[SOLVED] IOMMU on an AMD FX-8530 CPU

[xellos]

Hello all,

I am pretty new to Proxmox and I want to utilize some old hardware I have laying around. Here is my setup:
- Motherboard: Asrock 970 Pro3
- CPU: AMD FX-8350
- RAM: 16Gb DDR3
- Storage: 250Gb Crucial SSD for Proxmox + Intel DS SSD 480 GB for VMs
- GPU: AMD RX 590 8Gb

My settings are as follows.

In my motherboard Bios:
-> IOMMU Enabled
-> Secure VM Enabled

In my Proxmox:
My grub file contains the line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on"

I also updated grub and I rebooted

update-grub
reboot

My problem:
When I check IOMMU, I see the following message, saying IOMMU is not available:

[    0.000000] Warning: PCIe ACS overrides enabled; This may allow non-IOMMU protected peer-to-peer DMA
[    0.147258] AGP: Please enable the IOMMU option in the BIOS setup
[    0.669896] pci 0000:00:00.2: AMD-Vi: Found IOMMU cap 0x40
[    3.774839] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug.

I don't know how to fix this, I tried adjusting the flags and updating the bios but nothing worked.
I also checked online and some folks on reddit have IOMMU working with the same motherboard, but posts are quite old so I got no replies from them.

I also noticed that the message says IOMMUv2 and not just IOMMU. So maybe my CPU is just too old for v2? Is there a way to tell proxmox to use v1 instead?

Any help would be really appreciated.
Thank you guys

 

[Chris]

Hi,
please try this [0] script from the ArchLinux wiki to see if your devices are mapped to IOMMU groups.

[0] https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Ensuring_that_the_groups_are_valid

 

[xellos]

Hi,
please try this [0] script from the ArchLinux wiki to see if your devices are mapped to IOMMU groups.

[0] https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Ensuring_that_the_groups_are_valid

Thanks for the reply. They are, and actually I made some progress since my post and I even see the GPU in a Windows 10 VM.

Now I can install drivers (AMD Adrenaline), and I can also see the GPU in GPUZ and Device Manager, but it shows an error in Device Manager (Error 43) and I can't use it. Do you know what can cause this? I feel like am really close to making it work but I have no clue how.

 

[Dunuin]

Maybe the "radeon reset bug" where the GPU will only properly initialize once and it's already initialized by PVE first bwcauae it's your only GPU?

https://forum.proxmox.com/threads/amdgpu-reset-bug-fix-help.111412/

Not sure if PVE is meanwhile fixing that by default. I think I have seen some hook script resetting the GPU.

 

[xellos]

Maybe the "radeon reset bug" where the GPU will only properly initialize once and it's already initialized by PVE first bwcauae it's your only GPU?

Thanks for the reply, Indeed its my only GPU.
I am not familiar with this issue, do you know how to check / fix it?

 

[leesteken]

The RX590 requires vendor-reset and activation of it. Here is an old guide. You can easily test passthrough by booting a recent Ubuntu Live installer ISO (without installing it).
Passthrough of the boot GPU requires this work-around or with an AMD GPU (and vendor-reset) you can also install the latest optional kernel but make sure amdgpu is loaded for the VGA function of the GPU (so don't blacklist it or early bind it to vfio-pci, which is needed when using older kernels).
The AMD Windows Graphics drivers work better with Machine version 6.2 (machine: pc-q35-6.2) on Windows 10.
Lots of threads about this on this forum; I hope this gets you started.

 

[xellos]

The RX590 requires vendor-reset and activation of it. Here is an old guide. You can easily test passthrough by booting a recent Ubuntu Live installer ISO (without installing it).
Passthrough of the boot GPU requires this work-around or with an AMD GPU (and vendor-reset) you can also install the latest optional kernel but make sure amdgpu is loaded for the VGA function of the GPU (so don't blacklist it or early bind it to vfio-pci, which is needed when using older kernels).
The AMD Windows Graphics drivers work better with Machine version 6.2 (machine: pc-q35-6.2) on Windows 10.
Lots of threads about this on this forum; I hope this gets you started.

I can't thank you enough, you sir are a hero. I was pulling my hair out and your help solved my issues.
I installed vendor-reset and activated it, and I also changed the version of Machine to 6.2 and voilaa!

I can now see the GPU and use it normally, I even plugged an HDMI cable directly to it and was able to get a flawless display! With USB passthrough of a keyboard and mouse I was even able to use the VM like a normal desktop.

Some beautiful pictures of things working as expected.







Thank you again for the amazing help!
Next step before wrapping it is to do it all again to "learn" what exact parameters work for my hardware.

Cheers!

 

[g00f]

Any benefit to having 4GPUs in this same configuration? My old water cooled gaming rig for AMd Ifinity which was great at the time.