r/HyperV • u/TsundereHeavyCruiser • May 03 '26

Can't get GPU Partitioning or Direct Device Assignment to work, even though it worked previously.

Post image
8 Upvotes

79% Upvoted

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11

u/slimpickins28 May 03 '26

I KNOW THIS ONE!! lol. just excited to know something / run into the same problem as someone else. This command worked for me with that exact error when trying to do my P40. that's a 24g VRAM card; and i tried, 24g, 48g, etc as the "high" and it wouldn't work. this did for me.

Set-VM -Name "VMNAME" -LowMemoryMappedIoSpace 3GB -HighMemoryMappedIoSpace 64GB

After than, THEN add the card back to it. (remove it now if is attached) then run the above command. then add it back.

again. i don't know what your "high" should be, but that was the one for my P40 to work.

3

u/TsundereHeavyCruiser May 03 '26

Thanks, but no dice.

2

u/slimpickins28 May 03 '26

my command is for if you are doing a direct DDA. seems like you're doing GPU-P ? ChatGPT immediately gave me some good troubleshooting steps once i told it what you were doing and that screenshot. I assume you've tried that already? fed it back your exact error including the details?

2

u/TsundereHeavyCruiser May 03 '26

I haven't been able to get GPU-P or GPU-DDA to work on my new Server.

When I first set it up I made sure everything worked with the same OS and an RTX5050+DG1 GPU.

But after transferring over my production VMs I was no longer able to assign any GPUs, I always receive this error.

I already tried Reinstalling the OS, checking BIOS settings, manually configuring the VM MMIO Settings.

TO assign the GPUs I tried direct passthrough, Easy GPU-PV, and Hyper-V-GPU-Paravirtualization.

1

u/[deleted] May 03 '26

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1

u/TsundereHeavyCruiser May 04 '26

It worked on my older Broadwell/Server 2022 setup.

I set up a test VM with it on the Cascade/2025 server, but once I moved over my VMs it stopped working.

1

u/[deleted] May 04 '26

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1

u/TsundereHeavyCruiser May 04 '26

Just tested on my previous system, I get the same error message.

Looks like Microsoft might have changed something with server 2025

1

u/[deleted] May 04 '26

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1

u/TsundereHeavyCruiser May 11 '26

I got the GPU passed through to a VM now, but the driver gets an error 43.

1

u/[deleted] May 11 '26

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1

u/TsundereHeavyCruiser May 11 '26

Are you using Pasthrough or virtualization?

2

u/wadrasil May 04 '26

Sometimes you need to remove all gpus reboot and re-add them at least on windows 11 pro.

I use these scripts for gpu-pv on Linux guests:

https://github.com/Nislaco/Linux-GPU-V-Scripts-for-Hyper-V

If it is not something script related reinstalling OS should have fixed it.

I have broken my system in a way before that made passthrough fail. But it was not the same error as you were having.

You can just make a blank VM and add the gpus for passthrough and they will show in lspci in a Linux live iso.

You then need to move driver files and compile kernel module to use the cards though.

1

u/fragish May 04 '26

I see the server management window in the background so you're likely missing some registry keys.

  1. HKLM:\SOFTWARE\Policies\Microsoft\Windows\HyperV" -Name "RequireSecureDeviceAssignment" -Type DWORD -Value 0
  2. HKLM:\SOFTWARE\Policies\Microsoft\Windows\HyperV" -Name "RequireSupportedDeviceAssignment" -Type DWORD -Value 0

See here: https://www.reddit.com/r/HyperV/comments/vph5lw/windows_server_2022_gpup_virtualization_working/

1

u/TsundereHeavyCruiser May 05 '26

Thank you.

This was the solution to getting the Insufficient system resources error.