Design question for PV superpage support

[Dave McCracken <dcm@mccr.org>]

The solution I am working on for how to support Linux hugepages (Xen 
superpages) involves creating domains made up entirely of superpages.  I can 
create a working domain with superpages and am in the process of supporting 
it in save/restore.

For this to work properly this should be an attribute of a domain, specified 
somewhere in domain configuration and attached to that domain for its 
lifetime.  This way it could be checked at memory populate time, save/restore 
time, and by the various balloon drivers.

My question is for those of you who best know the overall Xen design 
principles.  Where should the flag be specified by the user?  Where should it 
best be set in the running domain?  I've seen some examples of flags being 
passed around, but would like some guidance on the best place to put it to 
fit into the Xen design.

Thanks,
Dave McCracken
Oracle Corp.