Re: [PATCH v2] vfio-ccw: Attempt to clean up all IRQs on error

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 4/28/21 10:36 AM, Eric Farman wrote:
> The vfio_ccw_unrealize() routine makes an unconditional attempt to
> unregister every IRQ notifier, though they may not have been registered
> in the first place (when running on an older kernel, for example).
> 
> Let's mirror this behavior in the error cleanups in vfio_ccw_realize()
> so that if/when new IRQs are added, it is less confusing to recognize
> the necessary procedures. The worst case scenario would be some extra
> messages about an undefined IRQ, but since this is an error exit that
> won't be the only thing to worry about.
> 
> And regarding those messages, let's change it to a warning instead of
> an error, to better reflect their severity. The existing code in both
> paths handles everything anyway.
> 
> Signed-off-by: Eric Farman <farman@linux.ibm.com>

Based on our prior conversation re: the safety of unconditional calls to 
vfio_ccw_unregister_irq_notifier, this looks good to me.

Acked-by: Matthew Rosato <mjrosato@linux.ibm.com>

> ---
> 
> Notes:
>      v1->v2:
>       - Downgrade unregister IRQ message from error to warning [CH]
>      
>      v1: https://lore.kernel.org/qemu-devel/20210427142511.2125733-1-farman@linux.ibm.com/
> 
>   hw/vfio/ccw.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> index 400bc07fe2..f64dd850db 100644
> --- a/hw/vfio/ccw.c
> +++ b/hw/vfio/ccw.c
> @@ -470,7 +470,7 @@ static void vfio_ccw_unregister_irq_notifier(VFIOCCWDevice *vcdev,
>   
>       if (vfio_set_irq_signaling(&vcdev->vdev, irq, 0,
>                                  VFIO_IRQ_SET_ACTION_TRIGGER, -1, &err)) {
> -        error_reportf_err(err, VFIO_MSG_PREFIX, vcdev->vdev.name);
> +        warn_reportf_err(err, VFIO_MSG_PREFIX, vcdev->vdev.name);
>       }
>   
>       qemu_set_fd_handler(event_notifier_get_fd(notifier),
> @@ -690,7 +690,7 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp)
>       if (vcdev->crw_region) {
>           vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_CRW_IRQ_INDEX, &err);
>           if (err) {
> -            goto out_crw_notifier_err;
> +            goto out_irq_notifier_err;
>           }
>       }
>   
> @@ -705,7 +705,9 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp)
>   
>       return;
>   
> -out_crw_notifier_err:
> +out_irq_notifier_err:
> +    vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_REQ_IRQ_INDEX);
> +    vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_CRW_IRQ_INDEX);
>       vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX);
>   out_io_notifier_err:
>       vfio_ccw_put_region(vcdev);
>