linux-kernel - Re: AMD EPYC microcode update bug?

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Date:   Tue, 9 Jan 2018 17:44:08 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Gabriel C <nix.or.die@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...en8.de>
Subject: Re: AMD EPYC microcode update bug?

On 1/9/2018 5:06 PM, Gabriel C wrote:
> 2018-01-09 23:47 GMT+01:00 Tom Lendacky <thomas.lendacky@....com>:
>> On 1/9/2018 4:28 PM, Gabriel C wrote:
>>> Hello ,
>>>
>>> I'm testing an EPYC system right now with 2 EPYC 7281 16-Core Processors.
>>>
>>> I'm on 4.15.0-rc7 and tested an update to microcode_amd_fam17h.bin.
>>>
>>> First run was made by using the early microcode option with dracut[1]
>>> so loading from a initrd. the driver reported 63 updated CPUs while CPU0
>>> got still old microcode.
>>
>> I'm guessing that memory encryption is enabled, correct?  I've submitted a
>> patch series to perform early initrd decryption for just this problem. I'm
>> incorporating some minor feedback and getting ready to submit the next
>> version.
> 
> Yes is correct I use mem_encrypt=on and SMT on in BIOS.
> 
> Can you give me an link to the patch series ?

Here's the link: https://marc.info/?l=linux-kernel&m=151389377606957&w=2

Thanks,
Tom

> 
>>
>> In the meantime, if you specify mem_encrypt=off on the kernel command line
>> it should show CPU0 updated properly (with mem_encrypt=on and SMT enabled,
>> I believe it really does get updated when the sibling hread is updated -
>> do a rdmsr of 0x0000008b to verify).
>>
> 
> I give that an test in a bit , the box is running now some test for a
> different EPYC issue :)
> 
> ( https://community.amd.com/thread/224000 )
> 
> Regards,
> 
> Gabriel C
>