Re: [PATCH v4 10/12] tests/qtest/migration: Support more than one QEMU binary

[Fabiano Rosas]

Thomas Huth <thuth@redhat.com> writes:

> On 18/10/2023 21.27, Fabiano Rosas wrote:
>> We have strict rules around migration compatibility between different
>> QEMU versions but no test to validate the migration state between
>> different binaries.
>> 
>> Add infrastructure to allow running the migration tests with two
>> different QEMU binaries as migration source and destination.
>> 
>> The code now recognizes two new environment variables
>> QTEST_QEMU_BINARY_SRC and QTEST_QEMU_BINARY_DST. In the absence of
>> either of them, the test will use the QTEST_QEMU_BINARY variable. If
>> both are missing then the tests are run with single binary as
>> previously.
>> 
>> The machine type is selected automatically as the latest machine type
>> version that works with both binaries.
>> 
>> Usage (only one of SRC|DST is allowed):
>> 
>> QTEST_QEMU_BINARY_SRC=../build-8.2.0/qemu-system-x86_64 \
>> QTEST_QEMU_BINARY=../build-8.1.0/qemu-system-x86_64 \
>> ./tests/qtest/migration-test
>> 
>> Reviewed-by: Juan Quintela <quintela@redhat.com>
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>>   tests/qtest/migration-test.c | 28 ++++++++++++++++++++++++----
>>   1 file changed, 24 insertions(+), 4 deletions(-)
>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
>
> I wonder whether we could test this in the gitlab-CI, too, e.g. by using a 
> Debian container and installing the qemu-system-x86_64 from the Debian 
> distro there (since this should be close enough to an older version of an 
> upstream release), then run the test with that version from Debian and the 
> one that has just been compiled from the master branch? Anyway, just an 
> idea, this can certainly be done later.

Yes, something like this is the goal. It's not in this series because my
docker-fu is a bit rusty, so I didn't want to delay the qtest part.

I think taking a built-from-tree QEMU would be better than a
distro-shipped one.

I also think that we should have this disabled in CI, due to the issues
I described in the other thread. And possibly enable it with fewer
migration-test tests. I don't see the need to run *all* of the
migration-tests in this "compat testing" scheme.