QEMU doesn't work on macOS 15.2 on Apple M4 cpus

[jandubois]

See lima-vm/lima#3032

Workaround is to use VZ, which we should make the default in 1.18.

For 1.17 we should check the CPU type:

$ system_profiler SPHardwareDataType -json | jq .SPHardwareDataType[0].chip_type
"Apple M1 Ultra"

If it starts with Apple M4 then we should set an alternate CPU in lima.yaml:

cpuType:
  aarch64: cortex-a57

Alternatively we should rebuild our QEMU binary with the patch from UTM: Homebrew/homebrew-core#201613

The problem is that there are no more macOS-12 GitHub runners, so we might lose support for Monterey if we do this (unless we set up a private GitHub runner for it).

[jandubois]

Fixed by #7993