Effective allocation of areas for memory mapped input and output in boot processing

A method performed by an information processing apparatus including a plurality of root ports serving as roots of bus connection of a plurality of devices including boot devices from which legacy boot is executed to boot an operating system (OS), the method comprising:

• identifying a single boot device among the boot devices and a single root port connected to the single boot device,
• allocating, as memory addresses to be used for memory mapped input and output, memory addresses with a bit width available during the legacy boot to devices connected to the identified single root port,
• determining whether the memory addresses have been allocated to all devices connected to the single root port, and
• executing the legacy boot to boot the OS from the single boot device when the memory addresses have been allocated to all the devices connected to the single root port.

A non-transitory, computer-readable recording medium having stored therein a program for causing a computer to execute a procedure comprising performing a process including:

• identifying a single boot device among the boot devices and a single root port connected to the single boot device,
• allocating, as memory addresses to be used for memory mapped input and output, memory addresses with a bit width available during the legacy boot to devices connected to the identified single root port,
• determining whether the memory addresses have been allocated to all devices connected to the single root port, and
• executing the legacy boot to boot the OS from the single boot device when the memory addresses have been allocated to all the devices connected to the single root port.