diff --git a/hcsshim.go b/hcsshim.go
index 46dd4dd3aa..ceb3ac85ee 100644
--- a/hcsshim.go
+++ b/hcsshim.go
@@ -9,6 +9,10 @@ import (
 	"github.com/Microsoft/hcsshim/internal/hcserror"
 )
 
+//go:generate go run mksyscall_windows.go -output zsyscall_windows.go hcsshim.go
+
+//sys SetCurrentThreadCompartmentId(compartmentId uint32) (hr error) = iphlpapi.SetCurrentThreadCompartmentId
+
 const (
 	// Specific user-visible exit codes
 	WaitErrExecFailed = 32767
diff --git a/internal/hns/hns.go b/internal/hns/hns.go
index 8957788bca..b2e475f53c 100644
--- a/internal/hns/hns.go
+++ b/internal/hns/hns.go
@@ -4,7 +4,6 @@ import "fmt"
 
 //go:generate go run ../../mksyscall_windows.go -output zsyscall_windows.go hns.go
 
-//sys SetCurrentThreadCompartmentId(compartmentId uint32) (hr error) = iphlpapi.SetCurrentThreadCompartmentId
 //sys _hnsCall(method string, path string, object string, response **uint16) (hr error) = vmcompute.HNSCall?
 
 type EndpointNotFoundError struct {
diff --git a/internal/hns/zsyscall_windows.go b/internal/hns/zsyscall_windows.go
index 71e14982b1..863e3429c7 100644
--- a/internal/hns/zsyscall_windows.go
+++ b/internal/hns/zsyscall_windows.go
@@ -38,21 +38,11 @@ func errnoErr(e syscall.Errno) error {
 }
 
 var (
-	modiphlpapi  = windows.NewLazySystemDLL("iphlpapi.dll")
 	modvmcompute = windows.NewLazySystemDLL("vmcompute.dll")
 
-	procSetCurrentThreadCompartmentId = modiphlpapi.NewProc("SetCurrentThreadCompartmentId")
-	procHNSCall                       = modvmcompute.NewProc("HNSCall")
+	procHNSCall = modvmcompute.NewProc("HNSCall")
 )
 
-func SetCurrentThreadCompartmentId(compartmentId uint32) (hr error) {
-	r0, _, _ := syscall.Syscall(procSetCurrentThreadCompartmentId.Addr(), 1, uintptr(compartmentId), 0, 0)
-	if int32(r0) < 0 {
-		hr = interop.Win32FromHresult(r0)
-	}
-	return
-}
-
 func _hnsCall(method string, path string, object string, response **uint16) (hr error) {
 	var _p0 *uint16
 	_p0, hr = syscall.UTF16PtrFromString(method)
diff --git a/zsyscall_windows.go b/zsyscall_windows.go
new file mode 100644
index 0000000000..cd471295b8
--- /dev/null
+++ b/zsyscall_windows.go
@@ -0,0 +1,52 @@
+// MACHINE GENERATED BY 'go generate' COMMAND; DO NOT EDIT
+
+package hcsshim
+
+import (
+	"syscall"
+	"unsafe"
+
+	"github.com/Microsoft/hcsshim/internal/interop"
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return nil
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modiphlpapi = windows.NewLazySystemDLL("iphlpapi.dll")
+
+	procSetCurrentThreadCompartmentId = modiphlpapi.NewProc("SetCurrentThreadCompartmentId")
+)
+
+func SetCurrentThreadCompartmentId(compartmentId uint32) (hr error) {
+	r0, _, _ := syscall.Syscall(procSetCurrentThreadCompartmentId.Addr(), 1, uintptr(compartmentId), 0, 0)
+	if int32(r0) < 0 {
+		hr = interop.Win32FromHresult(r0)
+	}
+	return
+}