From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58774) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZK1F-0003gZ-2W for qemu-devel@nongnu.org; Tue, 08 Sep 2015 10:37:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZZK1B-0005wK-NQ for qemu-devel@nongnu.org; Tue, 08 Sep 2015 10:37:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53827) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZK1B-0005wE-Ia for qemu-devel@nongnu.org; Tue, 08 Sep 2015 10:37:05 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 2C4A3461DB for ; Tue, 8 Sep 2015 14:37:05 +0000 (UTC) Date: Tue, 8 Sep 2015 15:37:02 +0100 From: "Daniel P. Berrange" Message-ID: <20150908143702.GG4307@redhat.com> References: <1441718858.14506.1.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1441718858.14506.1.camel@redhat.com> Subject: Re: [Qemu-devel] Target vs architecture for QEMU binary Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrea Bolognani Cc: qemu-devel@nongnu.org On Tue, Sep 08, 2015 at 03:27:38PM +0200, Andrea Bolognani wrote: > Hi, > > at the moment, libvirt is using some ad-hoc logic to allow > i686 guests to run on qemu-system-x86_64 (by using the CPU > model qemu32); in all other cases, it's assumed that a $arch > guest needs qemu-system-$arch to run. > > This is causing a problem right now with ppc64le guests > because, even though qemu-system-ppc64 is perfectly capable > of running them, libvirt will refuse to. Is there a bug report somewhere for that, because libvirt already has code in virQEMUCapsFindBinaryForArch() which forces it to look at qemu-system-ppc64 when asked to use ppc64le, so I'd expect it to already work. > We want to change the logic so that it reflects the actual > capabilities of the QEMU binary, but AFAICT there isn't eg. > a QMP command we can use to query the binary for the list > of architectures it implements. > > Am I missing something? Is such an interface available? We have a bit of a chicken and egg problem, because to query QEMU for capabilities, you already have to know what system emulator binary is required for the architeture you want to run. > Failing that, we'll have to map QEMU targets with implemented > guest architectures inside libvirt, in which case it would be > great if you could point me towards either some up-to-date > documentation or a reliable way to extract the information > myself. The various rules in virQEMUCapsFindBinaryForArch() already try todo a suitable mapping Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|