Questions about the ownership of /var/cache/libvirt/qemu

Hi all, When we change the user for QEMU process (change "user" and "group" in /etc/libvirt/qemu.conf) to a normal user, we found that libvirtd will also change the ownership of /var/cache/libvirt/qemu but will keep the ownership of /var/cache/libvirt/qemu/capabilities as root. Is it secure to put files/directories owned by root in a directory owned by a normal user? Could the normal user replace the root's file with a new one? Does it need to set sticky bit on /var/cache/libvirt/qemu or keep the ownership of /var/cache/libvirt/qemu as root?