Re: [libvirt] Incompatible CPU after upgrading qemu

On Thu, Apr 13, 2017 at 16:11:26 -0600, Jim Fehlig wrote: > Hi All, > > I've been doing some upgrade testing and noticed a problem starting some > existing VMs after upgrading qemu from 2.6 to 2.9 on one of my AMD machines. > Using libvirt 3.2.0 and qemu 2.6, I have no problems starting a VM with the > following machine/CPU config > > <os> > <type arch='x86_64' machine='pc-i440fx-2.6'>hvm</type> > <boot dev='hd'/> > </os> > <cpu mode='custom' match='exact'> > <model fallback='allow'>Opteron_G4</model> > </cpu> > > After upgrading qemu to 2.9 the VM fails to start with > > error: the CPU is incompatible with host CPU: Host CPU does not provide required > features: svm > > I see that qemu commit 75d373ef disables SVM in KVM mode, but that change was > made quite some time ago and pertains to all machine types > pc-i440fx-2.2. > Perhaps the problem was revealed by Jiri's recent libvirt changes to detect host > CPU model by asking qemu? > > My knee-jerk reaction is to remove 'svm' from Opteron CPUs in cpu_map.xml, but > I'm far from the expert on the evolving CPU code in libvirt, so asking the > experts here for some guidance. This issue should be fixed by "qemu: More CPU enhancements and fixes" series [1], specifically patch 9/9. See the commit message for more details. [1] https://www.redhat.com/archives/libvir-list/2017-April/msg00710.html