Re: [PATCH v3 2/5] KVM: MMU: check guest CR3 reserved bits based on its physical address width.

Yu Zhang
2017-08-24T15:45:42Z

On 8/24/2017 9:40 PM, Paolo Bonzini wrote:
> 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?

Sorry? I do not quite understand. When will e = s - 1?

Thanks
Yu
> Paolo
>