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Emulate the "CMP r/m, reg" instruction (opcode 39H).

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Reported and tested by:	Leon Dang (ldang@nahannisys.com)
MFC after:	1 week
This commit is contained in:
neel 2015-05-21 18:23:37 +00:00
parent 676f4d4526
commit a0ca6168e6
1 changed files with 22 additions and 6 deletions
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28
sys/amd64/vmm/vmm_instruction_emul.c
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@ -113,6 +113,10 @@ static const struct vie_op one_byte_opcodes[256] = {
.op_byte = 0x2B,
.op_type = VIE_OP_TYPE_SUB,
},
[0x39] = {
.op_byte = 0x39,
.op_type = VIE_OP_TYPE_CMP,
},
[0x3B] = {
.op_byte = 0x3B,
.op_type = VIE_OP_TYPE_CMP,
@ -1050,34 +1054,46 @@ emulate_cmp(void *vm, int vcpuid, uint64_t gpa, struct vie *vie,
mem_region_read_t memread, mem_region_write_t memwrite, void *arg)
{
int error, size;
uint64_t op1, op2, rflags, rflags2;
uint64_t regop, memop, op1, op2, rflags, rflags2;
enum vm_reg_name reg;
size = vie->opsize;
switch (vie->op.op_byte) {
case 0x39:
case 0x3B:
/*
* 39/r CMP r/m16, r16
* 39/r CMP r/m32, r32
* REX.W 39/r CMP r/m64, r64
*
* 3B/r CMP r16, r/m16
* 3B/r CMP r32, r/m32
* REX.W + 3B/r CMP r64, r/m64
*
* Compare first operand (reg) with second operand (r/m) and
* Compare the first operand with the second operand and
* set status flags in EFLAGS register. The comparison is
* performed by subtracting the second operand from the first
* operand and then setting the status flags.
*/
/* Get the first operand */
/* Get the register operand */
reg = gpr_map[vie->reg];
error = vie_read_register(vm, vcpuid, reg, &op1);
error = vie_read_register(vm, vcpuid, reg, &regop);
if (error)
return (error);
/* Get the second operand */
error = memread(vm, vcpuid, gpa, &op2, size, arg);
/* Get the memory operand */
error = memread(vm, vcpuid, gpa, &memop, size, arg);
if (error)
return (error);
if (vie->op.op_byte == 0x3B) {
op1 = regop;
op2 = memop;
} else {
op1 = memop;
op2 = regop;
}
rflags2 = getcc(size, op1, op2);
break;
case 0x80: