Can't do gvg-g passthrough for Windows VM

Using miniv2 latest byzantium image updated with dist-upgrade. I can’t get gvt-g passthrough to work.
I followed lots of different guides, tried many things. When I enter the Windows VM, I am able to run intel iGPU driver installer, however after a while the screen will go black and won’t come ever come back. Kernel version is 5.10, should I try to update it? (I don’t know how to do that though)

Can anybody help?

I add these modules to boot:

sudo nano /etc/modules

vfio
vfio_iommu_type1
vfio_mdev
vfio_virqfd
vfio_pci
kvmgt
kvm
i915

I use this systemd service to have the device ready on every boot:

sudo nano /etc/systemd/system/setup-gvt.service
sudo systemctl enable setup-gvt

[Unit]
Description=Setup GVT

[Service]
Type=oneshot
User=root
ExecStart=/usr/bin/bash -c 'echo 06f10f82-5430-4913-9dae-8f6b67239c21 > /sys/devices/pci0000:00/0000:00:02.0/mdev_supported_types/i915-GVTg_V5_4/create'

[Install]
WantedBy=multi-user.target

Changes I make to Libvirt’s XML (using virt-manager)

domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'

graphics type='spice'
  listen type='none'/
  gl enable='yes' rendernode='/dev/dri/by-path/pci-0000:00:02.0-render'/
/graphics

video
  model type='none'/
/video

hostdev mode='subsystem' type='mdev' managed='no' model='vfio-pci' display='on'
source
address uuid='06f10f82-5430-4913-9dae-8f6b67239c21'/
/source
address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/
/hostdev

Here are some results on Linux host
This one shows a firmware error:

sudo dmesg | ...
Command line: root=UUID=824b1303-1f00-4749-bd64-3775a198c9d2 ro i915.enable_gvt=1 kvm.ignore_msrs=1  i915.enable_fbc=0 i915.enable_guc=0 quiet splash intel_iommu=igfx_off 
Kernel command line: root=UUID=824b1303-1f00-4749-bd64-3775a198c9d2 ro i915.enable_gvt=1 kvm.ignore_msrs=1  i915.enable_fbc=0 i915.enable_guc=0 quiet splash intel_iommu=igfx_off 
**i915 0000:00:02.0: firmware: failed to load i915/gvt/vid_0x8086_did_0x9b41_rid_0x02.golden_hw_state (-2)**
**i915 0000:00:02.0: Direct firmware load for i915/gvt/vid_0x8086_did_0x9b41_rid_0x02.golden_hw_state failed with error -2**

Here, I should see 0000:00:02.0 (intel iGPU) in an IOMMU group, but can’t see it

 Command line: root=UUID=824b1303-1f00-4749-bd64-3775a198c9d2 ro i915.enable_gvt=1 kvm.ignore_msrs=1  i915.enable_fbc=0 i915.enable_guc=0 quiet splash intel_iommu=igfx_off 
 ACPI: DMAR 0x0000000099B61200 000088 (v01 COREv4 COREBOOT 00000000 CORE 20200925)
 ACPI: Reserving DMAR table memory at [mem 0x99b61200-0x99b61287]
 Kernel command line: root=UUID=824b1303-1f00-4749-bd64-3775a198c9d2 ro i915.enable_gvt=1 kvm.ignore_msrs=1  i915.enable_fbc=0 i915.enable_guc=0 quiet splash intel_iommu=igfx_off 
 DMAR: Disable GFX device mapping
 DMAR: Host address width 39
 DMAR: DRHD base: 0x000000fed90000 flags: 0x0
 DMAR: dmar0: reg_base_addr fed90000 ver 1:0 cap 1c0000c40660462 ecap 19e2ff0505e
 DMAR: DRHD base: 0x000000fed91000 flags: 0x1
 DMAR: dmar1: reg_base_addr fed91000 ver 1:0 cap d2008c40660462 ecap f050da
 DMAR: RMRR base: 0x0000009b000000 end: 0x0000009f7fffff
 DMAR-IR: IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
 DMAR-IR: HPET id 0 under DRHD base 0xfed91000
 DMAR-IR: Queued invalidation will be enabled to support x2apic and Intr-remapping.
 DMAR-IR: Enabled IRQ remapping in x2apic mode
 iommu: Default domain type: Translated 
 DMAR: No ATSR found
 DMAR: dmar1: Using Queued invalidation
 pci 0000:00:00.0: Adding to iommu group 0
 pci 0000:00:04.0: Adding to iommu group 1
 pci 0000:00:08.0: Adding to iommu group 2
 pci 0000:00:12.0: Adding to iommu group 3
 pci 0000:00:14.0: Adding to iommu group 4
 pci 0000:00:14.2: Adding to iommu group 4
 pci 0000:00:17.0: Adding to iommu group 5
 pci 0000:00:1d.0: Adding to iommu group 6
 pci 0000:00:1f.0: Adding to iommu group 7
 pci 0000:00:1f.3: Adding to iommu group 7
 pci 0000:00:1f.4: Adding to iommu group 7
 pci 0000:00:1f.5: Adding to iommu group 7
 pci 0000:01:00.0: Adding to iommu group 8
 DMAR: Intel(R) Virtualization Technology for Directed I/O
 AMD-Vi: AMD IOMMUv2 driver by Joerg Roedel <jroedel@suse.de>
AMD-Vi: AMD IOMMUv2 functionality not available on this system
     intel_iommu=igfx_off

There’s a also problem at 'lspci -vvvv’s result.

pcilib: sysfs_read_vpd: read failed: Input/output error
		Not readable
	Capabilities: [100 v1] Advanced Error Reporting
		UESta:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
		UEMsk:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
		UESvrt:	DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
		CESta:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
		CEMsk:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
		AERCap:	First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
			MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
		HeaderLog: 00000000 00000000 00000000 00000000
	Capabilities: [140 v1] Virtual Channel
		Caps:	LPEVC=0 RefClk=100ns PATEntryBits=1
		Arb:	Fixed- WRR32- WRR64- WRR128-
		Ctrl:	ArbSelect=Fixed
		Status:	InProgress-
		VC0:	Caps:	PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
			Arb:	Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
			Ctrl:	Enable+ ID=0 ArbSelect=Fixed TC/VC=ff
			Status:	NegoPending- InProgress-
	Capabilities: [160 v1] Device Serial Number 01-00-00-00-68-4c-e0-00
	Kernel driver in use: r8169
	Kernel modules: r8169