From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Mjbmc-00052C-0a for qemu-devel@nongnu.org; Fri, 04 Sep 2009 12:37:06 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MjbmW-0004yG-Py for qemu-devel@nongnu.org; Fri, 04 Sep 2009 12:37:04 -0400 Received: from [199.232.76.173] (port=55568 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MjbmW-0004y1-Dz for qemu-devel@nongnu.org; Fri, 04 Sep 2009 12:37:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52179) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MjbmU-00024l-Lw for qemu-devel@nongnu.org; Fri, 04 Sep 2009 12:36:59 -0400 Date: Fri, 4 Sep 2009 13:36:11 -0300 From: Marcelo Tosatti Message-ID: <20090904163611.GC5132@amt.cnet> References: <1252008114.3084.136.camel@blaa> <5d6222a80909031518h2bf804fbk1f7a52424d3e8649@mail.gmail.com> <1252048961.3144.8.camel@blaa> <1252080398.4625.47.camel@x200> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1252080398.4625.47.camel@x200> Subject: [Qemu-devel] Re: [PATCH] qemu-kvm: fix segfault when running kvm without /dev/kvm, falling back to non-accelerated mode List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Dustin Kirkland Cc: Mark McLoughlin , qemu-devel@nongnu.org, kvm@vger.kernel.org, Glauber Costa On Fri, Sep 04, 2009 at 11:06:38AM -0500, Dustin Kirkland wrote: > On Fri, 2009-09-04 at 08:22 +0100, Mark McLoughlin wrote: > > On Thu, 2009-09-03 at 19:18 -0300, Glauber Costa wrote: > > > On Thu, Sep 3, 2009 at 6:48 PM, Dustin Kirkland wrote: > > > > On Thu, Sep 3, 2009 at 3:01 PM, Mark McLoughlin wrote: > > > >> On Thu, 2009-09-03 at 12:31 -0500, Dustin Kirkland wrote: > > > >>> qemu-kvm: fix segfault when running kvm without /dev/kvm, falling back > > > >>> to non-accelerated mode > > > >>> > > > >>> We're seeing segfaults on systems without access to /dev/kvm. It > > > >>> looks like the global kvm_allowed is being set just a little too late > > > >>> in vl.c. This patch moves the kvm initialization a bit higher in the > > > >>> vl.c main, just after options processing, and solves the segfaults. > > > >>> We're carrying this patch in Ubuntu 9.10 Alpha. Please apply > > > >>> upstream, or advise if and why this might not be the optimal solution. > > > >> > > > >> Ah discussion about an alternative fix for this fizzled out recently: > > > >> > > > >> http://www.mail-archive.com/kvm@vger.kernel.org/msg19890.html > > > > > > > > Ah, thanks Mark. In that thread, I found Daniel's suggestion the most > > > > reasonable, and user-friendly: > > > > > > > > On Mon, Jul 27, 2009 at 1:44 PM, Daniel P. Berrange wrote: > > > >> Well, we could go for logic like: > > > >> > > > >> * No arg given => try kvm, try kqemu, try tcg > > > >> * --accelmode arg given => try $arg, and fail if unavailable > > > >> > > > >> then libvirt would simply always supply --accelmode for all VMs, > > > >> while people running qemu manually would get best available > > > I sent some patches to do that, but they were incomplete, and I was > > > preempted by something else. > > > If you want, you can wait for my cycles to come back, or pick from where I left > > Thanks for the pointer, Glauber. My cycles a bit constrained too, but > I'll have a look when I get a chance. > > > In the meantime, can we commit to stable-0.11 either Dustin's fix or > > this: > > > > http://git.et.redhat.com/?p=qemu-fedora.git;a=commitdiff;h=aa1620047b > > +1. We're looking for something agreeable in stable-0.11, that solves > the segfault and proceeds without VT acceleration. Dustin, Can you please resend the patch with the suggestion i made earlier, for stable-0.11?