linux-kernel - Re: [PATCH 3.17 100/141] x86, microcode: Fix accessing dis_ucode

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Date:	Wed, 26 Nov 2014 07:39:26 -0500
From:	boris ostrovsky <boris.ostrovsky@...cle.com>
To:	Borislav Petkov <bp@...e.de>
CC:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	Richard Hendershot <rshendershot@...si.com>,
	David Vrabel <david.vrabel@...rix.com>, x86-ml <x86@...nel.org>
Subject: Re: [PATCH 3.17 100/141] x86, microcode: Fix accessing dis_ucode_ldr
 on 32-bit


On 11/26/2014 5:55 AM, Borislav Petkov wrote:
> On Wed, Nov 26, 2014 at 12:00:45AM -0500, Boris Ostrovsky wrote:
>> Sigh... I take this back. It breaks 32-bit baremetal. I haven't looked any
>> further but it seems to be dying very early. I suspect cpuid pv_op is not
>> set up yet. If that's true, perhaps you could check whether it is valid in
>> x86_guest()?
> Right, this is why we're using the native variants in the early loader.
> So we need a different method for detecting very early whether we're
> running as a guest.
>
> What I'd like more, though, is if we continue debugging the original
> issue where we fail in load_ucode_intel_ap(). Does it happen on this line:
>
> initrd_start_addr = (unsigned long)__pa_nodebug(*initrd_start_p);

I don't have access to my test setup right now (and won't be until late 
today at best) but I am pretty sure this was the line when I was looking 
at this yesterday.

>
> where we deref the initrd_start_p? Do you have a full splat with a Code:
> section?

https://lkml.org/lkml/2014/11/25/973 is all I have right now.


-boris
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