feat: add configurable vhost option for monitors

PR: #415
Signed-off-by: vinayakjeet <vinayakjeetog@gmail.com>
Reviewed-by: Charalampos Mainas <cmainas@nubificus.co.uk>
Approved-by: Charalampos Mainas <cmainas@nubificus.co.uk>

Author: vinayakjeet

Makefile

@@ -231,7 +231,7 @@ test: unittest e2etest
 
 ## unittest Run all unit tests
 .PHONY: unittest
-unittest: test_unikontainers test_metrics test_network
+unittest: test_unikontainers test_metrics test_network test_hypervisors
 
 ## e2etest Run all end-to-end tests
 .PHONY: e2etest
@@ -255,6 +255,12 @@ test_network:
 	@GOFLAGS=$(TEST_FLAGS) $(GO) test $(TEST_OPTS) ./pkg/network -v
 	@echo " "
 
+## test_hypervisors Run unit tests for hypervisors package
+test_hypervisors:
+	@echo "Unit testing in hypervisors"
+	@GOFLAGS=$(TEST_FLAGS) $(GO) test $(TEST_OPTS) ./pkg/unikontainers/hypervisors -v
+	@echo " "
+
 ## test_nerdctl Run all end-to-end tests with nerdctl
 .PHONY: test_nerdctl
 test_nerdctl:

pkg/unikontainers/hypervisors/qemu.go

@@ -30,6 +30,7 @@ const (
 type Qemu struct {
 	binaryPath string
 	binary     string
+	vhost      bool
 }
 
 func (q *Qemu) Stop(pid int) error {
@@ -94,6 +95,9 @@ func (q *Qemu) BuildExecCmd(args types.ExecArgs, ukernel types.Unikernel) ([]str
 			netcli += args.Net.MAC
 			netcli += " -net tap,script=no,downscript=no,ifname="
 			netcli += args.Net.TapDev
+			if q.vhost {
+				netcli += ",vhost=on"
+			}
 		}
 		cmdString += netcli
 	} else {

pkg/unikontainers/hypervisors/vmm.go

@@ -32,25 +32,33 @@ var vmmLog = logrus.WithField("subsystem", "monitors")
 
 type VMMFactory struct {
 	binary     string
-	createFunc func(binary, binaryPath string) types.VMM
+	createFunc func(binary, binaryPath string, vhost bool) types.VMM
 }
 
 var vmmFactories = map[VmmType]VMMFactory{
 	SptVmm: {
-		binary:     SptBinary,
-		createFunc: func(binary, binaryPath string) types.VMM { return &SPT{binary: binary, binaryPath: binaryPath} },
+		binary: SptBinary,
+		createFunc: func(binary, binaryPath string, _ bool) types.VMM {
+			return &SPT{binary: binary, binaryPath: binaryPath}
+		},
 	},
 	HvtVmm: {
-		binary:     HvtBinary,
-		createFunc: func(binary, binaryPath string) types.VMM { return &HVT{binary: binary, binaryPath: binaryPath} },
+		binary: HvtBinary,
+		createFunc: func(binary, binaryPath string, _ bool) types.VMM {
+			return &HVT{binary: binary, binaryPath: binaryPath}
+		},
 	},
 	QemuVmm: {
-		binary:     QemuBinary,
-		createFunc: func(binary, binaryPath string) types.VMM { return &Qemu{binary: binary, binaryPath: binaryPath} },
+		binary: QemuBinary,
+		createFunc: func(binary, binaryPath string, vhost bool) types.VMM {
+			return &Qemu{binary: binary, binaryPath: binaryPath, vhost: vhost}
+		},
 	},
 	FirecrackerVmm: {
-		binary:     FirecrackerBinary,
-		createFunc: func(binary, binaryPath string) types.VMM { return &Firecracker{binary: binary, binaryPath: binaryPath} },
+		binary: FirecrackerBinary,
+		createFunc: func(binary, binaryPath string, _ bool) types.VMM {
+			return &Firecracker{binary: binary, binaryPath: binaryPath}
+		},
 	},
 }
 
@@ -80,7 +88,7 @@ func NewVMM(vmmType VmmType, monitors map[string]types.MonitorConfig) (vmm types
 		return nil, err
 	}
 
-	return factory.createFunc(factory.binary, vmmPath), nil
+	return factory.createFunc(factory.binary, vmmPath, monitors[string(vmmType)].Vhost), nil
 }
 
 func getVMMPath(vmmType VmmType, binary string, monitors map[string]types.MonitorConfig) (string, error) {

pkg/unikontainers/hypervisors/vmm_test.go

@@ -0,0 +1,71 @@
+// Copyright (c) 2023-2026, Nubificus LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hypervisors
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVMMFactoryQemuVhostFalse(t *testing.T) {
+	t.Parallel()
+	factory, exists := vmmFactories[QemuVmm]
+	assert.True(t, exists, "qemu factory should exist")
+
+	vmm := factory.createFunc(QemuBinary, "/usr/bin/qemu-system-x86_64", false)
+	qemu, ok := vmm.(*Qemu)
+	assert.True(t, ok, "factory should return *Qemu")
+	assert.False(t, qemu.vhost, "vhost should be false when passed as false")
+}
+
+func TestVMMFactoryQemuVhostTrue(t *testing.T) {
+	t.Parallel()
+	factory, exists := vmmFactories[QemuVmm]
+	assert.True(t, exists, "qemu factory should exist")
+
+	vmm := factory.createFunc(QemuBinary, "/usr/bin/qemu-system-x86_64", true)
+	qemu, ok := vmm.(*Qemu)
+	assert.True(t, ok, "factory should return *Qemu")
+	assert.True(t, qemu.vhost, "vhost should be true when passed as true")
+}
+
+func TestVMMFactoryNonQemuIgnoresVhost(t *testing.T) {
+	t.Parallel()
+
+	// SPT factory should ignore vhost parameter
+	factory, exists := vmmFactories[SptVmm]
+	assert.True(t, exists, "spt factory should exist")
+
+	vmm := factory.createFunc(SptBinary, "/usr/bin/solo5-spt", true)
+	_, ok := vmm.(*SPT)
+	assert.True(t, ok, "factory should return *SPT")
+
+	// HVT factory should ignore vhost parameter
+	factory, exists = vmmFactories[HvtVmm]
+	assert.True(t, exists, "hvt factory should exist")
+
+	vmm = factory.createFunc(HvtBinary, "/usr/bin/solo5-hvt", true)
+	_, ok = vmm.(*HVT)
+	assert.True(t, ok, "factory should return *HVT")
+
+	// Firecracker factory should ignore vhost parameter
+	factory, exists = vmmFactories[FirecrackerVmm]
+	assert.True(t, exists, "firecracker factory should exist")
+
+	vmm = factory.createFunc(FirecrackerBinary, "/usr/bin/firecracker", true)
+	_, ok = vmm.(*Firecracker)
+	assert.True(t, ok, "factory should return *Firecracker")
+}

pkg/unikontainers/types/types.go

@@ -131,4 +131,5 @@ type MonitorConfig struct {
 	DefaultVCPUs    uint   `toml:"default_vcpus"`
 	BinaryPath      string `toml:"path,omitempty"`      // Optional path to the hypervisor binary
 	DataPath        string `toml:"data_path,omitempty"` // Optional path to the hypervisor data files (e.g. qemu bios stuff)
+	Vhost           bool   `toml:"vhost,omitempty"`     // Optional: enable vhost for network performance optimization
 }

pkg/unikontainers/urunc_config.go

@@ -125,6 +125,7 @@ func (p *UruncConfig) Map() map[string]string {
 		cfgMap[prefix+"default_vcpus"] = strconv.FormatUint(uint64(hvCfg.DefaultVCPUs), 10)
 		cfgMap[prefix+"binary_path"] = hvCfg.BinaryPath
 		cfgMap[prefix+"data_path"] = hvCfg.DataPath
+		cfgMap[prefix+"vhost"] = strconv.FormatBool(hvCfg.Vhost)
 	}
 	for eb, ebCfg := range p.ExtraBins {
 		prefix := "urunc_config.extra_binaries." + eb + "."
@@ -171,6 +172,13 @@ func UruncConfigFromMap(cfgMap map[string]string) *UruncConfig {
 			hvCfg.BinaryPath = val
 		case "data_path":
 			hvCfg.DataPath = val
+		case "vhost":
+			boolVal, err := strconv.ParseBool(val)
+			if err != nil {
+				uniklog.Warnf("Invalid vhost value '%s' for monitor '%s': %v. Using default (false).", val, hv, err)
+			} else {
+				hvCfg.Vhost = boolVal
+			}
 		}
 		cfg.Monitors[hv] = hvCfg
 	}

pkg/unikontainers/urunc_config_test.go

@@ -27,6 +27,7 @@ const (
 	testQemuVCPUsKey     = "urunc_config.monitors.qemu.default_vcpus"
 	testQemuBinaryKey    = "urunc_config.monitors.qemu.binary_path"
 	testQemuDataKey      = "urunc_config.monitors.qemu.data_path"
+	testQemuVhostKey     = "urunc_config.monitors.qemu.vhost"
 	testHvtMemoryKey     = "urunc_config.monitors.hvt.default_memory_mb"
 	testVirtiofsdPathKey = "urunc_config.extra_binaries.virtiofsd.path"
 	testVirtiofsdOptsKey = "urunc_config.extra_binaries.virtiofsd.options"
@@ -56,6 +57,7 @@ func TestUruncConfigFromMap(t *testing.T) {
 			testQemuVCPUsKey:  "2",
 			testQemuBinaryKey: testQemuBinaryPath,
 			testQemuDataKey:   testQemuDataPath,
+			testQemuVhostKey:  "true",
 		}
 
 		config := UruncConfigFromMap(cfgMap)
@@ -67,6 +69,7 @@ func TestUruncConfigFromMap(t *testing.T) {
 		assert.Equal(t, uint(2), qemuConfig.DefaultVCPUs)
 		assert.Equal(t, testQemuBinaryPath, qemuConfig.BinaryPath)
 		assert.Equal(t, testQemuDataPath, qemuConfig.DataPath)
+		assert.True(t, qemuConfig.Vhost)
 	})
 
 	t.Run("multiple monitors", func(t *testing.T) {
@@ -323,6 +326,34 @@ func TestUruncConfigFromMap(t *testing.T) {
 		assert.Equal(t, testVirtiofsdDefOpts, vfsConfig.Options)
 	})
 
+	t.Run("vhost false is parsed correctly", func(t *testing.T) {
+		t.Parallel()
+		cfgMap := map[string]string{
+			testQemuMemoryKey: "512",
+			testQemuVhostKey:  "false",
+		}
+
+		config := UruncConfigFromMap(cfgMap)
+
+		assert.NotNil(t, config)
+		qemuConfig := config.Monitors["qemu"]
+		assert.False(t, qemuConfig.Vhost)
+	})
+
+	t.Run("invalid vhost value defaults to false", func(t *testing.T) {
+		t.Parallel()
+		cfgMap := map[string]string{
+			testQemuMemoryKey: "512",
+			testQemuVhostKey:  "invalid",
+		}
+
+		config := UruncConfigFromMap(cfgMap)
+
+		assert.NotNil(t, config)
+		qemuConfig := config.Monitors["qemu"]
+		assert.False(t, qemuConfig.Vhost, "invalid vhost value should default to false")
+	})
+
 }
 
 func TestUruncConfigMap(t *testing.T) {
@@ -415,6 +446,24 @@ func TestUruncConfigMap(t *testing.T) {
 		assert.NotNil(t, cfgMap)
 		assert.Empty(t, cfgMap)
 	})
+
+	t.Run("vhost true is serialized correctly", func(t *testing.T) {
+		t.Parallel()
+		config := &UruncConfig{
+			Monitors: map[string]types.MonitorConfig{
+				"qemu": {
+					DefaultMemoryMB: 512,
+					DefaultVCPUs:    2,
+					Vhost:           true,
+				},
+			},
+			ExtraBins: map[string]types.ExtraBinConfig{},
+		}
+
+		cfgMap := config.Map()
+
+		assert.Equal(t, "true", cfgMap[testQemuVhostKey])
+	})
 }
 
 func TestDefaultConfigs(t *testing.T) {
@@ -449,6 +498,7 @@ func TestDefaultConfigs(t *testing.T) {
 			assert.Equal(t, uint(256), hvConfig.DefaultMemoryMB)
 			assert.Equal(t, uint(1), hvConfig.DefaultVCPUs)
 			assert.Equal(t, "", hvConfig.BinaryPath)
+			assert.False(t, hvConfig.Vhost, "vhost should be false by default")
 		}
 	})