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] more segment/selector handling woes

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] more segment/selector handling woes
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Wed, 22 Nov 2006 11:43:25 +0100
Delivery-date: Wed, 22 Nov 2006 02:42:01 -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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Not only on VMX and in generic code, but also on SVM now:
svm_get_io_address() uses the segment base only when the guest
is not in long mode - what if outs has an fs/gs override? I'm pretty
sure the base address is needed then, which opens the question -
does the CPU guarantee a valid (zero) base also for the other
segment register, or does this need to be conditionalized?

Further, in the same function (and likely elsewhere) the injection
of GP faults seems pretty pointless - if either of the two
conditions is true, then the CPU itself should have raised a GP
fault for the guest already (i.e. execution flow would never get
here).

Thanks, Jan

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