Proxmox "failed to reset PCI device" on pass through

Operating Systems & Open Source Virtualization
1

Hi,

I’m working on setting up PCI pass through on proxmox VE 8.4.1
I have a working ubuntu vm that I am trying to pass a Nvdia Quadro K620 to. system is x10 intel supermicro. on starting the VM this error message is logged.

error writing '1' to '/sys/bus/pci/devices/0000:01:00.0/reset': Inappropriate ioctl for device
failed to reset PCI device '0000:01:00.0', but trying to continue as not all devices need a reset
TASK OK

The web UI for proxmox then crashes. The system is using a zfs boot. the current /etc/kernel/cmdline is this.

root=ZFS=rpool/ROOT/pve-1 boot=zfs intel_iommu=on iommu=pt pci=assign-busses pcie_acs_override=downstream,multifunction

I also tried it with just “intel_iommu=on iommu=pt”. all nvida drives both video and audio are blacklisted and not loaded (verified with lspci). disable_vga is set in modprobe for the device.

Does anyone have any idea what I should try? there not much I’m getting back from the system since the VM crashes the VE portal on launch. I have tried shutting down all other VM to ensure there is not resource contention else where.

2

Proxmox system requires one display device to operate and can pass additional display devices (/w some caveats) to virtual machines.
Do you have more than 1 GPU (other than the Nvidia Quadro) in the system? Otherwise you’re trying to accomplish something that isn’t possible.

3

ok i figured out my own issue. old xeon processors dont properly set up iommu. so you have to pass a lot of kernal command line args to get it to work right

for newer cpus:
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt "

for old xeons:
GRUB_CMDLINE_LINUX_DEFAULT=“quiet intel_iommu=on iommu=pt pci=assign-busses pcie_acs_override=downstream,multifunction”

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4

single GPU passthrough works without problems with Proxmox.
I passed the iGPU from a 7950x to an Kodi VM and Proxmox started headless.
But somehow the iGPU broke after a few days and the CPU part still works

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