diff --git a/xen/arch/x86/acpi/cpuidle_menu.c b/xen/arch/x86/acpi/cpuidle_menu.c
index c050972a9f..38a5543c00 100644
--- a/xen/arch/x86/acpi/cpuidle_menu.c
+++ b/xen/arch/x86/acpi/cpuidle_menu.c
@@ -270,9 +270,10 @@ static void menu_reflect(struct acpi_processor_power *power)
 
 static int menu_enable_device(struct acpi_processor_power *power)
 {
-    struct menu_device *data = &per_cpu(menu_devices, power->cpu);
+    if (!cpu_online(power->cpu))
+        return -1;
 
-    memset(data, 0, sizeof(struct menu_device));
+    memset(&per_cpu(menu_devices, power->cpu), 0, sizeof(struct menu_device));
 
     return 0;
 }