diff options
Diffstat (limited to 'drivers/virt/acrn/irqfd.c')
| -rw-r--r-- | drivers/virt/acrn/irqfd.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/drivers/virt/acrn/irqfd.c b/drivers/virt/acrn/irqfd.c new file mode 100644 index 000000000000..a8766d528e29 --- /dev/null +++ b/drivers/virt/acrn/irqfd.c @@ -0,0 +1,235 @@ +// 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); +static DEFINE_MUTEX(acrn_irqfds_mutex); + +/** + * 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; + unsigned int 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 = f.file->f_op->poll(f.file, &irqfd->pt); + + if (events & POLLIN) + 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); +} |