Re: [Xen-devel] [v3][PATCH 03/16] xen/vtd: create RMRR mapping

[Tim Deegan <tim@xxxxxxx>]

At 17:31 +0800 on 11 Jun (1434043916), Chen, Tiejun wrote:
> >>       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);
> >>
> >>           if ( err )
> >>               return err;
> >
> > Tim has another comment to replace earlier unmap with
> 
> Yes, I knew this.
> 
> > guest_physmap_remove_page() which will call iommu
> > unmap internally. Please include this change too.
> >
> 
> But,
> 
> guest_physmap_remove_page()
>      |
>      + p2m_remove_page()
>       |
>       + iommu_unmap_page()
>       |
>       + p2m_set_entry(p2m, gfn, _mfn(INVALID_MFN), xxx)
> 
> I think this already remove these pages both on ept/vt-d sides, right?

Yes; this is about this code further up in the same function:

           while ( base_pfn < end_pfn )
           {
               if ( intel_iommu_unmap_page(d, base_pfn) )
                   ret = -ENXIO;
               base_pfn++;
           }

which ought to be calling guest_physmap_remove_page() or similar, to
make sure that both iommu and EPT mappings get removed.

Cheers,

Tim.

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