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>

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 &&
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
-        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
             nvdimm_acpi_plug_cb(hotplug_dev, dev);
         } else {

hw/acpi/piix4.c

@@ -380,9 +380,17 @@ static void piix4_pm_powerdown_req(Notifier *n, void *opaque)
 static void piix4_device_pre_plug_cb(HotplugHandler *hotplug_dev,
                                     DeviceState *dev, Error **errp)
 {
+    PIIX4PMState *s = PIIX4_PM(hotplug_dev);
+
     if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_pre_plug_cb(hotplug_dev, dev, errp);
-    } else if (!object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        if (!s->acpi_memory_hotplug.is_enabled) {
+            error_setg(errp,
+                "memory hotplug is not enabled: %s.memory-hotplug-support "
+                "is not set", object_get_typename(OBJECT(s)));
+        }
+    } else if (
                !object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         error_setg(errp, "acpi: device pre plug request for not supported"
                    " device type: %s", object_get_typename(OBJECT(dev)));
@@ -394,8 +402,7 @@ static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
 {
     PIIX4PMState *s = PIIX4_PM(hotplug_dev);
 
-    if (s->acpi_memory_hotplug.is_enabled &&
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
-        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
             nvdimm_acpi_plug_cb(hotplug_dev, dev);
         } else {

hw/i386/pc.c

@@ -2090,6 +2090,8 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
         return;
     }
 
+    hotplug_handler_pre_plug(pcms->acpi_dev, dev, errp);
+
     if (is_nvdimm && !ms->nvdimms_state->is_enabled) {
         error_setg(errp, "nvdimm is not enabled: missing 'nvdimm' in '-M'");
         return;

hw/isa/lpc_ich9.c

@@ -805,6 +805,7 @@ static void ich9_lpc_class_init(ObjectClass *klass, void *data)
      * pc_q35_init()
      */
     dc->user_creatable = false;
+    hc->pre_plug = ich9_pm_device_pre_plug_cb;
     hc->plug = ich9_pm_device_plug_cb;
     hc->unplug_request = ich9_pm_device_unplug_request_cb;
     hc->unplug = ich9_pm_device_unplug_cb;

include/hw/acpi/ich9.h

@@ -74,6 +74,8 @@ extern const VMStateDescription vmstate_ich9_pm;
 
 void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp);
 
+void ich9_pm_device_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                                Error **errp);
 void ich9_pm_device_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                             Error **errp);
 void ich9_pm_device_unplug_request_cb(HotplugHandler *hotplug_dev,