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

[Wu, Feng]

> -----Original Message-----
> From: Paolo Bonzini [mailto:pbonzini@xxxxxxxxxx]
> Sent: Tuesday, July 07, 2015 7:01 PM
> To: Wu, Feng; Eric Auger; eric.auger@xxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx; christoffer.dall@xxxxxxxxxx; marc.zyngier@xxxxxxx;
> alex.williamson@xxxxxxxxxx; avi.kivity@xxxxxxxxx; mtosatti@xxxxxxxxxx;
> joro@xxxxxxxxxx; b.reynal@xxxxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; patches@xxxxxxxxxx
> Subject: Re: [RFC v2 3/6] irq: bypass: Extend skeleton for ARM forwarding
> control
> 
> 
> 
> On 07/07/2015 12:58, Wu, Feng wrote:
> >
> >
> >> -----Original Message-----
> >> From: Eric Auger [mailto:eric.auger@xxxxxxxxxx]
> >> Sent: Monday, July 06, 2015 8:11 PM
> >> To: eric.auger@xxxxxx; eric.auger@xxxxxxxxxx;
> >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx;
> >> kvm@xxxxxxxxxxxxxxx; christoffer.dall@xxxxxxxxxx; marc.zyngier@xxxxxxx;
> >> alex.williamson@xxxxxxxxxx; pbonzini@xxxxxxxxxx; avi.kivity@xxxxxxxxx;
> >> mtosatti@xxxxxxxxxx; Wu, Feng; joro@xxxxxxxxxx;
> >> b.reynal@xxxxxxxxxxxxxxxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx; patches@xxxxxxxxxx
> >> 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@xxxxxxxxxx>
> >>
> >> ---
> >>
> >> 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;

Do you mean this:

struct kvm_kernel_irqfd {
	
	......

	struct irq_bypass_consumer cons;
	struct irq_bypass_producer *prod;
};

Thanks,
Feng

> 
> 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
> >
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