Message-ID: <47C85294.9030902@zytor.com>
Date: Fri, 29 Feb 2008 10:44:36 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Alexander van Heukelum <heukelum@fastmail.fm>
CC: Mark McLoughlin <markmc@redhat.com>,
       Alexander van Heukelum <heukelum@mailshack.com>,
       Ingo Molnar <mingo@elte.hu>, Ian Campbell <ijc@hellion.org.uk>,
       Andi Kleen <ak@suse.de>, Thomas Gleixner <tglx@linutronix.de>,
       Jeremy Fitzhardinge <jeremy@goop.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit
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Alexander van Heukelum wrote:
> 
> My first guess is that the BIOS data area is completely non-existent for
> Xen.
> Is it guaranteed that the memory is zeroed out on boot? In that case we
> can
> special-case it easily:
> 
> change:
>         /* Paranoia: should never happen, but... */
>         if (lowmem >= 0x100000)
>                 lowmem = 0xa0000;
> 
> into:
>         /* Strange case, like Xen ;) */
>         if (lowmem == 0 || lowmem >= 0x100000)
>                 lowmem = 0x9f000;
> 
> Can you test that?
> 

The EBDA is optional anyway; I presume it should have a zero pointer if 
it isn't present.

	-hpa
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