[PATCH 2/8] qdev: hotplug: Add force_unplug handler callback

Add a HotplugHandlerClass force_unplug callback and a wrapper used by the
generic qdev unplug path.

When qdev_unplug() is called with force=true, delegate to the hotplug
controller if it implements force_unplug. Controllers without the callback
return a normal error. This makes forced removal available only for
controllers that explicitly implement the operation.

Signed-off-by: Dongli Zhang <[email protected]>
---
 hw/core/hotplug.c         | 11 +++++++++++
 include/hw/core/hotplug.h | 12 ++++++++++++
 system/qdev-monitor.c     | 10 +++++++++-
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/hw/core/hotplug.c b/hw/core/hotplug.c
index 68aabad8ae..0e44d98cf7 100644
--- a/hw/core/hotplug.c
+++ b/hw/core/hotplug.c
@@ -57,6 +57,17 @@ void hotplug_handler_unplug(HotplugHandler *plug_handler,
     }
 }
 
+void hotplug_handler_force_unplug(HotplugHandler *plug_handler,
+                                  DeviceState *plugged_dev,
+                                  Error **errp)
+{
+    HotplugHandlerClass *hdc = HOTPLUG_HANDLER_GET_CLASS(plug_handler);
+
+    if (hdc->force_unplug) {
+        hdc->force_unplug(plug_handler, plugged_dev, errp);
+    }
+}
+
 static const TypeInfo hotplug_handler_info = {
     .name          = TYPE_HOTPLUG_HANDLER,
     .parent        = TYPE_INTERFACE,
diff --git a/include/hw/core/hotplug.h b/include/hw/core/hotplug.h
index a9840ed485..300ac4fa8f 100644
--- a/include/hw/core/hotplug.h
+++ b/include/hw/core/hotplug.h
@@ -48,6 +48,8 @@ typedef void (*hotplug_fn)(HotplugHandler *plug_handler,
  * @unplug: unplug callback.
  *          Used for device removal with devices that implement
  *          asynchronous and synchronous (surprise) removal.
+ * @force_unplug: force unplug callback.
+ *                Used to complete enforced removal without guest cooperation.
  * @is_hotpluggable_bus: called to check if bus/its parent allow hotplug on bus
  */
 struct HotplugHandlerClass {
@@ -59,6 +61,7 @@ struct HotplugHandlerClass {
     hotplug_fn plug;
     hotplug_fn unplug_request;
     hotplug_fn unplug;
+    hotplug_fn force_unplug;
     bool (*is_hotpluggable_bus)(HotplugHandler *plug_handler, BusState *bus);
 };
 
@@ -96,4 +99,13 @@ void hotplug_handler_unplug_request(HotplugHandler *plug_handler,
 void hotplug_handler_unplug(HotplugHandler *plug_handler,
                             DeviceState *plugged_dev,
                             Error **errp);
+
+/**
+ * hotplug_handler_force_unplug:
+ *
+ * Calls #HotplugHandlerClass.force_unplug callback of @plug_handler.
+ */
+void hotplug_handler_force_unplug(HotplugHandler *plug_handler,
+                                  DeviceState *plugged_dev,
+                                  Error **errp);
 #endif
diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c
index 3606a347a0..fa3cae246b 100644
--- a/system/qdev-monitor.c
+++ b/system/qdev-monitor.c
@@ -937,7 +937,15 @@ void qdev_unplug(DeviceState *dev, bool force, Error **errp)
     /* If device supports async unplug just request it to be done,
      * otherwise just remove it synchronously */
     hdc = HOTPLUG_HANDLER_GET_CLASS(hotplug_ctrl);
-    if (hdc->unplug_request) {
+
+    if (force) {
+        if (!hdc->force_unplug) {
+            error_setg(&local_err, "Device '%s' does not support forced unplug",
+                       dev->id ? dev->id : object_get_typename(OBJECT(dev)));
+        } else {
+            hotplug_handler_force_unplug(hotplug_ctrl, dev, &local_err);
+        }
+    } else if (hdc->unplug_request) {
         hotplug_handler_unplug_request(hotplug_ctrl, dev, &local_err);
     } else {
         hotplug_handler_unplug(hotplug_ctrl, dev, &local_err);
-- 
2.43.5