Re: [PATCH v2] KVM: x86: Do not return host topology information from KVM_GET_SUPPORTED_CPUID

From: Greg KH
Date: Fri Jan 27 2023 - 02:23:21 EST


On Thu, Jan 26, 2023 at 12:45:58PM -0800, Jim Mattson wrote:
> On Thu, Jan 26, 2023 at 9:47 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> >
> > On 1/26/23 17:06, Jim Mattson wrote:
> > >>> Sadly, there isn't a single kernel involved. People running our VMM on
> > >>> their desktops are going to be impacted as soon as this patch hits
> > >>> that distro. (I don't know if I can say which distro that is.) So, now
> > >>> we have to get the VMM folks to urgently accommodate this change and
> > >>> get a new distribution out.
> > >>
> > >> Ok, this is what is needed to make a more informed choice. To be clear,
> > >> this is _still_ not public (for example it's not ChromeOS), so there is
> > >> at least some control on what version of the VMM they use? Would it
> > >> make sense to buy you a few months by deferring this patch to Linux 6.3-6.5?
> > >
> > > Mainline isn't a problem. I'm more worried about 5.19 LTS.
> >
> > 5.19 is not LTS, is it? This patch is only in 6.1.7 and 6.1.8 as far as
> > stable kernels is concerned, should I ask Greg to revert it there?
>
> It came to my attention when commit 196c6f0c3e21 ("KVM: x86: Do not
> return host topology information from KVM_GET_SUPPORTED_CPUID") broke
> some of our tests under 5.10 LTS.
>
> If it isn't bound for linux-5.19-y, then we have some breathing room.

5.19 is long end-of-life, it dropped off of being maintained back in
October of last year.

You can always use the front page of kernel.org to determine what is
still being maintained.

thanks,

greg k-h