LoongArch ipi can send interrupt to multiple CPUs, interrupt routing
to CPU comes from destination physical cpu id. Here hotplug interface
is added for IPI object, so that parent irq line can be connected, and
routing table can be added for new created cpu.

Here only basic hotplug framework is added, it is stub function.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 hw/intc/loongarch_ipi.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/hw/intc/loongarch_ipi.c b/hw/intc/loongarch_ipi.c
index 5376f1e084..90bbb7ac6e 100644
--- a/hw/intc/loongarch_ipi.c
+++ b/hw/intc/loongarch_ipi.c
@@ -6,6 +6,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/error-report.h"
 #include "hw/boards.h"
 #include "qapi/error.h"
 #include "hw/intc/loongarch_ipi.h"
@@ -76,9 +77,34 @@ static void loongarch_ipi_realize(DeviceState *dev, Error **errp)
     }
 }
 
+static void loongarch_ipi_cpu_plug(HotplugHandler *hotplug_dev,
+                                   DeviceState *dev, Error **errp)
+{
+    Object *obj = OBJECT(dev);
+
+    if (!object_dynamic_cast(obj, TYPE_LOONGARCH_CPU)) {
+        warn_report("LoongArch extioi: Invalid %s device type",
+                                       object_get_typename(obj));
+        return;
+    }
+}
+
+static void loongarch_ipi_cpu_unplug(HotplugHandler *hotplug_dev,
+                                     DeviceState *dev, Error **errp)
+{
+    Object *obj = OBJECT(dev);
+
+    if (!object_dynamic_cast(obj, TYPE_LOONGARCH_CPU)) {
+        warn_report("LoongArch extioi: Invalid %s device type",
+                                       object_get_typename(obj));
+        return;
+    }
+}
+
 static void loongarch_ipi_class_init(ObjectClass *klass, void *data)
 {
     LoongsonIPICommonClass *licc = LOONGSON_IPI_COMMON_CLASS(klass);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
     LoongarchIPIClass *lic = LOONGARCH_IPI_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);
 
@@ -86,6 +112,8 @@ static void loongarch_ipi_class_init(ObjectClass *klass, void *data)
                                     &lic->parent_realize);
     licc->get_iocsr_as = get_iocsr_as;
     licc->cpu_by_arch_id = loongarch_cpu_by_arch_id;
+    hc->plug = loongarch_ipi_cpu_plug;
+    hc->unplug = loongarch_ipi_cpu_unplug;
 }
 
 static const TypeInfo loongarch_ipi_types[] = {
@@ -95,6 +123,10 @@ static const TypeInfo loongarch_ipi_types[] = {
         .instance_size      = sizeof(LoongarchIPIState),
         .class_size         = sizeof(LoongarchIPIClass),
         .class_init         = loongarch_ipi_class_init,
+        .interfaces         = (InterfaceInfo[]) {
+            { TYPE_HOTPLUG_HANDLER },
+            { }
+        },
     }
 };
 
-- 
2.43.5