[PATCH v17 20/24] selftests/vm/pkeys: Detect write violation on a mapped access-denied-key page

[Sandipan Das]

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

Detect write-violation on a page to which access-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 | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index cb31a5cdf6d9..8bb4de103874 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1027,6 +1027,18 @@ void test_write_of_access_disabled_region(int *ptr, u16 pkey)
 	*ptr = __LINE__;
 	expected_pkey_fault(pkey);
 }
+
+void test_write_of_access_disabled_region_with_page_already_mapped(int *ptr,
+			u16 pkey)
+{
+	*ptr = __LINE__;
+	dprintf1("disabling access; after accessing the page, "
+		" to PKEY[%02d], doing write\n", pkey);
+	pkey_access_deny(pkey);
+	*ptr = __LINE__;
+	expected_pkey_fault(pkey);
+}
+
 void test_kernel_write_of_access_disabled_region(int *ptr, u16 pkey)
 {
 	int ret;
@@ -1423,6 +1435,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = {
 	test_write_of_write_disabled_region,
 	test_write_of_write_disabled_region_with_page_already_mapped,
 	test_write_of_access_disabled_region,
+	test_write_of_access_disabled_region_with_page_already_mapped,
 	test_kernel_write_of_access_disabled_region,
 	test_kernel_write_of_write_disabled_region,
 	test_kernel_gup_of_access_disabled_region,
-- 
2.17.1