xen/stub: driver for CPU hotplug

Add Xen stub driver for CPU hotplug, early occupy to block native,
will be replaced later by real Xen processor driver module.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/xen-stub.c

@@ -28,12 +28,12 @@
 #include <acpi/acpi_drivers.h>
 #include <xen/acpi.h>
 
+#ifdef CONFIG_ACPI
+
 /*--------------------------------------------
 	stub driver for Xen memory hotplug
 --------------------------------------------*/
 
-#ifdef CONFIG_ACPI
-
 static const struct acpi_device_id memory_device_ids[] = {
 	{ACPI_MEMORY_DEVICE_HID, 0},
 	{"", 0},
@@ -63,4 +63,39 @@ void xen_stub_memory_device_exit(void)
 }
 EXPORT_SYMBOL_GPL(xen_stub_memory_device_exit);
 
+
+/*--------------------------------------------
+	stub driver for Xen cpu hotplug
+--------------------------------------------*/
+
+static const struct acpi_device_id processor_device_ids[] = {
+	{ACPI_PROCESSOR_OBJECT_HID, 0},
+	{ACPI_PROCESSOR_DEVICE_HID, 0},
+	{"", 0},
+};
+
+static struct acpi_driver xen_stub_processor_driver = {
+	/* same name as native processor driver to block native loaded */
+	.name = "processor",
+	.class = ACPI_PROCESSOR_CLASS,
+	.ids = processor_device_ids,
+};
+
+int xen_stub_processor_init(void)
+{
+	if (!xen_initial_domain())
+		return -ENODEV;
+
+	/* just reserve space for Xen, block native driver loaded */
+	return acpi_bus_register_driver(&xen_stub_processor_driver);
+}
+EXPORT_SYMBOL_GPL(xen_stub_processor_init);
+subsys_initcall(xen_stub_processor_init);
+
+void xen_stub_processor_exit(void)
+{
+	acpi_bus_unregister_driver(&xen_stub_processor_driver);
+}
+EXPORT_SYMBOL_GPL(xen_stub_processor_exit);
+
 #endif

include/xen/acpi.h

@@ -47,6 +47,13 @@
 int xen_stub_memory_device_init(void);
 void xen_stub_memory_device_exit(void);
 
+#define ACPI_PROCESSOR_CLASS            "processor"
+#define ACPI_PROCESSOR_DEVICE_HID       "ACPI0007"
+#define ACPI_PROCESSOR_DEVICE_NAME      "Processor"
+
+int xen_stub_processor_init(void);
+void xen_stub_processor_exit(void);
+
 int xen_acpi_notify_hypervisor_state(u8 sleep_state,
 				     u32 pm1a_cnt, u32 pm1b_cnd);