[PATCH v6 5/5] KVM: selftests: Don't limit LE dirty-bitmap bitops to s390x

From: Ritesh Harjani (IBM)

Date: Sun Oct 04 2026 - 23:48:44 EST


dirty_log_test already has BITOP_LE_SWIZZLE helpers, but they were
compiled in only for s390x, so every other big-endian host used native
test_bit().

The test fails on big-endian powerpc because it treated dirty host pages
as clean (because of the endianness issue)

w/o the fix the test fails with:
Clear page 1 value (1) >= iteration (1)

Tested-by: Anushree Mathur <anushree.mathur@xxxxxxxxxxxxx>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile.kvm | 1 +
tools/testing/selftests/kvm/dirty_log_test.c | 12 ++++--------
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 57d1bf994fe8..38c350c5b5e3 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -264,6 +264,7 @@ TEST_GEN_PROGS_powerpc += set_memory_region_test
TEST_GEN_PROGS_powerpc += memslot_modification_stress_test
TEST_GEN_PROGS_powerpc += memslot_perf_test
TEST_GEN_PROGS_powerpc += access_tracking_perf_test
+TEST_GEN_PROGS_powerpc += dirty_log_test

SPLIT_TESTS += arch_timer
SPLIT_TESTS += get-reg-list
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index af5eb0334a74..8189eaac713c 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -44,8 +44,11 @@
#define TEST_MIN_WRITES_PER_ITERATION 0x100

/* Dirty bitmaps are always little endian, so we need to swap on big endian */
-#if defined(__s390x__)
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
# define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
+#else
+# define BITOP_LE_SWIZZLE 0
+#endif
# define test_bit_le(nr, addr) \
test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define __set_bit_le(nr, addr) \
@@ -56,13 +59,6 @@
__test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define __test_and_clear_bit_le(nr, addr) \
__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
-#else
-# define test_bit_le test_bit
-# define __set_bit_le __set_bit
-# define __clear_bit_le __clear_bit
-# define __test_and_set_bit_le __test_and_set_bit
-# define __test_and_clear_bit_le __test_and_clear_bit
-#endif

#define TEST_DIRTY_RING_COUNT 65536

--
2.39.5