Refactor code in hypervisor.go

Signed-off-by: Pramodh Pallapothu <[email protected]>

pkg/pillar/hypervisor/hypervisor.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/lf-edge/eve/pkg/pillar/base"
 	"github.com/lf-edge/eve/pkg/pillar/types"
+	fileutils "github.com/lf-edge/eve/pkg/pillar/utils/file"
 	uuid "github.com/satori/go.uuid"
 	"github.com/shirou/gopsutil/cpu"
 	"github.com/shirou/gopsutil/mem"
@@ -38,17 +39,17 @@ type Hypervisor interface {
 
 type hypervisorDesc struct {
 	constructor       func() Hypervisor
-	dom0handle        string
+	enabled           func() bool
 	hvTypeFileContent string
 }
 
 var knownHypervisors = map[string]hypervisorDesc{
-	XenHypervisorName:        {constructor: newXen, dom0handle: "/proc/xen", hvTypeFileContent: "xen"},
-	KVMHypervisorName:        {constructor: newKvm, dom0handle: "/dev/kvm", hvTypeFileContent: "kvm"},
-	KubevirtHypervisorName:   {constructor: newKubevirt, dom0handle: "/dev/kvm", hvTypeFileContent: "kubevirt"},
-	ACRNHypervisorName:       {constructor: newAcrn, dom0handle: "/dev/acrn", hvTypeFileContent: "acrn"},
-	ContainerdHypervisorName: {constructor: newContainerd, dom0handle: "/run/containerd/containerd.sock"},
-	NullHypervisorName:       {constructor: newNull, dom0handle: "/"},
+	XenHypervisorName:        {constructor: newXen, enabled: func() bool { return fileutils.FileExists(nil, "/proc/xen") }, hvTypeFileContent: "xen"},
+	KVMHypervisorName:        {constructor: newKvm, enabled: func() bool { return fileutils.FileExists(nil, "/dev/kvm") && !base.IsHVTypeKube() }, hvTypeFileContent: "kvm"},
+	KubevirtHypervisorName:   {constructor: newKubevirt, enabled: func() bool { return fileutils.FileExists(nil, "/dev/kvm") && base.IsHVTypeKube() }, hvTypeFileContent: "kubevirt"},
+	ACRNHypervisorName:       {constructor: newAcrn, enabled: func() bool { return fileutils.FileExists(nil, "/dev/acrn") }, hvTypeFileContent: "acrn"},
+	ContainerdHypervisorName: {constructor: newContainerd, enabled: func() bool { return fileutils.FileExists(nil, "/run/containerd/containerd.sock") }},
+	NullHypervisorName:       {constructor: newNull, enabled: func() bool { return fileutils.DirExists(nil, "/") }},
 }
 
 // this is a priority order to pick a default hypervisor if multiple are available (more to less likely)
@@ -96,18 +97,9 @@ func BootTimeHypervisor() Hypervisor {
 // the advice of this function and always ask for the enabled one.
 func GetAvailableHypervisors() (all []string, enabled []string) {
 	all = hypervisorPriority
-	isHVTypeKube := base.IsHVTypeKube()
 	for _, v := range all {
-		if _, err := os.Stat(knownHypervisors[v].dom0handle); err == nil {
-			// Both Kubevirt and KVM use same dom0handle.
-			// Lets differentiate by eve_flavor
-			if isHVTypeKube && strings.Compare(v, KVMHypervisorName) == 0 {
-				continue // kubevirt image don't set kvm
-			} else if !isHVTypeKube && strings.Compare(v, KubevirtHypervisorName) == 0 {
-				continue // kvm image don't set kubevirt
-			} else {
-				enabled = append(enabled, v)
-			}
+		if knownHypervisors[v].enabled() {
+			enabled = append(enabled, v)
 		}
 	}
 	return