Trying to Deploy graphics devices using Discrete Device Assignment in Hyper-V

McKnife
McKnife used Ask the Experts™
on
Hyper-V DDA makes me crazy.

I have installed a 2019 Hyper-V server with a 2019 server as guest - all up2date, all current drivers installe, all bios options for hyper-v are set.
I am trying to make a graphics card available to a machine via DDA.The script from https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/deploy/deploying-graphics-devices-using-dda works! However, as soon as I try to power on the VM, the hypervisor shows errors:
'NameOfMyMachine' failed to start.

Virtual Pci Express Port (Instance ID 540C1694-484B-4451-B6E7-91D6B2772D18): Failed to Power on with Error 'Element not found.'.

[Expanded Information]
'NameOfMyMachine' failed to start. (Virtual machine ID 96D073C6-E9B8-4095-96FD-E887B93C0EC5)

'NameOfMyMachine' Virtual Pci Express Port (Instance ID 540C1694-484B-4451-B6E7-91D6B2772D18): Failed to Power on with Error 'Element not found.' (0x80070490). (Virtual machine ID 96D073C6-E9B8-4095-96FD-E887B93C0EC5)

Could not allocate the PCI Express device with the Plug and Play Device Instance path 'PCIP\VEN_10DE&DEV_1C30&SUBSYS_11B310DE&REV_A1\4&25438C51&0&0008' because it is already in use by another VM.

Open in new window

Rest assured: that card is NOT in user by another VM since there is only one VM and there never was a 2nd. Using powershell, I can even determine that it is assigned to that very VM.

What should that funny error tell me?
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Most Valuable Expert 2013

Commented:
You need two graphics card instances, you can't piggy-back on the host's primary card for passthrough.
Distinguished Expert 2018

Author

Commented:
I know and I am not doing that.
Distinguished Expert 2018

Author

Commented:
You know what, please hold on.
I will retry on a different board on Tuesday and let you know.
Introduction to R

R is considered the predominant language for data scientist and statisticians. Learn how to use R for your own data science projects.

Distinguished Expert 2018

Author

Commented:
Some progress:

Took another board and another graphics card:
Supermicro x10-SRA-F
Nvidia Quadro K4000
Still, it does not work with the same symptom.

So instead of pulling my hair out, I installed server 2016 hyper-v and also a 2016 server guest machine and IT JUST WORKS.
So either Microsoft has crippled something (in favor of something else?) on purpose or it's just a bug in server 2019/hyper-v 2019.
Next week I will try with the AMD card.

Small question: would you consider it normal, that after installing the graphics card in the guest and rebooting, we see this in device manager / dcdiag? Shouldn't all be enabled, even if make a remote desktop connection to the virtual 2016 server?
Capture.PNGAll is enabled on the same VM if I use the hyper-v console (non-enhanced session) to connect via vmconnect.exe, see
Capture.PNG
Distinguished Expert 2018

Author

Commented:
This is just too funny... after installing the latest CU for server 2016 (the guest) hoping that might do something good to dxdiag, I find the nvidia card disabled after the reboot. Thanks MS!
Capture.PNG
Distinguished Expert 2018

Author

Commented:
I rebuilt the server from scratch and did the same again but this time without updating the guest.
The same happens nevertheless: after the 2nd reboot, the card cannot be used in the guest anymore.
Distinguished Expert 2018
Commented:
More tests revealed, that this just works with Win10 as guest system. Go figure... I will not use this technology, it is just not very well documented.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial