GPU Passthrough "device is already attached" error


New Member
Sep 6, 2019

I am new to proxmox and fiddle with it almost a week now. I installed on a mini-itx board w/ 1 PCI port. I want to passtrough the GPU. I already installed vm. Working fine. I followed offical proxmox pci passthrough guide.
- blacklisted gpu and hdmi audio both in modprobe.d and grub entry
- in vm pci passthrough bot gpu and hdmi audio
- Got untempared GPU rom and put it in /usr/share/kvm/
- Added "hostpci0: 01:00,x-vga=on,romfile=vbios.bin" conf file
- booted from onboard intel igpu
- checked the gpu and hdmi audio they are on vfio-pci

however I get this error:
"kvm: -device vfio-pci,host=01:00.0,id=hostpci1.0,bus=pci.0,addr=0x11.0,rombar=0,multifunction=on: vfio 0000:01:00.0: device is already attached"

could you help me?
Could you post your VM configuration (/etc/pve/qemu-server/<vmid>.conf) as well as the output of lspci -nnk and maybe qm showcmd <vmid> --pretty?

Also, have you tried without the "romfile" option? Often times that is actually not needed.


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