spapr_pci: emit hotplug add/remove events during hotplug

This uses extension of existing EPOW interrupt/event mechanism
to notify userspace tools like librtas/drmgr to handle
in-guest configuration/cleanup operations in response to
device_add/device_del.

Userspace tools that don't implement this extension will need
to be run manually in response/advance of device_add/device_del,
respectively.
Signed-off-by: NTyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

hw/ppc/spapr_pci.c

@@ -1075,6 +1075,9 @@ static void spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
         error_propagate(errp, local_err);
         return;
     }
+    if (plugged_dev->hotplugged) {
+        spapr_hotplug_req_add_event(drc);
+    }
 }
 
 static void spapr_phb_hot_unplug_child(HotplugHandler *plug_handler,
@@ -1101,6 +1104,7 @@ static void spapr_phb_hot_unplug_child(HotplugHandler *plug_handler,
             error_propagate(errp, local_err);
             return;
         }
+        spapr_hotplug_req_remove_event(drc);
     }
 }