Critical Real-Time Embedded Systems for industries such as railway, aerospace, automotive and energy face multiple challenges including a growing need to support mixed-criticality applications, power and timing restrictions and a need to develop and test these complex devices and the accompanying software. The approach adopted by the SAFEPOWER project, an EU Horizon 2020 program, was to develop a SoC architecture including a NoC plus the hypervisor to support spatial and/or temporal isolation of the various functional units. Advantages of this hardware/software architecture include the increased isolation provided by using both spatial and temporal isolation and the adaptability of this architecture to changing conditions. This paper discusses the virtual platform methodology employed by SAFEPOWER. Unique tools developed to provide observability into the hypervisor-based system are described, as well as the methods for providing timing and power estimation with sufficient accuracy.