userfaultfd: selftest

This test allocates two virtual areas and bounces the physical memory
across the two virtual areas using only userfaultfd.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Shuah Khan <shuah.kh@samsung.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/vm/run_vmtests

@@ -86,6 +86,17 @@ else
 	echo "[PASS]"
 fi
 
+echo "--------------------"
+echo "running userfaultfd"
+echo "--------------------"
+./userfaultfd 128 32
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+	exitcode=1
+else
+	echo "[PASS]"
+fi
+
 #cleanup
 umount $mnt
 rm -rf $mnt