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Re: [Qemu-devel] [PATCH] virtio: revert host notifiers to old semantics
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH] virtio: revert host notifiers to old semantics |
Date: |
Fri, 1 Jul 2016 10:42:56 +0200 |
Hi
On Thu, Jun 30, 2016 at 5:31 PM, Cornelia Huck <address@hidden> wrote:
> The host notifier rework tried both to unify host notifiers across
> transports and plug a possible hole during host notifier
> re-assignment. Unfortunately, this meant a change in semantics that
> breaks vhost and iSCSI+dataplane.
>
> As the minimal fix, keep the common host notifier code but revert
> to the old semantics so that we have time to figure out the proper
> fix.
>
> Fixes: 6798e245a3 ("virtio-bus: common ioeventfd infrastructure")
> Reported-by: Peter Lieven <address@hidden>
> Reported-by: Jason Wang <address@hidden>
> Reported-by: Marc-André Lureau <address@hidden>
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
> hw/virtio/virtio-bus.c | 26 ++++++++++----------------
> 1 file changed, 10 insertions(+), 16 deletions(-)
>
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index 1313760..a85b7c8 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -176,8 +176,8 @@ static int set_host_notifier_internal(DeviceState *proxy,
> VirtioBusState *bus,
> return r;
> }
> } else {
> - virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> k->ioeventfd_assign(proxy, notifier, n, assign);
> + virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> event_notifier_cleanup(notifier);
> }
> return r;
> @@ -251,31 +251,25 @@ int virtio_bus_set_host_notifier(VirtioBusState *bus,
> int n, bool assign)
> {
> VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
> DeviceState *proxy = DEVICE(BUS(bus)->parent);
> - VirtIODevice *vdev = virtio_bus_get_device(bus);
> - VirtQueue *vq = virtio_get_queue(vdev, n);
>
> if (!k->ioeventfd_started) {
> return -ENOSYS;
> }
> + k->ioeventfd_set_disabled(proxy, assign);
> if (assign) {
> /*
> * Stop using the generic ioeventfd, we are doing eventfd handling
> * ourselves below
> + *
> + * FIXME: We should just switch the handler and not deassign the
> + * ioeventfd.
> + * Otherwise, there's a window where we don't have an
> + * ioeventfd and we may end up with a notification where
> + * we don't expect one.
> */
> - k->ioeventfd_set_disabled(proxy, true);
> - }
> - /*
> - * Just switch the handler, don't deassign the ioeventfd.
> - * Otherwise, there's a window where we don't have an
> - * ioeventfd and we may end up with a notification where
> - * we don't expect one.
> - */
> - virtio_queue_set_host_notifier_fd_handler(vq, assign, !assign);
> - if (!assign) {
> - /* Use generic ioeventfd handler again. */
> - k->ioeventfd_set_disabled(proxy, false);
> + virtio_bus_stop_ioeventfd(bus);
> }
> - return 0;
> + return set_host_notifier_internal(proxy, bus, n, assign, false);
> }
>
> static char *virtio_bus_get_dev_path(DeviceState *dev)
> --
> 2.6.6
>
Tested-by: Marc-André Lureau <address@hidden>
thanks
--
Marc-André Lureau
- Re: [Qemu-devel] [PATCH] virtio: revert host notifiers to old semantics,
Marc-André Lureau <=