PING: RFR: 8250598: Hyper-V is detected in spite of running on host OS

[Baesken, Matthias]

Hello,  
     the latest webrev  looks good to me .
I tested additionally  on  VMWare / Xen / KVM  and  the detection worked nicely .

You might want to rephrase this comment  (it sounds a little strange to me) 

http://cr.openjdk.java.net/~ysuenaga/JDK-8250598/webrev.02/src/hotspot/cpu/x86/vm_version_x86.cpp.frames.html

1821   // In case of Xen, it might be appear until 0x40010000.


Don't  need to see another webrev for this .

Best regards, Matthias



>On 2020/08/18 23:39, Doerr, Martin wrote:
>> Hi Yasumasa,
>> 
>> thanks a lot for measuring and improving the overhead. This version looks much better.
>> 
>> I still wonder what the reason was for using a stub. There was probably a reason, but I don't remember.
>
>It might be called in many times, so I made change would generate stub in first.
>
>VM_Version::check_virtualizations() would call CPUID 256 times (0x40000000 to 0x40010000 step 0x100),
>and also I changed it is used to call CPUID with EAX = 0x40000007 in Hyper-V.
>
>
>> Hopefully, Matthias can find time for another review when he's back next week.
>
>Yeah, I want to commit this change after his review.