Description of problem:

qcow2 supports compressed images. The default is zlib, but zstd is
also supported upstream. However zstd compression is not enabled
in RHEL qemu-kvm at all, meaning that we cannot create, open etc
qcow2 zstd-compressed images.

Fedora and other distributions may switch to zstd compression for
qcow2, and this will create an interoperability issue in future.

Version-Release number of selected component (if applicable):

qemu-img-8.0.0-7.el9.x86_64

How reproducible:

100%

Steps to Reproduce:

$ qemu-img create -f qcow2 test.qcow2 1G -o compression_type=zstd
Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zstd size=1073741824 lazy_refcounts=off refcount_bits=16
qemu-img: test.qcow2: Parameter 'compression-type' does not accept value 'zstd'

On Fedora this works:

$ qemu-img create -f qcow2 test.qcow2 1G -o compression_type=zstd
Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zstd size=1073741824 lazy_refcounts=off refcount_bits=16