Re:Ubuntu successfully virtualized on M1
by saati on Thursday November 26, 2020 @02:58PM
(#25223088)
You just need access to precise timers to tell if you are virtualized. If you can measure how long a full TLB miss takes vs just a cache miss you should be able to tell how deeply is your page table nested.
Re:Ubuntu successfully virtualized on M1
by londons_explore on Thursday November 26, 2020 @04:09PM
(#25223548)
An emulator can emulate timers however it likes...
Re:Ubuntu successfully virtualized on M1
by amelius on Thursday November 26, 2020 @04:28PM
(#25223649)
Ok, but that means that you can't have accurate wall clock time inside your virtual machine. Also, it would make most games impossible as all physics is ultimately tied to a clock. And of course a connection to internet is impossible.
It goes hand in hand with the fact that an emulated or virtualized system shouldn't be able to tell that it is emulated (if the emulator doesn't want it to know). It should run as if on real hardware. Inability to do nested virtualization reveals immediately that emulation is in play.