Re: [PATCH v3 01/10] VFIO: platform: registration of a dummy IRQ bypass producer

[Eric Auger <eric.auger@linaro.org>]

Hi Alex,
On 08/12/2015 08:56 PM, Alex Williamson wrote:
> On Mon, 2015-08-10 at 15:20 +0200, Eric Auger wrote:
>> Register a dummy producer with void callbacks
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> v2 -> v3:
>> - rename vfio_platform_irq_bypass_resume into *_start
>> ---
>>  drivers/vfio/platform/vfio_platform_irq.c     | 32 +++++++++++++++++++++++++++
>>  drivers/vfio/platform/vfio_platform_private.h |  2 ++
>>  2 files changed, 34 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index 88bba57..b5cb8c7 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -20,6 +20,7 @@
>>  #include <linux/types.h>
>>  #include <linux/vfio.h>
>>  #include <linux/irq.h>
>> +#include <linux/irqbypass.h>
>>  
>>  #include "vfio_platform_private.h"
>>  
>> @@ -177,6 +178,27 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
>>  	return IRQ_HANDLED;
>>  }
>>  
>> +static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
>> +{
>> +}
>> +
>> +static void vfio_platform_irq_bypass_start(struct irq_bypass_producer *prod)
>> +{
>> +}
>> +
>> +static int vfio_platform_irq_bypass_add_consumer(
>> +			struct irq_bypass_producer *prod,
>> +			struct irq_bypass_consumer *cons)
>> +{
>> +	return 0;
>> +}
>> +
>> +static void vfio_platform_irq_bypass_del_consumer(
>> +			struct irq_bypass_producer *prod,
>> +			struct irq_bypass_consumer *cons)
>> +{
>> +}
>> +
>>  static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
>>  			    int fd, irq_handler_t handler)
>>  {
>> @@ -186,6 +208,7 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
>>  
>>  	if (irq->trigger) {
>>  		free_irq(irq->hwirq, irq);
>> +		irq_bypass_unregister_producer(&irq->producer);
>>  		kfree(irq->name);
>>  		eventfd_ctx_put(irq->trigger);
>>  		irq->trigger = NULL;
>> @@ -216,6 +239,15 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
>>  		return ret;
>>  	}
>>  
>> +	irq->producer.token = (void *)trigger;
>> +	irq->producer.irq = irq->hwirq;
>> +	irq->producer.add_consumer = vfio_platform_irq_bypass_add_consumer;
>> +	irq->producer.del_consumer = vfio_platform_irq_bypass_del_consumer;
>> +	irq->producer.stop = vfio_platform_irq_bypass_stop;
>> +	irq->producer.start = vfio_platform_irq_bypass_start;
>> +	ret = irq_bypass_register_producer(&irq->producer);
>> +	WARN_ON(ret);
> 
> For what purpose?
Yes. I will replace by a simple pr_info as done in eventfd.c.

Best Regards

Eric
> 
>> +
>>  	if (!irq->masked)
>>  		enable_irq(irq->hwirq);
>>  
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>> index 1c9b3d5..1d2d4d6 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -17,6 +17,7 @@
>>  
>>  #include <linux/types.h>
>>  #include <linux/interrupt.h>
>> +#include <linux/irqbypass.h>
>>  
>>  #define VFIO_PLATFORM_OFFSET_SHIFT   40
>>  #define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1)
>> @@ -37,6 +38,7 @@ struct vfio_platform_irq {
>>  	spinlock_t		lock;
>>  	struct virqfd		*unmask;
>>  	struct virqfd		*mask;
>> +	struct irq_bypass_producer producer;
>>  };
>>  
>>  struct vfio_platform_region {
> 
> 
>