Thanks Stefan for the quick fix! Sorry for not adding a Tested-by. It's implicit. :)
F. > On Nov 6, 2019, at 11:33 AM, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Tue, Nov 05, 2019 at 03:09:46PM +0100, Stefan Hajnoczi wrote: >> Host notifiers are used in several cases: >> 1. Traditional ioeventfd where virtqueue notifications are handled in >> the main loop thread. >> 2. IOThreads (aio_handle_output) where virtqueue notifications are >> handled in an IOThread AioContext. >> 3. vhost where virtqueue notifications are handled by kernel vhost or >> a vhost-user device backend. >> >> Most virtqueue notifications from the guest use the ioeventfd mechanism, >> but there are corner cases where QEMU code calls virtio_queue_notify(). >> This currently honors the host notifier for the IOThreads >> aio_handle_output case, but not for the vhost case. The result is that >> vhost does not receive virtqueue notifications from QEMU when >> virtio_queue_notify() is called. >> >> This patch extends virtio_queue_notify() to set the host notifier >> whenever it is enabled instead of calling the vq->(aio_)handle_output() >> function directly. We track the host notifier state for each virtqueue >> separately since some devices may use it only for certain virtqueues. >> >> This fixes the vhost case although it does add a trip through the >> eventfd for the traditional ioeventfd case. I don't think it's worth >> adding a fast path for the traditional ioeventfd case because calling >> virtio_queue_notify() is rare when ioeventfd is enabled. >> >> Reported-by: Felipe Franciosi <fel...@nutanix.com> >> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > > queued, thanks! > >> --- >> v2: >> * Track host notifier enabled/disabled state per virtqueue [Yongji Xie] >> * Tested with contrib/vhost-user-blk and contrib/vhost-user-scsi >> >> hw/virtio/virtio-bus.c | 4 ++++ >> hw/virtio/virtio.c | 9 ++++++++- >> include/hw/virtio/virtio.h | 1 + >> 3 files changed, 13 insertions(+), 1 deletion(-) >> >> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c >> index b2c804292e..d6332d45c3 100644 >> --- a/hw/virtio/virtio-bus.c >> +++ b/hw/virtio/virtio-bus.c >> @@ -288,6 +288,10 @@ int virtio_bus_set_host_notifier(VirtioBusState *bus, >> int n, bool assign) >> k->ioeventfd_assign(proxy, notifier, n, false); >> } >> >> + if (r == 0) { >> + virtio_queue_set_host_notifier_enabled(vq, assign); >> + } >> + >> return r; >> } >> >> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c >> index 762df12f4c..04716b5f6c 100644 >> --- a/hw/virtio/virtio.c >> +++ b/hw/virtio/virtio.c >> @@ -128,6 +128,7 @@ struct VirtQueue >> VirtIODevice *vdev; >> EventNotifier guest_notifier; >> EventNotifier host_notifier; >> + bool host_notifier_enabled; >> QLIST_ENTRY(VirtQueue) node; >> }; >> >> @@ -2271,7 +2272,7 @@ void virtio_queue_notify(VirtIODevice *vdev, int n) >> } >> >> trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); >> - if (vq->handle_aio_output) { >> + if (vq->host_notifier_enabled) { >> event_notifier_set(&vq->host_notifier); >> } else if (vq->handle_output) { >> vq->handle_output(vdev, vq); >> @@ -3145,6 +3146,7 @@ void virtio_init(VirtIODevice *vdev, const char *name, >> vdev->vq[i].vector = VIRTIO_NO_VECTOR; >> vdev->vq[i].vdev = vdev; >> vdev->vq[i].queue_index = i; >> + vdev->vq[i].host_notifier_enabled = false; >> } >> >> vdev->name = name; >> @@ -3436,6 +3438,11 @@ EventNotifier >> *virtio_queue_get_host_notifier(VirtQueue *vq) >> return &vq->host_notifier; >> } >> >> +void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled) >> +{ >> + vq->host_notifier_enabled = enabled; >> +} >> + >> int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, int n, >> MemoryRegion *mr, bool assign) >> { >> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h >> index 3448d67d2a..c32a815303 100644 >> --- a/include/hw/virtio/virtio.h >> +++ b/include/hw/virtio/virtio.h >> @@ -312,6 +312,7 @@ int virtio_device_grab_ioeventfd(VirtIODevice *vdev); >> void virtio_device_release_ioeventfd(VirtIODevice *vdev); >> bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev); >> EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq); >> +void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled); >> void virtio_queue_host_notifier_read(EventNotifier *n); >> void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext >> *ctx, >> VirtIOHandleAIOOutput >> handle_output); >> -- >> 2.23.0