[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-devel] Re: Xen MMU's requirement to pin pages RO and initial_memory_mapping.



> > xen_alloc_pte_init and xen_alloc_pmd_init are the ones that mark the
> > pagetable pages RO and pin them, calling make_lowmem_page_readonly and
> > pin_pagetable_pfn.
> > 
> > alloc_pte/pmd are called right before hooking them into the pagetable;
> > unfortunately that means that they fail at marking the pagetable pages
> > RO: make_lowmem_page_readonly uses lookup_address to find the pte
> > corresponding to a page, however at this point the pagetable pages are
> > not mapped yet (usually they are not hooked but when they are hooked, the
> > upper level pagetable page is not hooked), so lookup_address fails.
> 
> Right. We don't have to walk the hooked pagetable, I think. We are passed
> in the PMD/PGD of the PFN and we could look at the content of that PFN.

err, got that backwards. "passed in the PFN of the PMD/PGD".

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.