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List:       kvm
Subject:    Re: [PATCH v3 3/8] VFIO: platform: forwarded state tested when selecting IRQ handler
From:       Christoffer Dall <christoffer.dall () linaro ! org>
Date:       2014-11-30 12:47:30
Message-ID: 20141130124730.GD82106 () macair
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The subject reads strangely, perhaps just:

VFIO: platform: test forward state when selecting IRQ handler

On Sun, Nov 23, 2014 at 07:35:55PM +0100, Eric Auger wrote:
> In case the IRQ is forwarded, the VFIO platform IRQ handler does not
> need to disable the IRQ anymore.
> 
> When setting the IRQ handler we now also test the forwarded state. In
> case the IRQ is forwarded we select the edge handler (no automaske).
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> v2 -> v3:
> - forwarded state was tested in the handler. Now the forwarded state
>   is tested before setting the handler. This definitively limits
>   the dynamics of forwarded state changes but I don't think there is
>   a use case where we need to be able to change the state at any time.

user space can change this by calling the VFIO_IRQ_SET_ACTION_TRIGGER
whenever it wants, right?

> ---
>  drivers/vfio/platform/vfio_platform_irq.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index 08d400e..61a2920 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -230,8 +230,13 @@ static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
>  {
>  	struct vfio_platform_irq *irq = &vdev->irqs[index];
>  	irq_handler_t handler;
> +	struct irq_data *d;
> +	bool is_forwarded;
>  
> -	if (vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE)
> +	d = irq_get_irq_data(irq->hwirq);
> +	is_forwarded = irqd_irq_forwarded(d);
> +
> +	if ((vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE) && !is_forwarded)
>  		handler = vfio_maskable_irq_handler;
>  	else
>  		handler = vfio_irq_handler;
> -- 
> 1.9.1
> 
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