docs: Move deprecation, build and license info out of system/

Now that we have a single Sphinx manual rather than multiple manuals,
we can provide a better place for "common to all of QEMU" information
like the deprecation notices, build platforms, license information,
which we currently have in the system/ manual even though it applies
to all of QEMU.

Create a new directory about/ on the same level as system/, user/,
etc, and move these documents there.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20210705095547.15790-5-peter.maydell@linaro.org

1 files changed, 62 insertions, 0 deletions

diff --git a/docs/about/build-platforms.rst b/docs/about/build-platforms.rst
new file mode 100644
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+.. _Supported-build-platforms:
+
+Supported build platforms
+=========================
+
+QEMU aims to support building and executing on multiple host OS
+platforms. This appendix outlines which platforms are the major build
+targets. These platforms are used as the basis for deciding upon the
+minimum required versions of 3rd party software QEMU depends on. The
+supported platforms are the targets for automated testing performed by
+the project when patches are submitted for review, and tested before and
+after merge.
+
+If a platform is not listed here, it does not imply that QEMU won't
+work. If an unlisted platform has comparable software versions to a
+listed platform, there is every expectation that it will work. Bug
+reports are welcome for problems encountered on unlisted platforms
+unless they are clearly older vintage than what is described here.
+
+Note that when considering software versions shipped in distros as
+support targets, QEMU considers only the version number, and assumes the
+features in that distro match the upstream release with the same
+version. In other words, if a distro backports extra features to the
+software in their distro, QEMU upstream code will not add explicit
+support for those backports, unless the feature is auto-detectable in a
+manner that works for the upstream releases too.
+
+The `Repology`_ site is a useful resource to identify
+currently shipped versions of software in various operating systems,
+though it does not cover all distros listed below.
+
+Linux OS, macOS, FreeBSD, NetBSD, OpenBSD
+-----------------------------------------
+
+The project aims to support the most recent major version at all times. Support
+for the previous major version will be dropped 2 years after the new major
+version is released or when the vendor itself drops support, whichever comes
+first. In this context, third-party efforts to extend the lifetime of a distro
+are not considered, even when they are endorsed by the vendor (eg. Debian LTS).
+
+For the purposes of identifying supported software versions available on Linux,
+the project will look at CentOS, Debian, Fedora, openSUSE, RHEL, SLES and
+Ubuntu LTS. Other distros will be assumed to ship similar software versions.
+
+For FreeBSD and OpenBSD, decisions will be made based on the contents of the
+respective ports repository, while NetBSD will use the pkgsrc repository.
+
+For macOS, `HomeBrew`_ will be used, although `MacPorts`_ is expected to carry
+similar versions.
+
+Windows
+-------
+
+The project supports building with current versions of the MinGW toolchain,
+hosted on Linux (Debian/Fedora).
+
+The version of the Windows API that's currently targeted is Vista / Server
+2008.
+
+.. _HomeBrew: https://brew.sh/
+.. _MacPorts: https://www.macports.org/
+.. _Repology: https://repology.org/