BACKPORT: selftests/mm: add UFFDIO_MOVE ioctl test

Add tests for new UFFDIO_MOVE ioctl which uses uffd to move source into
destination buffer while checking the contents of both after the move.
After the operation the content of the destination buffer should match the
original source buffer's content while the source buffer should be zeroed.
Separate tests are designed for PMD aligned and unaligned cases because
they utilize different code paths in the kernel.

Link: https://lkml.kernel.org/r/20231206103702.3873743-6-surenb@google.com


Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

(cherry picked from commit a2bf6a9c)
Conflicts:
	tools/testing/selftests/mm/uffd-common.c
	tools/testing/selftests/mm/uffd-common.h
	tools/testing/selftests/mm/uffd-unit-tests.c
	tools/testing/selftests/vm/userfaultfd.c

1. Removed errmsg parameter from prevent_hugepages() and post_hugepages()
2. Removed uffd_test_args parameter from uffd_move_* functions
3. Added uffd_test_case_ops parameter in uffd_move_test_common()
4. Added userfaultfd_move_test() for all 'move' tests, called from
   userfaultfd_stress()
5. Added 'test_uffdio_move' global bool variable, which is set to true
   only when testing anon mappings
6. Added call to uffd_test_ctx_init() and uffd_test_ctx_clear() in
   uffd_move_test_common()
7. Replaced uffd_args with uffd_stats
8. Converted return type of uffd_move_test() and uffd_move_pmd_test() to
   `int`
9. Added uffd_test_page_fault_handler as uffd_args doesn't exist.
   uffd_poll_thread() checks if it is NULL then calls
   uffd_handle_page_fault().
10. Replaced uffd_register() (isn't defined on 6.1) with UFFDIO_REGISTER
    ioctl call
11. Added printf() calls to log when the test is starting and finishing.
12. Change return type of uffd_move_test_common() to int.

Bug: 274911254
Bug: 339845931
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:f15269151532fdeb5ea43be483a3e97531399f47)
Merged-In: I1c68445d9c64533aab0ba27c2e010347d0807981
Change-Id: I1c68445d9c64533aab0ba27c2e010347d0807981