diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bd35549..7250bef 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1095,6 +1095,8 @@
 /* First C function to be called on Xen boot */
 asmlinkage void __init xen_start_kernel(void)
 {
+	struct physdev_set_iopl set_iopl;
+	int rc;
 	pgd_t *pgd;
 
 	if (!xen_start_info)
@@ -1209,10 +1211,18 @@
 #else
 	pv_info.kernel_rpl = 0;
 #endif
-
 	/* set the limit of our address space */
 	xen_reserve_top();
 
+	/* We used to do this in xen_arch_setup, but that is too late on AMD
+	 * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
+	 * which pokes 0xcf8 port.
+	 */
+	set_iopl.iopl = 1;
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+	if (rc != 0)
+		xen_raw_printk("physdev_op failed %d\n", rc);
+
 #ifdef CONFIG_X86_32
 	/* set up basic CPUID stuff */
 	cpu_detect(&new_cpu_data);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 630fb53..38fdffa 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -336,9 +336,6 @@
 
 void __init xen_arch_setup(void)
 {
-	struct physdev_set_iopl set_iopl;
-	int rc;
-
 	xen_panic_handler_init();
 
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
@@ -355,11 +352,6 @@
 	xen_enable_sysenter();
 	xen_enable_syscall();
 
-	set_iopl.iopl = 1;
-	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
-	if (rc != 0)
-		printk(KERN_INFO "physdev_op failed %d\n", rc);
-
 #ifdef CONFIG_ACPI
 	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");