Provide alternative way to specify device parameters currently unsupported by libvirt
Goal
-set
QEMU command line is broken when using JSON syntax for device and libvirt has switched to use JSON syntax for device when QEMU has this capablity (version 6.2.0).
Maintainer of QEMU thought we shouldn't make -set
option work when using JSON argument, see https://lists.nongnu.org/archive/html/qemu-devel/2022-01/msg04129.html.
We need an alternative way to specify device parameters currently unsupported by libvirt.