1. A method of mapping platform configuration registers of a TRUSTED PLATFORM MODULE or virtual TRUSTED PLATFORM MODULE instance into the register space of a virtual TRUSTED PLATFORM MODULE, said method comprising: reading the state of a platform configuration register from an internal state of the processing TRUSTED PLATFORM MODULE if said platform configuration register is a non-mapped platform configuration register; and requesting selectively said state of a plurality of mapped platform configuration registers from a source providing said plurality of mapped platform configuration registers.