Get kvm exits info for vcpu from /sys/kernel/debug/kvm/vcpu_stat.
Related openeuler kernel commits:
    bbb5023b977aa3ec08d142daa63c86e8e4da81ff
    5ae004462e253e23690b47692d514705223c0305
    167fbfb3d28c267d98064a36c95cee21cdfd2fa7
Signed-off-by: NJiajun Chen <1250062498@qq.com>