1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * IRQ offload/bypass manager
4 *
5 * Copyright (C) 2015 Red Hat, Inc.
6 * Copyright (c) 2015 Linaro Ltd.
7 */
8#ifndef IRQBYPASS_H
9#define IRQBYPASS_H
10
11#include <linux/list.h>
12
13struct eventfd_ctx;
14struct irq_bypass_consumer;
15
16/*
17 * Theory of operation
18 *
19 * The IRQ bypass manager is a simple set of lists and callbacks that allows
20 * IRQ producers (ex. physical interrupt sources) to be matched to IRQ
21 * consumers (ex. virtualization hardware that allows IRQ bypass or offload)
22 * via a shared eventfd_ctx. Producers and consumers register independently.
23 * When a producer and consumer are paired, i.e. an eventfd match is found, the
24 * optional @stop callback will be called for each participant. The pair will
25 * then be connected via the @add_* callbacks, and finally the optional @start
26 * callback will allow any final coordination. When either participant is
27 * unregistered, the process is repeated using the @del_* callbacks in place of
28 * the @add_* callbacks. eventfds must be unique per producer/consumer, 1:N
29 * pairings are not supported.
30 */
31
32struct irq_bypass_consumer;
33
34/**
35 * struct irq_bypass_producer - IRQ bypass producer definition
36 * @eventfd: eventfd context used to match producers and consumers
37 * @consumer: The connected consumer (NULL if no connection)
38 * @irq: Linux IRQ number for the producer device
39 * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional)
40 * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional)
41 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
42 * @start: Perform any startup operations necessary after add/del (optional)
43 *
44 * The IRQ bypass producer structure represents an interrupt source for
45 * participation in possible host bypass, for instance an interrupt vector
46 * for a physical device assigned to a VM.
47 */
48struct irq_bypass_producer {
49 struct eventfd_ctx *eventfd;
50 struct irq_bypass_consumer *consumer;
51 int irq;
52 int (*add_consumer)(struct irq_bypass_producer *,
53 struct irq_bypass_consumer *);
54 void (*del_consumer)(struct irq_bypass_producer *,
55 struct irq_bypass_consumer *);
56 void (*stop)(struct irq_bypass_producer *);
57 void (*start)(struct irq_bypass_producer *);
58};
59
60/**
61 * struct irq_bypass_consumer - IRQ bypass consumer definition
62 * @eventfd: eventfd context used to match producers and consumers
63 * @producer: The connected producer (NULL if no connection)
64 * @add_producer: Connect the IRQ consumer to an IRQ producer
65 * @del_producer: Disconnect the IRQ consumer from an IRQ producer
66 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
67 * @start: Perform any startup operations necessary after add/del (optional)
68 *
69 * The IRQ bypass consumer structure represents an interrupt sink for
70 * participation in possible host bypass, for instance a hypervisor may
71 * support offloads to allow bypassing the host entirely or offload
72 * portions of the interrupt handling to the VM.
73 */
74struct irq_bypass_consumer {
75 struct eventfd_ctx *eventfd;
76 struct irq_bypass_producer *producer;
77
78 int (*add_producer)(struct irq_bypass_consumer *,
79 struct irq_bypass_producer *);
80 void (*del_producer)(struct irq_bypass_consumer *,
81 struct irq_bypass_producer *);
82 void (*stop)(struct irq_bypass_consumer *);
83 void (*start)(struct irq_bypass_consumer *);
84};
85
86int irq_bypass_register_producer(struct irq_bypass_producer *producer,
87 struct eventfd_ctx *eventfd, int irq);
88void irq_bypass_unregister_producer(struct irq_bypass_producer *producer);
89int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer,
90 struct eventfd_ctx *eventfd);
91void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer);
92
93#endif /* IRQBYPASS_H */
94

source code of linux/include/linux/irqbypass.h