On 24/08/2017 14:27, Yu Zhang wrote: > diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h > index 3ed6192..67e7ec2 100644 > --- a/arch/x86/kvm/mmu.h > +++ b/arch/x86/kvm/mmu.h > @@ -48,6 +48,9 @@ > > static inline u64 rsvd_bits(int s, int e) > { > + if (e < s) > + return 0; > + > return ((1ULL << (e - s + 1)) - 1) << s; > } e = s - 1 is already supported; why do you need e <= s - 2? Paolo