Message-ID: <47BE9C18.5060202@firstfloor.org>
Date: Fri, 22 Feb 2008 10:55:36 +0100
From: Andi Kleen <andi@firstfloor.org>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: Ian Campbell <ijc@hellion.org.uk>, "H. Peter Anvin" <hpa@zytor.com>,
       Jeremy Fitzhardinge <jeremy@goop.org>,
       Joel Becker <Joel.Becker@oracle.com>, Jody Belka <lists-lkml@pimb.org>,
       linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Mika Penttila <mika.penttila@kolumbus.fi>
Subject: Re: 2.6.25-rc1 xen pvops regression
References: <20080212235404.GY7980@pimb.org>	<47B2DBA5.6030001@goop.org>	<20080214022744.GA4160@mail.oracle.com>	<47B3F2DC.8080707@goop.org>	<20080215202336.GE26034@mail.oracle.com>	<1203274161.27987.6.camel@localhost.localdomain>	<20080218104025.GA15899@ca-server1.us.oracle.com>	<1203458366.26910.15.camel@cthulhu.hellion.org.uk>	<47BBDA20.8030105@zytor.com>	<1203497511.26910.39.camel@cthulhu.hellion.org.uk>	<47BCA275.7000504@goop.org>	<1203546597.26910.74.camel@cthulhu.hellion.org.uk>	<47BDEA11.6010302@goop.org>	<47BDEB57.5040203@zytor.com>	<47BDEF36.8000903@goop.org>	<1203631956.28436.4.camel@cthulhu.hellion.org.uk>	<47BDF9C7.6040400@zytor.com>	<47BE0017.1020205@goop.org>	<47BE0228.7020204@zytor.com>	<1203665106.28436.19.camel@cthulhu.hellion.org.uk> <20080222092855.6ace8845@core>
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Alan Cox wrote:
>> I'd been meaning to ask this. So the machines you have which don't
>> describe 0xf0000 as reserved also don't describe it as RAM? (I guess
>> it's either a hole in the table or one of the other e820 types).
> 
> Making 0xf0000 bus addresses RAM is probably a bad idea anyway. Most OS's
> treat the E820 map with paranoia because we do see real PCs which
> variously claim that the BIOS ROM space is RAM, ACPI, Reserved or just
> forget to mention it. 

Actually I switched 64bit over to trust e820 completely and not
reserve 640k-1MB explicitly some time ago
and AFAIK there hasn't been any reports that it causes problems.

So presumably trusting e802 is ok on modern systems (2003+)

-Andi
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