When the 'cont' command resumes guest execution the vm change state
handlers are invoked. Unfortunately there is no explicit ordering
between classic qemu_add_vm_change_state_handler() callbacks. When two
layers of code both use vm change state handlers, we don't control which
handler runs first.
virtio-scsi with iothreads hits a deadlock when a failed SCSI command is
restarted and completes before the iothread is re-initialized.
This patch uses the new qdev_add_vm_change_state_handler() API to
guarantee that virtio-scsi's virtio change state handler executes before
the SCSI bus children. This way DMA is restarted after the iothread has
re-initialized.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
hw/scsi/scsi-bus.c | 4 ++--
hw/virtio/virtio.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 196136a307..fdc3a0e4e0 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -207,8 +207,8 @@ static void scsi_qdev_realize(DeviceState *qdev, Error
**errp)
error_propagate(errp, local_err);
return;
}
- dev->vmsentry = qemu_add_vm_change_state_handler(scsi_dma_restart_cb,
- dev);
+ dev->vmsentry = qdev_add_vm_change_state_handler(DEVICE(dev),
+ scsi_dma_restart_cb, dev);
}
static void scsi_qdev_unrealize(DeviceState *qdev, Error **errp)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index e1e90fcfd6..e42e6710d2 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2354,8 +2354,8 @@ void virtio_init(VirtIODevice *vdev, const char *name,
} else {
vdev->config = NULL;
}
- vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
- vdev);
+ vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev),
+ virtio_vmstate_change, vdev);
vdev->device_endian = virtio_default_endian();
vdev->use_guest_notifier_mask = true;
}
--
2.21.0
