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Re: [Xen-users] 64-bit guest in 32-bit Xen/dom0 - ever?

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] 64-bit guest in 32-bit Xen/dom0 - ever?
From: Mark Williamson <mark.williamson@xxxxxxxxxxxx>
Date: Fri, 3 Mar 2006 01:03:03 +0000
Cc: Matt Ayres <matta@xxxxxxxxxxxx>
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> Will it ever be possible to run a 64-bit guest kernel under a 32-bit
> (PAE) Xen and domain0 ?

It seems pretty unlikely.  The guest kernel would be expecting 64-bit virtual 
addressing, 64-bit registers, etc, which just wouldn't be available on a CPU 
which wasn't in (or didn't have) 64-bit mode.

Supporting non-PAE 32bit kernels on a PAE hypervisor, and maybe supporting 
32-bit kernels on 64-bit Xen are rather more likely.  i.e. being able to run 
a guest on a hypervisor that only uses *more* features of the hardware.

The first effort in this direction may be (something like) supporting non-PAE 
guests on a PAE hypervisor.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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