This is a cool intro to how virtualization instructions work, but people need to understand that it is not revolutionary simplicity or anything like that. It's just a a cool tech demo lacking all the important bits of a modern hypervisor required to make it practical, like paravirtualized drivers for example.

Same when someone claims to have written an OS in 1000 lines and all it does is get you to real mode with VGA graphics and an interactive (but useless) prompt.

(Note that you can benefit from virtualization technology in specialized scenarios outside common hypervisors, but that's not really what's being demoed here.)

Why does it need qemu? Isn't it a qemu?

Also discussed at:

https://news.ycombinator.com/item?id=45070019

Hm I would like to see this in C rather than Rust. And I wonder if you can run the 1000 line OS in C along with the 1000 line hypervisor

It would be nice to see a demo!

See also https://ionescu007.github.io/SimpleVisor/ in around 500 lines of C.