Aspects provide for a virtual machine structure wherein processors are configured to create an encrypted code virtualization machine for code machine instructions of a retrieved package that has a security field value that indicates secure code, wherein the code machine instructions of the first retrieved package are allocated to encrypted code memory regions of a computer memory resource. Configured processors further create a non-encrypted code virtualization machine in non-encrypted code memory regions of a computer memory resource comprising code machine instructions of another retrieved package that has a security field value that does not indicate secure code; and define a union mixed secure virtual machine image to include (as a function of) the encrypted code virtualization machine and the non-encrypted code virtualization machine.