Re: [PATCH 4/4] x86: properly handle kvm emulation of hyperv

Jason Wang
2013-07-24T06:55:16Z

On 07/24/2013 12:48 PM, H. Peter Anvin wrote:
> On 07/23/2013 09:37 PM, Jason Wang wrote:
>> On 07/23/2013 10:48 PM, H. Peter Anvin wrote:
>>> On 07/23/2013 06:55 AM, KY Srinivasan wrote:
>>>> This strategy of hypervisor detection based on some detection order IMHO is not
>>>> a robust detection strategy. The current scheme works since the only hypervisor emulated
>>>> (by other hypervisors happens to be Hyper-V). What if this were to change.
>>>>
>>> One strategy would be to pick the *last* one in the CPUID list, since
>>> the ones before it are logically the one(s) being emulated...
>>>
>>> -hpa
>>>
>> How about simply does a reverse loop from 0x40010000 to 0x40010000?
>>
> Not all systems like being poked too far into hyperspace. Just remember
> the last match and walk the list.
>
> -hpa
>

Ok, but it raises a question - how to know it was the 'last' match
without knowing all signatures of other hyper-visor?