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Re: [Xen-devel] shadow2 corrupting PV guest state

To: Doi.Tsunehisa@xxxxxxxxxxxxxx
Subject: Re: [Xen-devel] shadow2 corrupting PV guest state
From: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
Date: Mon, 23 Oct 2006 13:42:19 +0100
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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At 20:21 +0900 on 23 Oct (1161634872), Doi.Tsunehisa@xxxxxxxxxxxxxx wrote:
> > Are you worried about a race where the foreign domain is destroyed and
> > another domain created, with the same struct domain pointer, and which
> > owns the same frame, between the __acquire_grant_for_copy() and the
> > get_page()?
> 
>   No, I'm worried that two domains use with same page frame.
> 
>   The released pages can be used by new domain, but old domain sturct
> exists between domain_kill and domain_destroy.

If the released frames are used by a new domain, get_page() will fail:
the old domain still exists (we have a reference to it), so the new
owner's domain pointer must be different from the one we pass to
get_page.

Cheers,

Tim.

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