diff options
| -rw-r--r-- | MAINTAINERS | 7 | ||||
| -rw-r--r-- | include/linux/irqbypass.h | 90 | ||||
| -rw-r--r-- | virt/lib/Kconfig | 2 | ||||
| -rw-r--r-- | virt/lib/Makefile | 1 | ||||
| -rw-r--r-- | virt/lib/irqbypass.c | 257 |
5 files changed, 357 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 797236b..3b738cb 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11177,6 +11177,13 @@ L: netdev@vger.kernel.org S: Maintained F: drivers/net/ethernet/via/via-velocity.* +VIRT LIB +M: Alex Williamson <alex.williamson@redhat.com> +M: Paolo Bonzini <pbonzini@redhat.com> +L: kvm@vger.kernel.org +S: Supported +F: virt/lib/ + VIVID VIRTUAL VIDEO DRIVER M: Hans Verkuil <hverkuil@xs4all.nl> L: linux-media@vger.kernel.org diff --git a/include/linux/irqbypass.h b/include/linux/irqbypass.h new file mode 100644 index 0000000..1551b5b --- /dev/null +++ b/include/linux/irqbypass.h @@ -0,0 +1,90 @@ +/* + * IRQ offload/bypass manager + * + * Copyright (C) 2015 Red Hat, Inc. + * Copyright (c) 2015 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef IRQBYPASS_H +#define IRQBYPASS_H + +#include <linux/list.h> + +struct irq_bypass_consumer; + +/* + * Theory of operation + * + * The IRQ bypass manager is a simple set of lists and callbacks that allows + * IRQ producers (ex. physical interrupt sources) to be matched to IRQ + * consumers (ex. virtualization hardware that allows IRQ bypass or offload) + * via a shared token (ex. eventfd_ctx). Producers and consumers register + * independently. When a token match is found, the optional @stop callback + * will be called for each participant. The pair will then be connected via + * the @add_* callbacks, and finally the optional @start callback will allow + * any final coordination. When either participant is unregistered, the + * process is repeated using the @del_* callbacks in place of the @add_* + * callbacks. Match tokens must be unique per producer/consumer, 1:N pairings + * are not supported. + */ + +/** + * struct irq_bypass_producer - IRQ bypass producer definition + * @node: IRQ bypass manager private list management + * @token: opaque token to match between producer and consumer + * @irq: Linux IRQ number for the producer device + * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional) + * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional) + * @stop: Perform any quiesce operations necessary prior to add/del (optional) + * @start: Perform any startup operations necessary after add/del (optional) + * + * The IRQ bypass producer structure represents an interrupt source for + * participation in possible host bypass, for instance an interrupt vector + * for a physical device assigned to a VM. + */ +struct irq_bypass_producer { + struct list_head node; + void *token; + int irq; + int (*add_consumer)(struct irq_bypass_producer *, + struct irq_bypass_consumer *); + void (*del_consumer)(struct irq_bypass_producer *, + struct irq_bypass_consumer *); + void (*stop)(struct irq_bypass_producer *); + void (*start)(struct irq_bypass_producer *); +}; + +/** + * struct irq_bypass_consumer - IRQ bypass consumer definition + * @node: IRQ bypass manager private list management + * @token: opaque token to match between producer and consumer + * @add_producer: Connect the IRQ consumer to an IRQ producer + * @del_producer: Disconnect the IRQ consumer from an IRQ producer + * @stop: Perform any quiesce operations necessary prior to add/del (optional) + * @start: Perform any startup operations necessary after add/del (optional) + * + * The IRQ bypass consumer structure represents an interrupt sink for + * participation in possible host bypass, for instance a hypervisor may + * support offloads to allow bypassing the host entirely or offload + * portions of the interrupt handling to the VM. + */ +struct irq_bypass_consumer { + struct list_head node; + void *token; + int (*add_producer)(struct irq_bypass_consumer *, + struct irq_bypass_producer *); + void (*del_producer)(struct irq_bypass_consumer *, + struct irq_bypass_producer *); + void (*stop)(struct irq_bypass_consumer *); + void (*start)(struct irq_bypass_consumer *); +}; + +int irq_bypass_register_producer(struct irq_bypass_producer *); +void irq_bypass_unregister_producer(struct irq_bypass_producer *); +int irq_bypass_register_consumer(struct irq_bypass_consumer *); +void irq_bypass_unregister_consumer(struct irq_bypass_consumer *); + +#endif /* IRQBYPASS_H */ diff --git a/virt/lib/Kconfig b/virt/lib/Kconfig new file mode 100644 index 0000000..89a414f --- /dev/null +++ b/virt/lib/Kconfig @@ -0,0 +1,2 @@ +config IRQ_BYPASS_MANAGER + tristate diff --git a/virt/lib/Makefile b/virt/lib/Makefile new file mode 100644 index 0000000..901228d --- /dev/null +++ b/virt/lib/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_IRQ_BYPASS_MANAGER) += irqbypass.o diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c new file mode 100644 index 0000000..09a03b5 --- /dev/null +++ b/virt/lib/irqbypass.c @@ -0,0 +1,257 @@ +/* + * IRQ offload/bypass manager + * + * Copyright (C) 2015 Red Hat, Inc. + * Copyright (c) 2015 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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("GPL v2"); +MODULE_DESCRIPTION("IRQ bypass manager utility module"); + +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) +{ + int ret = 0; + + if (prod->stop) + prod->stop(prod); + if (cons->stop) + cons->stop(cons); + + if (prod->add_consumer) + ret = prod->add_consumer(prod, cons); + + if (!ret) { + ret = cons->add_producer(cons, prod); + if (ret && prod->del_consumer) + prod->del_consumer(prod, cons); + } + + if (cons->start) + cons->start(cons); + if (prod->start) + prod->start(prod); + + return ret; +} + +/* @lock must be held 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); + + cons->del_producer(cons, prod); + + if (prod->del_consumer) + prod->del_consumer(prod, cons); + + if (cons->start) + cons->start(cons); + if (prod->start) + prod->start(prod); +} + +/** + * 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) +{ + struct irq_bypass_producer *tmp; + struct irq_bypass_consumer *consumer; + + might_sleep(); + + if (!try_module_get(THIS_MODULE)) + return -ENODEV; + + mutex_lock(&lock); + + list_for_each_entry(tmp, &producers, node) { + if (tmp->token == producer->token) { + mutex_unlock(&lock); + module_put(THIS_MODULE); + return -EBUSY; + } + } + + list_for_each_entry(consumer, &consumers, node) { + if (consumer->token == producer->token) { + int ret = __connect(producer, consumer); + if (ret) { + mutex_unlock(&lock); + module_put(THIS_MODULE); + return ret; + } + break; + } + } + + list_add(&producer->node, &producers); + + mutex_unlock(&lock); + + return 0; +} +EXPORT_SYMBOL_GPL(irq_bypass_register_producer); + +/** + * 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) +{ + struct irq_bypass_producer *tmp; + struct irq_bypass_consumer *consumer; + + might_sleep(); + + if (!try_module_get(THIS_MODULE)) + return; /* nothing in the list anyway */ + + mutex_lock(&lock); + + list_for_each_entry(tmp, &producers, node) { + if (tmp->token != producer->token) + continue; + + list_for_each_entry(consumer, &consumers, node) { + if (consumer->token == producer->token) { + __disconnect(producer, consumer); + break; + } + } + + list_del(&producer->node); + module_put(THIS_MODULE); + break; + } + + mutex_unlock(&lock); + + module_put(THIS_MODULE); +} +EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer); + +/** + * 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) +{ + struct irq_bypass_consumer *tmp; + struct irq_bypass_producer *producer; + + if (!consumer->add_producer || !consumer->del_producer) + return -EINVAL; + + might_sleep(); + + if (!try_module_get(THIS_MODULE)) + return -ENODEV; + + mutex_lock(&lock); + + list_for_each_entry(tmp, &consumers, node) { + if (tmp->token == consumer->token) { + mutex_unlock(&lock); + module_put(THIS_MODULE); + return -EBUSY; + } + } + + list_for_each_entry(producer, &producers, node) { + if (producer->token == consumer->token) { + int ret = __connect(producer, consumer); + if (ret) { + mutex_unlock(&lock); + module_put(THIS_MODULE); + return ret; + } + break; + } + } + + list_add(&consumer->node, &consumers); + + mutex_unlock(&lock); + + return 0; +} +EXPORT_SYMBOL_GPL(irq_bypass_register_consumer); + +/** + * 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) +{ + struct irq_bypass_consumer *tmp; + struct irq_bypass_producer *producer; + + might_sleep(); + + if (!try_module_get(THIS_MODULE)) + return; /* nothing in the list anyway */ + + mutex_lock(&lock); + + list_for_each_entry(tmp, &consumers, node) { + if (tmp->token != consumer->token) + continue; + + list_for_each_entry(producer, &producers, node) { + if (producer->token == consumer->token) { + __disconnect(producer, consumer); + break; + } + } + + list_del(&consumer->node); + module_put(THIS_MODULE); + break; + } + + mutex_unlock(&lock); + + module_put(THIS_MODULE); +} +EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer); |