KVM: x86: popf emulation should not change RF

RFLAGS.RF is always zero after popf. Therefore, popf should not updated RF, as
anyhow emulating popf, just as any other instruction should clear RFLAGS.RF.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -1675,7 +1675,7 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
 		return rc;
 
 	change_mask = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF | EFLG_OF
-		| EFLG_TF | EFLG_DF | EFLG_NT | EFLG_RF | EFLG_AC | EFLG_ID;
+		| EFLG_TF | EFLG_DF | EFLG_NT | EFLG_AC | EFLG_ID;
 
 	switch(ctxt->mode) {
 	case X86EMUL_MODE_PROT64: