> Nested virtualisation [...] challenging to emulate the underlying interfaces with flawless fidelity [...] dreadful performance
It is so sad that we've ended up with designs where this is the case. There is no intrinsic reason why nested virtualization should be hard to implement or should perform poorly. Path dependence strikes again.
It doesn't perform poorly in fact. It can be tuned at 90% of non-nested virtualization, and for workloads where it doesn't, that's more than anything else a testimony to how close virtualized performance is to bare-metal.
It is so sad that we've ended up with designs where this is the case. There is no intrinsic reason why nested virtualization should be hard to implement or should perform poorly. Path dependence strikes again.