system/runstate: add VM state change cb with return value

This patch adds the new VM state change cb type `VMChangeStateHandlerWithRet`,
which has return value for `VMChangeStateEntry`.

Thus, we can register a new VM state change cb with return value for device.
Note that `VMChangeStateHandler` and `VMChangeStateHandlerWithRet` are mutually
exclusive and cannot be provided at the same time.

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.

Virtio device will use VMChangeStateHandlerWithRet.

Signed-off-by: Haoqian He <haoqian.he@smartx.com>
Message-Id: <20250416024729.3289157-2-haoqian.he@smartx.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 70be4a7367..9b12ee7f1c 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -400,7 +400,7 @@ static void scsi_qdev_realize(DeviceState *qdev, Error **errp)
         return;
     }
     dev->vmsentry = qdev_add_vm_change_state_handler(DEVICE(dev),
-            scsi_dma_restart_cb, dev);
+            scsi_dma_restart_cb, NULL, dev);
 }
 
 static void scsi_qdev_unrealize(DeviceState *qdev)