There are cases folks want to disable spinlock optimization for debug/test purpose. Xen and hyperv already have parameters "xen_nopvspin" and "hv_nopvspin" to support that, but kvm doesn't.
The first patch adds that feature to KVM guest with "nopvspin". I also changed print code in first patch, I'm not sure if I should pick that part into a separate patch, just let me know if it's preferred. For compatibility reason original parameters "xen_nopvspin" and "hv_nopvspin" are retained and marked obsolete. Thanks Zhenzhong
