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Re: [PATCH v2] port/xen: map memory directly in privcmd PRIVCMD_MMAPBATCH



Cherry G.Mathew wrote:
"Roger" == Roger Pau Monne<roger.pau%citrix.com@localhost>  writes:

     Roger>  Cherry G.Mathew wrote:
     >>>>>>>  "Roger" == Roger Pau Monne<roger.pau%citrix.com@localhost>  
writes:
     >>
     Roger>  Cherry G.Mathew wrote:
     >>  >>>>>>>  "Roger" == Roger Pau Monne<roger.pau%citrix.com@localhost>  
writes:
     >>  >>  I'm still missing something here, but I think something is not
     >>  >>  right here. I *think* qemu or NetBSD is mixing up the guest's
     >>  >>  gmfns (pfns) and dom0 mfns here.
     >>  >>
     >>  >>  - qemu queries the hypervisor for the guest pfn (aka gmfn)
     >>  via:>>  [1] xc_get_hvm_param(xen_xc, xen_domid,>>
     >>  HVM_PARAM_IOREQ_PFN,&ioreq_pfn);
     >>
     Roger>  With this call we get a set of gfns of the guest.
     >>
     >>  what are "gfns" ? Are they mfns (ie; the fns go into the page
     >>  tables) or gmfns (what the guest *thinks* goes into page tables)
     >>  ?

     Roger>  They are gmfns.

Ok, that makes a *lot* of sense now :-)

But it doesn't answer my question of how pmap_kenter_ma() works, since
it's entering a mfn into the pmap VA. Where does this gmfn->mfn (or
P->M) translation take place ?

This translation is done by the hypervisor.


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