| Message ID | 20241214010721.2356923-18-seanjc@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [01/20] KVM: selftests: Support multiple write retires in dirty_log_test | expand |
On Fri, 2024-12-13 at 17:07 -0800, Sean Christopherson wrote: > Now that each iteration collects all dirty entries and ensures the guest > *completes* at least one write, tighten the exemptions for the last dirty > page of the previous iteration. Specifically, the only legal value (other > than the current iteration) is N-1. > > Unlike the last page for the current iteration, the in-progress write from > the previous iteration is guaranteed to have completed, otherwise the test > would have hung. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > tools/testing/selftests/kvm/dirty_log_test.c | 22 +++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c > index 8eb51597f762..18d41537e737 100644 > --- a/tools/testing/selftests/kvm/dirty_log_test.c > +++ b/tools/testing/selftests/kvm/dirty_log_test.c > @@ -517,14 +517,22 @@ static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long **bmap) > > if (host_log_mode == LOG_MODE_DIRTY_RING) { > /* > - * The last page in the ring from this iteration > - * or the previous can be written with the value > - * from the previous iteration (relative to the > - * last page's iteration), as the value to be > - * written may be cached in a CPU register. > + * The last page in the ring from previous > + * iteration can be written with the value > + * from the previous 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_prev_iteration_last_page && > + val == iteration - 1) > + continue; > + > + /* > + * Any value from a previous iteration is legal > + * for the last entry, as the write may not yet > + * have retired, i.e. the page may hold whatever > + * it had before this iteration started. > + */ > + if (page == dirty_ring_last_page && > val < iteration) > continue; > } else if (!val && iteration == 1 && bmap0_dirty) { Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c index 8eb51597f762..18d41537e737 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -517,14 +517,22 @@ static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long **bmap) if (host_log_mode == LOG_MODE_DIRTY_RING) { /* - * The last page in the ring from this iteration - * or the previous can be written with the value - * from the previous iteration (relative to the - * last page's iteration), as the value to be - * written may be cached in a CPU register. + * The last page in the ring from previous + * iteration can be written with the value + * from the previous 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_prev_iteration_last_page && + val == iteration - 1) + continue; + + /* + * Any value from a previous iteration is legal + * for the last entry, as the write may not yet + * have retired, i.e. the page may hold whatever + * it had before this iteration started. + */ + if (page == dirty_ring_last_page && val < iteration) continue; } else if (!val && iteration == 1 && bmap0_dirty) {
Now that each iteration collects all dirty entries and ensures the guest *completes* at least one write, tighten the exemptions for the last dirty page of the previous iteration. Specifically, the only legal value (other than the current iteration) is N-1. Unlike the last page for the current iteration, the in-progress write from the previous iteration is guaranteed to have completed, otherwise the test would have hung. Signed-off-by: Sean Christopherson <seanjc@google.com> --- tools/testing/selftests/kvm/dirty_log_test.c | 22 +++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)