Re: [Xen-devel] [PATCH v2 1/2] xen: introduce arch_iommu_grant_(un)map_page

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 24 Jul 2014, Julien Grall wrote:
> Hi Stefano,
> 
> The Title of the commit message is now wrong.

Thanks, I didn't notice.


> On 23/07/14 18:19, Stefano Stabellini wrote:
> > Introduce two arch specific functions to create a new p2m mapping of
> > granted pages at pfn == mfn.
> > The x86 implementation just returns ENOSYS.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > ---
> >   xen/arch/arm/p2m.c        |   19 +++++++++++++++++++
> >   xen/include/asm-arm/p2m.h |    4 ++++
> >   xen/include/asm-x86/p2m.h |   13 +++++++++++++
> >   3 files changed, 36 insertions(+)
> > 
> > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> > index 9960e17..c38af59 100644
> > --- a/xen/arch/arm/p2m.c
> > +++ b/xen/arch/arm/p2m.c
> > @@ -555,6 +555,25 @@ void guest_physmap_remove_page(struct domain *d,
> >                         pfn_to_paddr(mfn), MATTR_MEM, p2m_invalid);
> >   }
> > 
> > +int arch_grant_map_page_identity(struct domain *d, unsigned long frame,
> > +                                 bool_t writeable)
> > +{
> > +    p2m_type_t t;
> > +
> > +    if ( writeable )
> > +        t = p2m_ram_rw;
> > +    else
> > +        t = p2m_ram_ro;
> 
> This is not the right p2m type to use here. p2m_ram_{rw,ro} allow foreign
> mapping. So another guest could access to the grant.
>
> I would use p2m_iommu_map_{rw,ro}.


I see. I'll make the change and add a comment to explain why we are
using p2m_iommu types for non-iommu related mappings.

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