An apparatus and system for protecting memory of a virtual guest includes initializing a virtual guest on a host computing system. The host computing system includes a virtual machine manager that manages operation of the virtual guest. The virtual guest includes a distinct operating environment executing in a virtual operation platform provided by the virtual machine manager. The method includes receiving an allocation of run-time memory for the virtual guest, the allocation of run-time memory comprising a portion of run-time memory of the host computing system. The method includes setting, by the virtual guest, at least a portion of the allocation of run-time memory to be inaccessible by the virtual machine manager.