linux/virt/lib/irqbypass.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * IRQ offload/bypass manager
 *
 * Copyright (C) 2015 Red Hat, Inc.
 * Copyright (c) 2015 Linaro Ltd.
 *
 * Various virtualization hardware acceleration techniques allow bypassing or
 * offloading interrupts received from devices around the host kernel.  Posted
 * Interrupts on Intel VT-d systems can allow interrupts to be received
 * directly by a virtual machine.  ARM IRQ Forwarding allows forwarded physical
 * interrupts to be directly deactivated by the guest.  This manager allows
 * interrupt producers and consumers to find each other to enable this sort of
 * bypass.
 */

#include <linux/irqbypass.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>

MODULE_LICENSE(…) …;
MODULE_DESCRIPTION(…) …;

static LIST_HEAD(producers);
static LIST_HEAD(consumers);
static DEFINE_MUTEX(lock);

/* @lock must be held when calling connect */
static int __connect(struct irq_bypass_producer *prod,
		     struct irq_bypass_consumer *cons)
{ … }

/* @lock must be held when calling disconnect */
static void __disconnect(struct irq_bypass_producer *prod,
			 struct irq_bypass_consumer *cons)
{ … }

/**
 * irq_bypass_register_producer - register IRQ bypass producer
 * @producer: pointer to producer structure
 *
 * Add the provided IRQ producer to the list of producers and connect
 * with any matching token found on the IRQ consumers list.
 */
int irq_bypass_register_producer(struct irq_bypass_producer *producer)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * irq_bypass_unregister_producer - unregister IRQ bypass producer
 * @producer: pointer to producer structure
 *
 * Remove a previously registered IRQ producer from the list of producers
 * and disconnect it from any connected IRQ consumer.
 */
void irq_bypass_unregister_producer(struct irq_bypass_producer *producer)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * irq_bypass_register_consumer - register IRQ bypass consumer
 * @consumer: pointer to consumer structure
 *
 * Add the provided IRQ consumer to the list of consumers and connect
 * with any matching token found on the IRQ producer list.
 */
int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * irq_bypass_unregister_consumer - unregister IRQ bypass consumer
 * @consumer: pointer to consumer structure
 *
 * Remove a previously registered IRQ consumer from the list of consumers
 * and disconnect it from any connected IRQ producer.
 */
void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
{ … }
EXPORT_SYMBOL_GPL(…);