Re: [Xen-devel] [PATCH] Make get_page_from_l1e refcount correct

To:	Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>
Subject:	Re: [Xen-devel] [PATCH] Make get_page_from_l1e refcount correctly onforeign pagetables.
From:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date:	Wed, 03 Jun 2009 14:42:29 +0100
Cc:	Yunhong Jiang <yunhong.jiang@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 14/05/2009 10:57, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:

> Yes, there can be three domains involved: the one making the hypercall, the
> one who owns the PTE, and the one who owns the page being mapped into the
> PTE. I think some of the confusion around get_page_from_l1e() is that the
> domain argument is the page-owner not the PTE-owner. It would make sense for
> it to be the latter, and then as far as possible do the
> is-the-page-owner-valid checks hidden inside get_page_from_l1e(). The only
> fly in the ointment there is that FOREIGNDOM should only be permitted from
> mod_l1_entry(). Possibly that should be the only caller that directly
> accesses a more complex interface to get_page_from_l1e() (where the extra
> argument would be the page-owner, not the PTE-owner!).

Changeset 19708 should fix this satisfactorily, I hope.

 -- Keir



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Re: [Xen-devel] [PATCH] Make get_page_from_l1e refcount correctly onfor