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whook
Journeyman III

FPU Environment

Hello,

I am using Virtual Machines (VMWare) on my AMD Ryzen 9 3900x Host.

I just realized, that the FPU environment assembly commands like FSTENV doesn't work as they should. That Command pushes mostly 0x00 and 0xFF on the stack and no actual addresses.

The same VM on my Intel machine works as intended.

So it is either an AMD problem or a VMWare Problem with AMD

Could anyone help me with this issue?

 

cheers

Whook

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4 Replies
misterj
Big Boss

whook, wild guess since you supplied almost no useful information.  Try disabling SMT (Simultaneous MultiThreading).  If that does not correct it, please return and tell us lots more details.  Thanks and enjoy, John.

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First of all ty misterj for your fast response.

Nope Deactivating SMT did not do it.

I was not aware, that I did not supplied useful information.

CPU: AMD Ryzen 9 3900x
MB: Msi mpg x570
OS: Win 10
VMWare: Workstation 15.5.2
Guest OS: Win 7

Assembly:
After saving the FPU environment with FSTENV (28-BYTE) PTR SS:[ESP-C]:

0022F2D8 FFFF037F ÿÿ
0022F2DC FFFF3800 .8ÿÿ
0022F2E0 FFFF7FFF ÿÿÿ
0022F2E4 00000000 ....

--------------------
CPU: i7-4930K
MB: ???
OS: Win 10
VMWare: Workstation 15.5.2
Guest OS: Win 7

Assembly:
After saving the FPU environment with FSTENV (28-BYTE) PTR SS:[ESP-C]:

Assembly:
After saving the FPU environment with FSTENV (28-BYTE) PTR SS:[ESP-C]:
0022F474 FFFF037F ÿÿ
0022F478 FFFF3800 .8ÿÿ
0022F47C FFFF7FFF ÿÿÿ
0022F480 0022FFCF Ïÿ".

As you can see, Intel saves the EIP Address to the stack, AMD does not.

 

At the moment I have no clue if this is a AMD or a VMWARE problem and I will try Virtual Box, is the behavior is the same. But probably someone already had the issue or might know what the issue could be.

Thank you!

 

 

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Thanks, whook.  Need much more detail.  What version of W10 are you running?  I am running W10 X64 2004.19041.640.  All your tests should be on the same OS.  Why not W10 Guest?  Have you tried Hyper-V?  What is your memory, power supply and other HW?  I have seen no reference to "FPU Environment" here since Ryzen first shipped.  You should know that this is a User forum and seldom do AMD employees post here.  Please open a support ticket - https://www.amd.com/en/support/contact-email-form .

  Good luck and enjoy, John.

Hello,

Win 10 x64 OS Buld 19041.630

For the guest is not W10 needed, its not for any use beside demonstration.

You mean Hyper-V for Virtualization? No, not so far, but I do not think that would help, as I don't have that issue on my Intel machine.

So it is either an AMD or a VMWAR problem. 

So far no news on Virtualbox because of some lack of time. Who says home office just means watching Netflix *grrr*

Memory: Corsair 64 GB KIT DDR4 3600 MHz CL18

Power: be quiet! POWER ZONE, ATX 2.4, 850W

Thank you for the support ticket link. I will first try Virtualbox, just to know if it is the processor or if it is actually VMWARE

 

you where very kind ty!

 

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