@Override
protected synchronized void updateRuntime(ManagedObject mo) throws Exception {
VirtualMachine vm = (VirtualMachine)mo;
this.runtime = checkReady(vm.getRuntime());
Summary summary = checkReady(vm.getSummary());
StorageSummary storageSummary = checkReady(summary.getStorage());
storageUsage = new DiskSize(storageSummary.getUnshared());
storageCommitted = new DiskSize(storageSummary.getCommitted());
/* XXX Layout needs to be updated in both update() and updateRuntime()
* as it contains both configuration & runtime data.
*/