kmt: only create varstore if needed (#1757)

Co-authored-by: bryce.kahle <bryce.kahle@datadoghq.com>

Author: brycekahle

scenarios/aws/microVMs/microvms/domain.go

@@ -142,7 +142,6 @@ func newDomainConfiguration(e config.Env, set *vmconfig.VMSet, vcpu, memory, gdb
 	efi := filepath.Join(GetWorkingDirectory(set.Arch), "efi.fd")
 
 	// OS-dependent settings
-	var hypervisor string
 	var commandLine pulumi.StringInput = pulumi.String("")
 	var hostOS string
 	if set.Arch == LocalVMSet {
@@ -159,10 +158,8 @@ func newDomainConfiguration(e config.Env, set *vmconfig.VMSet, vcpu, memory, gdb
 
 	var driver string
 	if hostOS == "linux" {
-		hypervisor = "kvm"
 		driver = "<driver name=\"qemu\" type=\"qcow2\" io=\"io_uring\"/>"
 	} else if hostOS == "darwin" {
-		hypervisor = "hvf"
 		// We have to use QEMU network devices because libvirt does not support the macOS
 		// network devices.
 		netID := libvirtResourceName(domainName, "netdev")
@@ -192,7 +189,7 @@ func newDomainConfiguration(e config.Env, set *vmconfig.VMSet, vcpu, memory, gdb
 			resources.Efi:           pulumi.String(efi),
 			resources.VCPU:          pulumi.Sprintf("%d", vcpu),
 			resources.CPUTune:       pulumi.String(cputune),
-			resources.Hypervisor:    pulumi.String(hypervisor),
+			resources.Hypervisor:    pulumi.String(set.Hypervisor()),
 			resources.CommandLine:   commandLine,
 			resources.DiskDriver:    pulumi.String(driver),
 		},

scenarios/aws/microVMs/microvms/libvirt.go

@@ -158,7 +158,7 @@ func (vm *VMCollection) SetupCollectionDomainConfigurations(depends []pulumi.Res
 		}
 
 		// Setup individual Nvram disk for arm64 distro images
-		if resources.GetLocalArchRecipe(set.Recipe) == vmconfig.RecipeDistroARM64 {
+		if set.Hypervisor() != "hvf" && resources.GetLocalArchRecipe(set.Recipe) == vmconfig.RecipeDistroARM64 {
 			for _, domain := range domains {
 				varstorePath := filepath.Join(GetWorkingDirectory(domain.vmset.Arch), fmt.Sprintf("varstore.%s", domain.DomainName))
 				varstoreArgs := command.Args{

scenarios/aws/microVMs/vmconfig/config.go

@@ -1,5 +1,7 @@
 package vmconfig
 
+import "runtime"
+
 type PoolType string
 
 type VMSetID string
@@ -57,6 +59,13 @@ type VMSet struct {
 	VMHost      Host    `json:"host,omitempty"`
 }
 
+func (set VMSet) Hypervisor() string {
+	if set.Arch == "local" && runtime.GOOS == "darwin" {
+		return "hvf"
+	}
+	return "kvm"
+}
+
 type Config struct {
 	Workdir string  `json:"workdir"`
 	VMSets  []VMSet `json:"vmsets"`