Re: [PATCH] x86/AMD: Apply Erratum 688 fix when BIOS doesn't

From: Ingo Molnar
Date: Sun Oct 22 2017 - 08:14:51 EST



* Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Sun, Oct 22, 2017 at 01:04:38PM +0200, Ingo Molnar wrote:
> > Any objections to me adding a printk message that we applied a fix?
> >
> > pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");
> >
> > or so?
> >
> > That would also create some pressure for customers to prod manufacturers to prod
> > BIOS makers to fix the erratum in a BIOS update or so.
>
> Adding that would be purely useless because F14h is long out of
> production AFAIK. Especially those earlier models.

I've still added it, just out of principle - every time the kernel modifies low
level state in a rare fashion we should advertise it:

pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");

if it doesn't matter (which is likely as you say) then the message won't matter
really.

Thanks,

Ingo