KVM: x86 emulator: simplify r/m decoding
Consolidate the duplicated code when not in any special case.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index ca7ab24..c3a8231 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -740,9 +740,7 @@
c->modrm_ea = (u16)c->modrm_ea;
} else {
/* 32/64-bit ModR/M decode. */
- switch (c->modrm_rm) {
- case 4:
- case 12:
+ if ((c->modrm_rm & 7) == 4) {
sib = insn_fetch(u8, 1, c->eip);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
@@ -754,18 +752,11 @@
c->modrm_ea += c->regs[base_reg];
if (index_reg != 4)
c->modrm_ea += c->regs[index_reg] << scale;
- break;
- case 5:
- case 13:
- if (c->modrm_mod != 0)
- c->modrm_ea += c->regs[c->modrm_rm];
- else if (ctxt->mode == X86EMUL_MODE_PROT64)
+ } else if ((c->modrm_rm & 7) == 5 && c->modrm_mod == 0) {
+ if (ctxt->mode == X86EMUL_MODE_PROT64)
rip_relative = 1;
- break;
- default:
+ } else
c->modrm_ea += c->regs[c->modrm_rm];
- break;
- }
switch (c->modrm_mod) {
case 0:
if (c->modrm_rm == 5)