1. A non-transitory storage medium storing a virtualization program to run a host virtual machine manager and a guest virtual machine manager by being executed in a physical computer including a physical processor and a memory, the non-transitory storage medium causing the physical processor to execute the steps of: storing, by the guest virtual machine manager, first control information for specifying a status of a virtual processor to execute a user program to the memory; storing, by the guest virtual machine manager, second control information for specifying a status of the virtual processor to execute the guest virtual machine manager to the memory; updating, by the host virtual machine manager, third control information for specifying a status of the physical processor with one of the first control information and the second control information in accordance with determination of which of the user program and the guest virtual machine manager is to be executed; and issuing, by the host virtual machine manager, a first control instruction for the physical processor to execute one of the user program and the guest virtual machine manager based on the third control information.