diff --git a/hosts/hydra/default.nix b/hosts/hydra/default.nix
index 990c64e2..ed6df9fd 100644
--- a/hosts/hydra/default.nix
+++ b/hosts/hydra/default.nix
@@ -68,6 +68,7 @@ in
         maxJobs = "4";
         speedFactor = 10;
         sshUser = config.nix.remoteBuilder.name;
+        # kvm is not supported because /dev/kvm does not exist
         supportedFeatures = [ "big-parallel" "nixos-test" "benchmark" ];
         system = "aarch64-linux";
       }