Re: [Xen-devel] [PATCH V3] x86, amd_ucode: Skip microcode updates for final levels

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 03/08/2015 20:54, Boris Ostrovsky wrote:
> On 08/03/2015 03:34 PM, Aravind Gopalakrishnan wrote:
>> Some of older[Fam10h] systems require that certain number of
>> applied microcode patch levels should not be overwritten by
>> the microcode loader. Otherwise, system hangs are known to occur.
>>
>> The 'final_levels' of patch ids have been obtained empirically.
>> Refer bug https://bugzilla.suse.com/show_bug.cgi?id=913996
>> for details of the issue.
>>
>> The short version is that people have predominantly noticed
>> system hang issues when trying to update microcode levels
>> beyond the patch IDs below.
>> [0x01000098, 0x0100009f, 0x010000af]
>>
>>  From internal discussions, we gathered that OS/hypervisor
>> cannot reliably perform microcode updates beyond these levels
>> due to hardware issues. Therefore, we need to abort microcode
>> update process if we hit any of these levels.
>>
>> In this patch, we check for those microcode versions and abort
>> if the current core has one of those final patch levels applied
>> by the BIOS
>>
>> A linux version of the patch has already made it into tip-
>> http://marc.info/?l=linux-kernel&m=143703405627170
>>
>> Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@xxxxxxx>
>> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

For the avoidance of any confusion, I am happy for my R-b to stand,
given this addition to the patch.

~Andrew

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