diff --git a/vm/adb/adb.go b/vm/adb/adb.go
index 2fd401084ba7..67336f0081d5 100644
--- a/vm/adb/adb.go
+++ b/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 {
diff --git a/vm/bhyve/bhyve.go b/vm/bhyve/bhyve.go
index 57515ba22171..d00055a32d18 100644
--- a/vm/bhyve/bhyve.go
+++ b/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 {
diff --git a/vm/cuttlefish/cuttlefish.go b/vm/cuttlefish/cuttlefish.go
index 73014cf4e285..dcc825fbf2a2 100644
--- a/vm/cuttlefish/cuttlefish.go
+++ b/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 {
diff --git a/vm/gce/gce.go b/vm/gce/gce.go
index 8de0b56db3c8..e65ee836b81d 100644
--- a/vm/gce/gce.go
+++ b/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 {
diff --git a/vm/gvisor/gvisor.go b/vm/gvisor/gvisor.go
index ca3a8472ca99..4d0a8230002b 100644
--- a/vm/gvisor/gvisor.go
+++ b/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 {
diff --git a/vm/isolated/isolated.go b/vm/isolated/isolated.go
index 99e7ad78a4d4..3b8b8720d6c8 100755
--- a/vm/isolated/isolated.go
+++ b/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 {
diff --git a/vm/proxyapp/init.go b/vm/proxyapp/init.go
index 467187f4689b..0500298e67a8 100644
--- a/vm/proxyapp/init.go
+++ b/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.
diff --git a/vm/qemu/qemu.go b/vm/qemu/qemu.go
index 4d9859c0c973..a8faf54b9c6b 100644
--- a/vm/qemu/qemu.go
+++ b/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 {
diff --git a/vm/starnix/starnix.go b/vm/starnix/starnix.go
index 65c921ee3b0b..f722badcf5bf 100644
--- a/vm/starnix/starnix.go
+++ b/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 {
diff --git a/vm/vm_test.go b/vm/vm_test.go
index 278a4b63d5ba..eb642830fb84 100644
--- a/vm/vm_test.go
+++ b/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 {
diff --git a/vm/vmimpl/vmimpl.go b/vm/vmimpl/vmimpl.go
index ce2a0dfb6ab2..ac38a6634dfa 100644
--- a/vm/vmimpl/vmimpl.go
+++ b/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
 }
 
diff --git a/vm/vmm/vmm.go b/vm/vmm/vmm.go
index 6a6242882b4d..246a87fb1ead 100644
--- a/vm/vmm/vmm.go
+++ b/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 {
diff --git a/vm/vmware/vmware.go b/vm/vmware/vmware.go
index 210a4957a4d1..56a97e0160f2 100644
--- a/vm/vmware/vmware.go
+++ b/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 {