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Date: Fri, 22 Jun 2007 14:59:19 -0700
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] x86-64: disable the GART before allocate aperture
Cc: "Alan Cox" <alan@lxorguk.ukuu.org.uk>, "Muli Ben-Yehuda" <muli@il.ibm.com>,
       "Andi Kleen" <ak@suse.de>, "Andrew Morton" <akpm@linux-foundation.org>,
       "Vivek Goyal" <vgoyal@in.ibm.com>,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
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On 6/22/07, Eric W. Biederman <ebiederm@xmission.com> wrote:
> Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
>
> For a normal kexec we should shut everything down before the kernel
> transition so it should not be an issue.
>
> YH do you think you can look at simply reserving a portion of the iommu?
> And having the kexec on panic kernel use the reserved portion?
>
two copy region: one for first kernel, and one for second kernel? it
should work.
first kernel is using [64M, 128M), and the second will get assign to
[64M,128M) again.
when it try to memset to clear that region it will cause restart.
in that region, only first 256K can not touched, even read. rest could
be accessed.

YH