Re: [RFC v2 3/6] irq: bypass: Extend skeleton for ARM forwarding control

[Paolo Bonzini <pbonzini@redhat.com>]

On 07/07/2015 12:58, Wu, Feng wrote:
> 
> 
>> -----Original Message-----
>> From: Eric Auger [mailto:eric.auger@linaro.org]
>> Sent: Monday, July 06, 2015 8:11 PM
>> To: eric.auger@st.com; eric.auger@linaro.org;
>> linux-arm-kernel@lists.infradead.org; kvmarm@lists.cs.columbia.edu;
>> kvm@vger.kernel.org; christoffer.dall@linaro.org; marc.zyngier@arm.com;
>> alex.williamson@redhat.com; pbonzini@redhat.com; avi.kivity@gmail.com;
>> mtosatti@redhat.com; Wu, Feng; joro@8bytes.org;
>> b.reynal@virtualopensystems.com
>> Cc: linux-kernel@vger.kernel.org; patches@linaro.org
>> Subject: [RFC v2 3/6] irq: bypass: Extend skeleton for ARM forwarding control
>>
>> - [add,del]_[consumer,producer] updated to takes both the consumer and
>>   producer handles. This is requested to combine info from both,
>>   typically to link the source irq owned by the producer with the gsi
>>   owned by the consumer (forwarded IRQ setup).
>> - new methods are added:
>>   x stop/resume: Those are needed for forwarding since the state change
>>     requires to entermingle actions at consumer, producer.
>>   x consumer update for posted interrupts
>> - On handshake, we now call connect, disconnect which features the more
>>   complex sequence.
>> - add irq on producer side
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> v1 -> v2:
>> - remove vfio_device, kvm, gsi, opaque fields included in v1 except common
>> - all those in can be retrieved with container_of in callbacks
>> ---
>>  include/linux/irqbypass.h | 19 ++++++++++++++++---
>>  kernel/irq/bypass.c       | 44
>> ++++++++++++++++++++++++++++++++++++++++----
>>  2 files changed, 56 insertions(+), 7 deletions(-)
>>
>> diff --git a/include/linux/irqbypass.h b/include/linux/irqbypass.h
>> index 718508e..8f62235 100644
>> --- a/include/linux/irqbypass.h
>> +++ b/include/linux/irqbypass.h
>> @@ -3,17 +3,30 @@
>>
>>  #include <linux/list.h>
>>
>> +struct irq_bypass_consumer;
>> +
>>  struct irq_bypass_producer {
>>  	struct list_head node;
>>  	void *token;
>> -	/* TBD */
>> +	int irq; /* linux irq */
>> +	void (*stop)(struct irq_bypass_producer *);
>> +	void (*resume)(struct irq_bypass_producer *);
>> +	void (*add_consumer)(struct irq_bypass_producer *,
>> +			     struct irq_bypass_consumer *);
>> +	void (*del_consumer)(struct irq_bypass_producer *,
>> +			     struct irq_bypass_consumer *);
>>  };
>>
>>  struct irq_bypass_consumer {
>>  	struct list_head node;
>>  	void *token;
> 
> Can we add a pointer to ' struct irq_bypass_producer ', and
> assign it when connecting, de-assign it when disconnecting.
> since in some case, I need to update IRTE from the consumer
> side, where I cannot get the related producer info (I need irq info)
> without iterating it again.

You can use container_of to add it to your own struct, e.g.

	struct irq_bypass_consumer cons;
	struct irq_bypass_producer *prod;

Paolo

> Thanks,
> Feng
> 
>> -	void (*add_producer)(struct irq_bypass_producer *);
>> -	void (*del_producer)(struct irq_bypass_producer *);
>> +	void (*stop)(struct irq_bypass_consumer *);
>> +	void (*resume)(struct irq_bypass_consumer *);
>> +	void (*add_producer)(struct irq_bypass_consumer *,
>> +			     struct irq_bypass_producer *);
>> +	void (*del_producer)(struct irq_bypass_consumer *,
>> +			     struct irq_bypass_producer *);
>> +	void (*update)(struct irq_bypass_consumer *);
>>  };
>>
>>  int irq_bypass_register_producer(struct irq_bypass_producer *);
>> diff --git a/kernel/irq/bypass.c b/kernel/irq/bypass.c
>> index 5d0f92b..efadbe5 100644
>> --- a/kernel/irq/bypass.c
>> +++ b/kernel/irq/bypass.c
>> @@ -19,6 +19,42 @@ static LIST_HEAD(producers);
>>  static LIST_HEAD(consumers);
>>  static DEFINE_MUTEX(lock);
>>
>> +/* lock must be hold when calling connect */
>> +static void connect(struct irq_bypass_producer *prod,
>> +		    struct irq_bypass_consumer *cons)
>> +{
>> +	if (prod->stop)
>> +		prod->stop(prod);
>> +	if (cons->stop)
>> +		cons->stop(cons);
>> +	if (prod->add_consumer)
>> +		prod->add_consumer(prod, cons);
>> +	if (cons->add_producer)
>> +		cons->add_producer(cons, prod);
>> +	if (cons->resume)
>> +		cons->resume(cons);
>> +	if (prod->resume)
>> +		prod->resume(prod);
>> +}
>> +
>> +/* lock must be hold when calling disconnect */
>> +static void disconnect(struct irq_bypass_producer *prod,
>> +		       struct irq_bypass_consumer *cons)
>> +{
>> +	if (prod->stop)
>> +		prod->stop(prod);
>> +	if (cons->stop)
>> +		cons->stop(cons);
>> +	if (cons->del_producer)
>> +		cons->del_producer(cons, prod);
>> +	if (prod->del_consumer)
>> +		prod->del_consumer(prod, cons);
>> +	if (cons->resume)
>> +		cons->resume(cons);
>> +	if (prod->resume)
>> +		prod->resume(prod);
>> +}
>> +
>>  int irq_bypass_register_producer(struct irq_bypass_producer *producer)
>>  {
>>  	struct irq_bypass_producer *tmp;
>> @@ -38,7 +74,7 @@ int irq_bypass_register_producer(struct
>> irq_bypass_producer *producer)
>>
>>  	list_for_each_entry(consumer, &consumers, node) {
>>  		if (consumer->token == producer->token) {
>> -			consumer->add_producer(producer);
>> +			connect(producer, consumer);
>>  			break;
>>  		}
>>  	}
>> @@ -56,7 +92,7 @@ void irq_bypass_unregister_producer(struct
>> irq_bypass_producer *producer)
>>
>>  	list_for_each_entry(consumer, &consumers, node) {
>>  		if (consumer->token == producer->token) {
>> -			consumer->del_producer(producer);
>> +			disconnect(producer, consumer);
>>  			break;
>>  		}
>>  	}
>> @@ -86,7 +122,7 @@ int irq_bypass_register_consumer(struct
>> irq_bypass_consumer *consumer)
>>
>>  	list_for_each_entry(producer, &producers, node) {
>>  		if (producer->token == consumer->token) {
>> -			consumer->add_producer(producer);
>> +			connect(producer, consumer);
>>  			break;
>>  		}
>>  	}
>> @@ -104,7 +140,7 @@ void irq_bypass_unregister_consumer(struct
>> irq_bypass_consumer *consumer)
>>
>>  	list_for_each_entry(producer, &producers, node) {
>>  		if (producer->token == consumer->token) {
>> -			consumer->del_producer(producer);
>> +			disconnect(producer, consumer);
>>  			break;
>>  		}
>>  	}
>> --
>> 1.9.1
>