Ingo Molnar wrote:
> Subject: [patch] paravirt: isolate module ops
> From: Ingo Molnar <mingo@elte.hu>
>
> only export those operations to modules that have been available to them 
> historically: irq disable/enable, io-delay, udelay, etc.
>
> this isolates that functionality from other paravirtualization 
> functionality that modules have no business messing with.
>
> boot and build tested with CONFIG_PARAVIRT=y.
>   

I would suggest a slightly different carving.  For one, no TLB flushes.  
If you can't modify PTEs, why do you need to have TLB flushes?  And I 
would allow CR0 read / write for code which saves and restores FPU state 
- possibly even debug register access, although any code which touches 
DRs could be doing something sneaky.  I'm on the fence about that one.

Here is a partially tested patch against the -mm tree.  Let me know what 
you think of this slightly different approach.