krunkit: Disable offloading for faster networking

Newer krunkit allows disabling offloading for faster networking. Keep
the Offloading option in case offloading is improved in future versions.

Testing shows 6.7 times faster network performance, and 9p mount
is 3 times faster.

Starting cluster:

    % minikube start --driver krunkit --container-runtime containerd
    😄  minikube v1.36.0 on Darwin 15.6 (arm64)
    ✨  Using the krunkit (experimental) driver based on user configuration
    👍  Starting "minikube" primary control-plane node in "minikube" cluster
    🔥  Creating krunkit VM (CPUs=2, Memory=6144MB, Disk=20000MB) ...
    📦  Preparing Kubernetes v1.33.2 on containerd 1.7.23 ...
    🔗  Configuring bridge CNI (Container Networking Interface) ...
    🔎  Verifying Kubernetes components...
        ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
    🌟  Enabled addons: default-storageclass, storage-provisioner
    🏄  Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default

Testing iperf3:

    % kubectl apply -f iper3-server.yaml
    deployment.apps/iperf3 created
    service/iperf3 created

    % kubectl get deploy iperf3
    NAME     READY   UP-TO-DATE   AVAILABLE   AGE
    iperf3   1/1     1            1           9s

    % kubectl get service iperf3
    NAME     TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
    iperf3   NodePort   10.105.127.180   <none>        5201:30201/TCP   17s

    % iperf3 -c $(minikube ip) -p 30201
    Connecting to host 192.168.105.10, port 30201
    [  5] local 192.168.105.1 port 50630 connected to 192.168.105.10 port 30201
    [ ID] Interval           Transfer     Bitrate
    [  5]   0.00-1.00   sec  1.05 GBytes  9.03 Gbits/sec
    [  5]   1.00-2.01   sec  1.09 GBytes  9.29 Gbits/sec
    [  5]   2.01-3.01   sec  1.06 GBytes  9.09 Gbits/sec
    [  5]   3.01-4.00   sec  1.08 GBytes  9.33 Gbits/sec
    [  5]   4.00-5.00   sec  1.08 GBytes  9.31 Gbits/sec
    [  5]   5.00-6.00   sec  1.07 GBytes  9.23 Gbits/sec
    [  5]   6.00-7.00   sec  1.09 GBytes  9.35 Gbits/sec
    [  5]   7.00-8.01   sec  1.08 GBytes  9.20 Gbits/sec
    [  5]   8.01-9.00   sec  1.07 GBytes  9.18 Gbits/sec
    [  5]   9.00-10.01  sec  1.08 GBytes  9.28 Gbits/sec
    - - - - - - - - - - - - - - - - - - - - - - - - -
    [ ID] Interval           Transfer     Bitrate
    [  5]   0.00-10.01  sec  10.7 GBytes  9.23 Gbits/sec                  sender
    [  5]   0.00-10.01  sec  10.7 GBytes  9.23 Gbits/sec                  receiver

Testing 9p mount:

    % minikube mount ~/models:/mnt/models
    📁  Mounting host path /Users/nir/models into VM as /mnt/models ...
        ▪ Mount type:   9p
        ▪ User ID:      docker
        ▪ Group ID:     docker
        ▪ Version:      9p2000.L
        ▪ Message Size: 262144
        ▪ Options:      map[]
        ▪ Bind Address: 192.168.105.1:50614
    🚀  Userspace file server:
    ufs starting
    ✅  Successfully mounted /Users/nir/models to /mnt/models

    📌  NOTE: This process must stay alive for the mount to be accessible ...

    $ time cat /mnt/models/DeepSeek-R1-0528-Qwen3-8B-Q4_K_M.gguf >/dev/null

    real    0m10.219s
    user    0m0.007s
    sys     0m0.263s

Requires krunkit PR:
containers/krunkit#63

And installing local libkrun-efi from main.

Author: nirs

pkg/drivers/krunkit/krunkit.go

@@ -229,7 +229,8 @@ func (d *Driver) startKrunkit(socketPath string) error {
 		"--memory", fmt.Sprintf("%d", d.Memory),
 		"--cpus", fmt.Sprintf("%d", d.CPU),
 		"--restful-uri", d.restfulURI(),
-		"--device", fmt.Sprintf("virtio-net,unixSocketPath=%s,mac=%s", socketPath, d.MACAddress),
+		"--device", fmt.Sprintf("virtio-net,type=unixgram,path=%s,mac=%s,offloading=%t",
+			socketPath, d.MACAddress, d.VmnetHelper.Offloading),
 		"--device", fmt.Sprintf("virtio-serial,logFilePath=%s", d.serialPath()),
 		"--krun-log-level", logLevelInfo,
 

pkg/minikube/registry/drvs/krunkit/krunkit.go

@@ -86,8 +86,6 @@ func configure(cfg config.ClusterConfig, n config.Node) (interface{}, error) {
 		VmnetHelper: vmnet.Helper{
 			MachineDir:  filepath.Join(storePath, "machines", machineName),
 			InterfaceID: u,
-			// Required Until https://github.com/containers/libkrun/issues/264 is fixed.
-			Offloading: true,
 		},
 	}, nil
 }