1. Check the status of the virt_use_nfs boolean in SELinux.
getsebool virt_use_nfs
2. Temporarily turn on the boolean.
setsebool virt_use_nfs on
3. Check the status of the virt_use_nfs boolean in SELinux.
getsebool virt_use_nfs
4. If you want to make the change persistant, then add the -P option to setsebool.
setsebool -P virt_use_nfs on