Re: pvops microcode support for AMD FAM >= 15

[Konrad Rzeszutek Wilk <konrad@kernel.org>]

On Wed, Dec 05, 2012 at 12:46:39PM +0000, Ian Campbell wrote:
> On Mon, 2012-11-26 at 13:44 +0000, Jan Beulich wrote:
> > >>> On 26.11.12 at 14:21, Ian Campbell <ijc@hellion.org.uk> wrote:
> > > Debian has decided to take Jeremy's microcode patch [0] as an interim
> > > measure for their next release. (TL;DR -- Debian is shipping pvops Linux
> > > 3.2 and Xen 4.1 in the next release. See http://bugs.debian.org/693053 
> > > and https://lists.debian.org/debian-devel/2012/11/msg00141.html for some
> > > more background).
> > > 
> > > However the patch is a bit old and predates the use introduction of
> > > separate firmware files for AMD family >= 15h. Looking at the SuSE
> > > forward ported classic Xen patches it seems like the following patch is
> > > all that is required. But it seems a little too simple to be true and I
> > > don't have any such processors to test on.
> > > 
> > > Jan, can you recall if it really is that easy on the kernel side ;-)
> > 
> > While so far I didn't myself run anything on post-Fam10 systems
> > either, it really ought to be that easy - the patch format didn't
> > change, it's just that they decided to spit the files by family to
> > keep them manageable.
> > 
> > The only other thing to check for is that you don't have any
> > artificial size restriction left in that code (I think patch files early
> > on were limited to 4k in size, and that got lifted during the last
> > couple of years).
> 
> I managed to find a machine and try this and it turns out that all that
> was missing from the kernel side was:
> 
>         @@ -58,7 +58,7 @@
>          
>          static enum ucode_state xen_request_microcode_fw(int cpu, struct device *device)
>          {
>         -       char name[30];
>         +       char name[36];
>                 struct cpuinfo_x86 *c = &cpu_data(cpu);
>                 const struct firmware *firmware;
>                 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

Do you want to prep a patch that I can stick in my 'microcode' branch?
.. That I will at some point try to upstream.