virtcontainers: introduce hypervisor_darwin

Fixes: #5995

Placeholder skeleton at this point - implementation will be added after
basic build refactoring lands.

Signed-off-by: Eric Ernst <eric_ernst@apple.com>
Signed-off-by: Danny Canter <danny@dcantah.dev>

src/runtime/virtcontainers/hypervisor.go

@@ -49,6 +49,9 @@ const (
 	// DragonballHypervisor is the Dragonball hypervisor.
 	DragonballHypervisor HypervisorType = "dragonball"
 
+	// VirtFrameworkHypervisor is the Darwin Virtualization.framework hypervisor
+	VirtframeworkHypervisor HypervisorType = "virtframework"
+
 	// MockHypervisor is a mock hypervisor for testing purposes
 	MockHypervisor HypervisorType = "mock"
 
@@ -84,6 +87,8 @@ var (
 )
 
 // In some architectures the maximum number of vCPUs depends on the number of physical cores.
+// TODO (dcantah): Find a suitable value for darwin/vfw. Seems perf degrades if > number of host
+// cores.
 var defaultMaxVCPUs = govmm.MaxVCPUs()
 
 // agnostic list of kernel root parameters for NVDIMM
@@ -177,6 +182,9 @@ func (hType *HypervisorType) Set(value string) error {
 	case "dragonball":
 		*hType = DragonballHypervisor
 		return nil
+	case "virtframework":
+		*hType = VirtframeworkHypervisor
+		return nil
 	case "mock":
 		*hType = MockHypervisor
 		return nil

src/runtime/virtcontainers/hypervisor_darwin.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2023 Apple Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package virtcontainers
+
+import (
+	"fmt"
+)
+
+// NewHypervisor returns a hypervisor from a hypervisor type.
+func NewHypervisor(hType HypervisorType) (Hypervisor, error) {
+	switch hType {
+	case VirtframeworkHypervisor:
+		return &virtFramework{}, nil
+	case MockHypervisor:
+		return &mockHypervisor{}, nil
+	default:
+		return nil, fmt.Errorf("Unknown hypervisor type %s", hType)
+	}
+}
+
+func availableGuestProtection() (guestProtection, error) {
+	return noneProtection, nil
+}

src/runtime/virtcontainers/hypervisor_linux.go

@@ -27,7 +27,6 @@ func generateVMSocket(id string, vmStogarePath string) (interface{}, error) {
 
 // NewHypervisor returns an hypervisor from a hypervisor type.
 func NewHypervisor(hType HypervisorType) (Hypervisor, error) {
-
 	switch hType {
 	case QemuHypervisor:
 		return &qemu{}, nil