[SOLVED] Dual GPU PCI passthrough problem

[mailo95]

Hello all,

I have a problem with passing through the primary GPU but have no problem with the second one. The problem is that when trying to start the VM with the primary GPU attached returns -->

Dec 30 18:14:44 pve kernel: [  889.165695] vfio-pci 0000:01:00.0: vfio_ecap_init: hiding ecap 0x19@0x270
Dec 30 18:14:44 pve kernel: [  889.166236] vfio-pci 0000:01:00.0: BAR 0: can't reserve [mem 0xd0000000-0xdfffffff 64bit pref]

The configuration of the VM is this -->

affinity: 4-8
agent: 1
balloon: 0
bios: ovmf
boot: order=ide2;scsi0;net0
cores: 4
cpu: host,flags=+pdpe1gb;+aes
cpulimit: 4
cpuunits: 200
efidisk0: local-lvm:vm-105-disk-0,efitype=4m,pre-enrolled-keys=1,size=4M
hostpci0: 0000:01:00,pcie=1,x-vga=1,romfile=barts.rom
machine: pc-q35-7.1
memory: 8192
meta: creation-qemu=7.0.0,ctime=1664434421
name: Win10WS
net0: virtio=BE:22:DB:25:05:58,bridge=vmbr1,tag=100
numa: 0
ostype: win10
scsi0: local-lvm:vm-105-disk-1,cache=writeback,discard=on,size=50G,ssd=1
scsi1: local-lvm:vm-105-disk-2,cache=writeback,discard=on,size=100G,ssd=1
scsihw: virtio-scsi-pci
smbios1: uuid=00e766f9-1fe4-43a2-a5f7-5a4569d58dd3
sockets: 1
vcpus: 4
vga: none
vmgenid: fc2ecd18-83f1-4197-bb90-91784ab90b08

For tutorial I was using this one --> Official Proxmox Pci passthrough
The machine specs:
CPU: Intel E5-2660v2
MB: ASUS ROG Rampage IV Extreme
RAM: 32GB
GPU1: AMD R7 250x with dumped bios this card is also on first PCI-E slot and it's primary and have problem to passthrough
GPU2: ATI Radeon HD6870 with dumped bios have no problem with it

Can someone help me with this because these cards was working with my previous AMD machine and the problem persists after upgrading to Intel platform.

 

[leesteken]

Passthrough of the GPU used during boot often needs this work-around. My experience with AMD GPU's (with vendor-reset) is that it simply works with not blacklisting amdgpu and not early binding it to vfio-pci and with kernel version 5.19 or 6.1 it just works.

 

[mailo95]

Passthrough of the GPU used during boot often needs this work-around. My experience with AMD GPU's (with vendor-reset) is that it simply works with not blacklisting amdgpu and not early binding it to vfio-pci and with kernel version 5.19 or 6.1 it just works.

Thank you for the reply. My kernel is 5.15 with the latest PVE 7.3.x but will try it and hope will work.

 

[leesteken]

Thank you for the reply. My kernel is 5.15 with the latest PVE 7.3.x but will try it and hope will work.

Since kernel 5.15, you also need something like this to enable vendor-reset.

 

[mailo95]

Since kernel 5.15, you also need something like this to enable vendor-reset.

After removing

video=vesafb:off video=efifb:off video=simplefb:off

from

/etc/default/grub

and set this parameter to GRUB cfg

initcall_blacklist=sysfb_init

everything is working fine.