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Re: [Xen-devel] [PATCH 0 of 5] update xenctx to dump pagetables

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 0 of 5] update xenctx to dump pagetables
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Tue, 21 Jun 2011 10:59:11 +0100
Cc: Olaf Hering <olaf@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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At 17:56 -0400 on 20 Jun (1308592583), Konrad Rzeszutek Wilk wrote:
> > Any ideas why some mfns are not accessible?
> They look to be the special I/O PFNs. The ones that cover ACPI, framebuffer,
> PCI IO bars, MP tale.

I think they're too high for that, but if you can post the e820 map of
the system this happened on then we'll know. 

> > Are there any other paging states maintained outside of the guests
> > memory?
> They look to be I/O pages.
> But not sure why they are mapped to your guest?

But they're not mapped into the guest - from the look of them they're
not mapped anywhere.  You could add some extra printouts around that
warning in mm.c to show whether the MFNs are valid and if so which
domain owns them.

Also, interesting that it's the addresses just above 0xffff800000000000
that are different - what lives at that address in the PV kernel you're


Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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