From: Daniil Tatianin <d-tatia...@yandex-team.ru>
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-tatia...@yandex-team.ru>
Message-Id: <20250609212547.2859224-3-d-tatia...@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
include/hw/virtio/vhost.h | 15 +++++++++++
hw/virtio/vhost.c | 52 +++++++++++++++++++++++++++++----------
2 files changed, 54 insertions(+), 13 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
@@ -237,6 +237,21 @@ 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
*
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index c87861b31f..c30ea1156e 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1354,25 +1354,30 @@ fail_alloc_desc:
return r;
}
-int vhost_virtqueue_stop(struct vhost_dev *dev,
- struct VirtIODevice *vdev,
- struct vhost_virtqueue *vq,
- unsigned idx)
+static int do_vhost_virtqueue_stop(struct vhost_dev *dev,
+ struct VirtIODevice *vdev,
+ struct vhost_virtqueue *vq,
+ unsigned idx, bool force)
{
int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx);
struct vhost_vring_state state = {
.index = vhost_vq_index,
};
- int r;
+ int r = 0;
if (virtio_queue_get_desc_addr(vdev, idx) == 0) {
/* Don't stop the virtqueue which might have not been started */
return 0;
}
- r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
- if (r < 0) {
- VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r);
+ if (!force) {
+ r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
+ if (r < 0) {
+ VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r);
+ }
+ }
+
+ if (r < 0 || force) {
/* Connection to the backend is broken, so let's sync internal
* last avail idx to the device used idx.
*/
@@ -1401,6 +1406,14 @@ int vhost_virtqueue_stop(struct vhost_dev *dev,
return r;
}
+int vhost_virtqueue_stop(struct vhost_dev *dev,
+ struct VirtIODevice *vdev,
+ struct vhost_virtqueue *vq,
+ unsigned idx)
+{
+ return do_vhost_virtqueue_stop(dev, vdev, vq, idx, false);
+}
+
static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev,
int n, uint32_t timeout)
{
@@ -2119,7 +2132,8 @@ fail_features:
}
/* Host notifiers must be enabled at this point. */
-int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings)
+static int do_vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev,
+ bool vrings, bool force)
{
int i;
int rc = 0;
@@ -2141,10 +2155,11 @@ int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice
*vdev, bool vrings)
vhost_dev_set_vring_enable(hdev, false);
}
for (i = 0; i < hdev->nvqs; ++i) {
- rc |= vhost_virtqueue_stop(hdev,
- vdev,
- hdev->vqs + i,
- hdev->vq_index + i);
+ rc |= do_vhost_virtqueue_stop(hdev,
+ vdev,
+ hdev->vqs + i,
+ hdev->vq_index + i,
+ force);
}
if (hdev->vhost_ops->vhost_reset_status) {
hdev->vhost_ops->vhost_reset_status(hdev);
@@ -2164,6 +2179,17 @@ int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice
*vdev, bool vrings)
return rc;
}
+int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings)
+{
+ return do_vhost_dev_stop(hdev, vdev, vrings, false);
+}
+
+int vhost_dev_force_stop(struct vhost_dev *hdev, VirtIODevice *vdev,
+ bool vrings)
+{
+ return do_vhost_dev_stop(hdev, vdev, vrings, true);
+}
+
int vhost_net_set_backend(struct vhost_dev *hdev,
struct vhost_vring_file *file)
{
--
MST
