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

From: Jason Wang
Date: Wed Jul 24 2013 - 02:55:24 EST


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?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/