[PATCH v16 18/23] selftests/vm/pkeys: Associate key on a mapped page and detect write violation

[Sandipan Das]

From: Ram Pai <linuxram at us.ibm.com>

Detect write-violation on a page to which write-disabled
key is associated much after the page is mapped.

cc: Dave Hansen <dave.hansen at intel.com>
cc: Florian Weimer <fweimer at redhat.com>
Signed-off-by: Ram Pai <linuxram at us.ibm.com>
Acked-by: Dave Hansen <dave.hansen at intel.com>
Signed-off-by: Sandipan Das <sandipan at linux.ibm.com>
---
 tools/testing/selftests/vm/protection_keys.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 526ad2fea316..babe3f6310f2 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1001,6 +1001,17 @@ void test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
 	expected_pkey_fault(pkey);
 }
 
+void test_write_of_write_disabled_region_with_page_already_mapped(int *ptr,
+		u16 pkey)
+{
+	*ptr = __LINE__;
+	dprintf1("disabling write access; after accessing the page, "
+		"to PKEY[%02d], doing write\n", pkey);
+	pkey_write_deny(pkey);
+	*ptr = __LINE__;
+	expected_pkey_fault(pkey);
+}
+
 void test_write_of_write_disabled_region(int *ptr, u16 pkey)
 {
 	dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
@@ -1409,6 +1420,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = {
 	test_read_of_access_disabled_region,
 	test_read_of_access_disabled_region_with_page_already_mapped,
 	test_write_of_write_disabled_region,
+	test_write_of_write_disabled_region_with_page_already_mapped,
 	test_write_of_access_disabled_region,
 	test_kernel_write_of_access_disabled_region,
 	test_kernel_write_of_write_disabled_region,
-- 
2.17.1