WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] Live migration leaves page tables read-only?

To: "Joe Bonasera" <joe.bonasera@xxxxxxx>
Subject: RE: [Xen-devel] Live migration leaves page tables read-only?
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Mon, 11 Dec 2006 18:29:34 -0000
Cc: Christian Limpach <Christian.Limpach@xxxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, John Byrne <john.l.byrne@xxxxxx>
Delivery-date: Mon, 11 Dec 2006 10:30:06 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <456CD0A5.1060701@xxxxxx> <456CD2DC.2020201@xxxxxx> <8A87A9A84C201449A0C56B728ACF491E01FA12@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <456CF5F9.7070009@xxxxxx> <456F6AF5.2090005@xxxxxx> <8A87A9A84C201449A0C56B728ACF491E01FA69@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <457A4C68.6050800@xxxxxx> <8A87A9A84C201449A0C56B728ACF491E04EE29@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <457D8EB5.2030105@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AccdRQIo79cs9VxoTmidMxRFMH118QADME1A
Thread-topic: [Xen-devel] Live migration leaves page tables read-only?
 
> Solaris implements PROT_NONE by entirely invalidating the PTE (ie. it
> becomes zero). Hence our PTEs always had either zero or have the
PRESENT
> bit set.  The only exception to this was adding some fixage to allow
> for the old Xen writable page table approach which temporarily made
> the upper table non-PRESENT.
> 
> So you can make not-present, but non-zero entries mean anything you
want.
> As long as it's the guest OS that creates the entries, we'll just not
do
> it.

Just to be confirm: in Solaris there are no not-present PTE's that
contain machine addresses.

This means we need to implement the scheme that Keir suggested to enable
the guest OS to tell xen/xc_save/restore about flags in not-present PTEs
that should trigger a m2p conversion.

Ian 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel