linux-kernel - [PATCH 23/23] userfaultfd/selftests: Enable uffd-wp for shmem/hugetlbfs

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Date:   Mon, 22 Mar 2021 20:50:59 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Jerome Glisse <jglisse@...hat.com>,
        Hugh Dickins <hughd@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Axel Rasmussen <axelrasmussen@...gle.com>, peterx@...hat.com,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Matthew Wilcox <willy@...radead.org>
Subject: [PATCH 23/23] userfaultfd/selftests: Enable uffd-wp for shmem/hugetlbfs

After we added support for shmem and hugetlbfs, we can turn uffd-wp test on
always now.

Define HUGETLB_EXPECTED_IOCTLS to avoid using UFFD_API_RANGE_IOCTLS_BASIC,
because UFFD_API_RANGE_IOCTLS_BASIC is normally a superset of capabilities,
while the test may not satisfy them all.  E.g., when hugetlb registered without
minor mode, then we need to explicitly remove _UFFDIO_CONTINUE.  Same thing to
uffd-wp, as we'll need to explicitly remove _UFFDIO_WRITEPROTECT if not
registered with uffd-wp.

For the long term, we may consider dropping UFFD_API_* macros completely from
uapi/linux/userfaultfd.h header files, because it may cause kernel header
update to easily break userspace.

Signed-off-by: Peter Xu <peterx@...hat.com>
---
 tools/testing/selftests/vm/userfaultfd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 1f5f9362ec7b..5fa9a506ded5 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -80,7 +80,7 @@ static int test_type;
 static volatile bool test_uffdio_copy_eexist = true;
 static volatile bool test_uffdio_zeropage_eexist = true;
 /* Whether to test uffd write-protection */
-static bool test_uffdio_wp = false;
+static bool test_uffdio_wp = true;
 
 static bool map_shared;
 static int shm_fd;
@@ -319,6 +319,9 @@ struct uffd_test_ops {
 					 (1 << _UFFDIO_ZEROPAGE) | \
 					 (1 << _UFFDIO_WRITEPROTECT))
 
+#define HUGETLB_EXPECTED_IOCTLS		((1 << _UFFDIO_WAKE) |	\
+					 (1 << _UFFDIO_COPY))
+
 static struct uffd_test_ops anon_uffd_test_ops = {
 	.expected_ioctls = ANON_EXPECTED_IOCTLS,
 	.allocate_area	= anon_allocate_area,
@@ -334,7 +337,7 @@ static struct uffd_test_ops shmem_uffd_test_ops = {
 };
 
 static struct uffd_test_ops hugetlb_uffd_test_ops = {
-	.expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC & ~(1 << _UFFDIO_CONTINUE),
+	.expected_ioctls = HUGETLB_EXPECTED_IOCTLS,
 	.allocate_area	= hugetlb_allocate_area,
 	.release_pages	= hugetlb_release_pages,
 	.alias_mapping = hugetlb_alias_mapping,
@@ -1433,8 +1436,6 @@ static void set_test_type(const char *type)
 	if (!strcmp(type, "anon")) {
 		test_type = TEST_ANON;
 		uffd_test_ops = &anon_uffd_test_ops;
-		/* Only enable write-protect test for anonymous test */
-		test_uffdio_wp = true;
 	} else if (!strcmp(type, "hugetlb")) {
 		test_type = TEST_HUGETLB;
 		uffd_test_ops = &hugetlb_uffd_test_ops;
-- 
2.26.2