. When the operand size if 64-bits, the 2736 * processor sign-extends all immediates to 64-bits prior 2737 * to their use. 2738 */ 2739 if (vie->opsize == 4 || vie->opsize == 8) 2740 vie->imm_bytes = 4; 2741 else 2742 vie->imm_bytes = 2; 2743 } else if (vie->op.op_flags & VIE_OP_F_IMM8) { 2744 vie->imm_bytes = 1; 2745 } 2746 2747 if ((n = vie->imm_bytes) == 0) 2748 return (0); 2749 2750 KASSERT(n == 1 || n == 2 || n == 4, 2751 ("%s: invalid number of immediate bytes: %d", __func__, n)); 2752 2753 for (i = 0; i < n; i++) { 2754 if (vie_peek(vie, &x)) 2755 return (-1); 2756 2757 u.buf[i] = x; 2758 vie_advance(vie); 2759 } 2760 2761 /* sign-extend the immediate value before use */ 2762 if (n == 1) 2763 vie->immediate = u.signed8; 2764 else if (n == 2) 2765 vie->immediate = u.signed16; 2766 else 2767 vie->immediate = u.signed32; 2768 2769 return (0); 2770 } 2771 2772 static int 2773 decode_moffset(struct vie *vie) 2774 { 2775 int i, n; 2776 uint8_t x; 2777 union { 2778 char buf[8]; 2779 uint64_t u64; 2780 } u; 2781 2782 if ((vie->op.op_flags & VIE_OP_F_MOFFSET) == 0) 2783 return (0); 2784 2785 /* 2786 * Section 2.2.1.4, "Direct Memory-Offset MOVs", Intel SDM: 2787 * The memory offset size follows the address-size of the instruction. 2788 */ 2789 n = vie->addrsize; 2790 KASSERT(n == 2 || n == 4 || n == 8, ("invalid moffset bytes: %d", n)); 2791 2792 u.u64 = 0; 2793 for (i = 0; i < n; i++) { 2794 if (vie_peek(vie, &x)) 2795 return (-1); 2796 2797 u.buf[i] = x; 2798 vie_advance(vie); 2799 } 2800 vie->displacement = u.u64; 2801 return (0); 2802 } 2803 2804 #ifdef _KERNEL 2805 /* 2806 * Verify that the 'guest linear address' provided as collateral of the nested 2807 * page table fault matches with our instruction decoding. 2808 */ 2809 static int 2810 verify_gla(struct vm *vm, int cpuid, uint64_t gla, struct vie *vie, 2811 enum vm_cpu_mode cpu_mode) 2812 { 2813 int error; 2814 uint64_t base, segbase, idx, gla2; 2815 enum vm_reg_name seg; 2816 struct seg_desc desc; 2817 2818 /* Skip 'gla' verification */ 2819 if (gla == VIE_INVALID_GLA) 2820 return (0); 2821 2822 base = 0; 2823 if (vie->base_register != VM_REG_LAST) { 2824 error = vm_get_register(vm, cpuid, vie->base_register, &base); 2825 if (error) { 2826 printf("verify_gla: error %d getting base reg %d\n", 2827 error, vie->base_register); 2828 return (-1); 2829 } 2830 2831 /* 2832 * RIP-relative addressing starts from the following 2833 * instruction 2834 */ 2835 if (vie->base_register == VM_REG_GUEST_RIP) 2836 base += vie->num_processed; 2837 } 2838 2839 idx = 0; 2840 if (vie->index_register != VM_REG_LAST) { 2841 error = vm_get_register(vm, cpuid, vie->index_register, &idx); 2842 if (error) { 2843 printf("verify_gla: error %d getting index reg %d\n", 2844 error, vie->index_register); 2845 return (-1); 2846 } 2847 } 2848 2849 /* 2850 * From "Specifying a Segment Selector", Intel SDM, Vol 1 2851 * 2852 * In 64-bit mode, segmentation is generally (but not 2853 * completely) disabled. The exceptions are the FS and GS 2854 * segments. 2855 * 2856 * In legacy IA-32 mode, when the ESP or EBP register is used 2857 * as the base, the SS segment is the default segment. For 2858 * other data references, except when relative to stack or 2859 * string destination the DS segment is the default. These 2860 * can be overridden to allow other segments to be accessed. 2861 */ 2862 if (vie->segment_override) 2863 seg = vie->segment_register; 2864 else if (vie->base_register == VM_REG_GUEST_RSP || 2865 vie->base_register == VM_REG_GUEST_RBP) 2866 seg = VM_REG_GUEST_SS; 2867 else 2868 seg = VM_REG_GUEST_DS; 2869 if (cpu_mode == CPU_MODE_64BIT && seg != VM_REG_GUEST_FS && 2870 seg != VM_REG_GUEST_GS) { 2871 segbase = 0; 2872 } else { 2873 error = vm_get_seg_desc(vm, cpuid, seg, &desc); 2874 if (error) { 2875 printf("verify_gla: error %d getting segment" 2876 " descriptor %d", error, 2877 vie->segment_register); 2878 return (-1); 2879 } 2880 segbase = desc.base; 2881 } 2882 2883 gla2 = segbase + base + vie->scale * idx + vie->displacement; 2884 gla2 &= size2mask[vie->addrsize]; 2885 if (gla != gla2) { 2886 printf("verify_gla mismatch: segbase(0x%0lx)" 2887 "base(0x%0lx), scale(%d), index(0x%0lx), " 2888 "disp(0x%0lx), gla(0x%0lx), gla2(0x%0lx)\n", 2889 segbase, base, vie->scale, idx, vie->displacement, 2890 gla, gla2); 2891 return (-1); 2892 } 2893 2894 return (0); 2895 } 2896 #endif /* _KERNEL */ 2897 2898 int 2899 #ifdef _KERNEL 2900 vmm_decode_instruction(struct vm *vm, int cpuid, uint64_t gla, 2901 enum vm_cpu_mode cpu_mode, int cs_d, struct vie *vie) 2902 #else 2903 vmm_decode_instruction(enum vm_cpu_mode cpu_mode, int cs_d, struct vie *vie) 2904 #endif 2905 { 2906 2907 if (decode_prefixes(vie, cpu_mode, cs_d)) 2908 return (-1); 2909 2910 if (decode_opcode(vie)) 2911 return (-1); 2912 2913 if (decode_modrm(vie, cpu_mode)) 2914 return (-1); 2915 2916 if (decode_sib(vie)) 2917 return (-1); 2918 2919 if (decode_displacement(vie)) 2920 return (-1); 2921 2922 if (decode_immediate(vie)) 2923 return (-1); 2924 2925 if (decode_moffset(vie)) 2926 return (-1); 2927 2928 #ifdef _KERNEL 2929 if ((vie->op.op_flags & VIE_OP_F_NO_GLA_VERIFICATION) == 0) { 2930 if (verify_gla(vm, cpuid, gla, vie, cpu_mode)) 2931 return (-1); 2932 } 2933 #endif 2934 2935 vie->decoded = 1; /* success */ 2936 2937 return (0); 2938 } 2939