qmp-event: add event notification for memory hot unplug error

When memory hot unplug fails, this patch adds support to send
QMP event to notify mgmt about this failure.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

docs/qmp/qmp-events.txt

diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt
index d759d19..3be468f 100644
--- a/docs/qmp/qmp-events.txt
+++ b/docs/qmp/qmp-events.txt
@@ -226,6 +226,23 @@
 { "event": "GUEST_PANICKED",
      "data": { "action": "pause" } }
 
+MEM_HOT_UNPLUG_ERROR
+--------------------
+Emitted when memory hot unplug error occurs.
+
+Data:
+
+- "device": device name (json-string)
+- "msg": Informative message (e.g., reason for the error) (json-string)
+
+Example:
+
+{ "event": "MEM_HOT_UNPLUG_ERROR"
+  "data": { "device": "dimm1",
+            "msg": "acpi: device unplug for unsupported device"
+  },
+  "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
+
 NIC_RX_FILTER_CHANGED
 ---------------------
 

hw/acpi/memory_hotplug.c

diff --git a/hw/acpi/memory_hotplug.c b/hw/acpi/memory_hotplug.c
index 35bbfeb..34cef1e 100644
--- a/hw/acpi/memory_hotplug.c
+++ b/hw/acpi/memory_hotplug.c
@@ -94,6 +94,7 @@
     ACPIOSTInfo *info;
     DeviceState *dev = NULL;
     HotplugHandler *hotplug_ctrl = NULL;
+    Error *local_err = NULL;
 
     if (!mem_st->dev_count) {
         return;
@@ -148,7 +149,14 @@
             dev = DEVICE(mdev->dimm);
             hotplug_ctrl = qdev_get_hotplug_handler(dev);
             /* call pc-dimm unplug cb */
-            hotplug_handler_unplug(hotplug_ctrl, dev, NULL);
+            hotplug_handler_unplug(hotplug_ctrl, dev, &local_err);
+            if (local_err) {
+                trace_mhp_acpi_pc_dimm_delete_failed(mem_st->selector);
+                qapi_event_send_mem_unplug_error(dev->id,
+                                                 error_get_pretty(local_err),
+                                                 &error_abort);
+                break;
+            }
             trace_mhp_acpi_pc_dimm_deleted(mem_st->selector);
         }
         break;

qapi/event.json

diff --git a/qapi/event.json b/qapi/event.json
index c51dc49..378dda5 100644
--- a/qapi/event.json
+++ b/qapi/event.json
@@ -330,3 +330,17 @@
 ##
 { 'event': 'VSERPORT_CHANGE',
   'data': { 'id': 'str', 'open': 'bool' } }
+
+##
+# @MEM_UNPLUG_ERROR
+#
+# Emitted when memory hot unplug error occurs.
+#
+# @device: device name
+#
+# @msg: Informative message
+#
+# Since: 2.4
+##
+{ 'event': 'MEM_UNPLUG_ERROR',
+  'data': { 'device': 'str', 'msg': 'str' } }

trace-events

diff --git a/trace-events b/trace-events
index 46f6ef0..11387c3 100644
--- a/trace-events
+++ b/trace-events
@@ -1575,6 +1575,7 @@
 mhp_acpi_clear_insert_evt(uint32_t slot) "slot[0x%"PRIx32"] clear insert event"
 mhp_acpi_clear_remove_evt(uint32_t slot) "slot[0x%"PRIx32"] clear remove event"
 mhp_acpi_pc_dimm_deleted(uint32_t slot) "slot[0x%"PRIx32"] pc-dimm deleted"
+mhp_acpi_pc_dimm_delete_failed(uint32_t slot) "slot[0x%"PRIx32"] pc-dimm delete failed"
 
 # hw/i386/pc.c
 mhp_pc_dimm_assigned_slot(int slot) "0x%d"