Re: [Xen-devel] [v4][PATCH 03/19] xen/vtd: create RMRR mapping

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2015/6/23 18:12, Jan Beulich wrote:
> > > > On 23.06.15 at 11:57, <tiejun.chen@xxxxxxxxx> wrote:
> > --- a/xen/drivers/passthrough/vtd/iommu.c
> > +++ b/xen/drivers/passthrough/vtd/iommu.c
> > @@ -1839,7 +1839,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t 
> > map,
> >
> >               while ( base_pfn < end_pfn )
> >               {
> > -                if ( intel_iommu_unmap_page(d, base_pfn) )
> > +                if ( guest_physmap_remove_page(d, base_pfn, base_pfn, 0) )
Yeah, I also thought this may bring some confusions in this context.

> >                       ret = -ENXIO;
> >                   base_pfn++;
> >               }
> > @@ -1855,8 +1855,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t 
> > map,
> >
> >       while ( base_pfn < end_pfn )
> >       {
> > -        int err = intel_iommu_map_page(d, base_pfn, base_pfn,
> > -                                       IOMMUF_readable|IOMMUF_writable);
> > +        int err = set_identity_p2m_entry(d, base_pfn, p2m_access_rw);
> Shouldn't the two continue to be the inverse of one another?
Initially, instead of using guest_physmap_remove_page, I was trying to 
introduce a new, clear_identity_p2m_entry, which can wrapper 
p2m_remove_page().
But Tim just thought we'd better avoid duplicating code,

http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg02970.html

> Maybe guest_physmap_remove_page() does what you want,
Note actually we just need p2m_remove_page() to unmap these mapping on 
both ept and vt-d sides, and guest_physmap_remove_page is really a 
wrapper of p2m_remove_page().
Thanks
Tiejun

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