Features/HelperNetworking

Summary

Introduce infrastructure to allowed QEMU network backends to be implemented outside of QEMU in a generic way.

Owner

AnthonyLiguori

Detailed Summary

Replace ad-hoc network backends with a single -net fd option that allows for precise control of how QEMU interacts with a given file descriptor. Then introduce external helpers that can be invoked to create appropriate file descriptors and pass them back to QEMU. These helpers can run as a higher privileged user allowing QEMU to use complex network setups while being invoked as a non-privileged user. This also allows third parties to implement user-visible network backends without having to introduce them into QEMU itself.