Message-ID: <47C72432.3010606@zytor.com>
Date: Thu, 28 Feb 2008 13:14:26 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Ian Campbell <ijc@hellion.org.uk>
CC: Alexander van Heukelum <heukelum@mailshack.com>,
       Ingo Molnar <mingo@elte.hu>,
       Alexander van Heukelum <heukelum@fastmail.fm>, Andi Kleen <ak@suse.de>,
       Thomas Gleixner <tglx@linutronix.de>,
       Jeremy Fitzhardinge <jeremy@goop.org>,
       Mark McLoughlin <markmc@redhat.com>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] use realmode code to reserve end-of-conventional-memory
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Ian Campbell wrote:
> On Thu, 2008-02-28 at 14:28 +0100, Alexander van Heukelum wrote:
>> Instead of using early reservations inside the kernel code,
>> we could use the realmode code to modify the e820 memmap.
>> This patch shows what that would look like. I have not looked
>> at the case where the BIOS does not provide an e820 memmap
>> yet. Probably a full solution would need to create a fake
>> e820 memmap in that case.
> 
> An e820 is already faked up in machine_specific_memory_setup() if one
> doesn't already exist.
> 
>> Comments?
> 
> This won't work for Xen since the real-mode code never runs there. I
> think it could be fixed in xen_memory_setup() though if native goes down
> this route.
> 

s/could/should/.

You need to set up your memory map more sensibly; it's not just the 
kernel, user space tries to access these areas too.

	-hpa
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