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

[Ian Campbell <ijc@xxxxxxxxxxxxxx>]

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 ;-)

Ian.

[0]
http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=shortlog;h=refs/heads/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 ...


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