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Re: [Xen-devel] Is machine_to_phys_mapping a 4MB 'superpage'?

To: Jacob Gorm Hansen <jacobg@xxxxxxx>
Subject: Re: [Xen-devel] Is machine_to_phys_mapping a 4MB 'superpage'?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 31 Mar 2005 08:52:29 +0100
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On 31 Mar 2005, at 04:25, Jacob Gorm Hansen wrote:

The machine_to_phys_mapping table is mapped permanently at 0xFC000000 (on x86-32). I would like to experiment with letting the domU map it at other locations in its virtual address space, but I suppose that for performance it is mapped as a 4MB 'super' page, and as such needs special treatment, is this correct?

It doesn't *have* to be mapped as a superpage -- control tools don't when doing suspend/resume, for example. Fixing the permission checking so that other than domain0 can remap the m2p table shouldn't be very hard, but I'm not sure what the cleanest method would be.

 -- Keir

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