Intel iGPU passthrough error: VFIO_DEVICE_SET_IRQS failure

[warewagada]

I am trying to pass through the iGPU of my CPU (Intel i5 11400) to a VM. I have followed all the steps on the guide, including verifying that IOMMU is enabled, confirming that my motherboard supports remapping, and blacklisting all video drivers. When I attempt to start a VM with the iGPU added as a PCI device I get the following error:

kvm: -device vfio-pci,host=0000:00:02.0,id=hostpci0,bus=pci.0,addr=0x10: vfio 0000:00:02.0: Failed to set up TRIGGER eventfd signaling for interrupt INTX-0: VFIO_DEVICE_SET_IRQS failure: No such device
TASK ERROR: start failed: QEMU exited with code 1

The VM in question has the following configuration

bios: seabios
boot: order=scsi0;ide2;net0
cores: 8
hostpci0: 0000:00:02
ide2: local:iso/debian-12.0.0-amd64-netinst.iso,media=cdrom,size=738M
memory: 8000
meta: creation-qemu=7.2.0,ctime=1687472992
name: docker-stack
net0: virtio=AA:3C:7B:9A:AF:0C,bridge=vmbr0,firewall=1
numa: 0
onboot: 1
ostype: l26
scsi0: local:101/vm-101-disk-0.qcow2,iothread=1,size=32G
scsi1: HDD1:vm-101-disk-0,iothread=1,size=712G
scsihw: virtio-scsi-single
smbios1: uuid=0484d3fc-19a3-450d-aca4-03d7c6b51ddd
sockets: 1
vmgenid: 7e51a76b-0ee8-4914-9f1e-6533d30144a8

One thing of note is that my host (HP Pavilion TP01-2000i) requires the kernel flag

pci=noacpi

to boot at all. I have attempted numerous other pci/acpi related flags documented here, but every one other than

pci=noacpi

results in an indefinite freeze in the boot process. I have a suspicion that this flag is messing with the IRQ assignments. Looking for help debugging this.

 

[blebo]

Try hostpci0: 0000:00:02,pcie=1 in the VM config?
What is the output of lspci -k -s 00:02?

 

[warewagada]

Try hostpci0: 0000:00:02,pcie=1 in the VM config?
What is the output of lspci -k -s 00:02?

The added config line hostpci0: 0000:00:02,pcie=1 with q35 machine type results in the same error code.
The output of lspci -k -s 00:02 is

00:02.0 VGA compatible controller: Intel Corporation Device 4c8b (rev 04)
    DeviceName: Onboard - Video
    Subsystem: Hewlett-Packard Company Device 8860
    Kernel driver in use: vfio-pci
    Kernel modules: i915