Re: [Xen-devel] pvops microcode support for AMD FAM >= 15

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 26.11.12 at 14:21, Ian Campbell <ijc@xxxxxxxxxxxxxx> 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).

The hypervisor is really going to take care of all other aspects
here.

Jan

> [0]
> http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=shortlog;h=refs/h 
> eads/upstream/microcode
> 
> commit 109cf37876567ef346c0ecde8b473e7ad1e74e07
> Author: Ian Campbell <ijc@xxxxxxxxxxxxxx>
> Date:   Mon Nov 26 09:41:02 2012 +0000
> 
>     microcode_xen: Add support for AMD family >= 15h
>     
>     Signed-off-by: Ian Campbell <ijc@xxxxxxxxxxxxxx>
> 
> diff --git a/arch/x86/kernel/microcode_xen.c 
> b/arch/x86/kernel/microcode_xen.c
> index 9d2a06b..2b8a78a 100644
> --- a/arch/x86/kernel/microcode_xen.c
> +++ b/arch/x86/kernel/microcode_xen.c
> @@ -74,7 +74,11 @@ static enum ucode_state xen_request_microcode_fw(int cpu, 
> struct device *device)
>               break;
>  
>       case X86_VENDOR_AMD:
> -             snprintf(name, sizeof(name), "amd-ucode/microcode_amd.bin");
> +             /* Beginning with family 15h AMD uses family-specific firmware 
> files. */
> +             if (c->x86 >= 0x15)
> +                     snprintf(name, sizeof(name), 
> "amd-ucode/microcode_amd_fam%.2xh.bin", 
> c->x86);
> +             else
> +                     snprintf(name, sizeof(name), 
> "amd-ucode/microcode_amd.bin");
>               break;
>  
>       default:
> 
> 
> -- 
> Ian Campbell
> Current Noise: Dew-Scented - Metal Militia
> 
> Now KEN and BARBIE are PERMANENTLY ADDICTED to MIND-ALTERING DRUGS ...




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel