Re: [PATCH] EDAC/mce_amd: Reduce unnecessary spew in dmesg if SMCA feature bit is not exposed

From: Yazen Ghannam
Date: Tue Jun 15 2021 - 12:32:38 EST


On Tue, Jun 15, 2021 at 06:11:04PM +0200, Borislav Petkov wrote:
> On Tue, Jun 15, 2021 at 12:00:09PM -0400, Yazen Ghannam wrote:
> > So I think we can downgrade this warning to a debug message, if the
> > module stays builtin. And/or we change the default config option to
> > module, and we make sure the module only autoloads in the proper cases.
> >
> > What do you think?
>
> I think, as I said before, that we should simply not load this in
> guests. Then this will be taken care of once and for all and we can do
> whatever we want on baremetal, as to what error message to issue and how
> many times to issue it, whether the decoder is builtin or default y or
> yadda yadda.
>
> Because even if you say in a guest:
>
> pr_warn_once("Decoding supported only on Scalable MCA processors.\n");
>
> you're kinda misleading because the guest might be an SMCA processor but
> not all features are emulated, including SMCA. So it is not really an
> SMCA processor but some not really existant hybrid or so.
>
> So since this whole SMCA thing does not apply to virtualization, we
> should simply not load on virt and be done with it.
>

Yes, I agree. I was a bit confused about the X86_FEATURE_HYPERVISOR
thing, but I think I get it. This definitely looks simple to do.

Thanks,
Yazen