Subject: Re: Xen, PAE, and NetBSD
To: None <port-xen@netbsd.org>
From: Toru Nishimura <locore64@alkyltechnology.com>
List: port-xen
Date: 02/26/2007 18:44:06
Jed Davis wrote;

>> Why does a domU have to support PAE? AFAIK the page table is managed by
>> the Hypervisor. Is the interface to the Hypervisor so badly designed
>> that it can't hide such details?
>
> The page table is managed by the domain; it's just that writes to it
> have to be checked by the hypervisor in order to maintain security.

It's the strength of Xen para-virtualization is that it does _awefully smart_ with
page table manupulation across domains.  Hypervisior does not conceal page
table details, but mandates all guest OSes aware of how page table entries
are faked/transferred/CoW at any given moments.  So, DomU can not be free
from page table design underneath Hypervisor.

Toru Nishimura/ALKYL Technolgy