DATA PROCESSOR

A data processor includes: a central processing unit (CPU), in which a plurality of virtual machines ( 101 ), each running an application program under controls of different operating systems, and a virtual machine manager ( 190 ) for controlling the plurality of virtual machines are selectively arranged according to information set in mode registers ( 140, 150, 151 ); and a resource access management module ( 110 ) for managing access to hardware resource available for the plurality of virtual machines. The resource access management module accepts, as inputs, the information set in the mode registers and access control information of the central processing unit to the hardware resource, compares the information thus input with information set in a control register, and controls whether or not to permit access to the hardware resource in response to the access control information. As a result, redesign involved in changes in system specifications can be reduced, and a malfunction owing to resource contention can be prevented. The invention contributes to increase of security.