Emulation of obsolete hardware in open source virtualization software

Nuclear Power plants are built to last 40 years. From the beginning of their lifetime up to now, dozens of specific, but not critical, applications have been developed. Their cost does not only reside in the development but mainly in the qualification and validation processes. Most of the time, once these applications have been commissioned and have fulfilled their functions, no functional or performance reason require them to be modified later on. They should stay unchanged during the whole lifetime of the plant. Meanwhile the hardware has changed many times; the average lifespan of a standard PC is 1 to 2 years. In order to cope with these frequent changes, we have come out with a new solution: emulation of obsolete hardware through virtualization. Virtualization is used increasingly in Data Centers to achieve server consolidation as well as for testing purposes on desktop computers. Also, as it always emulates the same hardware, it may be used to increase the lifetime of industrial applications. A main limitation in this case is the limited type of peripherals supported by this technology. Virtualization software only supports standard hardware (serial, parallel, USB, SCSI, etc.); industrial applications often require specific peripherals to acquire data, communicate with PLCs or with other legacy applications. Hence, using virtualization requires developing interfaces to specific peripherals. In this paper we present how to implement a new network interface within the QEMU OpenSource virtualization software. We describe the structure of QEMU and the way those interfaces are defined in QEMU´s code.