Re: [Xen-devel] [PATCH] Paging and memory sharing for HVM guests

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 04/01/2010 14:14, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

> Isn't this undermining the purpose of privcmd_enforce_singleshot_mapping()?
> You don't check that the eventual single page re-mapping attempt is
> really due to an earlier -ENOENT failure, and hence the whole single
> shot mapping checks are now pointless (though other than possibly to
> enforce some minimal security I don't really know what its purpose
> is/was - Keir?).

It was just to avoid the BUG_ON(!pte_none(*pte)) in
direct_remap_area_pte_fn(). We trust privcmd users enough we could just get
rid of privcmd_enforce_singleshot_mapping(). We could instead forcibly clear
ptes before calling direct_remap_area(); or just do nothing.

 -- Keir



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