I am still confused regarding the mechanisms of virtualisation.
I understand why the x86 architecture is/was not by itself virtualisable and why other architectures are (and why the 68k architecture was except for the MC68000 itself etc.).
And then I read about Intel VT-x and AMD V which add virtualisation capabilities to x86.
However, the virtualised CPU appears to be a different CPU than the physical CPU; namely the physical CPU has VT-x while the virtual CPU does not.
While this is not a practical problem (no operating system one typically wants to run in a VM requires VT-x), it does make me wonder whether this constitutes real virtualisation.
The 80386 already had the ability to virtualise a CPU with fewer features than the 80386 itself, the virtual x86 mode. Is VT-x just another layer like that (ring -1, I suppose) or is it real virtualisation?
(What will happen if one wants to virtualise systems that use VT-x? Shouldn't true virtualisation allow for unlimited levels of virtualisation?)
Sorry for a dumb question. Or rather, sorry for a theoretical rather than practical question.
Update: I did this graphic to try to understand this all better: