[libvirt] How to replace the management procedure in the virsh

In virsh, I usr "version" and it shows 编译使用的库：libvir 0.8.2 使用的库：libvir 0.8.2 使用的 API: QEMU 0.8.2 运行管理程序: QEMU 0.9.1 I want to replace QEMU 0.9.1 to QEMU 0.12.2, because 0.12.2 adds many new functions. I download qemu-kvm-0.12.2.tar.gz and install it, but the management procedure is not replaced. I know I should modify the profile of libvirt but I don't know where it is and how to modify it.