[PATCH 15/20] KVM: sefltests: Verify value of dirty_log_test last page isn't bogus

Sean Christopherson
2024-12-14T01:07:50Z

Add a sanity check that a completely garbage value wasn't written to
the last dirty page in the ring, e.g. that it doesn't contain the *next*
iteration's value.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/testing/selftests/kvm/dirty_log_test.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 3a4e411353d7..500257b712e3 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -514,8 +514,9 @@ static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long **bmap)
* last page's iteration), as the value to be
* written may be cached in a CPU register.
*/
- if (page == dirty_ring_last_page ||
- page == dirty_ring_prev_iteration_last_page)
+ if ((page == dirty_ring_last_page ||
+ page == dirty_ring_prev_iteration_last_page) &&
+ val < iteration)
continue;
} else if (!val && iteration == 1 && bmap0_dirty) {
/*
--
2.47.1.613.gc27f4b7a9f-goog