svn commit: r283255 - head/sys/amd64/vmm
Neel Natu
neel at FreeBSD.org
Thu May 21 18:23:38 UTC 2015
Author: neel
Date: Thu May 21 18:23:37 2015
New Revision: 283255
URL: https://svnweb.freebsd.org/changeset/base/283255
Log:
Emulate the "CMP r/m, reg" instruction (opcode 39H).
Reported and tested by: Leon Dang (ldang at nahannisys.com)
MFC after: 1 week
Modified:
head/sys/amd64/vmm/vmm_instruction_emul.c
Modified: head/sys/amd64/vmm/vmm_instruction_emul.c
==============================================================================
--- head/sys/amd64/vmm/vmm_instruction_emul.c Thu May 21 17:40:53 2015 (r283254)
+++ head/sys/amd64/vmm/vmm_instruction_emul.c Thu May 21 18:23:37 2015 (r283255)
@@ -113,6 +113,10 @@ static const struct vie_op one_byte_opco
.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
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, ®op);
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:
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