From mboxrd@z Thu Jan 1 00:00:00 1970 From: Allan Graves Subject: Re: 64 bit Intel HVM Weirdness - setjmp\longjump fp exception in Xen, not on real hardware or AMD HVM Date: Sun, 01 Nov 2009 14:32:21 -0500 Message-ID: <4AEDE245.1030901@oracle.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Keir - Hmm... according to /sys/hypervisor/version, I'm running 3.4.0. Is there a reasonable chance this is fixed in 3.4.1? I haven't seen anything in the changelogs... Allan Keir Fraser wrote: > What version of Xen are you using? This bug may be fixed in Xen 3.3.2 and > Xen 3.4.1. > > -- Keir > > On 30/10/2009 01:23, "Allan Graves" wrote: > > >> (Please excuse double posting - I was told xen-users was not the right >> list, to put it on xen-devel, as it was not a technical support query, >> but an issue.) >> >> >> The following program will crash with a fp exception on an INTEL 64 bit >> HVM domU only: >> #include >> 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 >>>>> >>>>> 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:spz6vmdothb2njf >> b+state:results >> >> >> >> Anyone have a solution to this? :) >> >> Allan >> >> >> >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xensource.com >> http://lists.xensource.com/xen-devel >> > > >