infra/modules/vfio.nix

let
  gpuIDs = [
    "1002:744c" # Graphics
    "1002:ab30" # Audio
  ];
in
  {
    pkgs,
    lib,
    config,
    ...
  }: {
    options.vfio.enable = with lib;
      mkEnableOption "Configure the machine for VFIO";

    config = let
      cfg = config.vfio;
    in {
      boot = {
        kernelModules = ["kvm-amd" "vfio_pci" "vfio" "vfio_iommu_type1" "kvmfr"];
        extraModulePackages = with config.boot.kernelPackages; [
          kvmfr
        ];
        extraModprobeConfig = ''
          # The memory size is calculates in the same way as VM's shmem.
          options kvmfr static_size_mb=64
        '';

        kernelParams = [
          "amd_iommu=on"
          "pcie_acs_override=downstream,multifunction"
          "vfio-pci.ids=1002:744c,1002:ab30"
          "pcie_aspm=off"
        ];
      };
      services.udev.extraRules = ''
        SUBSYSTEM=="kvmfr", OWNER="gsimmer", GROUP="kvm", MODE="0660"
      '';
      hardware.opengl.enable = true;
      virtualisation.spiceUSBRedirection.enable = true;
      virtualisation.libvirtd = {
        qemu = {
          verbatimConfig = ''
            cgroup_device_acl = [
              "/dev/null", "/dev/full", "/dev/zero",
              "/dev/random", "/dev/urandom",
              "/dev/ptmx", "/dev/kvm", "/dev/kqemu",
              "/dev/rtc","/dev/hpet", "/dev/vfio/vfio",
              "/dev/kvmfr0"
            ]
          '';
        };
      };
    };
  }