* [EMAIL PROTECTED] [2008-01-14 07:55:57]
> So if there was a desire to try and do firewall/NAT in dom0
> on packets that come from domU, how would you recommend
> that be approached?  Would that require the dom0 telling the
> domU that it needs to make packets on writeable pages?
> Or something else?
> Or even just put ideas like that in the "too hard" basket?

Currently the approach is that a Solaris domU declares "I'll provide
writable mappings to pages that I loan." A Solaris dom0 notices this
and can take advantage of it. If the domU doesn't so declare then
backend network driver copies data from the loaned page into a dom0
local mblk.

It's worth noting that copying the data produces better throughput
with some network cards, due to the delay in free-ing loaned buffers
(there is a limit on the number of active buffers in the
frontend<->backend channel and holding on to the buffers for a long
time in dom0 can result in exhaustion).

dme.
-- 
David Edmondson, Sun Microsystems, http://www.dme.org
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