+#ifdef CONFIG_HOTPLUG_CPU
+static int hyperv_cpu_disable(void)
+{
+ return -ENOSYS;
+}
+
+static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
+{
+ static void *previous_cpu_disable;
+
+ /*
+ * Offlining a CPU when running on newer hypervisors (WS2012R2, Win8,
+ * ...) is not supported at this moment as channel interrupts are
+ * distributed across all of them.
+ */
+
+ if ((vmbus_proto_version == VERSION_WS2008) ||
+ (vmbus_proto_version == VERSION_WIN7))
+ return;
+
+ if (vmbus_loaded) {
+ previous_cpu_disable = smp_ops.cpu_disable;
+ smp_ops.cpu_disable = hyperv_cpu_disable;
+ pr_notice("CPU offlining is not supported by hypervisor\n");
+ } else if (previous_cpu_disable)
+ smp_ops.cpu_disable = previous_cpu_disable;
+}
+#else
+static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
+{
+}
+#endif
+