Re: [PATCH 2/7] s390/cio: Set vfio-ccw FSM state before ioeventfd

[Cornelia Huck <cohuck@redhat.com>]

On Fri,  3 May 2019 15:49:07 +0200
Eric Farman <farman@linux.ibm.com> wrote:

> Otherwise, the guest can believe it's okay to start another I/O
> and bump into the non-idle state.  This results in a cc=3
> (or cc=2 with the pending async CSCH/HSCH code [1]) to the guest,

I think you can now refer to cc=2, as the csch/hsch is on its way in :)

> which is unfortunate since everything is otherwise working normally.
> 
> [1] https://patchwork.kernel.org/comment/22588563/
> 
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> 
> ---
> 
> I think this might've been part of Pierre's FSM cleanup?

Not sure if I saw this before, but there have been quite a number of
patches going around...

> ---
>  drivers/s390/cio/vfio_ccw_drv.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 0b3b9de45c60..ddd21b6149fd 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -86,11 +86,11 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
>  	}
>  	memcpy(private->io_region->irb_area, irb, sizeof(*irb));
>  
> -	if (private->io_trigger)
> -		eventfd_signal(private->io_trigger, 1);
> -
>  	if (private->mdev && is_final)
>  		private->state = VFIO_CCW_STATE_IDLE;
> +
> +	if (private->io_trigger)
> +		eventfd_signal(private->io_trigger, 1);
>  }
>  
>  /*