vmimpl: refactor VM type registration

Pass Type struct directly during registration.
This allows to add additional optional parameters to VM types
without changing all VM implementations.
We we will need to add SupportsSnapshots flag and one flag to resolve #5028.
With this change it will be possible to add "SupportsSnapshots: true"
to just one VM type implemenetation.

vm/adb/adb.go

@@ -27,7 +27,9 @@ import (
 )
 
 func init() {
-	vmimpl.Register("adb", ctor, false)
+	vmimpl.Register("adb", vmimpl.Type{
+		Ctor: ctor,
+	})
 }
 
 type Device struct {

vm/bhyve/bhyve.go

@@ -21,7 +21,10 @@ import (
 )
 
 func init() {
-	vmimpl.Register("bhyve", ctor, true)
+	vmimpl.Register("bhyve", vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/cuttlefish/cuttlefish.go

@@ -28,7 +28,10 @@ const (
 )
 
 func init() {
-	vmimpl.Register("cuttlefish", ctor, true)
+	vmimpl.Register("cuttlefish", vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Pool struct {

vm/gce/gce.go

@@ -35,7 +35,10 @@ import (
 )
 
 func init() {
-	vmimpl.Register("gce", ctor, true)
+	vmimpl.Register("gce", vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/gvisor/gvisor.go

@@ -26,7 +26,10 @@ import (
 )
 
 func init() {
-	vmimpl.Register(targets.GVisor, ctor, true)
+	vmimpl.Register(targets.GVisor, vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/isolated/isolated.go

@@ -24,7 +24,9 @@ import (
 const pstoreConsoleFile = "/sys/fs/pstore/console-ramoops-0"
 
 func init() {
-	vmimpl.Register("isolated", ctor, false)
+	vmimpl.Register("isolated", vmimpl.Type{
+		Ctor: ctor,
+	})
 }
 
 type Config struct {

vm/proxyapp/init.go

@@ -27,12 +27,11 @@ func makeDefaultParams() *proxyAppParams {
 }
 
 func init() {
-	vmimpl.Register(
-		"proxyapp",
-		func(env *vmimpl.Env) (vmimpl.Pool, error) {
+	vmimpl.Register("proxyapp", vmimpl.Type{
+		Ctor: func(env *vmimpl.Env) (vmimpl.Pool, error) {
 			return ctor(makeDefaultParams(), env)
 		},
-		false)
+	})
 }
 
 // Package configuration VARs are mostly needed for tests.

vm/qemu/qemu.go

@@ -27,7 +27,10 @@ import (
 
 func init() {
 	var _ vmimpl.Infoer = (*instance)(nil)
-	vmimpl.Register("qemu", ctor, true)
+	vmimpl.Register("qemu", vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/starnix/starnix.go

@@ -25,7 +25,10 @@ import (
 
 func init() {
 	var _ vmimpl.Infoer = (*instance)(nil)
-	vmimpl.Register(targets.Starnix, ctor, true)
+	vmimpl.Register(targets.Starnix, vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/vm_test.go

@@ -81,7 +81,9 @@ func init() {
 	ctor := func(env *vmimpl.Env) (vmimpl.Pool, error) {
 		return &testPool{}, nil
 	}
-	vmimpl.Register("test", ctor, false)
+	vmimpl.Register("test", vmimpl.Type{
+		Ctor: ctor,
+	})
 }
 
 type Test struct {

vm/vmimpl/vmimpl.go

@@ -124,15 +124,14 @@ func (err InfraError) InfraError() (string, []byte) {
 }
 
 // Register registers a new VM type within the package.
-func Register(typ string, ctor ctorFunc, allowsOvercommit bool) {
-	Types[typ] = Type{
-		Ctor:       ctor,
-		Overcommit: allowsOvercommit,
-	}
+func Register(typ string, desc Type) {
+	Types[typ] = desc
 }
 
 type Type struct {
-	Ctor       ctorFunc
+	Ctor ctorFunc
+	// It's possible to create out-of-thin-air instances of this type.
+	// Out-of-thin-air instances are used by syz-ci for image testing, patch testing, bisection, etc.
 	Overcommit bool
 }
 

vm/vmm/vmm.go

@@ -25,7 +25,10 @@ import (
 var vmctlStatusRegex = regexp.MustCompile(`^\s+([0-9]+)\b.*\brunning`)
 
 func init() {
-	vmimpl.Register("vmm", ctor, true)
+	vmimpl.Register("vmm", vmimpl.Type{
+		Ctor:       ctor,
+		Overcommit: true,
+	})
 }
 
 type Config struct {

vm/vmware/vmware.go

@@ -23,7 +23,9 @@ import (
 )
 
 func init() {
-	vmimpl.Register("vmware", ctor, false)
+	vmimpl.Register("vmware", vmimpl.Type{
+		Ctor: ctor,
+	})
 }
 
 type Config struct {