qemu-user-static

(5) Docker Image (amd64) ^ | (4) QEMU Binfmt (arm64 <-> amd64 binary emulation layer) ^ | (3) Linux VM (arm64) ^ | (2) Hypervisor.framework (arm64, macOS native virtualization framework) ^ | (1) Docker for Mac Linux Kernel has a feature to allow using a wrapper to execute userspace program based on file header (binfmt[1]). In this case, Linux VM in (3) has QEMU user mode emulation registered as binfmt, so any amd64 binaries are automatically wrapped into `qemu-x86_64-static /path/to/bin` and run. Docker Image itself doesn't run a Linux kernel but use one from the VM host, so this scenario is possible. This is also how multiarch[2] works (for amd64 to arm64/ppc64le/etc.

From their roadmap, it does not appear they have really investigated this yet. [1] Rosetta 2 translates Mac apps and can deal with JIT, but I do not believe it will work through virtualization. It should be relatively light lifting to make Docker for Mac run an ARM linux installation and ARM-built containers. From there, you likely would want to strategically add multi-arch container support to the docker runtime. This might be implemented based on existing qemu containers [2] 1: https://github.com/docker/roadmap/issues/142 2: https://github.com/multiarch/qemu-user-static

I'm using https://github.com/multiarch/qemu-user-static - that's what it is, right ?