GrabbenD GrabbenD

VFIO Setup on NixOS

Disclaimer: Nobody else tested my setup so far, so this is a "works on my machine" scenario. I am not responsible for anything you break on your machine (although I'd not expect much harm).

Hardware

My system has the following hardware:

Board: ASRock X570 Pro4

Force RGB pixel format over YCbCr

There are some monitors, in my case Dell U2413, that report having YCbCr support when plugged in over HDMI. My AMD Radeon RX 570 Series video card sees this YCbCr pixel format and then prefers that over the RGB pixel format. The result is that fonts, graphics and other visuals are pixelated and not smooth in Ubuntu.

This actually is not just a Linux problem. A similar problem exists on macOS with the same monitor hooked up over HDMI. In fact an article by John Ruble on the Atomic Object blog called Fixing the External Monitor Color Problem with My 2018 MacBook Pro attempts to fix the exact same thing.

Solution

All of the articles I could find exploring this topic advocate patching the EDID for the monitor. Unfortunately the macOS solution would not work here. Luckily I found a Reddit post that covered how to get it working.

Update: As of June 2023, Chrome has officially added support for prefers-color-scheme as of this in version 114!

Paste the following into your terminal. You'll have to fully close the browser with pkill chrome each time you want Chrome to re-read the settings.

Also, use the following flags for full GPU acceleration:

ignore-gpu-blocklist
enable-webrtc-pipewire-capturer
enable-gpu-rasterization
enable-vulkan

Installing Arch without pacstrap is easy. No, you won't use archbootstrap. That is only for chroots. Instead, you will do it hand made.

First, make the file system.

mkdir -m 0755 -p /path/to/root/var/{cache/pacman/pkg,lib/pacman,log} /path/to/root/{dev,run,etc/pacman.d}
mkdir -m 1777 -p /path/to/root/tmp
mkdir -m 0555 -p /path/to/root/{sys,proc}
cp -a /etc/pacman.d/gnupg "/path/to/root/etc/pacman.d/"

Looking-glass kvmfr setup Arch

More in-depth setup-guide for usage of kvmfr (see https://looking-glass.io/docs/B6/module/)

This setup was done on EndeavourOs (Arch) on Kernel 6.1.12-arch1-1.
QEMU-version 7.2 and libvirt version 9.0.0 .
Running cGroups Policy (if you have AppArmor, some things are different)

Check respective sections in looking-glass docs for other versions (specifcally QEMU <6.2 and libvirt <7.9)

Arch Linux SilverBlue - Bootstrap Process

Create an arch linux chroot using podman:

podman run --rm -it \
    -v "$PWD:$PWD" \
    -w "$PWD" \
    archlinux:latest

By default Linux distros are unoptimized in terms of I/O latency. So, here are some tips to improve that.

Most apps still don't do multi-threaded I/O access, so it's a thread-per-app which makes per-app speed always bottlenecked by single-core CPU performance (that's not even accounting for stuttering on contention between multiple processes), so even with NVMe capable of 3-6 GB/s of linear read you may get only 1-2 GB/s with ideal settings and 50-150/100-400 MB/s of un/buffered random read (what apps actually use in real life) is the best you can hope for.

All writes are heavily buffered on 3 layers (OS' RAM cache, device's RAM cache, device's SLC-like on-NAND cache), so it's difficult to get real or stable numbers but writes are largelly irrelevant for system's responsiveness, so they may be sacrificed for better random reads.

The performance can be checked by:

`fio --name=read --readonly --rw={read/randread} --ioengine=libaio --iodepth={jobs_per_each_worker's_command} --bs={4k/2M} --direct={0/1} --num

	# Install docker or podman package on your distro (podman doesn't need a daemon like dockerd to work). All args are exactly same, just replace ``podman`` with ``docker`` in command if you want to.
	sudo pacman -S podman

	# Run an archlinux container with dbus and wayland sockets.
	sudo podman run \
	--volume "$XDG_RUNTIME_DIR/$WAYLAND_DISPLAY":/tmp/wayland-0 \
	--device /dev/dri \
	--volume /run/user/1000/bus:/tmp/bus \
	--rm -it archlinux /bin/bash

	#!/bin/bash

	# Execute Windows programs with Proton from Steams installation folder, without
	# starting Steam client.
	#
	# 1. Create a directory for Proton environment to run in. As an example make a
	# folder "proton" in your home directory. This folder must exist in order
	# to make Proton work.
	#
	# 2. Point the variable "env_dir" in this script to that folder or...

	#!/usr/bin/env bash

	usage() {
	echo "Usage: $(basename "$0") [-d DEFAULT_BORDER_PX] [-m MAXIMIZED_BORDER_PX]"
	}

	get_waybar_height() {
	# Waybar's config is JSONC, ie it contains comments. We need to strip
	# these for jq.
	grep -v '//' ~/.config/waybar/config \| jq -er '.height'