LIMA VENV: arch detect fails

[rreho]

Eeesi fails in detecting the CPU microarchitecutre using the lima virtual environment on an apple M4 pro. The architecture detected is aarch64/neoverse_v1 which causes Illegal instructions errors.

A workaround would be to override the detection via:
export EESSI_SOFTWARE_SUBDIR_OVERRIDE=aarch64/generic

Finetuning of CPU detection would be optimal to avoid this issue,

[ocaisa]

From https://forum.parallels.com/threads/parallels-26-1-1-incorrectly-reports-sve2-capability-in-arm-guest-on-apple-m4-pro.368736/, this seems to be a problem of the Linux kernel that gets exposed when using Lima. The kernal is reporting SVE support but the CPU actually does not have it. There are a couple of solutions:

• Use an OS, that has a kernel > 6.1 (e.g., Ubuntu 24.04 has a 6.8 kernel)
  • If you are installing from the instructions at https://www.eessi.io/docs/getting_access/eessi_limactl/, we should just update that to Debain Trixie
• Force EESSI to use the "right" option: export EESSI_SOFTWARE_SUBDIR_OVERRIDE=aarch64/neoverse_n1
• Apply a workaround for the kernel (too complicated in practice for people I think)

[ocaisa]

From our side, the easiest fix may be to just update the docs at https://www.eessi.io/docs/getting_access/eessi_limactl/ with more  recent OSes (>kernel 6.1): Rocky 10, Ubuntu 26.04, Debian Trixie