go-sev-guest client modification to work around throttling without sev-guest device patches

client.go.patch

@@ func UseDefaultSevGuest() bool {
 }
 
 func message(d Device, command uintptr, req *labi.SnpUserGuestRequest) error {
-	result, err := d.Ioctl(command, req)
-	if err != nil {
-		// The ioctl could have failed with a firmware error that
-		// indicates a problem certificate length. We need to
-		// communicate that specifically.
-		if req.FwErr != 0 {
-			return &abi.SevFirmwareErr{Status: abi.SevFirmwareStatus(req.FwErr)}
+	for {
+		result, err := d.Ioctl(command, req)
+		if err != nil {
+			// The ioctl could have failed with a firmware error that
+			// indicates a problem certificate length. We need to
+			// communicate that specifically.
+			if req.FwErr != 0 {
+				if req.FwErr == uint64(abi.GuestRequestThrottled) {
+					continue
+				}
+				return &abi.SevFirmwareErr{Status: abi.SevFirmwareStatus(req.FwErr)}
+			}
+			return err
 		}
-		return err
-	}
-	if result != uintptr(labi.EsOk) {
-		return &labi.SevEsErr{Result: labi.EsResult(result)}
+
+		if result != uintptr(labi.EsOk) {
+			return &labi.SevEsErr{Result: labi.EsResult(result)}
+		}
+		return nil
 	}
-	return nil
 }