Re: [RFC PATCH] virtio: re-order vm_running and use_started checks

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Oct 14, 2022 at 02:21:08PM +0100, Alex Bennée wrote:
> During migration the virtio device state can be restored before we
> restart the VM. As no devices can be running while the VM is paused it
> makes sense to bail out early in that case.
> 
> This returns the order introduced in:
> 
>  9f6bcfd99f (hw/virtio: move vm_running check to virtio_device_started)
> 
> to what virtio-sock was doing longhand.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Cc: Christian Borntraeger <borntraeger@linux.ibm.com>

Still checking but this seems to cause make check to fail on Fedora 36 under ubsan.

> ---
>  include/hw/virtio/virtio.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index f41b4a7e64..ebb58feaac 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -385,14 +385,14 @@ static inline bool virtio_is_big_endian(VirtIODevice *vdev)
>  
>  static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
>  {
> -    if (vdev->use_started) {
> -        return vdev->started;
> -    }
> -
>      if (!vdev->vm_running) {
>          return false;
>      }
>  
> +    if (vdev->use_started) {
> +        return vdev->started;
> +    }
> +
>      return status & VIRTIO_CONFIG_S_DRIVER_OK;
>  }
>  
> -- 
> 2.34.1