Optimized VM setup

[Rusi Mody <rustompmody@gmail.com>]

I teach programming.
Students of my class have their own laptops required to have (some recent) linux.
And this time (for the first time?) I saw that majority of the class were 
running Linux (usually but not always Ubuntu) on a VM on a Windows — typically Windows-10

This made those machines markedly sluggish.

I was wondering if its possible to have a setup in which Linux is installed
(probably on a separate NTFS partition) such that one can choose
- Boot to Windows, start VM, start Linux
OR
- Boot to (native) Linux

Note: This option only makes sense if the Linux booted is the SAME one
Otherwise its trivial and useless