Description of problem: Currently the QEMU process is able to set WRITE_SAME/UNMAP granularity. This option is not available in libvirt
and workaround needs to be used to set it up.

Current workaround is to set additional commands while starting qemu:

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
<qemu:commandline>
<qemu:arg value='-set'/>
<qemu:arg value='block.scsi0-0-0.discard_granularity=4194304'/>
</qemu:commandline>
</domain>

Version-Release number of selected component (if applicable):
libvirt-6.0.0-17.2.module+el8.2.0+6629+3fc0f2c2.x86_64

How reproducible:
Every time

Steps to Reproduce:
1. try to define discard granularity option in libvirt

Actual results:
No such option is available.

Expected results:
Option is available in the libvirt xml when defining storage backend.

Additional info: