diff mbox

[v3,05/10] VFIO: platform: add vfio_platform_is_active

Message ID 1439212864-12954-6-git-send-email-eric.auger@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger Aug. 10, 2015, 1:20 p.m. UTC
This function returns whether the IRQ is active at irqchip level or
VFIO masked. If either is true, it is considered the IRQ is active.
Currently there is no way to differentiate userspace masked IRQ from
automasked IRQ. There might be false detection of activity. However
it is currently acceptable to have false detection.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
---
 drivers/vfio/platform/vfio_platform_irq.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Alex Williamson Aug. 12, 2015, 6:56 p.m. UTC | #1
On Mon, 2015-08-10 at 15:20 +0200, Eric Auger wrote:
> This function returns whether the IRQ is active at irqchip level or
> VFIO masked. If either is true, it is considered the IRQ is active.
> Currently there is no way to differentiate userspace masked IRQ from
> automasked IRQ. There might be false detection of activity. However
> it is currently acceptable to have false detection.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> ---
>  drivers/vfio/platform/vfio_platform_irq.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index a285384..efaee58 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -205,6 +205,23 @@ static int vfio_platform_set_automasked(struct vfio_platform_irq *irq,
>  	return 0;
>  }
>  
> +static int vfio_platform_is_active(struct vfio_platform_irq *irq)

vfio_platform_irq_is_active()?

> +{
> +	unsigned long flags;
> +	bool active, masked, outstanding;
> +	int ret;
> +
> +	spin_lock_irqsave(&irq->lock, flags);
> +
> +	ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
> +	BUG_ON(ret);

Why can't we propagate this error to the caller and let them decide?

> +	masked = irq->masked;
> +	outstanding = active || masked;
> +
> +	spin_unlock_irqrestore(&irq->lock, flags);
> +	return outstanding;
> +}
> +
>  static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
>  {
>  }



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Eric Auger Aug. 17, 2015, 3:39 p.m. UTC | #2
On 08/12/2015 08:56 PM, Alex Williamson wrote:
> On Mon, 2015-08-10 at 15:20 +0200, Eric Auger wrote:
>> This function returns whether the IRQ is active at irqchip level or
>> VFIO masked. If either is true, it is considered the IRQ is active.
>> Currently there is no way to differentiate userspace masked IRQ from
>> automasked IRQ. There might be false detection of activity. However
>> it is currently acceptable to have false detection.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>> ---
>>  drivers/vfio/platform/vfio_platform_irq.c | 17 +++++++++++++++++
>>  1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index a285384..efaee58 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -205,6 +205,23 @@ static int vfio_platform_set_automasked(struct vfio_platform_irq *irq,
>>  	return 0;
>>  }
>>  
>> +static int vfio_platform_is_active(struct vfio_platform_irq *irq)
> 
> vfio_platform_irq_is_active()?
OK
> 
>> +{
>> +	unsigned long flags;
>> +	bool active, masked, outstanding;
>> +	int ret;
>> +
>> +	spin_lock_irqsave(&irq->lock, flags);
>> +
>> +	ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
>> +	BUG_ON(ret);
> 
> Why can't we propagate this error to the caller and let them decide?
sure

Eric
> 
>> +	masked = irq->masked;
>> +	outstanding = active || masked;
>> +
>> +	spin_unlock_irqrestore(&irq->lock, flags);
>> +	return outstanding;
>> +}
>> +
>>  static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
>>  {
>>  }
> 
> 
> 

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Christoffer Dall Sept. 2, 2015, 7:29 p.m. UTC | #3
On Mon, Aug 10, 2015 at 03:20:59PM +0200, Eric Auger wrote:
> This function returns whether the IRQ is active at irqchip level or
> VFIO masked. If either is true, it is considered the IRQ is active.
> Currently there is no way to differentiate userspace masked IRQ from
> automasked IRQ. There might be false detection of activity. However
> it is currently acceptable to have false detection.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> ---
>  drivers/vfio/platform/vfio_platform_irq.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index a285384..efaee58 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -205,6 +205,23 @@ static int vfio_platform_set_automasked(struct vfio_platform_irq *irq,
>  	return 0;
>  }
>  
> +static int vfio_platform_is_active(struct vfio_platform_irq *irq)
> +{
> +	unsigned long flags;
> +	bool active, masked, outstanding;
> +	int ret;
> +
> +	spin_lock_irqsave(&irq->lock, flags);
> +
> +	ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
> +	BUG_ON(ret);
> +	masked = irq->masked;
> +	outstanding = active || masked;

outstanding?

why not just return active || masked ?

-Christoffer

> +
> +	spin_unlock_irqrestore(&irq->lock, flags);
> +	return outstanding;
> +}
> +
>  static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
>  {
>  }
> -- 
> 1.9.1
> 
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diff mbox

Patch

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index a285384..efaee58 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -205,6 +205,23 @@  static int vfio_platform_set_automasked(struct vfio_platform_irq *irq,
 	return 0;
 }
 
+static int vfio_platform_is_active(struct vfio_platform_irq *irq)
+{
+	unsigned long flags;
+	bool active, masked, outstanding;
+	int ret;
+
+	spin_lock_irqsave(&irq->lock, flags);
+
+	ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
+	BUG_ON(ret);
+	masked = irq->masked;
+	outstanding = active || masked;
+
+	spin_unlock_irqrestore(&irq->lock, flags);
+	return outstanding;
+}
+
 static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
 {
 }