vhost: add a helper for force stopping a device

This adds an ability to skip GET_VRING_BASE during device stop entirely,
and thus the expensive drain operation that this call entails as well,
which may be useful during a non-graceful shutdown in case the guest
operating system hangs or refuses to react to a previously requested
ACPI shutdown for whatever reason.

Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Message-Id: <20250609212547.2859224-3-d-tatianin@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 38800a7156..eb3dd7616b 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -238,6 +238,21 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings);
 int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings);
 
 /**
+ * vhost_dev_force_stop() - force stop the vhost device
+ * @hdev: common vhost_dev structure
+ * @vdev: the VirtIODevice structure
+ * @vrings: true to have vrings disabled in this call
+ *
+ * Force stop the vhost device. After the device is stopped the notifiers
+ * can be disabled (@vhost_dev_disable_notifiers) and the device can
+ * be torn down (@vhost_dev_cleanup). Unlike @vhost_dev_stop, this doesn't
+ * attempt to flush in-flight backend requests by skipping GET_VRING_BASE
+ * entirely.
+ */
+int vhost_dev_force_stop(struct vhost_dev *hdev, VirtIODevice *vdev,
+                         bool vrings);
+
+/**
  * DOC: vhost device configuration handling
  *
  * The VirtIO device configuration space is used for rarely changing