x86 emulator: fix parity calculation for AAD instruction

Reported-by: NPaolo Bonzini <pbonzini@redhat.com>
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

arch/x86/kvm/emulate.c

@@ -2995,14 +2995,11 @@ static int em_aad(struct x86_emulate_ctxt *ctxt)
 
 	ctxt->dst.val = (ctxt->dst.val & 0xffff0000) | al;
 
-	ctxt->eflags &= ~(X86_EFLAGS_PF | X86_EFLAGS_SF | X86_EFLAGS_ZF);
-
-	if (!al)
-		ctxt->eflags |= X86_EFLAGS_ZF;
-	if (!(al & 1))
-		ctxt->eflags |= X86_EFLAGS_PF;
-	if (al & 0x80)
-		ctxt->eflags |= X86_EFLAGS_SF;
+	/* Set PF, ZF, SF */
+	ctxt->src.type = OP_IMM;
+	ctxt->src.val = 0;
+	ctxt->src.bytes = 1;
+	fastop(ctxt, em_or);
 
 	return X86EMUL_CONTINUE;
 }