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

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Message-ID: <20141127163639.GJ4828@pd.tnic>
Date:	Thu, 27 Nov 2014 17:36:39 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:	Boris Ostrovsky <boris.ostrovsky@...cle.com>, x86@...nel.org,
	gregkh@...uxfoundation.org, david.vrabel@...rix.com,
	stable@...r.kernel.org, rshendershot@...si.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3.17 100/141] x86, microcode: Fix accessing dis_ucode_ldr
 on 32-bit

On Thu, Nov 27, 2014 at 11:21:19AM -0500, Konrad Rzeszutek Wilk wrote:
> > Ok, but let's have a clean design: maybe have a weak default stub which
> > returns false when PARAVIRT is not enabled in the .config and then add
> > an override in, say, arch/x86/kernel/paravirt.c which returns true when
> > running as a guest. Something like that, at least.
> 
> You are describing 'paravirt_enabled()' :-)

Haha.

Although I have a suspicion this won't work either because we're loading
microcode very early on 32-bit, before paging has been enabled, and
accessing pv_info.paravirt_enabled will probably go boom. AFAICT, from a
quick glance.

-- 
Regards/Gruss,
    Boris.

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