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

[Xen-devel] Switching from writeable pagetable to shadow log-dirty at ru

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Switching from writeable pagetable to shadow log-dirty at runtime
From: "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
Date: Thu, 13 Oct 2005 10:20:38 -0700
Delivery-date: Thu, 13 Oct 2005 17:18:04 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcXQGm4ov65UksHAQt6gJoFmEOnrJg==
Thread-topic: Switching from writeable pagetable to shadow log-dirty at runtime
When we switch from writeable pagetable to shadow log-dirty mode at
runtime, there are some PTEs with write-protected; once we do
ptwr_flush(), we write-protect back the page table. If we simply consult
the guest page tables when building the shadow page tables, then we also
copy the write protection to the shadow pages tables. Since the shadow
code does not have the logic for the writeable page table, the guest
kernel, for exmaple, can see write-protected page table, resulting a
panic. We are experiencing the problem with PAE log-dirty mode (that we
are working on now).

So I think the current state in the writeable page should be flushed and
adjusted (in audit, for example, make the write-protected pages back to
writeable) before we switch to shadow mode. Given the fact that we can
switch writeable pagetable to shadow log-dirty at runtime for the plain
32-bit, I'm wondering where we are doing that kind of thing.

Jun
---
Intel Open Source Technology Center 

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

<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] Switching from writeable pagetable to shadow log-dirty at runtime, Nakajima, Jun <=