nixos/configurations/adrastea/vm: init with "add-vfio" package

.gitignore

@@ -0,0 +1 @@
+target

nixos/configurations/adrastea/default.nix

@@ -29,6 +29,7 @@
     ./gitea.nix
     ./hardware-configuration.nix
     ./networking.nix
+    ./vm
     ./wireguard.nix
   ];
 

nixos/configurations/adrastea/vm/add-vfio/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "add-vfio"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

nixos/configurations/adrastea/vm/add-vfio/default.nix

@@ -0,0 +1,17 @@
+{
+  lib,
+  rustPlatform,
+}:
+
+rustPlatform.buildRustPackage {
+  name = "add-vfio";
+
+  src = ./.;
+
+  cargoHash = "sha256-uDN154Y3QFw6jksEA0Z+AFgB1n0s4EFznXIC7Q+xOtQ=";
+
+  meta = {
+    license = lib.licenses.unlicense;
+    maintainers = [ lib.maintainers.inclyc ];
+  };
+}

nixos/configurations/adrastea/vm/add-vfio/src/main.rs

@@ -0,0 +1,48 @@
+use std::env;
+use std::fs;
+use std::path::Path;
+
+fn main() {
+    // Take the isolating device from argv[1]
+    let isolating_device = env::args().nth(1).expect("No device specified");
+
+    let sys_bus_pci = Path::new("/sys/bus/pci");
+
+    let iommu_group_path = sys_bus_pci
+        .join("devices")
+        .join(&isolating_device)
+        .join("iommu_group")
+        .join("devices");
+
+    let iommu_group = fs::read_dir(&iommu_group_path).expect("Failed to read iommu group");
+
+    for entry in iommu_group {
+        let file_name = entry.expect("Failed to read entry").file_name();
+        let device = file_name.to_str().unwrap();
+
+        let device_dir = sys_bus_pci.join("devices").join(device);
+
+        let driver_path = device_dir.join("driver");
+        let driver = fs::read_link(&driver_path).unwrap_or_default();
+
+        if driver.to_string_lossy().contains("vfio-pci") {
+            println!("skip({}): this device is already bound to vfio-pci", device);
+            continue;
+        }
+
+        // Remove from previous driver
+        if device_dir.join(&driver).exists() {
+            println!("driver/remove({}): remove from previous driver ...", device);
+            let _ = fs::write(device_dir.join("driver/unbind"), device);
+        }
+
+        // Bind to vfio-pci
+        println!("bind ...");
+        fs::write(device_dir.join("driver_override"), "vfio-pci")
+            .expect("driver/override: Failed to write driver_override");
+
+        // Probe device
+        println!("probe({}) ...", device);
+        fs::write("/sys/bus/pci/drivers_probe", device).expect("Failed to probe device");
+    }
+}

nixos/configurations/adrastea/vm/default.nix

@@ -0,0 +1,10 @@
+{ pkgs, ... }:
+
+let
+  add-vfio = pkgs.callPackage ./add-vfio { };
+in
+{
+  environment.systemPackages = [
+    add-vfio
+  ];
+}