Document QEMU support, what it does, and how to use it in kunit_tool. Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx> --- Changes since last revision: - Finally, I added a new section to the kunit_tool documentation to document the new command line flags I added. --- Documentation/dev-tools/kunit/kunit-tool.rst | 48 +++++++++++++++++++ Documentation/dev-tools/kunit/usage.rst | 50 +++++++++++++++----- 2 files changed, 87 insertions(+), 11 deletions(-) diff --git a/Documentation/dev-tools/kunit/kunit-tool.rst b/Documentation/dev-tools/kunit/kunit-tool.rst index 4247b7420e3ba..c7ff9afe407a5 100644 --- a/Documentation/dev-tools/kunit/kunit-tool.rst +++ b/Documentation/dev-tools/kunit/kunit-tool.rst @@ -145,6 +145,54 @@ to run KUnit resource tests, you could use: This uses the standard glob format for wildcards. +Running Tests on QEMU +===================== + +kunit_tool supports running tests on QEMU as well as via UML (as mentioned +elsewhere). The default way of running tests on QEMU requires two flags: + +``--arch`` + Selects a collection of configs (Kconfig as well as QEMU configs + options, etc) that allow KUnit tests to be run on the specified + architecture in a minimal way; this is usually not much slower than + using UML. The architecture argument is the same as the name of the + option passed to the ``ARCH`` variable used by Kbuild. Not all + architectures are currently supported by this flag, but can be handled + by the ``--qemu_config`` discussed later. If ``um`` is passed (or this + this flag is ignored) the tests will run via UML. Non-UML architectures, + e.g. i386, x86_64, arm, um, etc. Non-UML run on QEMU. + +``--cross_compile`` + Specifies the use of a toolchain by Kbuild. The argument passed here is + the same passed to the ``CROSS_COMPILE`` variable used by Kbuild. As a + reminder this will be the prefix for the toolchain binaries such as gcc + for example ``sparc64-linux-gnu-`` if you have the sparc toolchain + installed on your system, or + ``$HOME/toolchains/microblaze/gcc-9.2.0-nolibc/microblaze-linux/bin/microblaze-linux-`` + if you have downloaded the microblaze toolchain from the 0-day website + to a directory in your home directory called ``toolchains``. + +In many cases it is likely that you may want to run an architecture which is +not supported by the ``--arch`` flag, or you may want to just run KUnit tests +on QEMU using a non-default configuration. For this use case, you can write +your own QemuConfig. These QemuConfigs are written in Python. They must have an +import line ``from ..qemu_config import QemuArchParams`` at the top of the file +and the file must contain a variable called ``QEMU_ARCH`` that has an instance +of ``QemuArchParams`` assigned to it. An example can be seen in +``tools/testing/kunit/qemu_configs/x86_64.py``. + +Once you have a QemuConfig you can pass it into kunit_tool using the +``--qemu_config`` flag; when used this flag replaces the ``--arch`` flag. If we +were to do this with the ``x86_64.py`` example from above, the invocation would +look something like this: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py run \ + --timeout=60 \ + --jobs=12 \ + --qemu_config=./tools/testing/kunit/qemu_configs/x86_64.py + Other Useful Options ==================== diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 650f99590df57..888c341701da4 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -609,17 +609,45 @@ non-UML architectures: None of these are reasons not to run your KUnit tests on real hardware; they are only things to be aware of when doing so. -The biggest impediment will likely be that certain KUnit features and -infrastructure may not support your target environment. For example, at this -time the KUnit Wrapper (``tools/testing/kunit/kunit.py``) does not work outside -of UML. Unfortunately, there is no way around this. Using UML (or even just a -particular architecture) allows us to make a lot of assumptions that make it -possible to do things which might otherwise be impossible. - -Nevertheless, all core KUnit framework features are fully supported on all -architectures, and using them is straightforward: all you need to do is to take -your kunitconfig, your Kconfig options for the tests you would like to run, and -merge them into whatever config your are using for your platform. That's it! +Currently, the KUnit Wrapper (``tools/testing/kunit/kunit.py``) (aka +kunit_tool) only fully supports running tests inside of UML and QEMU; however, +this is only due to our own time limitations as humans working on KUnit. It is +entirely possible to support other emulators and even actual hardware, but for +now QEMU and UML is what is fully supported within the KUnit Wrapper. Again, to +be clear, this is just the Wrapper. The actualy KUnit tests and the KUnit +library they are written in is fully architecture agnostic and can be used in +virtually any setup, you just won't have the benefit of typing a single command +out of the box and having everything magically work perfectly. + +Again, all core KUnit framework features are fully supported on all +architectures, and using them is straightforward: Most popular architectures +are supported directly in the KUnit Wrapper via QEMU. Currently, supported +architectures on QEMU include: + +* i386 +* x86_64 +* arm +* arm64 +* alpha +* powerpc +* riscv +* s390 +* sparc + +In order to run KUnit tests on one of these architectures via QEMU with the +KUnit wrapper, all you need to do is specify the flags ``--arch`` and +``--cross_compile`` when invoking the KUnit Wrapper. For example, we could run +the default KUnit tests on ARM in the following manner (assuming we have an ARM +toolchain installed): + +.. code-block:: bash + + tools/testing/kunit/kunit.py run --timeout=60 --jobs=12 --arch=arm --cross_compile=arm-linux-gnueabihf- + +Alternatively, if you want to run your tests on real hardware or in some other +emulation environment, all you need to do is to take your kunitconfig, your +Kconfig options for the tests you would like to run, and merge them into +whatever config your are using for your platform. That's it! For example, let's say you have the following kunitconfig: -- 2.31.1.818.g46aad6cb9e-goog
