Re: [Xen-devel] Mapping HVM memory to dom0 address space

[Tim Deegan <tim@xxxxxxx>]

At 14:42 +0200 on 21 May (1369147374), Marek Marczykowski wrote:
> Hi,
> 
> Is it possible to map domU pages based on PFNs in that domain? Or is it
> possible to get MFNs from inside of HVM?
> For PV guests I can MFNs from inside of guest, then pass it to
> xc_map_foreign_pages in dom0, how achieve the same for HVM?

For HVM domains, all the mapping functions take PFNs, so I think it
should Just Work.  (Memory operations on both PV and HVM memory use
'GFNs', i.e. the same namespace that the guest puts in its own
pagetables).

> It isn't possible directly, how is most efficient way to translate a bunch of
> PFNs to MFNs for a given domain? xc_get_pfn_list, or there is something 
> better?

For HVM domains, I don't think it's possible; for PV guests you need the
assitance of the guest itself.  But because all the mapping APIs &c take
GFNs, hopefully it's not necessary.

Cheers,

Tim.

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