Re: [PATCH V3 4/4] microcode/x86/amd: early microcode patch loadingsupport for AMD

[Jacob Shin]

On Fri, May 31, 2013 at 06:30:39PM -0300, Henrique de Moraes Holschuh wrote:
> On Fri, 31 May 2013, Andreas Herrmann wrote:
> > On Fri, May 31, 2013 at 01:26:49AM -0300, Henrique de Moraes Holschuh wrote:
> > > On Thu, 30 May 2013, Jacob Shin wrote:
> > > >  mkdir initrd
> > > >  cd initrd
> > > > -mkdir kernel
> > > > -mkdir kernel/x86
> > > > -mkdir kernel/x86/microcode
> > > > -cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin
> > > > -find .|cpio -oc >../ucode.cpio
> > > > +mkdir -p kernel/x86/microcode
> > > > +cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin (or AuthenticAMD.bin)
> > > 
> > > Can I just 
> > > 'cat /lib/firmware/amd-ucode/*bin >kernel/x86/microcode/AuthenticAMD.bin' 
> > > to get a valid microcode container for all amd processors?
> > > 
> > > The answer for Intel is "yes".  I sure hope it is the same for AMD...
> > 
> > No, this doesn't work for AMD.
> > 
> > The container file includes a header section with information how to
> > map CPU F/M/S to microcode revisions provided with a container
> > file. Concatenating several container files will not create an
> > all-embracing header section.
> > 
> > More details were available on the amd64.org web pages.  But it seems
> > that the web site is not available anymore ...
> 
> Well, this is a problem for userspace.  Maybe the easier solution would be
> to make kernel/x86/microcode/AuthenticAMD a folder, and look for files there
> with names we can derivate from the ones used by the firmware interface (or
> even the same names)?
> 
> The early-initramfs API easily allows this to be implemented...

Yeah, but since that will break symmetry with Intel's GenuineIntel.bin
file path, so I decided to add some more logic to early loading code
to be able to parse through multiple containers files concatanated
together.

Any thoughts on this Boris?

Patch below:

---8<---