QEMU's sysemu is a little unwieldy for CI, but the linux userspace support is perfect for this use case.

In case you haven't encountered it -- it's terribly clever. Userspace instructions are translated just like they are in full system mode, but when a system call is encountered, the arguments are translated between the host and guest system. So the guest architecture linux program 'just works'. There's also hooks you can enable in binfmt-misc to make the loader invoke the qemu binary automagically.

Sounds interesting. Do you have a link with more info about these things?

[1] [2] are handy links.

[1] https://www.qemu.org/docs/master/user/main.html

[2] https://wiki.debian.org/QemuUserEmulation

BTW, how does ExaGear compare to qemu for running x86_64 on arm64 hosts ?

For something faster than Qemu, there's this: https://threedots.ovh/blog/2020/12/houdini-run-arm-32-bit-an...