Hacker News Reader

Comment by goykasi | Hacker News Reader

Thats sounds pretty interesting. Ive been running a hacked together windows VM gaming setup via qemu with vfio passthrough for the past 1.5 years on my local linux server. Im pretty pleased with it. Ive got it down to simply executing a small script and everything comes up. It could be even more automated using evdev potentially (recognizing mouse/keyboard events).

I was thinking about expanding the setup to include a beefier linux host (more gpus and better hardware) and more seats -- windows gaming for me and osx for my wife. But you mentioned several possible osx specific caveats: amd gpus, clover (?) bootloader w/ dsdt (?), disable_idle_d3, etc. Can you link to some info or READMEs regarding your setup or how you came across these solutions?

View on HN

I don't have any specific guides about my setup, but here are a few things that have been helpful to me:

- Good starting point for setting up macOS under QEMU/KVM: https://github.com/kholia/OSX-KVM

- DSDT/SSDT patching: https://www.tonymacx86.com/threads/ssdt-gpu-graphics-card-in...

- AMD reset bug: https://www.reddit.com/r/VFIO/comments/5h351m/gpu_stuck_in_d...

- Kernel extension that can help with some GPU issues: https://github.com/acidanthera/WhateverGreen

The DSDT/SSDT patch was probably the trickiest thing. I've posted my particular patch here if you're interested: https://pastebin.com/ngvkVZYN

Also, a few of my other scripts/config: https://pastebin.com/9Nh5rheZ

In case anyone runs across similar AMD GPU issues, the "disable_idle_d3=1" option in the second pastebin link (when used as a kernel parameter) should be prefixed as "vfio-pci.disable_idle_d3=1". Even then, it can still be hit-or-miss with some cards (it works most of the time for me, but some VM restarts still find that the GPU has entered D3 and won't come back without rebooting the host).

is this a macOS guest specific issue? would I have similar issues on a Windows or Linux guest?

I believe it happens for any guest OS (search for "amd reset bug"). Some people are using a workaround that involves removing the device (in the sysfs), suspending the host, and then rescanning, but for me, that's not much better than a host reboot, so when the AMD GPU occasionally does get stuck in D3 (preventing starting the VM after a VM reboot), I just reboot the host. It doesn't happen very often, and when it does, it's only when I'm in the process of rebooting the VM anyway.

Previously, I also attempted using a kernel patch that's been floating around (DECLARE_PCI_FIXUP_HEADER ... quirk_no_bus_reset), but it just gives me corrupt graphics when rebooting the VM.

Thank you for the links. Time to build a new server!

Reply on news.ycombinator.com