At it's core, this device file is responsible for managing a GPU local address space, and sharing memory securely with that address space in order to have a pla

At it's core, this device file is responsible for managing a GPU local address space, and sharing memory securely with that address space in order to have a place to write command buffers and data that the gpu can see. It doesn't really make sense without a heavy memory mapping component. A plan 9 like model that's heavily just a standard file would massively cut into gpu performance.