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

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Message-ID: <5a9dde8d-1936-4910-a78a-15d4f9bfffc2@default>
Date:	Thu, 27 Nov 2014 09:14:11 -0800 (PST)
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	<bp@...e.de>
Cc:	<konrad.wilk@...cle.com>, <x86@...nel.org>,
	<gregkh@...uxfoundation.org>, <stable@...r.kernel.org>,
	<david.vrabel@...rix.com>, <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


----- bp@...e.de wrote:

> 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.


The overnight tests passed. This includes baremetal, HVM and PV(H), 32- and 64-bit.

-boris
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