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] [PATCh][VT] do_block upon hlt instruction

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCh][VT] do_block upon hlt instruction
From: "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
Date: Wed, 21 Sep 2005 10:37:44 -0700
Cc: xen-devel List <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 21 Sep 2005 17:35:32 +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: AcW+zWOoRTfZpuknRuea9hRchnQi1wAAPB7A
Thread-topic: [Xen-devel] [PATCh][VT] do_block upon hlt instruction
Keir Fraser wrote:
> On 21 Sep 2005, at 17:39, Nakajima, Jun wrote:
> 
>> At the same time, it disables the monitor/mwait
>> feature as it's not feasible to implement for vcpu.
> 
> Why is that?
> 
>   -- Keir

The major usage model of MONITOR/MWAIT is, the MONITOR instruction
specifies the address to watch, and MWAIT waits for any modification to
that address:
- The current VMX does not support VMExit upon the MONITOR instrucion,
so 
  we don't know which address the guest wants to minitor.
- even if it did, it's not efficient to check if modification is made 
  to that address range in shadow (so that we can unblock the guest from
  MWAIT).

Jun
---
Intel Open Source Technology Center

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