Ask HN: Real Double Boot

Does any of you know of any possibility (real or theoretical), of having a computer "double boot". I am specifically not talking about "dual boot", but Real Double Boot (TM) in the sense:

- a single computer, with a single screen, keyboard, ... is being controlled, at the same time, by two different operating systems (say, Windows and Linux)

- not related to VM (VirtualBox or similar)

- there is a special hotkey to cycle through the different active OSes

- whenever an OS gets activated, it takes control of I/O

- the CPUs / cores are "split" between the different OSes. During boot time, one OS gets assigned one of the cores, the other OS the other core, or something similar.

This would amount to multiple computers connected to a single I/O system.

- Is there any research on this?

- Are there any examples of this kind of architecture?

- If not, why not? I assume there are big complications regarding CPU architecture, and maybe problems setting / resetting the I/O system each time a handover is performed.

My motivation for this is that I am currently using VirtualBox inside Windows 10, and although it works quite well, the VM has sub-par performance compared to the host system.