linux-kernel - Re: [PATCH] x86: Unbreak early processor microcode loading

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Date:	Thu, 19 Mar 2015 15:30:23 +0800
From:	Daniel J Blueman <daniel@...ascale.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Quentin Casasnovas <quentin.casasnovas@...cle.com>,
	Steffen Persvold <sp@...ascale.com>,
	linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86: Unbreak early processor microcode loading

On Thu, Mar 19, 2015 at 2:42 AM, Borislav Petkov <bp@...en8.de> wrote:
> On Wed, Mar 18, 2015 at 11:02:27AM +0100, Borislav Petkov wrote:
>>  I don't like the ifdeffery in your solution and would like to try 
>> to fix
>>  it in a cleaner way. Unless you come up with a better solution 
>> first.
> 
> Ok, how about this below? It is more involved but finds and loads the
> microcode built-in into the kernel in the early loader which is when
> you want to load microcode anyway. Only AMD for now but that should be
> enough for testing.
[]

Neat; I added the 'amd-ucode/' directory prefix to the string and 
adjusted the buffer size, and the microcode is loaded, but we see 
consistent hangs when onlining core 32 on the first server.

Further investigation shows the BIOS in this platform isn't loading the 
microcode after the Hypertransport reconfig warm-boot (though other 
platforms do), so it's a better solution I engage with the vendor to 
fix their BIOS, rather than working around it in the kernel at this 
time.

Many thanks!
  Daniel

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