[PATCH 4.14 062/159] selftests/x86/ldt_gdt: Run most existing LDT test cases against the GDT as well

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andy Lutomirski <luto@xxxxxxxxxx>

commit adedf2893c192dd09b1cc2f2dcfdd7cad99ec49d upstream.

Now that the main test infrastructure supports the GDT, run tests
that will pass the kernel's GDT permission tests against the GDT.

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/686a1eda63414da38fcecc2412db8dba1ae40581.1509794321.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 tools/testing/selftests/x86/ldt_gdt.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -189,7 +189,15 @@ static bool install_valid_mode(const str
 
 static bool install_valid(const struct user_desc *desc, uint32_t ar)
 {
-	return install_valid_mode(desc, ar, false, true);
+	bool ret = install_valid_mode(desc, ar, false, true);
+
+	if (desc->contents <= 1 && desc->seg_32bit &&
+	    !desc->seg_not_present) {
+		/* Should work in the GDT, too. */
+		install_valid_mode(desc, ar, false, false);
+	}
+
+	return ret;
 }
 
 static void install_invalid(const struct user_desc *desc, bool oldmode)