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/
Home Products Support Community News


Re: [Xen-users] 64 bit Intel HVM Weirdness - setjmp\longjump fp exceptio

To: Allan Graves <allan.graves@xxxxxxxxxx>
Subject: Re: [Xen-users] 64 bit Intel HVM Weirdness - setjmp\longjump fp exception in Xen, not on real hardware or AMD HVM
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Fri, 30 Oct 2009 15:16:46 +0200
Cc: Adnaan Jiwaji <adnaan.jiwaji@xxxxxxxxxx>, Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 30 Oct 2009 08:35:21 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4AEA22D6.9060403@xxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <4AEA22D6.9060403@xxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.13 (2006-08-11)
On Thu, Oct 29, 2009 at 07:18:46PM -0400, Allan Graves wrote:
> The following program will crash with a fp exception on an INTEL 64 bit HVM 
> domU only:
> #include <setjmp.h>
> jmp_buf env; main() { if(setjmp(env)) return; longjmp(env, 1); }
> This can be seen using both Linux and Windows 64 bit Guests.
> My machine is a Core 2 Duo with both VT-D and VT-X extensions enabled.  
> Unfortunately, this is blocking our usage of 64 bit HVM Windows guests.  
> A similar issue was reported in KVM and recently fixed, some of their 
> analysis is below:
> --------------------------------------------------
> >>> It seems that the problem can be reproduced by compiling the
> >>> following simple program using cygwin's gcc. The program crashes on
> >>> w2k3-amd64 on kvm-83 on core2-duo, and it does not crash on the
> >>> same w2k3-amd64 installation on kvm-83 on AMD Phenom.
> >>>
> >>> #include <setjmp.h>
> >>>
> >>> jmp_buf env; main() { if(setjmp(env)) return; longjmp(env, 1); }
> >>>
> >>> The problem seems to be in the instruction ``mov gs,ax'' (Intel
> >>> syntax) in the longjmp() code. If I let the virtual machine execute
> >>> the instruction, the program crashes. However, if I step over the 
> >>> instruction using the vs2008 debugger, the program completes
> >>> without crashing. Thus, I think that this is the instruction that
> >>> Avi is looking for, but I don't know how to proceed from here.
> >>> -------------------------------------------------------
> http://markmail.org/message/owy3x7pf6oywdx5e#query:+page:1+mid:spz6vmdothb2njfb+state:results
> Anyone have a solution to this? :)  

I think this should be sent to xen-devel instead :)

-- Pasi

Xen-users mailing list

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