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

cc: Dave Hansen <dave.han...@intel.com>
cc: Florian Weimer <fwei...@redhat.com>
Signed-off-by: Ram Pai <linux...@us.ibm.com>
Acked-by: Dave Hansen <dave.han...@intel.com>
---
 tools/testing/selftests/vm/protection_keys.c |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/tools/testing/selftests/vm/protection_keys.c 
b/tools/testing/selftests/vm/protection_keys.c
index e8ad970..04d0249 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1024,6 +1024,24 @@ void test_read_of_access_disabled_region(int *ptr, u16 
pkey)
        dprintf1("*ptr: %d\n", ptr_contents);
        expected_pkey_fault(pkey);
 }
+
+void test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
+               u16 pkey)
+{
+       int ptr_contents;
+
+       dprintf1("disabling access to PKEY[%02d], doing read @ %p\n",
+                               pkey, ptr);
+       ptr_contents = read_ptr(ptr);
+       dprintf1("reading ptr before disabling the read : %d\n",
+                       ptr_contents);
+       read_pkey_reg();
+       pkey_access_deny(pkey);
+       ptr_contents = read_ptr(ptr);
+       dprintf1("*ptr: %d\n", ptr_contents);
+       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);
@@ -1402,6 +1420,7 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 
pkey)
 void (*pkey_tests[])(int *ptr, u16 pkey) = {
        test_read_of_write_disabled_region,
        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_access_disabled_region,
        test_kernel_write_of_access_disabled_region,
-- 
1.7.1

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