KVM: x86 emulator: 0f (20|21|22|23) ignore mod bits.
Resent spec says that for 0f (20|21|22|23) the 2 bits in the mod field
are ignored. Interestingly enough older spec says that 11 is only valid
encoding.
Signed-off-by: Gleb Natapov <gleb@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 7c7debb..fa4604e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2520,28 +2520,20 @@
c->dst.type = OP_NONE;
break;
case 0x20: /* mov cr, reg */
- if (c->modrm_mod != 3)
- goto cannot_emulate;
c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x21: /* mov from dr to reg */
- if (c->modrm_mod != 3)
- goto cannot_emulate;
if (emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]))
goto cannot_emulate;
rc = X86EMUL_CONTINUE;
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x22: /* mov reg, cr */
- if (c->modrm_mod != 3)
- goto cannot_emulate;
ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu);
c->dst.type = OP_NONE;
break;
case 0x23: /* mov from reg to dr */
- if (c->modrm_mod != 3)
- goto cannot_emulate;
if (emulator_set_dr(ctxt, c->modrm_reg, c->regs[c->modrm_rm]))
goto cannot_emulate;
rc = X86EMUL_CONTINUE;