From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 3/9] change order of kvm_init call. Date: Mon, 27 Jul 2009 12:49:06 -0500 Message-ID: <4A6DE892.7050801@us.ibm.com> References: <1248131416-11272-1-git-send-email-glommer@redhat.com> <1248131416-11272-2-git-send-email-glommer@redhat.com> <1248131416-11272-3-git-send-email-glommer@redhat.com> <1248131416-11272-4-git-send-email-glommer@redhat.com> <4A6CA7A0.8020901@web.de> <20090727173851.GC4776@poweredge.glommer> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Kiszka , kvm@vger.kernel.org, avi@redhat.com To: Glauber Costa Return-path: Received: from e36.co.us.ibm.com ([32.97.110.154]:38906 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750779AbZG0RtK (ORCPT ); Mon, 27 Jul 2009 13:49:10 -0400 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e36.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id n6RHlW6w010082 for ; Mon, 27 Jul 2009 11:47:32 -0600 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n6RHn8QZ212118 for ; Mon, 27 Jul 2009 11:49:09 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n6RHn7SE024505 for ; Mon, 27 Jul 2009 11:49:08 -0600 In-Reply-To: <20090727173851.GC4776@poweredge.glommer> Sender: kvm-owner@vger.kernel.org List-ID: Glauber Costa wrote: > On Sun, Jul 26, 2009 at 08:59:44PM +0200, Jan Kiszka wrote: > >> Glauber Costa wrote: >> >>> The goal is to get rid of the call to kvm_init. But those things >>> are subtle, and often break. So do it in a separate patch, to help >>> finding potential issues in future bisections. >>> >> Found such an issued: This patch triggers a segfault if no kvm modules >> are loaded and you start qemu without -no-kvm. Please have a look. >> >> Jan >> > > ok, the culprit seems to be a > > if (kvm_enabled()) > return; > > in the beginning of code_gen_alloc. > > It is 7f3d0cbe, by Avi, and according to changelog, suggested by anthony. > I however, fail to realise the purpose of this optimization. For one thing, > it totally dictates that kvm has absolutely to be enabled or disabled prior > to this point. No mind changing later. Also, the real deal is to be able > to compile out tcg entirely. The strategy of just disabling the code gen > alloc is a minor nitpick that just papers over this. > I agree with you in principle but I think reverting this papers over an issue. Why are we touching code_gen_ptr when using KVM? Can someone post the full back trace? -- Regards, Anthony Liguori