[libvirt-users] LibVirt query CPU Model support and restore operation

Hello , It was working good working with kvm management tools using libvirt . virsh/virt-manager . But then i got annoyed when management tool did not allow me to change the CPU model while creating new virtual machine . error root@kvm-server qemu]# virt-install --virt-type kvm --name compute-2 --cpu Haswell-noTSX --ram=61440 --vcpus=20 --os-type=linux --os-variant=generic --disk compute2-disk0.qcow2,device=disk,bus=ide,size=300,sparse=true,format=qcow2 --pxe --network bridge=virbr0,model=e1000 --network bridge=virbr0,model=e1000 --network bridge=virbr0,model=virtio --network bridge=virbr0,model=virtio --graphics vnc,port=5906 --noautoconsole Starting install... ERROR unsupported configuration: guest and host CPU are not compatible: Host CPU does not provide required features: invpcid, erms, bmi2, smep, avx2, bmi1, fsgsbase, movbe, fma Domain installation does not appear to have been successful. I could not resolve this error . Finally i came across the post which say that libvirt cross verifies flags under CPU model present in /usr/share/libvirt/cpu_map.xml and cat /proc/cpuinfo . An yes the flag complained were not present in host proc/cpuinfo. Question 1: Is it really needed for Libvirt to do this check . AS KVM seems to allow support Haswell with native commands . Why libvirt is doing this check then ? As i was not sure where the problem lies and i was using libvirt 2.0.0 version i upgraded to 2.5.0 by compiling form source . But then i faces issue using virsh/virt-manager as seem it was not compatilble with upgarded version of libvirt. Now my system is little messed around libvirt . I did reinstall/reboot Quite many things not working . Question 2 : How can i restore original Libvirt 2.0.0 . br aki