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[Xen-devel] Re: user/hypervisor address space solution

To: Stefan Berger <stefanb@xxxxxxxxxx>
Subject: [Xen-devel] Re: user/hypervisor address space solution
From: Hollis Blanchard <hollisb@xxxxxxxxxx>
Date: Tue, 14 Feb 2006 13:44:30 +1100
Cc: Dan Magenheimer <dan.magenheimer@xxxxxx>, Jimi Xenidis <jimix@xxxxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Reiner Sailer <sailer@xxxxxxxxxx>
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On Mon, 2006-02-13 at 21:23 -0500, Stefan Berger wrote:
>   - force copying of all structures into arrays allocated with
> __get_free_pages() using a wrapper function (for contig. memory to
> avoid scatter-gather) 
>     function returns the physical address 

The kernel's physically-contiguous memory is not necessarily
machine-contiguous, so a scatter/gather approach would still be
required... and of course, since you need the scatter/gather logic
anyways, you might as well avoid the copy and directly reference the
original user pages.

Hollis Blanchard
IBM Linux Technology Center

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