Re: [Xen-devel] [PATCH] Remove physmap page upon granttab xfer

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 28/5/08 11:28, "Isaku Yamahata" <yamahata@xxxxxxxxxxxxx> wrote:

> Although I know that grant table page transfer is obsoleted,
> what is the expected exact semantics of GNTTABOP_transfer with
> the p2m/m2p table?
> 
> I suppose the right fix would be
> - revert this patch and
> - put the iommu opration of pv domain into MMU_MACHPHYS_UPDATE.

After the grant transfer operation completes the page no longer belongs to
the backend domain. Thus, for absolute safety and isolation, the page must
be removed from the backend domain's IOMMU mappings before completion of the
grant transfer operation. Actually we should be flushing host CPU TLBs too.

 -- Keir



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