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

Maxim Levitsky
2024-12-18T00:02:51Z

On Fri, 2024-12-13 at 17:07 -0800, Sean Christopherson wrote:
> 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) {
> /*
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>