diff options
| -rw-r--r-- | hw/virtio/vhost.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 87c49fa..eb8c4c3 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -1562,16 +1562,25 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) return 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 (i = 0; i < hdev->nvqs; ++i) { r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, true); if (r < 0) { error_report("vhost VQ %d notifier binding failed: %d", i, -r); + memory_region_transaction_commit(); vhost_dev_disable_notifiers(hdev, vdev); return r; } } + memory_region_transaction_commit(); + return 0; } @@ -1585,6 +1594,12 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); int i, 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 (i = 0; i < hdev->nvqs; ++i) { r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, false); @@ -1592,6 +1607,15 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) error_report("vhost VQ %d notifier cleanup failed: %d", i, -r); } 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 (i = 0; i < hdev->nvqs; ++i) { virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i); } virtio_device_release_ioeventfd(vdev); |