Re: [Xen-devel] Grant Table problem mapping dom0 mem to domU

["Carlos-Rene Perez" <carlosrene@xxxxxxxxx>]

Thanks guys, that totally solved the problem.

On 7/25/07, Derek Murray <Derek.Murray@xxxxxxxxxxxx> wrote:
> Hi Carlos,
>
> The problem you are facing is that the grant_operation_permitted()
> test (in the GNTTABOP_map_grant_ref case of the do_grant_table_op
> function in xen/common/grant_table.c) is failing. At present, only
> domains with iomem permissions can map grant references: typically,
> the only such domain is dom0. This is due to a TLB flush issue which
> was addressed in a recent patchset from Kieran Mansley. You can
> either try giving some dummy iomem privileges to your domU, or change
> the definition of grant_operation_permitted(d) to 1, so that it
> always succeeds.
>
> Regards,
>
> Derek Murray.
>
> On 25 Jul 2007, at 16:41, Carlos Perez wrote:
>
> > I've been looking through some back-end drivers and I notice that
> > grant tables are used to map domU memory into the privileged domain,
> > is the opposite possible? Can I map dom0 memory into a domU?
> >
> > I've written code grants foreign access to a page from dom0 (take the
> > grant ref_id) then on domU I try to map it (basically the same way ex
> > blkback does it, or just any other driver for that matter) and all I
> > get from HYPERVISOR_grant_table_op() is a -1 return value, op.status
> > is empty=0.
> >
> > I'll send more information on the specific error, if I at least know
> > that this can be done and I'm just not falling of a cliff. Also, if it
> > is possible, can you point me to some example code?
> >
> > thanks,
> > C. René
> >
> > _______________________________________________
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> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
>
>
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> h
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