The edk2 package already ships builds targeting the uefi-vars QEMU device, both on x86_64 and aarch64:

%files ovmf                                                                     
...
%{_datadir}/%{name}/ovmf/OVMF.qemuvars.fd

%files aarch64
...
%{_datadir}/%{name}/aarch64/QEMU_EFI-qemuvars-pflash.*

Matching JSON descriptors are however not included in the package, and neither are JSON variable store templates for the enrolled-keys and no enrolled-keys use cases.

Now that a way to describe such combinations has become available with QEMU patch [PATCH v3 0/1] docs/interop/firmware: Add 'uefi-vars' member for FirmwareMappingMemory (currently queued for inclusion) and that libvirt support is being developed as part of RHEL-82645, it's time to introduce the additional files.

libvirt patch [PATCH v3 29/38] DONOTMERGE: tests: Add firmware descriptors for uefi-vars builds describes what these files could look like. That's of course just a suggestion and the details could end up being different.