vhost_virtqueue_start() unmasks the call notifier by calling vhost_virtqueue_mask(), whose vhost_set_vring_call ioctl can fail (closed vhost-user socket, kernel ENOMEM, revoked guest_notifier fd) but whose void signature throws the error away. vhost_dev_start() then reports success while the backend has no valid call eventfd for that vq, leaving the guest with a working kick path but no virtqueue interrupts -- a half-up state harder to diagnose than a clean failure.
Make vhost_virtqueue_mask() return int and handle the error in the start path via the existing fail unwind. Other callers reach the function through VirtioDeviceClass.guest_notifier_mask, whose void signature offers no upward error channel; they invoke it as a statement and remain unchanged. Signed-off-by: Bin Guo <[email protected]> --- hw/virtio/vhost.c | 9 ++++++--- include/hw/virtio/vhost.h | 2 +- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index af41841b52..ad22c37c33 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -1470,8 +1470,10 @@ int vhost_virtqueue_start(struct vhost_dev *dev, * will do it later. */ if (!vdev->use_guest_notifier_mask) { - /* TODO: check and handle errors. */ - vhost_virtqueue_mask(dev, vdev, idx, false); + r = vhost_virtqueue_mask(dev, vdev, idx, false); + if (r < 0) { + goto fail; + } } if (k->query_guest_notifiers && @@ -1918,7 +1920,7 @@ bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n) } /* Mask/unmask events from this vq. */ -void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, +int vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, bool mask) { struct VirtQueue *vvq = virtio_get_queue(vdev, n); @@ -1940,6 +1942,7 @@ void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, if (r < 0) { error_report("vhost_set_vring_call failed %d", -r); } + return r; } bool vhost_config_pending(struct vhost_dev *hdev) diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index 684bafcaad..1f62332d60 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -312,7 +312,7 @@ bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n); /* Mask/unmask events from this vq. */ -void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, +int vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, bool mask); /** -- 2.50.1 (Apple Git-155)
