[burke]

Yep. However, before the Apple Silicon migration, VT-x gave us extremely low-overhead virtualization. We built a tiny linux kernel that booted in a second or two and were able to run whatever we wanted with minimal perf overhead.

In the Apple Silicon migration, obviously emulating x86_64 got slow, but even when we built ARM64 VMs, performance was still miserable: there was (is?) no way -- at least no way we ever figured out -- to get reasonable perf out of virtualization on a macbook.

It's possible that this changed post-M1 and it sounds likely it's set to change with M4.

EDIT: ok, I'm probably hallucinating more problem than there actually turned out to be based on the pain in the first year of the M1 chips.

[inkyoto]

If you are referring to the nested virtualisation support in ARM v8, it was added in the ARM v8.3-A revision of the architecture, and M1 uses ARM v8.5-A as the baseline.

But yes, virtualisaiton support for ARM (in general) was abysmal and Apple Silicon was the catalyst that pushed people over the edge towards improving it across aarch64 (also in general).