--- a/arch/x86/realmode/rm/wakeup_asm.S	2013-05-02 17:20:25.266667541 +0200
+++ b/arch/x86/realmode/rm/wakeup_asm.S	2013-05-02 21:44:57.973334207 +0200
@@ -119,6 +119,9 @@
 	jnc	1f
 	movl	pmode_efer, %eax
 	movl	pmode_efer + 4, %edx
+	movl	%eax, %ecx
+	orl	%edx, %ecx
+	jz	1f
 	movl	$MSR_EFER, %ecx
 	wrmsr
 1: