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// SPDX-License-Identifier: GPL-2.0
/*
* ACRN HSM irqfd: use eventfd objects to inject virtual interrupts
*
* Copyright (C) 2020 Intel Corporation. All rights reserved.
*
* Authors:
* Shuo Liu <shuo.a.liu@intel.com>
* Yakui Zhao <yakui.zhao@intel.com>
*/
#include <linux/eventfd.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include "acrn_drv.h"
static LIST_HEAD(acrn_irqfd_clients);
/**
* struct hsm_irqfd - Properties of HSM irqfd
* @vm: Associated VM pointer
* @wait: Entry of wait-queue
* @shutdown: Async shutdown work
* @eventfd: Associated eventfd
* @list: Entry within &acrn_vm.irqfds of irqfds of a VM
* @pt: Structure for select/poll on the associated eventfd
* @msi: MSI data
*/
struct hsm_irqfd {
struct acrn_vm *vm;
wait_queue_entry_t wait;
struct work_struct shutdown;
struct eventfd_ctx *eventfd;
struct list_head list;
poll_table pt;
struct acrn_msi_entry msi;
};
static void acrn_irqfd_inject(struct hsm_irqfd *irqfd)
{
struct acrn_vm *vm = irqfd->vm;
acrn_msi_inject(vm, irqfd->msi.msi_addr,
irqfd->msi.msi_data);
}
static void hsm_irqfd_shutdown(struct hsm_irqfd *irqfd)
{
u64 cnt;
lockdep_assert_held(&irqfd->vm->irqfds_lock);
/* remove from wait queue */
list_del_init(&irqfd->list);
eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
eventfd_ctx_put(irqfd->eventfd);
kfree(irqfd);
}
static void hsm_irqfd_shutdown_work(struct work_struct *work)
{
struct hsm_irqfd *irqfd;
struct acrn_vm *vm;
irqfd = container_of(work, struct hsm_irqfd, shutdown);
vm = irqfd->vm;
mutex_lock(&vm->irqfds_lock);
if (!list_empty(&irqfd->list))
hsm_irqfd_shutdown(irqfd);
mutex_unlock(&vm->irqfds_lock);
}
/* Called with wqh->lock held and interrupts disabled */
static int hsm_irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode,
int sync, void *key)
{
unsigned long poll_bits = (unsigned long)key;
struct hsm_irqfd *irqfd;
struct acrn_vm *vm;
irqfd = container_of(wait, struct hsm_irqfd, wait);
vm = irqfd->vm;
if (poll_bits & POLLIN)
/* An event has been signaled, inject an interrupt */
acrn_irqfd_inject(irqfd);
if (poll_bits & POLLHUP)
/* Do shutdown work in thread to hold wqh->lock */
queue_work(vm->irqfd_wq, &irqfd->shutdown);
return 0;
}
static void hsm_irqfd_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
{
struct hsm_irqfd *irqfd;
irqfd = container_of(pt, struct hsm_irqfd, pt);
add_wait_queue(wqh, &irqfd->wait);
}
/*
* Assign an eventfd to a VM and create a HSM irqfd associated with the
* eventfd. The properties of the HSM irqfd are built from a &struct
* acrn_irqfd.
*/
static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args)
{
struct eventfd_ctx *eventfd = NULL;
struct hsm_irqfd *irqfd, *tmp;
__poll_t events;
struct fd f;
int ret = 0;
irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
if (!irqfd)
return -ENOMEM;
irqfd->vm = vm;
memcpy(&irqfd->msi, &args->msi, sizeof(args->msi));
INIT_LIST_HEAD(&irqfd->list);
INIT_WORK(&irqfd->shutdown, hsm_irqfd_shutdown_work);
f = fdget(args->fd);
if (!f.file) {
ret = -EBADF;
goto out;
}
eventfd = eventfd_ctx_fileget(f.file);
if (IS_ERR(eventfd)) {
ret = PTR_ERR(eventfd);
goto fail;
}
irqfd->eventfd = eventfd;
/*
* Install custom wake-up handling to be notified whenever underlying
* eventfd is signaled.
*/
init_waitqueue_func_entry(&irqfd->wait, hsm_irqfd_wakeup);
init_poll_funcptr(&irqfd->pt, hsm_irqfd_poll_func);
mutex_lock(&vm->irqfds_lock);
list_for_each_entry(tmp, &vm->irqfds, list) {
if (irqfd->eventfd != tmp->eventfd)
continue;
ret = -EBUSY;
mutex_unlock(&vm->irqfds_lock);
goto fail;
}
list_add_tail(&irqfd->list, &vm->irqfds);
mutex_unlock(&vm->irqfds_lock);
/* Check the pending event in this stage */
events = vfs_poll(f.file, &irqfd->pt);
if (events & EPOLLIN)
acrn_irqfd_inject(irqfd);
fdput(f);
return 0;
fail:
if (eventfd && !IS_ERR(eventfd))
eventfd_ctx_put(eventfd);
fdput(f);
out:
kfree(irqfd);
return ret;
}
static int acrn_irqfd_deassign(struct acrn_vm *vm,
struct acrn_irqfd *args)
{
struct hsm_irqfd *irqfd, *tmp;
struct eventfd_ctx *eventfd;
eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
mutex_lock(&vm->irqfds_lock);
list_for_each_entry_safe(irqfd, tmp, &vm->irqfds, list) {
if (irqfd->eventfd == eventfd) {
hsm_irqfd_shutdown(irqfd);
break;
}
}
mutex_unlock(&vm->irqfds_lock);
eventfd_ctx_put(eventfd);
return 0;
}
int acrn_irqfd_config(struct acrn_vm *vm, struct acrn_irqfd *args)
{
int ret;
if (args->flags & ACRN_IRQFD_FLAG_DEASSIGN)
ret = acrn_irqfd_deassign(vm, args);
else
ret = acrn_irqfd_assign(vm, args);
return ret;
}
int acrn_irqfd_init(struct acrn_vm *vm)
{
INIT_LIST_HEAD(&vm->irqfds);
mutex_init(&vm->irqfds_lock);
vm->irqfd_wq = alloc_workqueue("acrn_irqfd-%u", 0, 0, vm->vmid);
if (!vm->irqfd_wq)
return -ENOMEM;
dev_dbg(acrn_dev.this_device, "VM %u irqfd init.\n", vm->vmid);
return 0;
}
void acrn_irqfd_deinit(struct acrn_vm *vm)
{
struct hsm_irqfd *irqfd, *next;
dev_dbg(acrn_dev.this_device, "VM %u irqfd deinit.\n", vm->vmid);
destroy_workqueue(vm->irqfd_wq);
mutex_lock(&vm->irqfds_lock);
list_for_each_entry_safe(irqfd, next, &vm->irqfds, list)
hsm_irqfd_shutdown(irqfd);
mutex_unlock(&vm->irqfds_lock);
}
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