This patch captures the error of vhost_virtqueue_stop() in vhost_dev_stop()
and returns the error upward.
Specifically, if QEMU is disconnected from the vhost backend, some actions
in vhost_dev_stop() will fail, such as sending vhost-user messages to the
backend (GET_VRING_BASE, SET_VRING_ENABLE) and vhost_reset_status.
Considering that both set_vring_enable and vhost_reset_status require setting
the specific virtio feature bit, we can capture vhost_virtqueue_stop()'s
error to indicate that QEMU has lost connection with the backend.
This patch is the pre patch for 'vhost-user: return failure if backend crashes
when live migration', which makes the live migration aware of the loss of
connection with the vhost-user backend and aborts the live migration.
Signed-off-by: Haoqian He <haoqian...@smartx.com>
---
hw/virtio/vhost.c | 23 +++++++++++++----------
include/hw/virtio/vhost.h | 8 +++++---
2 files changed, 18 insertions(+), 13 deletions(-)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 6aa72fd434..bdd945c18d 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1368,10 +1368,10 @@ fail_alloc_desc:
return r;
}
-void vhost_virtqueue_stop(struct vhost_dev *dev,
- struct VirtIODevice *vdev,
- struct vhost_virtqueue *vq,
- unsigned idx)
+int vhost_virtqueue_stop(struct vhost_dev *dev,
+ struct VirtIODevice *vdev,
+ struct vhost_virtqueue *vq,
+ unsigned idx)
{
int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx);
struct vhost_vring_state state = {
@@ -1381,7 +1381,7 @@ void vhost_virtqueue_stop(struct vhost_dev *dev,
if (virtio_queue_get_desc_addr(vdev, idx) == 0) {
/* Don't stop the virtqueue which might have not been started */
- return;
+ return 0;
}
r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
@@ -1412,6 +1412,7 @@ void vhost_virtqueue_stop(struct vhost_dev *dev,
0, virtio_queue_get_avail_size(vdev, idx));
vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx),
0, virtio_queue_get_desc_size(vdev, idx));
+ return r;
}
static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev,
@@ -2136,9 +2137,10 @@ fail_features:
}
/* Host notifiers must be enabled at this point. */
-void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings)
+int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings)
{
int i;
+ int rc = 0;
/* should only be called after backend is connected */
assert(hdev->vhost_ops);
@@ -2157,10 +2159,10 @@ void 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) {
- vhost_virtqueue_stop(hdev,
- vdev,
- hdev->vqs + i,
- hdev->vq_index + i);
+ rc |= vhost_virtqueue_stop(hdev,
+ vdev,
+ hdev->vqs + i,
+ hdev->vq_index + i);
}
if (hdev->vhost_ops->vhost_reset_status) {
hdev->vhost_ops->vhost_reset_status(hdev);
@@ -2177,6 +2179,7 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice
*vdev, bool vrings)
hdev->started = false;
vdev->vhost_started = false;
hdev->vdev = NULL;
+ return rc;
}
int vhost_net_set_backend(struct vhost_dev *hdev,
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index a9469d50bc..fd96ec9c39 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -232,8 +232,10 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice
*vdev, bool vrings);
* 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).
+ *
+ * Return: 0 on success, != 0 on error when stopping dev.
*/
-void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings);
+int vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings);
/**
* DOC: vhost device configuration handling
@@ -333,8 +335,8 @@ int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t
iova, int write);
int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
struct vhost_virtqueue *vq, unsigned idx);
-void vhost_virtqueue_stop(struct vhost_dev *dev, struct VirtIODevice *vdev,
- struct vhost_virtqueue *vq, unsigned idx);
+int vhost_virtqueue_stop(struct vhost_dev *dev, struct VirtIODevice *vdev,
+ struct vhost_virtqueue *vq, unsigned idx);
void vhost_dev_reset_inflight(struct vhost_inflight *inflight);
void vhost_dev_free_inflight(struct vhost_inflight *inflight);
--
2.44.0
