qemu driver must not use hardcoded "/machine/unattached/device[0]" QOM path when probing cpu flags

Description of problem

QEMU is going to change the QOM path for cpus, which will break libvirt's cpu flag probing code:

qemu developers suggest to use 'query-hotpluggable-cpus' to fetch the QOM path to the default CPU

Edited Feb 07, 2022 by Peter Krempa

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information