Xen 
 
Home About Xen.org Xen Xen Summit Wiki Mailing List Bug Tracker Xen Downloads
 
   
 

xen-devel

Re: [Xen-devel] long latency of domain shutdown

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] long latency of domain shutdown
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Mon, 28 Apr 2008 15:42:09 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 28 Apr 2008 07:43:10 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <4815FBB8.76E4.0078.0@xxxxxxxxxx>
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: AcipPglZSAVakhUxEd2neQAX8io7RQ==
Thread-topic: [Xen-devel] long latency of domain shutdown
User-agent: Microsoft-Entourage/11.4.0.080122


On 28/4/08 15:30, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> Okay, thanks - so I indeed missed the call to hypercall_preempt_check()
> in relinquish_memory(), which is the key indicator here.
> 
> However, that change deals exclusively with domain shutdown, but not
> with the more general page table pinning/unpinning operations, which I
> believe are (as described) vulnerable to mis-use by a malicious guest (I
> realize that well behaved guests would not normally present a heavily
> populated address space here, but it also cannot  be entirely excluded)
> - the upper bound to the number of operations on x86-64 is 512**4
> or 2**36 l1 table entries (ignoring the hypervisor hole which doesn't
> need processing).

True. It turns out to be good enough in practice though.

 -- Keir



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

<Prev in Thread] Current Thread [Next in Thread>