METHOD AND APPARATUS FOR SIMULATION OF DATA IN A VIRTUAL ENVIRONMENT USING A QUEUED DIRECT INPUT-OUTPUT DEVICE

A method and an apparatus for simulation of data in a computing system environment having a controlling program, a main memory, a plurality of hosts, at least one adapter and a queued-direct input/output device using a queued-direct input/output protocol. A pageable virtual machine is provided under control of a virtual-machine hypervisor in processing communication with one or more hosts. Simulation is then provided by strictly separating a set of protocol control blocks between those that contain main-memory addresses and those that do not. Copies of those control blocks that contain main-memory addresses is created and their addresses converted by the hypervisor from addresses used by the program in its virtual machine to real-memory addresses usable by the adapter.