[RFC 12/17] irq: bypass: Extend skeleton for ARM forwarding control

[Wu, Feng]

> -----Original Message-----
> From: Eric Auger [mailto:eric.auger at linaro.org]
> Sent: Thursday, July 02, 2015 9:17 PM
> To: eric.auger at st.com; eric.auger at linaro.org;
> linux-arm-kernel at lists.infradead.org; kvmarm at lists.cs.columbia.edu;
> kvm at vger.kernel.org; christoffer.dall at linaro.org; marc.zyngier at arm.com;
> alex.williamson at redhat.com; pbonzini at redhat.com; avi.kivity at gmail.com;
> mtosatti at redhat.com; Wu, Feng; joro at 8bytes.org;
> b.reynal at virtualopensystems.com
> Cc: linux-kernel at vger.kernel.org; patches at linaro.org
> Subject: [RFC 12/17] 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 functions are added: [stop,resume]_[consumer, producer]. Those are
>   needed for forwarding since the state change requires to entermingle
>   actions at consumer, producer.
> - On handshake, we now call connect, disconnect which features the more
>   complex sequence.
> - new fields are added on producer side: linux irq, vfio_device handle,
>   active which reflects whether the source is active (at interrupt
>   controller level or at VFIO level - automasked -) and finally an
>   opaque pointer which will be used to point to the vfio_platform_device
>   in this series.
> - new fields on consumer side: the kvm handle, the gsi
> 
> Integration of posted interrupt series will help to refine those choices

On PI side, I need another filed as below,

struct irq_bypass_consumer {
       struct list_head node;
       void *token;
+      unsigned irq;	/*got from producer when registered*/
       void (*add_producer)(struct irq_bypass_producer *,
                            struct irq_bypass_consumer *);
       void (*del_producer)(struct irq_bypass_producer *,
                            struct irq_bypass_consumer *);
+      void (*update)(struct irq_bypass_consumer *);
};

'update' is used to update the IRTE, while irq is initialized when
registered, which is used to find the right IRTE.

Thanks,
Feng

> 
> Signed-off-by: Eric Auger <eric.auger at linaro.org>
> 
> ---
> 
> - connect/disconnect could become a cb too. For forwarding it may make
>   sense to have failure at connection: this would happen when the physical
>   IRQ is either active at irqchip level or VFIO masked. This means some
>   of the cb should return an error and this error management could be
>   prod/cons specific. Where to attach the connect/disconnect cb: to the
>   cons or prod, to both?
> - Hence may be sensible to do the list_add only if connect returns 0
> - disconnect would not be allowed to fail.
> ---
>  include/linux/irqbypass.h | 26 ++++++++++++++++++++++---
>  kernel/irq/bypass.c       | 48
> +++++++++++++++++++++++++++++++++++++++++++----
>  2 files changed, 67 insertions(+), 7 deletions(-)
> 
> diff --git a/include/linux/irqbypass.h b/include/linux/irqbypass.h
> index 718508e..591ae3f 100644
> --- a/include/linux/irqbypass.h
> +++ b/include/linux/irqbypass.h
> @@ -3,17 +3,37 @@
> 
>  #include <linux/list.h>
> 
> +struct vfio_device;
> +struct irq_bypass_consumer;
> +struct kvm;
> +
>  struct irq_bypass_producer {
>  	struct list_head node;
>  	void *token;
> -	/* TBD */
> +	unsigned int irq; /* host physical irq */
> +	struct vfio_device *vdev; /* vfio device that requested irq */
> +	/* is irq active at irqchip or VFIO masked? */
> +	bool active;
> +	void *opaque;
> +	void (*stop_producer)(struct irq_bypass_producer *);
> +	void (*resume_producer)(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;
> -	void (*add_producer)(struct irq_bypass_producer *);
> -	void (*del_producer)(struct irq_bypass_producer *);
> +	unsigned int gsi;		/* the guest gsi */
> +	struct kvm *kvm;
> +	void (*stop_consumer)(struct irq_bypass_consumer *);
> +	void (*resume_consumer)(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 *);
>  };
> 
>  int irq_bypass_register_producer(struct irq_bypass_producer *);
> diff --git a/kernel/irq/bypass.c b/kernel/irq/bypass.c
> index 5d0f92b..fb31fef 100644
> --- a/kernel/irq/bypass.c
> +++ b/kernel/irq/bypass.c
> @@ -19,6 +19,46 @@ 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)
> +{
> +	pr_info("++++ %s prod(%d) -> cons(%d)\n",
> +		__func__, prod->irq, cons->gsi);
> +	if (prod->stop_producer)
> +		prod->stop_producer(prod);
> +	if (cons->stop_consumer)
> +		cons->stop_consumer(cons);
> +	if (prod->add_consumer)
> +		prod->add_consumer(prod, cons);
> +	if (cons->add_producer)
> +		cons->add_producer(cons, prod);
> +	if (cons->resume_consumer)
> +		cons->resume_consumer(cons);
> +	if (prod->resume_producer)
> +		prod->resume_producer(prod);
> +}
> +
> +/* lock must be hold when calling disconnect */
> +static void disconnect(struct irq_bypass_producer *prod,
> +		       struct irq_bypass_consumer *cons)
> +{
> +	pr_info("---- %s prod(%d) -> cons(%d)\n",
> +		__func__, prod->irq, cons->gsi);
> +	if (prod->stop_producer)
> +		prod->stop_producer(prod);
> +	if (cons->stop_consumer)
> +		cons->stop_consumer(cons);
> +	if (cons->del_producer)
> +		cons->del_producer(cons, prod);
> +	if (prod->del_consumer)
> +		prod->del_consumer(prod, cons);
> +	if (cons->resume_consumer)
> +		cons->resume_consumer(cons);
> +	if (prod->resume_producer)
> +		prod->resume_producer(prod);
> +}
> +
>  int irq_bypass_register_producer(struct irq_bypass_producer *producer)
>  {
>  	struct irq_bypass_producer *tmp;
> @@ -38,7 +78,7 @@ 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 +96,7 @@ 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 +126,7 @@ 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 +144,7 @@ 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