On Mon, 10 Oct 2016 13:53:40 +0200
Paolo Bonzini <pbonz...@redhat.com> wrote:
> Of the three possible parameter combinations for
> virtio_queue_set_host_notifier_fd_handler:
>
> - assign=true/set_handler=true is only called from
> virtio_device_start_ioeventfd
>
> - assign=false/set_handler=false is called from
> set_host_notifier_internal but it only does something when
> reached from virtio_device_stop_ioeventfd_impl; otherwise
> there is no EventNotifier set on qemu_get_aio_context().
>
> - assign=true/set_handler=false is called from
> set_host_notifier_internal, but it is not doing anything:
> with the new start_ioeventfd and stop_ioeventfd methods,
> there is never an EventNotifier set on qemu_get_aio_context()
> at this point. This is enforced by the assertion in
> virtio_bus_set_host_notifier.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> hw/virtio/virtio-bus.c | 19 +++++++++++--------
> hw/virtio/virtio.c | 27 +++++++++------------------
> include/hw/virtio/virtio.h | 3 +--
> 3 files changed, 21 insertions(+), 28 deletions(-)
>
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index d6feaaf..96b7e76 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -163,19 +163,22 @@ static int set_host_notifier_internal(DeviceState
> *proxy, VirtioBusState *bus,
> __func__, strerror(-r), r);
> return r;
> }
> - virtio_queue_set_host_notifier_fd_handler(vq, true, false);
> - r = k->ioeventfd_assign(proxy, notifier, n, assign);
> + r = k->ioeventfd_assign(proxy, notifier, n, true);
> if (r < 0) {
> error_report("%s: unable to assign ioeventfd: %d", __func__, r);
> - virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> - event_notifier_cleanup(notifier);
> - return r;
> + goto cleanup_event_notifier;
> }
> + return 0;
> } else {
> - k->ioeventfd_assign(proxy, notifier, n, assign);
> - virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> - event_notifier_cleanup(notifier);
> + k->ioeventfd_assign(proxy, notifier, n, false);
> }
> +
> +cleanup_event_notifier:
> + /* Test and clear notifier before after disabling event,
Now is the time to get rid of "before after" :)
> + * in case poll callback didn't have time to run.
> + */
> + virtio_queue_host_notifier_read(notifier);
> + event_notifier_cleanup(notifier);
> return r;
> }
Reviewed-by: Cornelia Huck <cornelia.h...@de.ibm.com>
