Loose Proxmox connection when HDMI audio passthrough enabled

[RavenNL]

Hi,

Specs: Intel Nuc7i5bnb

Having a little bit of an issue when I enable HDMI AUDIO passthrough in a VM (Ubuntu 22.04) I loose my connection to the Proxmox GUI. Audio is working fine in the VM.
By the looks of it the audio device is in the device id as the networkcard (00:1f). I don't need the hardware network card in the VM. The bridge mode will do just fine.

Spoiler

root@proxmox:~# lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Iris Plus Graphics 640 (rev 06)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1)
00:1c.5 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #6 (rev f1)
00:1c.7 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #8 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #9 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point LPC Controller/eSPI Controller (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (4) I219-V (rev 21)
3a:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev 78)
3b:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5229 PCI Express Card Reader (rev 01)
3c:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983

I tried adding the audio device without the option 'full device'

Grub:

Spoiler

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on"
#GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt pcie_acs_override=downstream,multifunction initcall_blacklist=sysfb_i>
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

/etc/modules

Spoiler

GNU nano 5.4 /etc/modules
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

# Modules required for PCI passthrough
vfio
vfio_iommu_type1
vfio_pci
vfio_virqfd

/etc/pve/qemu-server/100.conf

Spoiler

bios: ovmf
boot: order=scsi0;ide2;net0
cores: 1
cpu: host
efidisk0: local-lvm:vm-100-disk-1,efitype=4m,pre-enrolled-keys=1,size=4M
hostpci0: 0000:00:02
hostpci1: 0000:00:1f.3,rombar=0
ide2: local:iso/ubuntu-22.04.1-desktop-amd64.iso,media=cdrom,size=3737140K
machine: q35
memory: 4096
meta: creation-qemu=7.0.0,ctime=1665769274
name: Ubuntu
net0: virtio=82:C8:20:2B:65:B5,bridge=vmbr0,firewall=1
numa: 0
ostype: l26
scsi0: local-lvm:vm-100-disk-0,size=32G
scsihw: virtio-scsi-pci
smbios1: uuid=467e9f1c-e337-40f1-b858-d5be4d82b8a1
sockets: 4
usb0: host=046d:c52b,usb3=1
vga: none
vmgenid: 7fbfa4d6-b8f5-41e5-8ee1-a9ba6935bc81

Is there any way when the VM starts to disable the networkcard so it doesn't get started.

 

[leesteken]

Are the audio and network devices in the same IOMMU group? You cannot share devices in the same group between VMs and/or the Proxmox host. You can check with for d in /sys/kernel/iommu_groups/*/devices/*; do n=${d#*/iommu_groups/*}; n=${n%%/*}; printf 'IOMMU group %s ' "$n"; lspci -nns "${d##*/}"; done

 

[RavenNL]

Are the audio and network devices in the same IOMMU group? You cannot share devices in the same group between VMs and/or the Proxmox host. You can check with for d in /sys/kernel/iommu_groups/*/devices/*; do n=${d#*/iommu_groups/*}; n=${n%%/*}; printf 'IOMMU group %s ' "$n"; lspci -nns "${d##*/}"; done

Yes, that's what I also mentioned in the description.

Spoiler

IOMMU group 10 00:1f.0 ISA bridge [0601]: Intel Corporation Sunrise Point LPC Controller/eSPI Controller [8086:9d4e] (rev 21)
IOMMU group 10 00:1f.2 Memory controller [0580]: Intel Corporation Sunrise Point-LP PMC [8086:9d21] (rev 21)
IOMMU group 10 00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-LP HD Audio [8086:9d71] (rev 21)
IOMMU group 10 00:1f.4 SMBus [0c05]: Intel Corporation Sunrise Point-LP SMBus [8086:9d23] (rev 21)
IOMMU group 10 00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection (4) I219-V [8086:15d8] (rev 21)

Is there no way at all to just isolate the audio device only?

 

[leesteken]

Yes, that's what I also mentioned in the description.

Sorry, I could not find your IOMMU groups in the description .

Is there no way at all to just isolate the audio device only?

The physical motherboard PCIe layout and motherboard BIOS determine the IOMMU groups. You could check for a BIOS update (or sometimes downgrade).
There is the pcie_acs_override=downstream.multifunction kernel parameter: it makes the system ignore/lie about the groups, breaks proper device isolation and comes with no guarantees.

 

[RavenNL]

I upgraded bios earlier today and made no difference.

I guess I need to revert to a usb to ethernetcable to workaround this then.,

Thanks though