KVM: x86 emulator: mix decode bits from opcode and group decode tables
Allow bits that are common to all members of a group to be specified in the
opcode table instead of the group table. This allows some simplification
of the decode tables.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b1e3e8c..ef2b5af 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -955,7 +955,7 @@
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
int mode = ctxt->mode;
- int def_op_bytes, def_ad_bytes, group;
+ int def_op_bytes, def_ad_bytes, group, dual;
/* we cannot decode insn before we complete previous rep insn */
@@ -1055,14 +1055,16 @@
if (c->d & Group) {
group = c->d & GroupMask;
+ dual = c->d & GroupDual;
c->modrm = insn_fetch(u8, 1, c->eip);
--c->eip;
group = (group << 3) + ((c->modrm >> 3) & 7);
- if ((c->d & GroupDual) && (c->modrm >> 6) == 3)
- c->d = group2_table[group];
+ c->d &= ~(Group | GroupDual | GroupMask);
+ if (dual && (c->modrm >> 6) == 3)
+ c->d |= group2_table[group];
else
- c->d = group_table[group];
+ c->d |= group_table[group];
}
/* Unrecognised? */