Subject: Re: can MEXTADD() storage be remapped ?
To: Jason Thorpe <>
From: Manuel Bouyer <>
List: tech-kern
Date: 05/24/2005 23:40:51
On Tue, May 24, 2005 at 02:26:18PM -0700, Jason Thorpe wrote:
> On May 24, 2005, at 2:07 PM, Manuel Bouyer wrote:
> >Yes, what I'm trying to know if other mappings have ever existed  
> >(in which
> >case, their removal may still be in the queue).
> Oh, I see.  But why should this matter?  There still shouldn't be any  
> references to the buffer if it has been freed.  Even double-mapped  
> ones (which there shouldn't be anyway).

Because when freed, the page will be passed back to the hypervisor,
and and this doesn't work if there are mappings left at the hypervisor
level (in this case, if the pmap update to remove the mapping is still in the
domain's pmap queue).

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference