Re: [PATCH 11/12] acpi/tests/bits: add README file for bits qtests

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Jun 28, 2022 at 11:46:13AM +0530, Ani Sinha wrote:
> On Tue, Jun 28, 2022 at 11:36 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Tue, Jun 28, 2022 at 10:27:38AM +0530, Ani Sinha wrote:
> > > On Tue, Jun 28, 2022 at 3:56 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > >
> > > > On Mon, Jun 27, 2022 at 12:58:55PM +0530, Ani Sinha wrote:
> > > > > The README file is added describing the directory structure and the purpose
> > > > > of every file it contains. It also describes how to add new tests, make changes
> > > > > to existing tests or bits config files or regenerate the bits software.
> > > > >
> > > > > Signed-off-by: Ani Sinha <ani@anisinha.ca>
> > > > > ---
> > > > >  tests/qtest/acpi-bits/README | 168 +++++++++++++++++++++++++++++++++++
> > > > >  1 file changed, 168 insertions(+)
> > > > >  create mode 100644 tests/qtest/acpi-bits/README
> > > > >
> > > > > diff --git a/tests/qtest/acpi-bits/README b/tests/qtest/acpi-bits/README
> > > > > new file mode 100644
> > > > > index 0000000000..97b15f1665
> > > > > --- /dev/null
> > > > > +++ b/tests/qtest/acpi-bits/README
> > > > > @@ -0,0 +1,168 @@
> > > > > +=============================================================================
> > > > > +ACPI/SMBIOS QTESTS USING BIOSBITS
> > > > > +=============================================================================
> > > > > +
> > > > > +Biosbits is a software written by Josh Triplett that can be downloaded by
> > > > > +visiting https://biosbits.org/. The github codebase can be found here:
> > > > > +https://github.com/biosbits/bits/tree/master. It is a software that exercizes
> > > > > +the bios components such as acpi and smbios tables directly through acpica
> > > > > +bios interpreter (a freely available C based library written by Intel,
> > > > > +downloadable from https://acpica.org/ and is included with biosbits) without an
> > > > > +operating system getting involved in between.
> > > > > +There are several advantages to directly testing the bios in a real physical
> > > > > +machine or VM as opposed to indirectly discovering bios issues through the
> > > > > +operating system. For one thing, the OSes tend to hide bios problems from the
> > > > > +end user. The other is that we have more control of what we wanted to test
> > > > > +and how by directly using acpica interpreter on top of the bios on a running
> > > > > +system. More details on the inspiration for developing biosbits and its real
> > > > > +life uses can be found in (a) and (b).
> > > > > +This directory contains QEMU qtests written in python that exercizes the QEMU
> > > > > +bios components using biosbits and reports test failures.
> > > > > +
> > > > > +These tests use python virtual environment. In debian/ubuntu system, the tests
> > > > > +would require python3.8-venv and python3-pip packages to be installed.
> > > >
> > > > Why do we mess with venv and pip? Certainly possible but
> > > > what's wrong with using distro provided packages?
> > >
> > > There are two things:
> > > (a) We are already using pip and venv for our avocado based
> > > integration tests. Look for TESTS_VENV_DIR in Makefile.include under
> > > tests.
> > > (b) the venv is primarily needed because I wanted to take advantage of
> > > our rich python library that handles QEMU based machines. There are
> > > python qtest libraries as well. These are well tested and used with
> > > integration tests and I wanted to keep the test part of the code
> > > simple by simply reusing them. however, in order to use them, we need
> > > a venv environment within which these qemu python libraries are
> > > installed. Integration tests does the same thing.
> > >
> > > A note about my language of choice - python. I gave a lot of thoughts
> > > on this. We do not do a lot of stuff here. All we do is:
> > > (a) generate bits iso.
> > > (b) spawn a QEMU vm with the iso which then runs a bunch of tests within the vm.
> > > (c) collect and analyze logs.
> > >
> > > We are not inspecting guest memory or manipulating devices or pci
> > > buses. We do not need the power of C here. We need something that is
> > > simple to write, easy to maintain and understand and can deal with
> > > things like manipulating text files and configs easily. Python seems a
> > > better fit for the role.
> >
> > No problem with that. So that's venv. But do we need pip and pulling
> > packages from the net during testing?
> 
> We do that too. See requirements.txt in tests/
> Following two are downloaded:
> avocado-framework==88.1
> pycdlib==1.11.0
> 
> Also see this line in Makefie.include:
> 
> $(call quiet-venv-pip,install -r $(TESTS_VENV_REQ))

Right but that's avocado since it pulls lots of stuff from
the net anyway.
Are the libraries in question not packaged on major distros?

> >
> > > >
> > > > > +
> > > > > +A brief description of the contents of this directory follows:
> > > > > +
> > > > > +├── acpi-bits-test.py
> > > > > +├── acpi-bits-test-venv.sh
> > > > > +├── bits-config
> > > > > +│   ├── bits-cfg.txt
> > > > > +│   └── meson.build
> > > > > +├── bits-tests
> > > > > +│   ├── meson.build
> > > > > +│   ├── smbios.py
> > > > > +│   ├── smilatency.py
> > > > > +│   ├── testacpi.py
> > > > > +│   └── testcpuid.py
> > > > > +├── meson.build
> > > > > +├── prebuilt
> > > > > +│   ├── bits-2095-grub.tar.gz
> > > > > +│   ├── bits-2095.zip
> > > > > +│   └── meson.build
> > > > > +├── README
> > > > > +└── requirements.txt
> > > > > +
> > > > > +acpi-bits:
> > > > > + - acpi-bits-test-venv.sh: This is a shell script that sets up the virtual
> > > > > +   environment necessary for the actual python test script to run. Amongst
> > > > > +   other things, it makes sure that QEMU python library is available within
> > > > > +   that venv so that QEMU machines can be forked. QEMU python library can be
> > > > > +   found within python/ directory in QEMU source.
> > > > > +   After setting up the virtual environment, it runs the python test script
> > > > > +   from within that environment.
> > > > > +   If you want to enable verbose mode only for bits test and run make check,
> > > > > +   one trick is to add V=1 before the call to execute the python script in
> > > > > +   this file.
> > > > > + - acpi-bits-test.py: This is the main python test script that generates a
> > > > > +   biosbits iso. It then spawns a QEMU VM with it, collects the logs and reports
> > > > > +   test failures. This is the script one would be interested in if they wanted
> > > > > +   to add or change some component of the log parsing, add a new commandline to
> > > > > +   how QEMU is spawned etc. Test writers typically would not need to modify
> > > > > +   this script unless they wanted to enhance or change the log parsing for
> > > > > +   their tests.
> > > > > + - requirements.txt: This text file contains the dependent python libraries
> > > > > +   needed for the tests to run. If a new dependent library is needed, it would
> > > > > +   be added here as a new entry and then acpi-bits-test-venv.sh would install
> > > > > +   it when setting up the python virtual environment using pip.
> > > > > + - README: This text file.
> > > > > +
> > > > > +acpi-bits/bits-config:
> > > > > +   This location contains biosbits config files that determine how the software
> > > > > +   runs the tests.
> > > > > + - bits-config.txt: this is the biosbits config file that determines what tests
> > > > > +   or actions are performed by bits. The description of the config options are
> > > > > +   provided in the file itself.
> > > > > +
> > > > > +acpi-bits/prebuilt:
> > > > > +   This location contains prebuilt biosbits binaries that are used to generate
> > > > > +   the bits iso file for testing.
> > > > > + - bits-2095.zip: The contents from this zip archive are the main contents of
> > > > > +    the iso file that are used for testing. This binary zip archive also
> > > > > +    contains the full source of the bits software including the full text of
> > > > > +    the license agreement listed here:
> > > > > +    https://github.com/biosbits/bits/blob/master/COPYING
> > > > > +    The source tarball can be found in this location in the zip file:
> > > > > +    boot/src/bits-2095.tar.gz
> > > > > +    The additional changes beyond those that are present in the official
> > > > > +    biosbits github repository can be found here:
> > > > > +    https://github.com/ani-sinha/bits/tree/bits-qemu-logging
> > > > > +
> > > > > +    Basically these changes can be categorized into the following:
> > > > > +    (a) changes to make sure biosbits builds with the latest gcc compiler
> > > > > +    (gcc 9.4).
> > > > > +    (b) upgrade of acpica to the latest version (march 2022).
> > > > > +    (c) send bits logs to the debug IO port at addresss 0x403 so that isa
> > > > > +    debugcon can be used to collect the logs.
> > > > > +    (d) send a gub halt command to shutdown the VM once all the tests have been
> > > > > +    executed.
> > > > > +
> > > > > +    This zip file is automatically generated by the bits build system. It can
> > > > > +    be found in the bits build directory and it is suffixed by the bits build
> > > > > +    number.
> > > > > +    Normally, there is no need to make any alteration to this zip archive
> > > > > +    unless one wanted to change the bits software itself (for example to add
> > > > > +    a new config option or change actions of existing options or change the
> > > > > +    debug IO port etc). When such changes are made and a new biosbits software
> > > > > +    is needed to be generated, please refresh this zip archive as well as the
> > > > > +    grub tarball at the same time. Tests will break if changes are made to bits
> > > > > +    that are incompatible with existing behavior. So care must be taken to make
> > > > > +    sure that the change is compatible with existing bits software as much as
> > > > > +    possible. When a new config option is introduced for example, bits must
> > > > > +    be upadated here first before introducing the new config option through
> > > > > +    a later commit.
> > > >
> > > > I don't think playing with source tarballs is a reasonable work environment.
> > >
> > > I agree. However, we do not do much with the source tarball. It is
> > > there as part of bits to satisfy the license requirement. If we need
> > > to manipulate any test script that is in the source file, we would
> > > copy it over and keep it in the bits-test directory and change it
> > > there.
> > >
> > > > Let's use submodules just like e.g. firmware does?
> > >
> > > Yes I also proposed this to Igor on IRC. We can/maybe need to figure
> > > out a place to store the bits source if we think my github is not the
> > > best place. However, we need the source only if/when we need to
> > > rebuild bits. I suspect it won't be too often if at all.
> >
> > Why not on git.qemu.org ?
> 
> Sounds good to me. Do I get push access? :-)
> 
> >
> > > >
> > > >
> > > >
> > > > > + - prebuilt/bits-2095-grub.tar.gz: This tarbball contains bits generated grub
> > > > > +    scripts and modules to the prebuilt directory. These prebuilt grub
> > > > > +    artifacts are required in order to generate a bootable bits iso file that
> > > > > +    can run tests.
> > > > > +    In order to generate this tar archive, please put the following two
> > > > > +    directories that can be found in the bits build directory in a single
> > > > > +    tar archive file named as bits-<n>-grub.tar.gz where n is the version of
> > > > > +    bits that generated the archive:
> > > > > +
> > > > > +    grub-inst-x86_64-efi
> > > > > +    grub-inst
> > > > > +
> > > > > +    This version should be the same as the version number of bits that generated
> > > > > +    bits-<n>.zip file. In other words, the two files must be in sync and should
> > > > > +    come from the same build of biosbits of the same version. Things may still
> > > > > +    work if they come from different versions but mixing version numbers are
> > > > > +    not recommended.
> > > > > +    There is normally no need to regenerate this archive unless some fixes or
> > > > > +    changes have gone into the grub that are part of biosbits.
> > > > > +
> > > > > +acpi-bits/bits-tests:
> > > > > +   This directory contains biosbits python based tests that are run from within
> > > > > +   the biosbits environment in the spawned VM. New additions of test cases can
> > > > > +   be made in the appropriate test file. For example, new acpi tests can go
> > > > > +   into testacpi.py and one would call testsuite.add_test() to register the new
> > > > > +   test so that it gets executed as a part of the ACPI tests.
> > > > > +   It might be occassionally necessary to disable some subtests or add a new
> > > > > +   test that belongs to a test suite not already present in this directory. To
> > > > > +   do this, please extract the bits source from the zip file mentioned above.
> > > > > +   Copy the test suite/script that needs modification (addition of new tests
> > > > > +   or disabling them) from boot/python location of the extracted directory
> > > > > +   into this directory.
> > > > > +
> > > > > +   step (a): copy unmodified test script to this directory.
> > > > > +   step (b): update meson.build and add this file to the list.
> > > > > +   Commit (a) and (b) together in the same commit.
> > > > > +
> > > > > +   step (c): perform modifications to the test.
> > > > > +   Commit (c) in a separate commit.
> > > > > +
> > > > > +   The test framework will then use your modified test script to run the test.
> > > > > +   No further changes would be needed. Please check the logs to make sure that
> > > > > +   appropriate changes have taken effect.
> > > > > +
> > > > > +meson.build files makes sure that the bits qtests are appropriately integrated
> > > > > +into the QEMU qtest framework and are run with "make check-qtest".
> > > > > +Currently, the bits test is configured to run only for x86_64 architectures. Bits
> > > > > +has been built only for this architecture.
> > > > > +
> > > > > +
> > > > > +Author: Ani Sinha <ani@anisinha.ca>
> > > > > +
> > > > > +References:
> > > > > +(a) https://blog.linuxplumbersconf.org/2011/ocw/system/presentations/867/original/bits.pdf
> > > > > +(b) https://www.youtube.com/watch?v=36QIepyUuhg
> > > > > --
> > > > > 2.25.1
> > > >
> >