From: Jeff Xu jeffxu@chromium.org
This change creates the initial version of memorysealing.c.
The introduction of memorysealing.c, which replaces mseal_test.c and uses the kselftest_harness, aims to initiate a discussion on using the selftest harness for memory sealing tests. Upon approval of this approach, the migration of tests from mseal_test.c to memorysealing.c can be implemented in a step-by-step manner.
This tests addresses following feedbacks from previous reviews:
1> Use kselftest_harness instead of custom macro, such as EXPECT_XX, ASSERT_XX, etc. (Lorenzo Stoakes, Mark Brown, etc) [1]
2> Use MAP_FAILED to check the return of mmap (Lorenzo Stoakes).
3> Adding a check for vma size and prot bits. The discussion for this can be found in [2] [3], here is a brief summary: This is to follow up on Pedro’s in-loop change (from can_modify_mm to can_modify_vma). When mseal_test is initially created, they have a common pattern: setup memory layout, seal the memory, perform a few mm-api steps, verify return code (not zero). Because of the nature of out-of-loop, it is sufficient to just verify the error code in a few cases.
With Pedro's in-loop change, the sealing check happens later in the stack, thus there are more things and scenarios to verify. And there were feedbacks to me that mseal_test should be extensive enough to discover all regressions. Hence I'm adding check for vma size and prot bits.
In this change: we created two fixtures:
Fixture basic: This creates a single VMA, the VMA has a PROT_NONE page at each end to prevent auto-merging.
Fixture wo_vma: Two VMAs back to end, a PROT_NONE page at each end to prevent auto-merging.
In addition, I add one test (mprotec) in each fixture for discussion.
[1] https://lore.kernel.org/all/20240830180237.1220027-5-jeffxu@chromium.org/ [2] https://lore.kernel.org/all/CABi2SkUgDZtJtRJe+J9UNdtZn=EQzZcbMB685P=1rR7DUhg... [3] https://lore.kernel.org/all/2qywbjb5ebtgwkh354w3lj3vhaothvubjokxq5fhyri5jeet...
Jeff Xu (1): selftest/mm: refactor mseal_test
tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/memorysealing.c | 182 +++++++++++++++++++++ tools/testing/selftests/mm/memorysealing.h | 116 +++++++++++++ tools/testing/selftests/mm/mseal_test.c | 67 +------- 5 files changed, 301 insertions(+), 66 deletions(-) create mode 100644 tools/testing/selftests/mm/memorysealing.c create mode 100644 tools/testing/selftests/mm/memorysealing.h