Re: Xen 4.18 release: Reminder about code freeze

[George Dunlap <george.dunlap@xxxxxxxxx>]

On Fri, Oct 13, 2023 at 4:56 PM Julien Grall <julien@xxxxxxx> wrote:
> > The initial patch that
> > introduced it didn't mention wanting to include dom0 specifically; on
> > the contrary it said:
> >
> > "The extra notification is harmless for domains that don't require it."
>
> ... even if this is what the commit message says, we can't tell whether
> someone would start to rely on it. I definitely see use-cases for it.
>
> But I agree that the chance they are actualy used is slim as we didn't
> document it.

If a dom0 kernel started relying on the behavior, it would be a bug,
since it would be incompatible with releases before 4.16.  So I think
the only risk here would be if some bit of a system's userspace
tooling relied on it; but I can't really see how that would come to
be.

If someone reports a bug, we can always add the reporting back, when
we're not under time pressure.

> Your reasoning makes sense. I don't fully agree with it, but at the end
> of the day we need to have a solution for dom0less guests... So if the
> others agree with you, then I will disagree and commit.
>
> That said, I think the commit message should explain why removing dom0
> notification is ok.

Yes, absolutely.

Do you or Stefano want to pick it up?  I think you'd be able to test
it more thoroughly.  I can build-test it and send it to gitlab-CI, but
anything more will take a lot more setup.

 -George