--- old/test/hotspot/jtreg/TEST.ROOT	2020-06-03 14:12:28.000000000 -0700
+++ new/test/hotspot/jtreg/TEST.ROOT	2020-06-03 14:12:28.000000000 -0700
@@ -68,7 +68,8 @@
     vm.compiler1.enabled \
     vm.compiler2.enabled \
     docker.support \
-    test.vm.gc.nvdimm
+    test.vm.gc.nvdimm \
+    vm.flagless
 
 # Minimum jtreg version
 requiredVersion=5.1 b1
--- old/test/hotspot/jtreg/applications/scimark/Scimark.java	2020-06-03 14:12:30.000000000 -0700
+++ new/test/hotspot/jtreg/applications/scimark/Scimark.java	2020-06-03 14:12:30.000000000 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,6 +24,7 @@
 /*
  * @test
  * @library /test/lib
+ * @requires vm.flagless
  * @run driver Scimark
  */
 
--- old/test/hotspot/jtreg/gtest/GTestWrapper.java	2020-06-03 14:12:31.000000000 -0700
+++ new/test/hotspot/jtreg/gtest/GTestWrapper.java	2020-06-03 14:12:31.000000000 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,6 +26,7 @@
  * @library /test/lib
  * @modules java.base/jdk.internal.misc
  *          java.xml
+ * @requires vm.flagless
  * @run main/native GTestWrapper
  */
 
--- old/test/hotspot/jtreg/testlibrary_tests/process/TestNativeProcessBuilder.java	2020-06-03 14:12:33.000000000 -0700
+++ new/test/hotspot/jtreg/testlibrary_tests/process/TestNativeProcessBuilder.java	2020-06-03 14:12:33.000000000 -0700
@@ -25,6 +25,7 @@
  * @test
  * @summary Test the native process builder API.
  * @library /test/lib
+ * @requires vm.flagless
  * @build Test
  * @run main/native TestNativeProcessBuilder
  */
--- old/test/jtreg-ext/requires/VMProps.java	2020-06-03 14:12:34.000000000 -0700
+++ new/test/jtreg-ext/requires/VMProps.java	2020-06-03 14:12:34.000000000 -0700
@@ -31,10 +31,12 @@
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
+import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
@@ -115,6 +117,7 @@
         map.put("docker.support", this::dockerSupport);
         map.put("release.implementor", this::implementor);
         map.put("test.vm.gc.nvdimm", this::isNvdimmTestEnabled);
+        map.put("vm.flagless", this::isFlagless);
         vmGC(map); // vm.gc.X = true/false
         vmOptFinalFlags(map);
 
@@ -437,7 +440,7 @@
         return "" + Compiler.isC2Enabled();
     }
 
-   /**
+    /**
      * A simple check for docker support
      *
      * @return true if docker is supported in a given environment
@@ -502,6 +505,65 @@
     }
 
     /**
+     * Checks if we are in <i>almost</i> out-of-box configuration, i.e. the flags
+     * which JVM is started with don't affect its behavior "significantly".
+     * {@code TEST_VM_FLAGLESS} enviroment variable can be used to force this
+     * method to return true and allow any flags.
+     *
+     * @return true if there are no JVM flags
+     */
+    private String isFlagless() {
+        boolean result = true;
+        if (System.getenv("TEST_VM_FLAGLESS") != null) {
+            return "" + result;
+        }
+
+        List<String> allFlags = new ArrayList<String>();
+        Collections.addAll(allFlags, System.getProperty("test.vm.opts", "").trim().split("\\s+"));
+        Collections.addAll(allFlags, System.getProperty("test.java.opts", "").trim().split("\\s+"));
+
+        // check -XX flags
+        var ignoredXXFlags = Set.of(
+                // added by run-test framework
+                "MaxRAMPercentage",
+                // added by test environment
+                "CreateCoredumpOnCrash"
+        );
+        result &= allFlags.stream()
+                          .filter(s -> s.startsWith("-XX:"))
+                          // map to names:
+                              // remove -XX:
+                              .map(s -> s.substring(4))
+                              // remove +/- from bool flags
+                              .map(s -> s.charAt(0) == '+' || s.charAt(0) == '-' ? s.substring(1) : s)
+                              // remove =.* from others
+                              .map(s -> s.contains("=") ? s.substring(0, s.indexOf('=')) : s)
+                          // skip known-to-be-there flags
+                          .filter(s -> !ignoredXXFlags.contains(s))
+                          .findAny()
+                          .isEmpty();
+
+        // check -X flags
+        var ignoredXFlags = Set.of(
+                // default, yet still seen to be explicitly set
+                "mixed"
+        );
+        result &= allFlags.stream()
+                          .filter(s -> s.startsWith("-X") && !s.startsWith("-XX:"))
+                          // map to names:
+                              // remove -X
+                              .map(s -> s.substring(2))
+                              // remove :.* from flags with values
+                              .map(s -> s.contains(":") ? s.substring(0, s.indexOf(':')) : s)
+                          // skip known-to-be-there flags
+                          .filter(s -> !ignoredXFlags.contains(s))
+                          .findAny()
+                          .isEmpty();
+
+        return "" + result;
+    }
+
+    /**
      * Dumps the map to the file if the file name is given as the property.
      * This functionality could be helpful to know context in the real
      * execution.