From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:36543) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RcDVj-0008SR-PU for qemu-devel@nongnu.org; Sun, 18 Dec 2011 04:58:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RcDVi-0004qe-Qg for qemu-devel@nongnu.org; Sun, 18 Dec 2011 04:58:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60396) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RcDVi-0004qX-KB for qemu-devel@nongnu.org; Sun, 18 Dec 2011 04:58:26 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id pBI9wNlI002050 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 18 Dec 2011 04:58:23 -0500 Date: Sun, 18 Dec 2011 11:58:16 +0200 From: Gleb Natapov Message-ID: <20111218095816.GG21664@redhat.com> References: <20111215145415.GA265695@orkuz.home> <20111215154243.GA8829@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111215154243.GA8829@redhat.com> Subject: Re: [Qemu-devel] [libvirt] Modern CPU models cannot be used with libvirt List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: libvir-list@redhat.com, qemu-devel@nongnu.org On Thu, Dec 15, 2011 at 03:42:44PM +0000, Daniel P. Berrange wrote: > On Thu, Dec 15, 2011 at 03:54:15PM +0100, Jiri Denemark wrote: > > Hi, > > > > Recently I realized that all modern CPU models defined in > > /etc/qemu/target-x86_64.conf are useless when qemu is used through libvirt. > > That's because we start qemu with -nodefconfig which results in qemu ignoring > > that file with CPU model definitions. We have a very good reason for using > > -nodefconfig because we need to control the ABI presented to a guest OS and we > > don't want any configuration file that can contain lots of things including > > device definitions to be read by qemu. However, we would really like the new > > CPU models to be understood by qemu even if used through libvirt. What would > > be the best way to solve this? > > Ideally libvirt would just write out a config file with the CPU > that was configured in libvirt and pass -readconfig /var/lib/libvirt/qemu/guestcpu.conf > That way libvirt can configure CPU models without regard for > what the particular QEMU version might have in its config. > And how libvirt would know that particular QEMU/kvm version can create this CPU. Managing cpuid shouldn't be libvirt busyness. -- Gleb.