Re: [PATCH] disable writable pagetables on FreeBSD

[Kip Macy <kip.macy@gmail.com>]

On 4/30/05, Keir Fraser <Keir.Fraser@cl.cam.ac.uk> wrote:
> 
> On 30 Apr 2005, at 03:30, Kip Macy wrote:
> 
> > Presumably as a result of recent changes, FreeBSD no longer works with
> > writable page tables. In the short-term I'm more interested in
> > functionality than performance. This patch disables them and fixes a
> > compile issue.
> 
> The obvious change is we reenabled batched wrpt mode. This requires the
> guest to deal with reading page directory entries that have the present
> bit (bit 0) cleared, even though that entry is logically present. :-)
> 
> You may hav eforgotten to handle this, since it was not required all
> the while we were using emulation mode only.

Entirely possible. There is only one place in the machine-independent
code where we check for it. Removing it there doesn't help. It may
require changing the machine-dependent code (I hope not, I'd rather it
be a bug in my port or in xen).

                 -Kip