diff options
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 ab516ac614..6dcf3baf56 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -3728,6 +3728,10 @@ static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); int i, n, r, err; + /* + * Batch all the host notifiers in a single transaction to avoid + * quadratic time complexity in address_space_update_ioeventfds(). + */ memory_region_transaction_begin(); for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { VirtQueue *vq = &vdev->vq[n]; @@ -3766,6 +3770,10 @@ assign_error: r = virtio_bus_set_host_notifier(qbus, n, false); assert(r >= 0); } + /* + * The transaction expects the ioeventfds to be open when it + * commits. Do it now, before the cleanup loop. + */ memory_region_transaction_commit(); while (--i >= 0) { @@ -3790,6 +3798,10 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); int n, r; + /* + * Batch all the host notifiers in a single transaction to avoid + * quadratic time complexity in address_space_update_ioeventfds(). + */ memory_region_transaction_begin(); for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { VirtQueue *vq = &vdev->vq[n]; @@ -3801,6 +3813,10 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) r = virtio_bus_set_host_notifier(qbus, n, false); assert(r >= 0); } + /* + * The transaction expects the ioeventfds to be open when it + * commits. Do it now, before the cleanup loop. + */ memory_region_transaction_commit(); for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { |