On 1/15/26 10:01 AM, Daniel P. Berrangé wrote:
Informally we have approximately three groups of platforms* Tier 1: fully built and fully tested by CI. Must always be kept working & regressions fixed immediately * Tier 2: fully built and partially tested by CI. Should always be kept working & regressions fixed quickly * Tier 3: code exists but is not built or tested by CI. Should not be intentionally broken but not guaranteed to work at any time. Downstream must manually test, report & fix bugs. Anything else is "unclassified" and any historical code remnants may be removed. It is somewhat tricky to define unambiguous rules for each tier, but this doc takes a stab at it. We don't need to cover every eventuality. If we get the core points of view across, then it at least sets the direction for maintainers/contributors/users. Other aspects can be inferred with greater accuracy than today. Signed-off-by: Daniel P. Berrangé <[email protected]> --- This came out of the discussion about recent unnoticed breakage in NetBSD builds and what maintainers are expected todo about it (if anything) https://lists.nongnu.org/archive/html/qemu-devel/2026-01/msg02543.html docs/about/build-platforms.rst | 152 +++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) diff --git a/docs/about/build-platforms.rst b/docs/about/build-platforms.rst index e95784cdb5..950e164c02 100644 --- a/docs/about/build-platforms.rst +++ b/docs/about/build-platforms.rst @@ -171,3 +171,155 @@ Only 64-bit Windows is supported. .. _MacPorts: https://www.macports.org/ .. _MSYS2: https://www.msys2.org/ .. _Repology: https://repology.org/ + +OS Support Tiers +---------------- + +While the QEMU code targets a number of different OS platforms, they don't +all get the same level of support from the project. This applies to +contributor & maintainer expectations, CI automation and requirements +for merge gating. + +Tier 1 +~~~~~~ + +These platforms attain the highest level of quality offered by +the QEMU project. + + * Builds and all tests pass at all times in both git HEAD and releases + + * Builds for multiple build configuration are integrated in CI + + * Runs all available tests frameworks (unit, qtest, iotests, functional) + in CI + + * Merging code is gated on successful CI jobs + +This covers + + * Linux (x86_64, aarch64, s390x) + +Responsibilities: + + * Contributors MUST test submitted patches on one of Tier 1 platforms. + + * Contributors SHOULD test submitted patches on Tier 1 platforms + by running a GitLab CI pipeline in their fork. + + * Maintainers MUST request contributors to fix problems with Tier 1 + platforms. + + * Maintainers MUST test pull requests on Tier 1 platforms + by running a GitLab CI pipeline in their fork. + + * Maintainers MUST co-ordinate fixing regressions identified + post-merge immediately. + + +Tier 2 +~~~~~~ + +These platforms are considered to be near Tier 1 level, but are +lacking sufficient automated CI testing cover to guarantee this. + + * Builds and all tests pass at all times in both git HEAD and releases + + * Builds for multiple build configuration are integrated in CI + + * Runs some test frameworks in CI + +This covers + + * Linux (mips64el, ppc64el, riscv64) + + * FreeBSD (x86_64) + + * macOS (aarch64) + + * Windows (x86_64) + +Responsibilities: + + * Contributors MAY test patches on Tier 2 platforms + by running a GitLab CI pipeline in their fork + + * Maintainers SHOULD request contributors to fix problems with Tier 2 + platforms. + + * Maintainers MUST test pull requests on all Tier 2 platforms, + by running a GitLab CI pipeline in their fork. + + * Maintainers MUST co-ordinate fixing regressions identified + post-merge quickly. + + +Tier 3 +~~~~~~ + +These platforms have theoretical support in the code, but have +little, or no, automated build and test coverage. Downstream +consumers (users or distributors) who care about these platforms +are requested to perform manual testing, report bugs and provide +patches. + + * Builds and tests may be broken at any time in Git HEAD and + releases + + * Builds are not integrated into CI + + * Tests are not integrated into CI + + * Merging code is not gated + +This covers: + + * NetBSD + * OpenBSD + * macOS (except aarch64) + * FreeBSD (except x86_64) + * Windows (except x86_64) + * Solaris + +Responsibilities: + + * Contributors MAY test patches on Tier 3 platforms manually + + * Maintainers MAY request contributors to fix problems + on Tier 3 platforms + + * Maintainers MAY test patches on Tier 3 platforms manually + + * Maintainers SHOULD NOT accept patches that remove code + targetting Tier 3 platforms even if currently broken + + * Downstream vendors SHOULD test RC releases on Tier 3 platforms + and provide bug reports and patches to address problems + +Note: if a Tier 3 platform is found to be significantly broken, +no patches are contributed for a prolonged period, and there is +no sign of downstream usage, it is liable to be moved to +"Unclassified" and thus be subject to removal. + + +Unclassified +~~~~~~~~~~~~ + +These platforms are not intended to be supported in the code +and outside the scope of any support tiers. + + * Code supporting these platforms can removed at any time + * Bugs reports related to these platforms will generally + be ignored + +This covers: + + * All 32-bit architectures on any OS + * Any OS not listed above + +Responsibilities: + + * Maintainers MAY decline patches that add code targetting + unclassified platforms + + * Maintainers MAY accept patches that remove code targetting + unclassified platforms
That's a good summary, but it should differentiate testing/runtime issues from building issues.
In general, maintainers should ensure code build on all platforms/configs. Of course, it's a best effort considering not all of them are built in CI, but in case a build issue is caught on time, it should be fixed before hitting master.
It may be worth to mention that all platforms can be accessed for free using: https://github.com/second-reality/github-runners. If you're open to it, we could move this project under https://github.com/qemu and preinstall all dependencies on each runner, so people can easily jump on a shell and start debugging things without wasting time.
With this at hand, there is no reason to let a build failure be merged. Thanks, Pierrick
