From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH] Fix segfault with ram_size > 4095M without kvm Date: Tue, 23 Feb 2010 22:24:26 +0100 Message-ID: <20100223212426.GC24081@volta.aurel32.net> References: <20100223151314.GN17350@us.ibm.com> <4B840A17.9050809@aurel32.net> <8B153AFB-E0D5-406A-A360-389A8A9C9D69@suse.de> <4B844388.9080705@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Alexander Graf , Ryan Harper , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from hall.aurel32.net ([88.191.82.174]:51276 "EHLO hall.aurel32.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753779Ab0BWVYe (ORCPT ); Tue, 23 Feb 2010 16:24:34 -0500 Content-Disposition: inline In-Reply-To: <4B844388.9080705@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Feb 23, 2010 at 03:07:20PM -0600, Anthony Liguori wrote: > On 02/23/2010 02:30 PM, Alexander Graf wrote: > >On 23.02.2010, at 18:02, Aurelien Jarno wrote: > > > >>Ryan Harper a =E9crit : > >>>Currently, x86_64-softmmu qemu segfaults when trying to use> 4095= M memsize. > >>>This patch adds a simple check and error message (much like the 20= 47 limit on > >>>32-bit hosts) on ram_size in the control path after we determine w= e're > >>>not using kvm > >>> > >>>Upstream qemu-kvm is affected if using the -no-kvm option; this pa= tch address > >>>the segfault there as well. > >>It looks like workarounding the real bug. At some point both > >>i386-softmmu (via PAE) and x86_64-softmmu were able to support> 4G= B of > >>memory. I remember adding the support long time ago, and testing it= with > >>32GB of emulated RAM. > >Sounds like a perfect candidate for -stable then. For HEAD I agree t= hat finding the cause would be the way to go. >=20 > No, it's wrong. A good candidate for -stable would be something > that fixes the SEGV :-) >=20 It actually depends on the patch and how invasive it is. I'll bisect that later this week. For now what I can say it hasn't worked for a lot of time. It works in 0.9.1, but not in 0.10.0. It probably hasn't been noticed due to kqemu which was limiting the=20 size to 2GB. --=20 Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net