Linux fails to boot after adding Kernel Flags about macos-simple-kvm HOT 7 OPEN

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

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@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?

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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.

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

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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

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

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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.

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