This is the first time I've seen this suggestion; it is something that could be done relatively easily for systems that otherwise have no updates/mitigations.
If performance is better some variant of this (auto-scaling dedicated cores) may even become the default solution rather than all the other workarounds! Bare metal hypervisors should get their own core(s) too.
I remember seeing this suggestion earlier. If I'm not mistaken a commentor stated that a) this would come with a huge performance penalty b) there would be synchronization problems in multithreaded scenarios.
Don't take my word for it though, I might have understood it wrong. I imagine concurrent/parallel execution involving system calls could maybe suffer from synchronization issues if processes/threads run on different physical cores with separate caches?
If performance is better some variant of this (auto-scaling dedicated cores) may even become the default solution rather than all the other workarounds! Bare metal hypervisors should get their own core(s) too.
Is anyone already doing this? (Qubes, etc.)