From mboxrd@z Thu Jan  1 00:00:00 1970
From: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Subject: Re: [PATCH V3] x86,
 amd_ucode: Skip microcode updates for final levels
Date: Tue, 11 Aug 2015 10:14:34 -0500
Message-ID: <55CA115A.1050701@amd.com>
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To: Jan Beulich <JBeulich@suse.com>
Cc: andrew.cooper3@citrix.com, boris.ostrovsky@oracle.com, keir@xen.org, Suravee.Suthikulpanit@amd.com, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

On 8/11/2015 9:53 AM, Jan Beulich wrote:
>>>> On 03.08.15 at 21:34, <aravind.gopalakrishnan@amd.com> wrote:
>> --- a/xen/arch/x86/microcode_amd.c
>> +++ b/xen/arch/x86/microcode_amd.c
>> @@ -347,6 +347,43 @@ static int container_fast_forward(const void *data, size_t size_left, size_t *of
>>       return 0;
>>   }
>>   
>> +/*
>> + * 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
>> + * using certain Fam10h systems noticed system hang issues when
>> + * trying to update microcode levels beyond the patch IDs below.
>> + * 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.
>> + */
>> +static unsigned int final_levels[] = {
> const

Okay, will fix this.

>> +    0x01000098,
>> +    0x0100009f,
>> +    0x010000af
>> +};
>> +
>> +static bool_t check_final_patch_levels(int cpu)
> unsigned int
>

I can change this too, but- Any specific reason for this?
The other sanity checker or verification functions like 
verify_patch_size() or microcode_fits() return a bool_t too..

Thanks,
-Aravind.