cc'ing KVM and LKML this time... Why does KVM use the atomic load/store lists to load MSR_IA32_UMWAIT_CONTROL on VM-Enter/VM-Exit? Unless the host kernel is doing UWMAIT, which it really shouldn't and AFAICT doesn't, isn't it better to use the shared MSR mechanism to load the host value only when returning to userspace, and reload the guest value on demand?
