+ EFI_STATUS Status;\r
+ XENBUS_DEVICE *Dev;\r
+\r
+ Dev = AllocateZeroPool (sizeof (*Dev));\r
+ Dev->Signature = XENBUS_DEVICE_SIGNATURE;\r
+ Dev->This = This;\r
+ Dev->ControllerHandle = ControllerHandle;\r
+\r
+ EfiAcquireLock (&mMyDeviceLock);\r
+ if (mMyDevice != NULL) {\r
+ EfiReleaseLock (&mMyDeviceLock);\r
+ //\r
+ // There is already a XenBus running, only one can be used at a time.\r
+ //\r
+ Status = EFI_ALREADY_STARTED;\r
+ goto ErrorAllocated;\r
+ }\r
+ mMyDevice = Dev;\r
+ EfiReleaseLock (&mMyDeviceLock);\r
+\r
+ Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,\r
+ NotifyExitBoot,\r
+ (VOID*) Dev,\r
+ &Dev->ExitBootEvent);\r
+ ASSERT_EFI_ERROR (Status);\r
+\r
+ return EFI_SUCCESS;\r
+\r
+ErrorAllocated:\r
+ FreePool (Dev);\r
+ return Status;\r