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Emulate the 'CMP r/m8, imm8' instruction encountered when booting a Windows

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Vista guest.

Reported by:	Leon Dang (ldang@nahannisys.com)
MFC after:	1 week
This commit is contained in:
Neel Natu 2015-05-04 04:27:23 +00:00
parent fc4d77c3ce
commit 6a273d5ef7
1 changed files with 14 additions and 2 deletions
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16
sys/amd64/vmm/vmm_instruction_emul.c
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@ -178,14 +178,20 @@ static const struct vie_op one_byte_opcodes[256] = {
.op_byte = 0x23,
.op_type = VIE_OP_TYPE_AND,
},
[0x80] = {
/* Group 1 extended opcode */
.op_byte = 0x80,
.op_type = VIE_OP_TYPE_GROUP1,
.op_flags = VIE_OP_F_IMM8,
},
[0x81] = {
/* XXX Group 1 extended opcode */
/* Group 1 extended opcode */
.op_byte = 0x81,
.op_type = VIE_OP_TYPE_GROUP1,
.op_flags = VIE_OP_F_IMM,
},
[0x83] = {
/* XXX Group 1 extended opcode */
/* Group 1 extended opcode */
.op_byte = 0x83,
.op_type = VIE_OP_TYPE_GROUP1,
.op_flags = VIE_OP_F_IMM8,
@ -1066,9 +1072,13 @@ emulate_cmp(void *vm, int vcpuid, uint64_t gpa, struct vie *vie,
rflags2 = getcc(size, op1, op2);
break;
case 0x80:
case 0x81:
case 0x83:
/*
* 80 /7 cmp r/m8, imm8
* REX + 80 /7 cmp r/m8, imm8
*
* 81 /7 cmp r/m16, imm16
* 81 /7 cmp r/m32, imm32
* REX.W + 81 /7 cmp r/m64, imm32 sign-extended to 64
@ -1084,6 +1094,8 @@ emulate_cmp(void *vm, int vcpuid, uint64_t gpa, struct vie *vie,
* the status flags.
*
*/
if (vie->op.op_byte == 0x80)
size = 1;
/* get the first operand */
error = memread(vm, vcpuid, gpa, &op1, size, arg);