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: > <os> > <type arch='x86_64' machine='pc-i440fx-utopic'>hvm</type> > .... > > <cpu mode='custom' match='exact'> > <model fallback='allow'>qemu64</model> > <topology sockets='1' cores='1' threads='1'/> > </cpu> > > 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@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/libvir-list -- /kashyap -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list