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Re: [Xen-devel] xenpaging crashes xen in is_iomem_page()



Hi, 

At 15:39 +0100 on 26 Jul (1280158794), Patrick Colp wrote:
> On 26 July 2010 10:08, Olaf Hering <olaf@xxxxxxxxx> wrote:
> > Is there a portable way to check for the EPT flag in xenpaging?
> 
> Yeah, this can be added. Probably not a bad idea, really. I actually
> have some code to test if a machine has EPT enabled or not (by
> borrowing some of the Xen start-up code which checks for things like
> EPT)

Good idea.  From inside Xen you should be checking hap_enabled(d) (since
even on an EPT machine the tools can request shadow pagetables for
individual domains).  Outside Xen I'm not sure there's a reliable way of
detecting HAP; maybe the xenpaging hypercalls should return an error?

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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