Re: [Xen-devel] Re: [PATCH v4 2/2] xen: modify kernel mappings corresponding to granted pages

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 29 Sep 2011, Konrad Rzeszutek Wilk wrote:
> > > > But aren't that 'range of virtual address' of struct pages? You
> > > > are using 'alloc_xenballooned_pages' to get those pages and that is
> > > > what the 'range of virtual adresses' is walking through.
> > > 
> > > it is not the same range of virtual addresses
> > 
> > OK, but the pte_maddr is the same, isn't it?
> 
> No it is not. It is the machine address of the PTE entry that
> points to the 'struct page' (kernel linear address), while the
> find_grant_pte's gets the machine address of the PTE entry that
> points to the user pages. Completlely different machine addresses
> of the PTEs.

Right


> Can you add a comment to the patch saying something along what
> I just said? Just in case somebody is as thick as I am when looking
> at this code/patch.

Sure


> Otherwise the patch looks fine - just fix up the SetPagePrivate,
> the PAGE_GRANT bit, and add extra comments and I am ready to stick it
> on my queue.

OK!

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