I experimented with booting Arm macOS 14-26 in QEMU a while back, building on the work of Alexander Graf for macOS 12-13, and reverse-engineered substantial parts of Hypervisor.framework, the in-kernel hypervisor, and a bit of Virtualization.framework. Got newer versions of Sequoia to boot past the log in screen, with GPU acceleration too.

Unless there's another method I missed, the internal GPU "pass through" of Virtualization.framework you're thinking of might actually just be paravirualization, at least that's what the name suggests. It's implemented in the public ParavirtualizedGraphics framework [0], albeit for PG on Arm macOS, the relevant interfaces are private [1]. I haven't looked that deep into it per se, but, fixing the bugs around it, I've run into a few clues suggesting that it's just a command stream + shared memory being passed around. It also uses its own generic driver on the guest side.

Great job, by the way! Love how authors of pieces like this casually come here to comment :)

[0] https://developer.apple.com/documentation/paravirtualizedgra...

[1] https://github.com/qemu/qemu/blob/edcc429e9e41a8e0e415dcdab6...