[PATCH v2 15/20] KVM: sefltests: Verify value of dirty_log_test last page isn't bogus

[Sean Christopherson]

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.

Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 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