A method for controlling file access on computer systems is disclosed. Initially, a virtual machine manager (VMM) is provided in a computer system. In response to a write request, the VMM determines whether or not a location field is valid. If the location field is not valid, then the VMM writes the write request information to a storage device; but if the location field is valid, then the VMM encrypts the write request information before writing the write request information to the storage device. In response to a read request, the VMM again determines whether or not a location field is valid. If the location field is not valid, then the VMM sends the read request information to a read requester; but, if the location field is valid, then the VMM decrypts the read request information before sending the read request information to the read requester.