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SubjectRe: [PATCH v3 04/10] VFIO: platform: add vfio_platform_set_automasked
On 08/12/2015 08:56 PM, Alex Williamson wrote:
> On Mon, 2015-08-10 at 15:20 +0200, Eric Auger wrote:
>> This function makes possible to change the automasked mode.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> v1 -> v2:
>> - set forwarded flag
>> ---
>> drivers/vfio/platform/vfio_platform_irq.c | 19 +++++++++++++++++++
>> 1 file changed, 19 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index b31b1f0..a285384 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -186,6 +186,25 @@ static irqreturn_t vfio_handler(int irq, void *dev_id)
>> return ret;
>> }
>>
>> +static int vfio_platform_set_automasked(struct vfio_platform_irq *irq,
>> + bool automasked)
>> +{
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&irq->lock, flags);
>> + if (automasked) {
>> + irq->forwarded = true;
>> + irq->flags |= VFIO_IRQ_INFO_AUTOMASKED;
>> + irq->handler = vfio_automasked_irq_handler;
>> + } else {
>> + irq->forwarded = false;
>> + irq->flags &= ~VFIO_IRQ_INFO_AUTOMASKED;
>> + irq->handler = vfio_irq_handler;
>> + }
>> + spin_unlock_irqrestore(&irq->lock, flags);
>> + return 0;
>
> In vfio-speak, automasked means level and we're not magically changing
> the IRQ from level to edge, we're simply able to handle level
> differently based on a hardware optimization. Should the user visible
> flags therefore change based on this? Aren't we really setting the
> forwarded state rather than the automasked state?

Well actually this was following the discussion we had a long time ago
about that topic:

http://lkml.iu.edu/hypermail/linux/kernel/1409.1/03659.html

I did not really know how to conclude ...

If it is preferred I can hide this to the userspace, no problem.

Eric


>
>> +}
>> +
>> static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
>> {
>> }
>
>
>



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