Recently, we've advertised a new SDK package for a hypervisor driver that makes it possible to the emulator on AMD CPUs without needing to enable Hyper-V and with performance on par with HAXM (More details).
As part of this effort, we've released the source code of this hypervisor driver to Github:
https://github.com/google/android-emulator-hypervisor-driver-for-amd-processors
Although it is only compatible with the Android Emulator's engine at the moment, it should not be inherently difficult to port to QEMU or other VMMs, as it is contained in a target backend.