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// SPDX-License-Identifier: GPL-2.0-only
/*
* VFIO platform devices interrupt handling
*
* Copyright (C) 2013 - Virtual Open Systems
* Author: Antonios Motakis <a.motakis@virtualopensystems.com>
*/
#include <linux/eventfd.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/vfio.h>
#include <linux/irq.h>
#include "vfio_platform_private.h"
static void vfio_platform_mask(struct vfio_platform_irq *irq_ctx)
{
unsigned long flags;
spin_lock_irqsave(&irq_ctx->lock, flags);
if (!irq_ctx->masked) {
disable_irq_nosync(irq_ctx->hwirq);
irq_ctx->masked = true;
}
spin_unlock_irqrestore(&irq_ctx->lock, flags);
}
static int vfio_platform_mask_handler(void *opaque, void *unused)
{
struct vfio_platform_irq *irq_ctx = opaque;
vfio_platform_mask(irq_ctx);
return 0;
}
static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags,
void *data)
{
if (start != 0 || count != 1)
return -EINVAL;
if (!(vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE))
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
int32_t fd = *(int32_t *)data;
if (fd >= 0)
return vfio_virqfd_enable((void *) &vdev->irqs[index],
vfio_platform_mask_handler,
NULL, NULL,
&vdev->irqs[index].mask, fd);
vfio_virqfd_disable(&vdev->irqs[index].mask);
return 0;
}
if (flags & VFIO_IRQ_SET_DATA_NONE) {
vfio_platform_mask(&vdev->irqs[index]);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t mask = *(uint8_t *)data;
if (mask)
vfio_platform_mask(&vdev->irqs[index]);
}
return 0;
}
static void vfio_platform_unmask(struct vfio_platform_irq *irq_ctx)
{
unsigned long flags;
spin_lock_irqsave(&irq_ctx->lock, flags);
if (irq_ctx->masked) {
enable_irq(irq_ctx->hwirq);
irq_ctx->masked = false;
}
spin_unlock_irqrestore(&irq_ctx->lock, flags);
}
static int vfio_platform_unmask_handler(void *opaque, void *unused)
{
struct vfio_platform_irq *irq_ctx = opaque;
vfio_platform_unmask(irq_ctx);
return 0;
}
static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags,
void *data)
{
if (start != 0 || count != 1)
return -EINVAL;
if (!(vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE))
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
int32_t fd = *(int32_t *)data;
if (fd >= 0)
return vfio_virqfd_enable((void *) &vdev->irqs[index],
vfio_platform_unmask_handler,
NULL, NULL,
&vdev->irqs[index].unmask,
fd);
vfio_virqfd_disable(&vdev->irqs[index].unmask);
return 0;
}
if (flags & VFIO_IRQ_SET_DATA_NONE) {
vfio_platform_unmask(&vdev->irqs[index]);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t unmask = *(uint8_t *)data;
if (unmask)
vfio_platform_unmask(&vdev->irqs[index]);
}
return 0;
}
/*
* The trigger eventfd is guaranteed valid in the interrupt path
* and protected by the igate mutex when triggered via ioctl.
*/
static void vfio_send_eventfd(struct vfio_platform_irq *irq_ctx)
{
if (likely(irq_ctx->trigger))
eventfd_signal(irq_ctx->trigger, 1);
}
static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
{
struct vfio_platform_irq *irq_ctx = dev_id;
unsigned long flags;
int ret = IRQ_NONE;
spin_lock_irqsave(&irq_ctx->lock, flags);
if (!irq_ctx->masked) {
ret = IRQ_HANDLED;
/* automask maskable interrupts */
disable_irq_nosync(irq_ctx->hwirq);
irq_ctx->masked = true;
}
spin_unlock_irqrestore(&irq_ctx->lock, flags);
if (ret == IRQ_HANDLED)
vfio_send_eventfd(irq_ctx);
return ret;
}
static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
{
struct vfio_platform_irq *irq_ctx = dev_id;
vfio_send_eventfd(irq_ctx);
return IRQ_HANDLED;
}
static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
int fd)
{
struct vfio_platform_irq *irq = &vdev->irqs[index];
struct eventfd_ctx *trigger;
if (irq->trigger) {
disable_irq(irq->hwirq);
eventfd_ctx_put(irq->trigger);
irq->trigger = NULL;
}
if (fd < 0) /* Disable only */
return 0;
trigger = eventfd_ctx_fdget(fd);
if (IS_ERR(trigger))
return PTR_ERR(trigger);
irq->trigger = trigger;
/*
* irq->masked effectively provides nested disables within the overall
* enable relative to trigger. Specifically request_irq() is called
* with NO_AUTOEN, therefore the IRQ is initially disabled. The user
* may only further disable the IRQ with a MASK operations because
* irq->masked is initially false.
*/
enable_irq(irq->hwirq);
return 0;
}
static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags,
void *data)
{
struct vfio_platform_irq *irq = &vdev->irqs[index];
irq_handler_t handler;
if (vdev->irqs[index].flags & VFIO_IRQ_INFO_AUTOMASKED)
handler = vfio_automasked_irq_handler;
else
handler = vfio_irq_handler;
if (!count && (flags & VFIO_IRQ_SET_DATA_NONE))
return vfio_set_trigger(vdev, index, -1);
if (start != 0 || count != 1)
return -EINVAL;
if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
int32_t fd = *(int32_t *)data;
return vfio_set_trigger(vdev, index, fd);
}
if (flags & VFIO_IRQ_SET_DATA_NONE) {
handler(irq->hwirq, irq);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t trigger = *(uint8_t *)data;
if (trigger)
handler(irq->hwirq, irq);
}
return 0;
}
int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
uint32_t flags, unsigned index, unsigned start,
unsigned count, void *data)
{
int (*func)(struct vfio_platform_device *vdev, unsigned index,
unsigned start, unsigned count, uint32_t flags,
void *data) = NULL;
/*
* For compatibility, errors from request_irq() are local to the
* SET_IRQS path and reflected in the name pointer. This allows,
* for example, polling mode fallback for an exclusive IRQ failure.
*/
if (IS_ERR(vdev->irqs[index].name))
return PTR_ERR(vdev->irqs[index].name);
switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
case VFIO_IRQ_SET_ACTION_MASK:
func = vfio_platform_set_irq_mask;
break;
case VFIO_IRQ_SET_ACTION_UNMASK:
func = vfio_platform_set_irq_unmask;
break;
case VFIO_IRQ_SET_ACTION_TRIGGER:
func = vfio_platform_set_irq_trigger;
break;
}
if (!func)
return -ENOTTY;
return func(vdev, index, start, count, flags, data);
}
int vfio_platform_irq_init(struct vfio_platform_device *vdev)
{
int cnt = 0, i, ret = 0;
while (vdev->get_irq(vdev, cnt) >= 0)
cnt++;
vdev->irqs = kcalloc(cnt, sizeof(struct vfio_platform_irq), GFP_KERNEL);
if (!vdev->irqs)
return -ENOMEM;
for (i = 0; i < cnt; i++) {
int hwirq = vdev->get_irq(vdev, i);
irq_handler_t handler = vfio_irq_handler;
if (hwirq < 0) {
ret = -EINVAL;
goto err;
}
spin_lock_init(&vdev->irqs[i].lock);
vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD;
if (irq_get_trigger_type(hwirq) & IRQ_TYPE_LEVEL_MASK) {
vdev->irqs[i].flags |= VFIO_IRQ_INFO_MASKABLE
| VFIO_IRQ_INFO_AUTOMASKED;
handler = vfio_automasked_irq_handler;
}
vdev->irqs[i].count = 1;
vdev->irqs[i].hwirq = hwirq;
vdev->irqs[i].masked = false;
vdev->irqs[i].name = kasprintf(GFP_KERNEL,
"vfio-irq[%d](%s)", hwirq,
vdev->name);
if (!vdev->irqs[i].name) {
ret = -ENOMEM;
goto err;
}
ret = request_irq(hwirq, handler, IRQF_NO_AUTOEN,
vdev->irqs[i].name, &vdev->irqs[i]);
if (ret) {
kfree(vdev->irqs[i].name);
vdev->irqs[i].name = ERR_PTR(ret);
}
}
vdev->num_irqs = cnt;
return 0;
err:
for (--i; i >= 0; i--) {
if (!IS_ERR(vdev->irqs[i].name)) {
free_irq(vdev->irqs[i].hwirq, &vdev->irqs[i]);
kfree(vdev->irqs[i].name);
}
}
kfree(vdev->irqs);
return ret;
}
void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev)
{
int i;
for (i = 0; i < vdev->num_irqs; i++) {
vfio_virqfd_disable(&vdev->irqs[i].mask);
vfio_virqfd_disable(&vdev->irqs[i].unmask);
if (!IS_ERR(vdev->irqs[i].name)) {
free_irq(vdev->irqs[i].hwirq, &vdev->irqs[i]);
if (vdev->irqs[i].trigger)
eventfd_ctx_put(vdev->irqs[i].trigger);
kfree(vdev->irqs[i].name);
}
}
vdev->num_irqs = 0;
kfree(vdev->irqs);
}
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