From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55995) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bJxqm-0000yh-Fo for qemu-devel@nongnu.org; Mon, 04 Jul 2016 02:59:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bJxqi-0005OQ-EF for qemu-devel@nongnu.org; Mon, 04 Jul 2016 02:59:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46957) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bJxqi-0005OM-5M for qemu-devel@nongnu.org; Mon, 04 Jul 2016 02:59:20 -0400 References: <1467300702-97031-1-git-send-email-cornelia.huck@de.ibm.com> From: Jason Wang Message-ID: <577A0941.7010200@redhat.com> Date: Mon, 4 Jul 2016 14:59:13 +0800 MIME-Version: 1.0 In-Reply-To: <1467300702-97031-1-git-send-email-cornelia.huck@de.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] virtio: revert host notifiers to old semantics List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck , qemu-devel@nongnu.org Cc: famz@redhat.com, mst@redhat.com, pl@kamp.de, marcandre.lureau@gmail.com, stefanha@redhat.com, pbonzini@redhat.com On 2016=E5=B9=B406=E6=9C=8830=E6=97=A5 23:31, Cornelia Huck 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 > Reported-by: Jason Wang > Reported-by: Marc-Andr=C3=A9 Lureau > Signed-off-by: Cornelia Huck > --- > 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 =3D VIRTIO_BUS_GET_CLASS(bus); > DeviceState *proxy =3D DEVICE(BUS(bus)->parent); > - VirtIODevice *vdev =3D virtio_bus_get_device(bus); > - VirtQueue *vq =3D virtio_get_queue(vdev, n); > =20 > if (!k->ioeventfd_started) { > return -ENOSYS; > } > + k->ioeventfd_set_disabled(proxy, assign); > if (assign) { > /* > * Stop using the generic ioeventfd, we are doing eventfd han= dling > * ourselves below > + * > + * FIXME: We should just switch the handler and not deassign t= he > + * 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); > } > =20 > static char *virtio_bus_get_dev_path(DeviceState *dev) Reviewed-by: Jason Wang Tested-by: Jason Wang