Hypervisor detector for Windows

[David Holmes]

Please follow up on the review thread.

Thanks,
David

On 27/07/2020 5:16 pm, Yasumasa Suenaga wrote:
> On 2020/07/27 15:59, Baesken, Matthias wrote:
>> Hi  Yasumasa , I'll  put  your  patch  into our build/test  queue  and 
>> check the outcome.
> 
> Thanks Matthias, can you check this webrev rather than in my first email?
> 
>    http://cr.openjdk.java.net/~ysuenaga/JDK-8250598/webrev.00/
> 
> 
> Yasumasa
> 
> 
>> And thanks for filing the JBS issue too .
>> Regarding ...
>>
>>> Does not support x86 (32bit) platform
>>
>> Yes , I think 32bit is not very important any more in current OpenJDK .
>> But if your patch addresses it too , then  it's not a bad thing for 
>> sure !
>>
>> Best regards, Matthias
>>
>>
>>
>>
>> -----Original Message-----
>> From: Yasumasa Suenaga <suenaga at oss.nttdata.com>
>> Sent: Samstag, 25. Juli 2020 17:02
>> To: David Holmes <david.holmes at oracle.com>; 
>> hotspot-runtime-dev at openjdk.java.net; Baesken, Matthias 
>> <matthias.baesken at sap.com>
>> Subject: Re: Hypervisor detector for Windows
>>
>> Thanks David!
>>
>> On 2020/07/25 21:13, David Holmes wrote:
>>> Hi Yasumasa,
>>>
>>> My recollection from reviewing this was that it was all based on 
>>> vendor strings. Best to ask Matthias (cc'd) if you need more details.
>>
>> I think we can fix like following webrev. It works fine on Windows 10 
>> (host), Windows 10 (guest) on Hyper-V, and Fedora 32 on Hyper-V.
>> Matthias, what do you think? If this webrev seems good, I will file it 
>> to JBS and will send review request.
>>
>>     http://cr.openjdk.java.net/~ysuenaga/hv-detection/
>>
>>
>> Thanks,
>>
>> Yasumasa
>>
>>
>>> Cheers,
>>> David
>>>
>>> On 25/07/2020 3:51 pm, Yasumasa Suenaga wrote:
>>>> Hi all,
>>>>
>>>> When I got hs_err log on Windows, I saw "HyperV virtualization 
>>>> detected" in it in spite of running on host OS.
>>>>
>>>> I tried to file it to JBS and to fix it, but I have some questions 
>>>> for this.
>>>> (This feature has been introduced in JDK-8219241)
>>>>
>>>>
>>>>     - According to [1] (it is mentioned in the source code), we need 
>>>> to check bit 31 in ECX when CPUID is called with EAX = 1h. Why it 
>>>> would not do so?
>>>>
>>>>     - Why would VM_Version::check_virtualizations() call CPUID with 
>>>> 40000000h to 4000FF00h? 40000000h should be used if we want to get 
>>>> vendor ID.
>>>>
>>>>     - Why VM_Version::check_virt_cpuid() is separated for GNU C 
>>>> (GAS) and MacroAssembler? I guess we can use MacroAssembler for x86 
>>>> / x86_64.
>>>>
>>>>     - In case of Hyper-V, host OS is treated as root partition [2], 
>>>> so we cannot use this CPUID solution for Hyper-V. I guess we need to 
>>>> check it with other solutions like [3].
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>> [1] https://kb.vmware.com/s/article/1009458
>>>> [2] 
>>>> https://docs.microsoft.com/virtualization/hyper-v-on-windows/reference/hyper-v-architecture 
>>>>
>>>> [3] 
>>>> https://stackoverflow.com/questions/10544498/detect-the-virtualization-layer-from-a-guest-instancevm-vpc-or-hyper-v-in-c 
>>>>