From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36403) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b5rrU-0001Lb-T8 for qemu-devel@nongnu.org; Thu, 26 May 2016 05:45:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b5rrR-0006Jh-MN for qemu-devel@nongnu.org; Thu, 26 May 2016 05:45:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37101) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b5rrR-0006JH-HO for qemu-devel@nongnu.org; Thu, 26 May 2016 05:45:49 -0400 Date: Thu, 26 May 2016 11:45:46 +0200 From: Kashyap Chamarthy Message-ID: <20160526094546.slj7r3rkpv24ihjx@eukaryote> References: <574685F4.8070304@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <574685F4.8070304@windriver.com> Subject: Re: [Qemu-devel] [libvirt] inconsistent handling of "qemu64" CPU model List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Chris Friesen Cc: libvir-list@redhat.com, "qemu-devel@nongnu.org" On Wed, May 25, 2016 at 11:13:24PM -0600, Chris Friesen wrote: [...] > However, if I explicitly specify a custom CPU model of "qemu64" the > instance refuses to boot and I get a log saying: [Not a direct answer to the exact issue you're facing, but a related issue that is being investigated presently...] Currently there's a related (regression) in upstream libvirt 1.3.4: The crux of the issue here is: the libvirt custom 'gate64' model is not being translated into a CPU definition that QEMU can recognize (which you can find from `qemu-system-x86 -cpu \?`). See this bug (it has reproducer, and discussion): https://bugzilla.redhat.com/show_bug.cgi?id=1339680 -- libvirt CPU driver fails to translate a custom CPU model into something that QEMU recognizes The bug (regression) is bisected, by Jiri Denemark, to this commit: v1.2.9-31-g445a09b "qemu: Don't compare CPU against host for TCG". > libvirtError: unsupported configuration: guest and host CPU are not > compatible: Host CPU does not provide required features: svmlibvirtError: > unsupported configuration: guest and host CPU are not compatible: Host CPU > does not provide required features: svm > > When this happens, some of the XML for the domain looks like this: > > hvm > .... > > > qemu64 > > > > Of course "svm" is an AMD flag and I'm running an Intel CPU. But why does > it work when I just rely on the default virtual CPU? Is > kvm_default_unset_features handled differently when it's implicit vs > explicit? > > If I explicitly specify a custom CPU model of "kvm64" then it boots, but of > course I get a different virtual CPU from what I get if I don't specify > anything. > > Following some old suggestions I tried turning off nested kvm, deleting > /var/cache/libvirt/qemu/capabilities/*, and restarting libvirtd. Didn't > help. > > So...anyone got any ideas what's going on? Is there no way to explicitly > specify the model that you get by default? > > > Thanks, > Chris > > -- > libvir-list mailing list > libvir-list@redhat.com > https://www.redhat.com/mailman/listinfo/libvir-list -- /kashyap