I think that depends ... I'm not an expert on virtualisation but I've seen some cases where VMs get full bare-metal access to system functions, albeit supervise

I think that depends ... I'm not an expert on virtualisation but I've seen some cases where VMs get full bare-metal access to system functions, albeit supervised. I think this is the purpose of virtualisation extensions on modern architectures (e.g. VT-x) - this is how it's possible to have a 64-bit OS run virtualised on a 64-bit processor. EDIT - but even without this, the comparison with user-space holds.