Re: [Xen-devel] about grant table

[Daniel Stodden <stodden@xxxxxxxxxx>]

On Wed, 2008-03-05 at 00:07 +0800, 余上 wrote:
> >  1. domU writes a shared entry at index <gref>
> So I guess there needs a transfer between guest OS and Xen ?

not sure what you mean. grant transfer? certainly not. control transfer?
also not.

grant tables are just a bunch of pages allocated to the domain during
creation. mapped r/w both by the hypervisor and the guest. the guest
writes the bigger part of its entries. shared flags are altered
atomically via compare-and-swap instructions from both sides. 

the active entries are because xen needs to keep the fields private once
they are in use.

regards,
daniel


-- 
Daniel Stodden
LRR     -      Lehrstuhl für Rechnertechnik und Rechnerorganisation
Institut für Informatik der TU München             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
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