Commit b9fa9d6b authored by Avi Kivity's avatar Avi Kivity

KVM: x86 emulator: Move rep processing before instruction execution

Currently rep processing is handled somewhere in the middle of instruction
processing.  Move it to a sensible place.
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 51e29625
......@@ -64,6 +64,7 @@
#define Mov (1<<7)
#define BitOp (1<<8)
#define MemAbs (1<<9) /* Memory operand is absolute displacement */
#define String (1<<10) /* String instruction (rep capable) */
static u16 opcode_table[256] = {
/* 0x00 - 0x07 */
......@@ -133,12 +134,12 @@ static u16 opcode_table[256] = {
/* 0xA0 - 0xA7 */
ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
ByteOp | ImplicitOps, ImplicitOps,
ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
ByteOp | ImplicitOps | String, ImplicitOps | String,
/* 0xA8 - 0xAF */
0, 0, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
ByteOp | ImplicitOps, ImplicitOps,
0, 0, ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
ByteOp | ImplicitOps | String, ImplicitOps | String,
/* 0xB0 - 0xBF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 0xC0 - 0xC7 */
......@@ -1228,6 +1229,36 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
memop = c->modrm_ea;
if (c->rep_prefix && (c->d & String)) {
/* All REP prefixes have the same first termination condition */
if (c->regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = c->eip;
goto done;
}
/* The second termination condition only applies for REPE
* and REPNE. Test if the repeat string operation prefix is
* REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
* corresponding termination condition according to:
* - if REPE/REPZ and ZF = 0 then done
* - if REPNE/REPNZ and ZF = 1 then done
*/
if ((c->b == 0xa6) || (c->b == 0xa7) ||
(c->b == 0xae) || (c->b == 0xaf)) {
if ((c->rep_prefix == REPE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == 0)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
if ((c->rep_prefix == REPNE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
}
c->regs[VCPU_REGS_RCX]--;
c->eip = ctxt->vcpu->rip;
}
if (c->src.type == OP_MEM) {
c->src.ptr = (unsigned long *)memop;
c->src.val = 0;
......@@ -1534,35 +1565,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
c->dst.type = OP_NONE; /* Disable writeback. */
break;
}
if (c->rep_prefix) {
/* All REP prefixes have the same first termination condition */
if (c->regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = c->eip;
goto done;
}
/* The second termination condition only applies for REPE
* and REPNE. Test if the repeat string operation prefix is
* REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
* corresponding termination condition according to:
* - if REPE/REPZ and ZF = 0 then done
* - if REPNE/REPNZ and ZF = 1 then done
*/
if ((c->b == 0xa6) || (c->b == 0xa7) ||
(c->b == 0xae) || (c->b == 0xaf)) {
if ((c->rep_prefix == REPE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == 0)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
if ((c->rep_prefix == REPNE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
}
c->regs[VCPU_REGS_RCX]--;
c->eip = ctxt->vcpu->rip;
}
switch (c->b) {
case 0xa4 ... 0xa5: /* movs */
c->dst.type = OP_MEM;
......
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