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

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Message-ID: <20141126105517.GA29982@pd.tnic>
Date:	Wed, 26 Nov 2014 11:55:18 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
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 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);

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

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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