It seems it is the android kernel, but as long as some modules are supported (HDMI, external keyboard, ...) no virtual machine should be necessary to run non-android Linux software.
To run android apps side-by-side on the big screen a virtual machine might be necessary.
If the video driver supports it, the latter can be some version of a dual-monitor setup with no virtual machine at all, that can be activated when switching to a special terminal.