Re: [PATCH net 2/7] selftests: openvswitch: add config file

On 20/07/2026 16:43, Aaron Conole wrote:

Matthieu Baerts [off-list ref] writes:

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Hi Aaron,

Thank you for the review!

On 16/07/2026 22:00, Aaron Conole wrote:

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Aaron Conole [off-list ref] writes:

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"Matthieu Baerts (NGI0)" [off-list ref] writes:

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The kselftests doc mentions that a config file should be present "if a
test needs specific kernel config options enabled". This selftest
requires some kernel config, but no config file was provided.

We could say that a sub-target could use the parent's config file, but
the kselftests doc doesn't mention anything about that. Plus the
net/openvswitch target is the only net target without a config file.

We've been operating on that assumption from the openvswitch side, but
it's true that isn't explicitly documented anywhere, and I guess it
isn't officially supported in the kselftest framework.  I guess we'll
need to keep updating this config as we add tests for things like SCTP,
and others, and maybe that's a good thing like we can add a comment
describing which tests take which configs.

The downside is for most of the OVS testing we use the NIPA scripts
and those 'inherit' the parent config, so it would be a change on our
side from the development standpoint (but probably something we should
have been doing from the beginning).

That said, would it be worth also exploring the 'cascading
configuration' support?  It seems like a useful feature, but maybe it
should be a separate discussion.  I ask because of how OVS interacts
with the networking stack as an 'alternative bridge' so-to-speak, I do
worry about having to duplicate lots of configurations between the two
as we expand the test coverage on OVS side.

It is not clear to me what you are using on your side, but I guess it
should be doable to modify some scripts to merge this new config file
and the net one in your case.

This doesn't seem to break the NIPA case (at least I can see the
'contest test' output is not SKIP, but PASS for the openvswitch.sh).

Note that currently, the net/openvswitch target on NIPA is executed on
the same runner as the net one. In other words, the config files are
merged, so at the end, my patch shouldn't change anything with the way
NIPA is currently deployed (but that could change).

I'm not sure about the suggestion to change the script in
tools/testing/selftests/net/openvswitch/openvswitch.sh to do a config
merge.  It isn't out-of-tree or anything, and seems like that would
create confusing git state (and not desirable from my end) - the
upstream test would leave a modified, tracked file.  Was that your
suggestion?  Or do you mean NIPA itself (but I think it already just
uses the top-level config).

No, sorry, I thought my modification would have caused issues with other
tests on your side. Good to hear it is not.

The config change itself looks fine to me.

Thank you!

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Here is a new config file, which is a trimmed version of the net one,
with hopefully the minimal required kconfig on top of 'make defconfig'.

Should this also remove the OVS configs from the upper level since there
shouldn't be OVS tests executing there (ie: CONFIG_OPENVSWITCH*)?

Actually, forget this part.  The P-MTU tests in pmtu.sh use ovs to
create a datapath through OVS.  So these configurations need to stay at
the top level as well.

Indeed. I don't know these tests well, but maybe this P-MTU selftest
should move to the net/openvswitch target?

Well, it is testing path MTU across multiple topologies, so it isn't
really an openvswitch specific test.  Just one that happens to use
openvswitch in one of the test cases.

OK, it is fine there then.

Note that the openvswitch test could also be moved to the 'net' one. It
looks like the sub-targets are often created when there are multiple
tests linked to one sub-subsystem, and also because the 'net' config is
quite big, and it takes time to compile all that. But I'm not pushing
for one or the other, I just wanted to be able to build all targets in
small containers :)

Cheers,
Matt