Re: [libvirt] Question about the host-model CPU mode

On 20.10.2017 14:50, Jiri Denemark wrote: > The thing is libvirt calls query-cpu-model-expansion to check what the > host CPU is. This 'host-model' CPU is replaced with the probed CPU model > when a domain starts. The problem described by Marc is that the probed > CPU model cannot be used universally with all machine types. So starting > a domain on such host with machine type s390-virtio-ccw-2.10 works, but > a domain with machine type s390-virtio-ccw-2.9 fails to start with the > same probed CPU model. > My assumption would be that the CPU model is copied into the XML when the domain fist starts. This is what the documentation describes.

So when upgrading QEMU, the CPU model in the XML is still the same (z13), even though something different is now reported in the host info after upgrading QEMU (z14). In this case it would continue to work. The problem is that the CPU model is not copied into the XML doesn't remain there, right? It is suddenly replaced with a z14 host model.