i386, acpi: check acpi_memory_hotplug capacity in pre_plug

Currently we do device realization like below:

   hotplug_handler_pre_plug()
   dc->realize()
   hotplug_handler_plug()

Before we do device realization and plug, we should allocate necessary
resources and check if memory-hotplug-support property is enabled.

At the piix4 and ich9, the memory-hotplug-support property is checked at
plug stage. This means that device has been realized and mapped into guest
address space 'pc_dimm_plug()' by the time acpi plug handler is called,
where it might fail and crash QEMU due to reaching g_assert_not_reached()
(piix4) or error_abort (ich9).

Fix it by checking if memory hotplug is enabled at pre_plug stage
where we can gracefully abort hotplug request.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
CC: Igor Mammedov <imammedo@redhat.com>
CC: Eric Blake <eblake@redhat.com>
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Message-Id: <20190301033548.6691-1-richardw.yang@linux.intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index c5d8646..e53dfe1 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -483,13 +483,24 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp)
                              NULL);
 }
 
+void ich9_pm_device_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                                Error **errp)
+{
+    ICH9LPCState *lpc = ICH9_LPC_DEVICE(hotplug_dev);
+
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
+        !lpc->pm.acpi_memory_hotplug.is_enabled)
+        error_setg(errp,
+                   "memory hotplug is not enabled: %s.memory-hotplug-support "
+                   "is not set", object_get_typename(OBJECT(lpc)));
+}
+
 void ich9_pm_device_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                             Error **errp)
 {
     ICH9LPCState *lpc = ICH9_LPC_DEVICE(hotplug_dev);
 
-    if (lpc->pm.acpi_memory_hotplug.is_enabled &&
-        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
             nvdimm_acpi_plug_cb(hotplug_dev, dev);
         } else {