diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-11-18 16:07:00 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2016-11-18 17:29:25 +0200 |
| commit | 310837de6c1e0badfd736b1b316b1698c53120a7 (patch) | |
| tree | eeb77c5a02121666e56900bc5da0cd578dfcd7f5 /hw/virtio/virtio.c | |
| parent | 600f5ce356b44d8fa5a611ff6b034eb95ecf04e7 (diff) | |
virtio: introduce grab/release_ioeventfd to fix vhost
Following the recent refactoring of virtio notifiers [1], more specifically
the patch ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to
start/stop ioeventfd") that uses virtio_bus_set_host_notifier [2]
by default, core virtio code requires 'ioeventfd_started' to be set
to true/false when the host notifiers are configured.
When vhost is stopped and started, however, there is a stop followed by
another start. Since ioeventfd_started was never set to true, the 'stop'
operation triggered by virtio_bus_set_host_notifier() will not result
in a call to virtio_pci_ioeventfd_assign(assign=false). This leaves
the memory regions with stale notifiers and results on the next start
triggering the following assertion:
kvm_mem_ioeventfd_add: error adding ioeventfd: File exists
Aborted
This patch reintroduces (hopefully in a cleaner way) the concept
that was present with ioeventfd_disabled before the refactoring.
When ioeventfd_grabbed>0, ioeventfd_started tracks whether ioeventfd
should be enabled or not, but ioeventfd is actually not started at
all until vhost releases the host notifiers.
[1] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07748.html
[2] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07760.html
Reported-by: Felipe Franciosi <felipe@nutanix.com>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Fixes: ed08a2a0b ("virtio: use virtio_bus_set_host_notifier to start/stop ioeventfd")
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/virtio/virtio.c')
| -rw-r--r-- | hw/virtio/virtio.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 55a00cdf9e..b7d5828601 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2191,6 +2191,22 @@ void virtio_device_stop_ioeventfd(VirtIODevice *vdev) virtio_bus_stop_ioeventfd(vbus); } +int virtio_device_grab_ioeventfd(VirtIODevice *vdev) +{ + BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); + VirtioBusState *vbus = VIRTIO_BUS(qbus); + + return virtio_bus_grab_ioeventfd(vbus); +} + +void virtio_device_release_ioeventfd(VirtIODevice *vdev) +{ + BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); + VirtioBusState *vbus = VIRTIO_BUS(qbus); + + virtio_bus_release_ioeventfd(vbus); +} + static void virtio_device_class_init(ObjectClass *klass, void *data) { /* Set the default value here. */ |