systemd-networkd: add option to ignore devices by pciAddress

Author: pogobanane

hosts/adelaide.nix

@@ -5,6 +5,7 @@
     # iommu for sebastians students
     ../modules/vfio/iommu-intel.nix
     ../modules/disko-zfs.nix
+    ../modules/dpdk.nix
   ];
 
   disko.rootDisk = "/dev/sdc";
@@ -15,4 +16,9 @@
 
   system.stateVersion = "21.11";
 
+  boot.hugepages1GB.number = 20;
+  systemd.network.ignorePci = [
+    "0000:00:1c.0"
+    "0000:00:1c.1"
+  ];
 }

hosts/christina.nix

@@ -8,6 +8,10 @@
   ];
 
   boot.hugepages1GB.number = 8;
+  systemd.network.ignorePci = [ 
+    "0000:00:1c.0"
+    "0000:00:1c.1"
+  ];
 
   networking.hostName = "christina";
 

modules/dpdk.nix

@@ -27,6 +27,13 @@ with lib;
       '';
       default = true;
     };
+    systemd.network.ignorePci = mkOption {
+      type = types.listOf types.nonEmptyStr;
+      description = ''
+        Pci addresses to be ignored by systemd-networkd.
+      '';
+      default = [];
+    };
   };
   config = {
     boot.kernelParams = [
@@ -59,8 +66,21 @@ with lib;
     users.groups.kvm.members = lib.optionals config.users.addAllToKvm (
       builtins.attrNames (lib.filterAttrs (_userName: user: user.isNormalUser) config.users.users)
     );
-    systemd.network.networks = {
-      # leave container interfaces alone
+    systemd.network.networks = let 
+      ignoreConfig = pciAddress: ''
+        [Match]
+        Property=DEVPATH=/devices/pci0000:00/${pciAddress}/*
+
+        [Link]
+        Unmanaged = yes
+      '';
+      pciIgnoreRules = builtins.listToAttrs ( builtins.map (
+        pciAddress: { 
+          name = "09-ignore-${pciAddress}"; 
+          value = { extraConfig = (ignoreConfig pciAddress); }; 
+        }) config.systemd.network.ignorePci);
+    in pciIgnoreRules // {
+      # leave 100G interfaces alone
       "09-ignore-e810".extraConfig = ''
         [Match]
         Driver = ice