Subject: Re: Xen, PAE, and NetBSD
To: Matthias Scheler <tron@zhadum.org.uk>
From: Todd Vierling <tv@pobox.com>
List: port-xen
Date: 02/12/2007 13:14:31
On 2/12/07, Matthias Scheler <tron@zhadum.org.uk> wrote:
> > Runs fine on a PAE mode 32-bit Linux host that you do not have the
> > option to reconfigure?
>
> Out of technical curiosity:
> 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?

See messages in mail-index:port-xen for August 2006, with the subject

    Xen3/PAE problems with domainU

There are some web link pointers to xen-users in that thread.  What I
gathered from it without digging for major technical details is that
the page tables are manipulated in a native-like format in all
domains, so their structural layout must match in all domains (PAE vs.
non-PAE).

From a user's perspective, if you try to load a non-PAE-capable domU
on a PAE host, xend will spit out EINVAL and refuse to complete the
domain construction.

-- 
-- Todd Vierling <tv@duh.org> <tv@pobox.com> <todd@vierling.name>