1. An information processing device comprising: an operating system which accesses a hardware resource including a nonvolatile semiconductor memory and a semiconductor memory used as a cache memory of the nonvolatile semiconductor memory; first and second virtual machines operating on the operating system; a cache-miss detection section which detects cache miss to the semiconductor memory in a process executed by the first virtual machine; a cache control section which executes a cache process when the cache-miss detection section detects the cache miss in the process; and a virtual machine switching section which, when the cache-miss detection section detects the cache miss in the process executed by the first virtual machine, switches a virtual machine in execution from the first virtual machine to the second virtual machine while the cache control section executes the cache process, wherein the operating system selects process switching when a time required for the cache process is shorter than or equal to a reference time, and selects virtual machine switching when the time required for the cache process is longer than the reference time.