Linux fails to boot after adding Kernel Flags

[AwlsomeAlex]

Distro: Xubuntu 19.04
Graphics: Intel UHD 620 (ASUS Zenbook UX330UAR)

After following the Guide Passthrough, adding the following to my kernel flags
iommu=pt intel_iommu=on vfio-pci.ids=8086:5917,1=8086:9d71
results in my kernel freezing around 3 seconds in. I'm not sure what debug files you need.
5917: GPU, 9d71: Sound Card

Getting rid of the kernel flags allowed the kernel to boot, but am I doing something wrong?

Might want to add the vfio-pci Module is loaded.

Could it be a missing kernel module or an incorrect one @foxlet ? Or an incompatibility with kernel 5.0?

[PhilipDeegan]

iommu can be a pain to configure, perhaps have a look here https://github.com/RadeonOpenCompute/ROCm_Documentation/blob/master/ROCm_Virtualization_Containers/ROCm-Virtualization-%26-Containers.rst

Here's a sample QEMU launch too RadeonOpenCompute/ROCm_Documentation#15

this helped me

[AwlsomeAlex]

@dekken I get to the point where I'm adding the PCI devices with vfio-bind 0000:00:00.0 as shown by lspci -n -d 8086: and the computer screen goes blank. Let me note I am using a laptop with only one GPU, does that make a difference?

[PhilipDeegan]

I think if you do this with only one GPU you make it impossible to use it outside the guest

I have had a similar experience when I set two GPUs in a two GPU system to use iommu.

[AwlsomeAlex]

@dekken That's unfortunate to hear. Is there anything I can do to improve performance inside the VM with graphics?

[PhilipDeegan]

I can't say, however I did have issues with Windows 10 in virtual box, and apparently the fixes for Meltdown and Specter really slow things down - so adding grub flags to disable the fixes helped, no that I suggest you do that of course

[AwlsomeAlex]

@dekken Performance isn't really the issue, it's more like graphics are slow and Hardware Acceleration is non-existent.

[ctrl-b]

The only way to increase graphics performance –at least for now, is to pass through a compatible card. On laptops look for a dedicate mode to separate igpu from dgpu into different iommu groups, there's a chance to make it work when that option is available, tbc thought. Otherwise, I think it won't be possible.