Recently more developers are enthusiast to use Docker/Podman, and have been confused by the different configurations currently in the QEMU repository.
There are at least 3 kind of categories I use: 1/ Image used to build QEMU These images should be restricted/updated to our "supported targets". They are useful to (cross)build QEMU on variety of host/target/distributions/distrib_versions. Example: - cross build Cris binary using the Fedora 30 toolchain on a Ubuntu 18.04 x86_64. host:Ubuntu18.04/x86_64 docker_image:fedora-cris-cross - cross build MinGW64 binary using Debian 9 MXE toolchain on a Ubuntu aarch64: host:Ubuntu18.04/x86_64 docker_image:debian-win64-cross An image can not be meant to use on a daily basis, but to avoid regression previous to release (I'd run them only on release candidate). Example: building QEMU for the Gentoo PlayStation2 port: https://www.mail-archive.com/qemu-devel@nongnu.org/msg574468.html 2/ Image used to build test program used by QEMU These images provide enough to build binaries you can then use to test QEMU. If you want to build more of these binaries, there is probably a better way. Here we are only interested in testing. Example: - Test PowerPC Linux-user binaries with qemu-powerpc-linux-user docker_image:debian-powerpc-user-cross - Build EDK2 payload for Virt/AArch64 It currently doesn't build with Fedora 30 and I'v to use a Fedora 29 image. Another case I had is when I tried to build a kernel for the Mipssim machine (supported by QEMU). The Linux kernel code has been removed, so I had to checkout an old kernel which is not buildable with my recent host GCC. Using a docker based on a very old distribution worked. Anyway Thomas Huth found it is easier to use buildroot for pre-3.6 kernels. Similarly, I am testing QEMU port from Stefan Weil, and he shared a working binary supporting the MIPS AR7 target. To be able to use this QEMU I use Debian Lenny and set DEB_URL=https://snapshot.debian.org/archive/debian/20091004T111800Z. Yes, this will instanciate a Debian from 10 years ago. 3/ Bisecting Another of my docker uses is when bisecting before QEMU v3. I use image using snapshot slighly older than the QEMU release, so my bisect script can run without worrying about the library API incompatibilities or newer GCC warnings. So not all image have the same use. While they might not be useful to build the latest QEMU, there are still useful for day-to-day development. Anyhow I agree we should document that better. Maybe the wiki is a good starting point. Regards, Phil.
