forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
983 lines
23 KiB
983 lines
23 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* kvm eventfd support - use eventfd objects to signal various KVM events |
|
* |
|
* Copyright 2009 Novell. All Rights Reserved. |
|
* Copyright 2010 Red Hat, Inc. and/or its affiliates. |
|
* |
|
* Author: |
|
* Gregory Haskins <[email protected]> |
|
*/ |
|
|
|
#include <linux/kvm_host.h> |
|
#include <linux/kvm.h> |
|
#include <linux/kvm_irqfd.h> |
|
#include <linux/workqueue.h> |
|
#include <linux/syscalls.h> |
|
#include <linux/wait.h> |
|
#include <linux/poll.h> |
|
#include <linux/file.h> |
|
#include <linux/list.h> |
|
#include <linux/eventfd.h> |
|
#include <linux/kernel.h> |
|
#include <linux/srcu.h> |
|
#include <linux/slab.h> |
|
#include <linux/seqlock.h> |
|
#include <linux/irqbypass.h> |
|
#include <trace/events/kvm.h> |
|
|
|
#include <kvm/iodev.h> |
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQFD |
|
|
|
static struct workqueue_struct *irqfd_cleanup_wq; |
|
|
|
bool __attribute__((weak)) |
|
kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args) |
|
{ |
|
return true; |
|
} |
|
|
|
static void |
|
irqfd_inject(struct work_struct *work) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd = |
|
container_of(work, struct kvm_kernel_irqfd, inject); |
|
struct kvm *kvm = irqfd->kvm; |
|
|
|
if (!irqfd->resampler) { |
|
kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1, |
|
false); |
|
kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0, |
|
false); |
|
} else |
|
kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
|
irqfd->gsi, 1, false); |
|
} |
|
|
|
/* |
|
* Since resampler irqfds share an IRQ source ID, we de-assert once |
|
* then notify all of the resampler irqfds using this GSI. We can't |
|
* do multiple de-asserts or we risk racing with incoming re-asserts. |
|
*/ |
|
static void |
|
irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) |
|
{ |
|
struct kvm_kernel_irqfd_resampler *resampler; |
|
struct kvm *kvm; |
|
struct kvm_kernel_irqfd *irqfd; |
|
int idx; |
|
|
|
resampler = container_of(kian, |
|
struct kvm_kernel_irqfd_resampler, notifier); |
|
kvm = resampler->kvm; |
|
|
|
kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
|
resampler->notifier.gsi, 0, false); |
|
|
|
idx = srcu_read_lock(&kvm->irq_srcu); |
|
|
|
list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link, |
|
srcu_read_lock_held(&kvm->irq_srcu)) |
|
eventfd_signal(irqfd->resamplefd, 1); |
|
|
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
} |
|
|
|
static void |
|
irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd) |
|
{ |
|
struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler; |
|
struct kvm *kvm = resampler->kvm; |
|
|
|
mutex_lock(&kvm->irqfds.resampler_lock); |
|
|
|
list_del_rcu(&irqfd->resampler_link); |
|
synchronize_srcu(&kvm->irq_srcu); |
|
|
|
if (list_empty(&resampler->list)) { |
|
list_del(&resampler->link); |
|
kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier); |
|
kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
|
resampler->notifier.gsi, 0, false); |
|
kfree(resampler); |
|
} |
|
|
|
mutex_unlock(&kvm->irqfds.resampler_lock); |
|
} |
|
|
|
/* |
|
* Race-free decouple logic (ordering is critical) |
|
*/ |
|
static void |
|
irqfd_shutdown(struct work_struct *work) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd = |
|
container_of(work, struct kvm_kernel_irqfd, shutdown); |
|
struct kvm *kvm = irqfd->kvm; |
|
u64 cnt; |
|
|
|
/* Make sure irqfd has been initialized in assign path. */ |
|
synchronize_srcu(&kvm->irq_srcu); |
|
|
|
/* |
|
* Synchronize with the wait-queue and unhook ourselves to prevent |
|
* further events. |
|
*/ |
|
eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt); |
|
|
|
/* |
|
* We know no new events will be scheduled at this point, so block |
|
* until all previously outstanding events have completed |
|
*/ |
|
flush_work(&irqfd->inject); |
|
|
|
if (irqfd->resampler) { |
|
irqfd_resampler_shutdown(irqfd); |
|
eventfd_ctx_put(irqfd->resamplefd); |
|
} |
|
|
|
/* |
|
* It is now safe to release the object's resources |
|
*/ |
|
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
|
irq_bypass_unregister_consumer(&irqfd->consumer); |
|
#endif |
|
eventfd_ctx_put(irqfd->eventfd); |
|
kfree(irqfd); |
|
} |
|
|
|
|
|
/* assumes kvm->irqfds.lock is held */ |
|
static bool |
|
irqfd_is_active(struct kvm_kernel_irqfd *irqfd) |
|
{ |
|
return list_empty(&irqfd->list) ? false : true; |
|
} |
|
|
|
/* |
|
* Mark the irqfd as inactive and schedule it for removal |
|
* |
|
* assumes kvm->irqfds.lock is held |
|
*/ |
|
static void |
|
irqfd_deactivate(struct kvm_kernel_irqfd *irqfd) |
|
{ |
|
BUG_ON(!irqfd_is_active(irqfd)); |
|
|
|
list_del_init(&irqfd->list); |
|
|
|
queue_work(irqfd_cleanup_wq, &irqfd->shutdown); |
|
} |
|
|
|
int __attribute__((weak)) kvm_arch_set_irq_inatomic( |
|
struct kvm_kernel_irq_routing_entry *irq, |
|
struct kvm *kvm, int irq_source_id, |
|
int level, |
|
bool line_status) |
|
{ |
|
return -EWOULDBLOCK; |
|
} |
|
|
|
/* |
|
* Called with wqh->lock held and interrupts disabled |
|
*/ |
|
static int |
|
irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd = |
|
container_of(wait, struct kvm_kernel_irqfd, wait); |
|
__poll_t flags = key_to_poll(key); |
|
struct kvm_kernel_irq_routing_entry irq; |
|
struct kvm *kvm = irqfd->kvm; |
|
unsigned seq; |
|
int idx; |
|
int ret = 0; |
|
|
|
if (flags & EPOLLIN) { |
|
u64 cnt; |
|
eventfd_ctx_do_read(irqfd->eventfd, &cnt); |
|
|
|
idx = srcu_read_lock(&kvm->irq_srcu); |
|
do { |
|
seq = read_seqcount_begin(&irqfd->irq_entry_sc); |
|
irq = irqfd->irq_entry; |
|
} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq)); |
|
/* An event has been signaled, inject an interrupt */ |
|
if (kvm_arch_set_irq_inatomic(&irq, kvm, |
|
KVM_USERSPACE_IRQ_SOURCE_ID, 1, |
|
false) == -EWOULDBLOCK) |
|
schedule_work(&irqfd->inject); |
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
ret = 1; |
|
} |
|
|
|
if (flags & EPOLLHUP) { |
|
/* The eventfd is closing, detach from KVM */ |
|
unsigned long iflags; |
|
|
|
spin_lock_irqsave(&kvm->irqfds.lock, iflags); |
|
|
|
/* |
|
* We must check if someone deactivated the irqfd before |
|
* we could acquire the irqfds.lock since the item is |
|
* deactivated from the KVM side before it is unhooked from |
|
* the wait-queue. If it is already deactivated, we can |
|
* simply return knowing the other side will cleanup for us. |
|
* We cannot race against the irqfd going away since the |
|
* other side is required to acquire wqh->lock, which we hold |
|
*/ |
|
if (irqfd_is_active(irqfd)) |
|
irqfd_deactivate(irqfd); |
|
|
|
spin_unlock_irqrestore(&kvm->irqfds.lock, iflags); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static void |
|
irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, |
|
poll_table *pt) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd = |
|
container_of(pt, struct kvm_kernel_irqfd, pt); |
|
add_wait_queue_priority(wqh, &irqfd->wait); |
|
} |
|
|
|
/* Must be called under irqfds.lock */ |
|
static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd) |
|
{ |
|
struct kvm_kernel_irq_routing_entry *e; |
|
struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; |
|
int n_entries; |
|
|
|
n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); |
|
|
|
write_seqcount_begin(&irqfd->irq_entry_sc); |
|
|
|
e = entries; |
|
if (n_entries == 1) |
|
irqfd->irq_entry = *e; |
|
else |
|
irqfd->irq_entry.type = 0; |
|
|
|
write_seqcount_end(&irqfd->irq_entry_sc); |
|
} |
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
|
void __attribute__((weak)) kvm_arch_irq_bypass_stop( |
|
struct irq_bypass_consumer *cons) |
|
{ |
|
} |
|
|
|
void __attribute__((weak)) kvm_arch_irq_bypass_start( |
|
struct irq_bypass_consumer *cons) |
|
{ |
|
} |
|
|
|
int __attribute__((weak)) kvm_arch_update_irqfd_routing( |
|
struct kvm *kvm, unsigned int host_irq, |
|
uint32_t guest_irq, bool set) |
|
{ |
|
return 0; |
|
} |
|
|
|
bool __attribute__((weak)) kvm_arch_irqfd_route_changed( |
|
struct kvm_kernel_irq_routing_entry *old, |
|
struct kvm_kernel_irq_routing_entry *new) |
|
{ |
|
return true; |
|
} |
|
#endif |
|
|
|
static int |
|
kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd, *tmp; |
|
struct fd f; |
|
struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; |
|
int ret; |
|
__poll_t events; |
|
int idx; |
|
|
|
if (!kvm_arch_intc_initialized(kvm)) |
|
return -EAGAIN; |
|
|
|
if (!kvm_arch_irqfd_allowed(kvm, args)) |
|
return -EINVAL; |
|
|
|
irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL_ACCOUNT); |
|
if (!irqfd) |
|
return -ENOMEM; |
|
|
|
irqfd->kvm = kvm; |
|
irqfd->gsi = args->gsi; |
|
INIT_LIST_HEAD(&irqfd->list); |
|
INIT_WORK(&irqfd->inject, irqfd_inject); |
|
INIT_WORK(&irqfd->shutdown, irqfd_shutdown); |
|
seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock); |
|
|
|
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; |
|
|
|
if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) { |
|
struct kvm_kernel_irqfd_resampler *resampler; |
|
|
|
resamplefd = eventfd_ctx_fdget(args->resamplefd); |
|
if (IS_ERR(resamplefd)) { |
|
ret = PTR_ERR(resamplefd); |
|
goto fail; |
|
} |
|
|
|
irqfd->resamplefd = resamplefd; |
|
INIT_LIST_HEAD(&irqfd->resampler_link); |
|
|
|
mutex_lock(&kvm->irqfds.resampler_lock); |
|
|
|
list_for_each_entry(resampler, |
|
&kvm->irqfds.resampler_list, link) { |
|
if (resampler->notifier.gsi == irqfd->gsi) { |
|
irqfd->resampler = resampler; |
|
break; |
|
} |
|
} |
|
|
|
if (!irqfd->resampler) { |
|
resampler = kzalloc(sizeof(*resampler), |
|
GFP_KERNEL_ACCOUNT); |
|
if (!resampler) { |
|
ret = -ENOMEM; |
|
mutex_unlock(&kvm->irqfds.resampler_lock); |
|
goto fail; |
|
} |
|
|
|
resampler->kvm = kvm; |
|
INIT_LIST_HEAD(&resampler->list); |
|
resampler->notifier.gsi = irqfd->gsi; |
|
resampler->notifier.irq_acked = irqfd_resampler_ack; |
|
INIT_LIST_HEAD(&resampler->link); |
|
|
|
list_add(&resampler->link, &kvm->irqfds.resampler_list); |
|
kvm_register_irq_ack_notifier(kvm, |
|
&resampler->notifier); |
|
irqfd->resampler = resampler; |
|
} |
|
|
|
list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); |
|
synchronize_srcu(&kvm->irq_srcu); |
|
|
|
mutex_unlock(&kvm->irqfds.resampler_lock); |
|
} |
|
|
|
/* |
|
* Install our own custom wake-up handling so we are notified via |
|
* a callback whenever someone signals the underlying eventfd |
|
*/ |
|
init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); |
|
init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); |
|
|
|
spin_lock_irq(&kvm->irqfds.lock); |
|
|
|
ret = 0; |
|
list_for_each_entry(tmp, &kvm->irqfds.items, list) { |
|
if (irqfd->eventfd != tmp->eventfd) |
|
continue; |
|
/* This fd is used for another irq already. */ |
|
ret = -EBUSY; |
|
spin_unlock_irq(&kvm->irqfds.lock); |
|
goto fail; |
|
} |
|
|
|
idx = srcu_read_lock(&kvm->irq_srcu); |
|
irqfd_update(kvm, irqfd); |
|
|
|
list_add_tail(&irqfd->list, &kvm->irqfds.items); |
|
|
|
spin_unlock_irq(&kvm->irqfds.lock); |
|
|
|
/* |
|
* Check if there was an event already pending on the eventfd |
|
* before we registered, and trigger it as if we didn't miss it. |
|
*/ |
|
events = vfs_poll(f.file, &irqfd->pt); |
|
|
|
if (events & EPOLLIN) |
|
schedule_work(&irqfd->inject); |
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
|
if (kvm_arch_has_irq_bypass()) { |
|
irqfd->consumer.token = (void *)irqfd->eventfd; |
|
irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer; |
|
irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer; |
|
irqfd->consumer.stop = kvm_arch_irq_bypass_stop; |
|
irqfd->consumer.start = kvm_arch_irq_bypass_start; |
|
ret = irq_bypass_register_consumer(&irqfd->consumer); |
|
if (ret) |
|
pr_info("irq bypass consumer (token %p) registration fails: %d\n", |
|
irqfd->consumer.token, ret); |
|
} |
|
#endif |
|
|
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
|
|
/* |
|
* do not drop the file until the irqfd is fully initialized, otherwise |
|
* we might race against the EPOLLHUP |
|
*/ |
|
fdput(f); |
|
return 0; |
|
|
|
fail: |
|
if (irqfd->resampler) |
|
irqfd_resampler_shutdown(irqfd); |
|
|
|
if (resamplefd && !IS_ERR(resamplefd)) |
|
eventfd_ctx_put(resamplefd); |
|
|
|
if (eventfd && !IS_ERR(eventfd)) |
|
eventfd_ctx_put(eventfd); |
|
|
|
fdput(f); |
|
|
|
out: |
|
kfree(irqfd); |
|
return ret; |
|
} |
|
|
|
bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) |
|
{ |
|
struct kvm_irq_ack_notifier *kian; |
|
int gsi, idx; |
|
|
|
idx = srcu_read_lock(&kvm->irq_srcu); |
|
gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); |
|
if (gsi != -1) |
|
hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list, |
|
link, srcu_read_lock_held(&kvm->irq_srcu)) |
|
if (kian->gsi == gsi) { |
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
return true; |
|
} |
|
|
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
|
|
return false; |
|
} |
|
EXPORT_SYMBOL_GPL(kvm_irq_has_notifier); |
|
|
|
void kvm_notify_acked_gsi(struct kvm *kvm, int gsi) |
|
{ |
|
struct kvm_irq_ack_notifier *kian; |
|
|
|
hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list, |
|
link, srcu_read_lock_held(&kvm->irq_srcu)) |
|
if (kian->gsi == gsi) |
|
kian->irq_acked(kian); |
|
} |
|
|
|
void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) |
|
{ |
|
int gsi, idx; |
|
|
|
trace_kvm_ack_irq(irqchip, pin); |
|
|
|
idx = srcu_read_lock(&kvm->irq_srcu); |
|
gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); |
|
if (gsi != -1) |
|
kvm_notify_acked_gsi(kvm, gsi); |
|
srcu_read_unlock(&kvm->irq_srcu, idx); |
|
} |
|
|
|
void kvm_register_irq_ack_notifier(struct kvm *kvm, |
|
struct kvm_irq_ack_notifier *kian) |
|
{ |
|
mutex_lock(&kvm->irq_lock); |
|
hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); |
|
mutex_unlock(&kvm->irq_lock); |
|
kvm_arch_post_irq_ack_notifier_list_update(kvm); |
|
} |
|
|
|
void kvm_unregister_irq_ack_notifier(struct kvm *kvm, |
|
struct kvm_irq_ack_notifier *kian) |
|
{ |
|
mutex_lock(&kvm->irq_lock); |
|
hlist_del_init_rcu(&kian->link); |
|
mutex_unlock(&kvm->irq_lock); |
|
synchronize_srcu(&kvm->irq_srcu); |
|
kvm_arch_post_irq_ack_notifier_list_update(kvm); |
|
} |
|
#endif |
|
|
|
void |
|
kvm_eventfd_init(struct kvm *kvm) |
|
{ |
|
#ifdef CONFIG_HAVE_KVM_IRQFD |
|
spin_lock_init(&kvm->irqfds.lock); |
|
INIT_LIST_HEAD(&kvm->irqfds.items); |
|
INIT_LIST_HEAD(&kvm->irqfds.resampler_list); |
|
mutex_init(&kvm->irqfds.resampler_lock); |
|
#endif |
|
INIT_LIST_HEAD(&kvm->ioeventfds); |
|
} |
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQFD |
|
/* |
|
* shutdown any irqfd's that match fd+gsi |
|
*/ |
|
static int |
|
kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd, *tmp; |
|
struct eventfd_ctx *eventfd; |
|
|
|
eventfd = eventfd_ctx_fdget(args->fd); |
|
if (IS_ERR(eventfd)) |
|
return PTR_ERR(eventfd); |
|
|
|
spin_lock_irq(&kvm->irqfds.lock); |
|
|
|
list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { |
|
if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) { |
|
/* |
|
* This clearing of irq_entry.type is needed for when |
|
* another thread calls kvm_irq_routing_update before |
|
* we flush workqueue below (we synchronize with |
|
* kvm_irq_routing_update using irqfds.lock). |
|
*/ |
|
write_seqcount_begin(&irqfd->irq_entry_sc); |
|
irqfd->irq_entry.type = 0; |
|
write_seqcount_end(&irqfd->irq_entry_sc); |
|
irqfd_deactivate(irqfd); |
|
} |
|
} |
|
|
|
spin_unlock_irq(&kvm->irqfds.lock); |
|
eventfd_ctx_put(eventfd); |
|
|
|
/* |
|
* Block until we know all outstanding shutdown jobs have completed |
|
* so that we guarantee there will not be any more interrupts on this |
|
* gsi once this deassign function returns. |
|
*/ |
|
flush_workqueue(irqfd_cleanup_wq); |
|
|
|
return 0; |
|
} |
|
|
|
int |
|
kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) |
|
{ |
|
if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE)) |
|
return -EINVAL; |
|
|
|
if (args->flags & KVM_IRQFD_FLAG_DEASSIGN) |
|
return kvm_irqfd_deassign(kvm, args); |
|
|
|
return kvm_irqfd_assign(kvm, args); |
|
} |
|
|
|
/* |
|
* This function is called as the kvm VM fd is being released. Shutdown all |
|
* irqfds that still remain open |
|
*/ |
|
void |
|
kvm_irqfd_release(struct kvm *kvm) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd, *tmp; |
|
|
|
spin_lock_irq(&kvm->irqfds.lock); |
|
|
|
list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) |
|
irqfd_deactivate(irqfd); |
|
|
|
spin_unlock_irq(&kvm->irqfds.lock); |
|
|
|
/* |
|
* Block until we know all outstanding shutdown jobs have completed |
|
* since we do not take a kvm* reference. |
|
*/ |
|
flush_workqueue(irqfd_cleanup_wq); |
|
|
|
} |
|
|
|
/* |
|
* Take note of a change in irq routing. |
|
* Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards. |
|
*/ |
|
void kvm_irq_routing_update(struct kvm *kvm) |
|
{ |
|
struct kvm_kernel_irqfd *irqfd; |
|
|
|
spin_lock_irq(&kvm->irqfds.lock); |
|
|
|
list_for_each_entry(irqfd, &kvm->irqfds.items, list) { |
|
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
|
/* Under irqfds.lock, so can read irq_entry safely */ |
|
struct kvm_kernel_irq_routing_entry old = irqfd->irq_entry; |
|
#endif |
|
|
|
irqfd_update(kvm, irqfd); |
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
|
if (irqfd->producer && |
|
kvm_arch_irqfd_route_changed(&old, &irqfd->irq_entry)) { |
|
int ret = kvm_arch_update_irqfd_routing( |
|
irqfd->kvm, irqfd->producer->irq, |
|
irqfd->gsi, 1); |
|
WARN_ON(ret); |
|
} |
|
#endif |
|
} |
|
|
|
spin_unlock_irq(&kvm->irqfds.lock); |
|
} |
|
|
|
/* |
|
* create a host-wide workqueue for issuing deferred shutdown requests |
|
* aggregated from all vm* instances. We need our own isolated |
|
* queue to ease flushing work items when a VM exits. |
|
*/ |
|
int kvm_irqfd_init(void) |
|
{ |
|
irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0); |
|
if (!irqfd_cleanup_wq) |
|
return -ENOMEM; |
|
|
|
return 0; |
|
} |
|
|
|
void kvm_irqfd_exit(void) |
|
{ |
|
destroy_workqueue(irqfd_cleanup_wq); |
|
} |
|
#endif |
|
|
|
/* |
|
* -------------------------------------------------------------------- |
|
* ioeventfd: translate a PIO/MMIO memory write to an eventfd signal. |
|
* |
|
* userspace can register a PIO/MMIO address with an eventfd for receiving |
|
* notification when the memory has been touched. |
|
* -------------------------------------------------------------------- |
|
*/ |
|
|
|
struct _ioeventfd { |
|
struct list_head list; |
|
u64 addr; |
|
int length; |
|
struct eventfd_ctx *eventfd; |
|
u64 datamatch; |
|
struct kvm_io_device dev; |
|
u8 bus_idx; |
|
bool wildcard; |
|
}; |
|
|
|
static inline struct _ioeventfd * |
|
to_ioeventfd(struct kvm_io_device *dev) |
|
{ |
|
return container_of(dev, struct _ioeventfd, dev); |
|
} |
|
|
|
static void |
|
ioeventfd_release(struct _ioeventfd *p) |
|
{ |
|
eventfd_ctx_put(p->eventfd); |
|
list_del(&p->list); |
|
kfree(p); |
|
} |
|
|
|
static bool |
|
ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) |
|
{ |
|
u64 _val; |
|
|
|
if (addr != p->addr) |
|
/* address must be precise for a hit */ |
|
return false; |
|
|
|
if (!p->length) |
|
/* length = 0 means only look at the address, so always a hit */ |
|
return true; |
|
|
|
if (len != p->length) |
|
/* address-range must be precise for a hit */ |
|
return false; |
|
|
|
if (p->wildcard) |
|
/* all else equal, wildcard is always a hit */ |
|
return true; |
|
|
|
/* otherwise, we have to actually compare the data */ |
|
|
|
BUG_ON(!IS_ALIGNED((unsigned long)val, len)); |
|
|
|
switch (len) { |
|
case 1: |
|
_val = *(u8 *)val; |
|
break; |
|
case 2: |
|
_val = *(u16 *)val; |
|
break; |
|
case 4: |
|
_val = *(u32 *)val; |
|
break; |
|
case 8: |
|
_val = *(u64 *)val; |
|
break; |
|
default: |
|
return false; |
|
} |
|
|
|
return _val == p->datamatch; |
|
} |
|
|
|
/* MMIO/PIO writes trigger an event if the addr/val match */ |
|
static int |
|
ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr, |
|
int len, const void *val) |
|
{ |
|
struct _ioeventfd *p = to_ioeventfd(this); |
|
|
|
if (!ioeventfd_in_range(p, addr, len, val)) |
|
return -EOPNOTSUPP; |
|
|
|
eventfd_signal(p->eventfd, 1); |
|
return 0; |
|
} |
|
|
|
/* |
|
* This function is called as KVM is completely shutting down. We do not |
|
* need to worry about locking just nuke anything we have as quickly as possible |
|
*/ |
|
static void |
|
ioeventfd_destructor(struct kvm_io_device *this) |
|
{ |
|
struct _ioeventfd *p = to_ioeventfd(this); |
|
|
|
ioeventfd_release(p); |
|
} |
|
|
|
static const struct kvm_io_device_ops ioeventfd_ops = { |
|
.write = ioeventfd_write, |
|
.destructor = ioeventfd_destructor, |
|
}; |
|
|
|
/* assumes kvm->slots_lock held */ |
|
static bool |
|
ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) |
|
{ |
|
struct _ioeventfd *_p; |
|
|
|
list_for_each_entry(_p, &kvm->ioeventfds, list) |
|
if (_p->bus_idx == p->bus_idx && |
|
_p->addr == p->addr && |
|
(!_p->length || !p->length || |
|
(_p->length == p->length && |
|
(_p->wildcard || p->wildcard || |
|
_p->datamatch == p->datamatch)))) |
|
return true; |
|
|
|
return false; |
|
} |
|
|
|
static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags) |
|
{ |
|
if (flags & KVM_IOEVENTFD_FLAG_PIO) |
|
return KVM_PIO_BUS; |
|
if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY) |
|
return KVM_VIRTIO_CCW_NOTIFY_BUS; |
|
return KVM_MMIO_BUS; |
|
} |
|
|
|
static int kvm_assign_ioeventfd_idx(struct kvm *kvm, |
|
enum kvm_bus bus_idx, |
|
struct kvm_ioeventfd *args) |
|
{ |
|
|
|
struct eventfd_ctx *eventfd; |
|
struct _ioeventfd *p; |
|
int ret; |
|
|
|
eventfd = eventfd_ctx_fdget(args->fd); |
|
if (IS_ERR(eventfd)) |
|
return PTR_ERR(eventfd); |
|
|
|
p = kzalloc(sizeof(*p), GFP_KERNEL_ACCOUNT); |
|
if (!p) { |
|
ret = -ENOMEM; |
|
goto fail; |
|
} |
|
|
|
INIT_LIST_HEAD(&p->list); |
|
p->addr = args->addr; |
|
p->bus_idx = bus_idx; |
|
p->length = args->len; |
|
p->eventfd = eventfd; |
|
|
|
/* The datamatch feature is optional, otherwise this is a wildcard */ |
|
if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) |
|
p->datamatch = args->datamatch; |
|
else |
|
p->wildcard = true; |
|
|
|
mutex_lock(&kvm->slots_lock); |
|
|
|
/* Verify that there isn't a match already */ |
|
if (ioeventfd_check_collision(kvm, p)) { |
|
ret = -EEXIST; |
|
goto unlock_fail; |
|
} |
|
|
|
kvm_iodevice_init(&p->dev, &ioeventfd_ops); |
|
|
|
ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length, |
|
&p->dev); |
|
if (ret < 0) |
|
goto unlock_fail; |
|
|
|
kvm_get_bus(kvm, bus_idx)->ioeventfd_count++; |
|
list_add_tail(&p->list, &kvm->ioeventfds); |
|
|
|
mutex_unlock(&kvm->slots_lock); |
|
|
|
return 0; |
|
|
|
unlock_fail: |
|
mutex_unlock(&kvm->slots_lock); |
|
|
|
fail: |
|
kfree(p); |
|
eventfd_ctx_put(eventfd); |
|
|
|
return ret; |
|
} |
|
|
|
static int |
|
kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx, |
|
struct kvm_ioeventfd *args) |
|
{ |
|
struct _ioeventfd *p, *tmp; |
|
struct eventfd_ctx *eventfd; |
|
struct kvm_io_bus *bus; |
|
int ret = -ENOENT; |
|
bool wildcard; |
|
|
|
eventfd = eventfd_ctx_fdget(args->fd); |
|
if (IS_ERR(eventfd)) |
|
return PTR_ERR(eventfd); |
|
|
|
wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); |
|
|
|
mutex_lock(&kvm->slots_lock); |
|
|
|
list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) { |
|
|
|
if (p->bus_idx != bus_idx || |
|
p->eventfd != eventfd || |
|
p->addr != args->addr || |
|
p->length != args->len || |
|
p->wildcard != wildcard) |
|
continue; |
|
|
|
if (!p->wildcard && p->datamatch != args->datamatch) |
|
continue; |
|
|
|
kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); |
|
bus = kvm_get_bus(kvm, bus_idx); |
|
if (bus) |
|
bus->ioeventfd_count--; |
|
ioeventfd_release(p); |
|
ret = 0; |
|
break; |
|
} |
|
|
|
mutex_unlock(&kvm->slots_lock); |
|
|
|
eventfd_ctx_put(eventfd); |
|
|
|
return ret; |
|
} |
|
|
|
static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) |
|
{ |
|
enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags); |
|
int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); |
|
|
|
if (!args->len && bus_idx == KVM_MMIO_BUS) |
|
kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); |
|
|
|
return ret; |
|
} |
|
|
|
static int |
|
kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) |
|
{ |
|
enum kvm_bus bus_idx; |
|
int ret; |
|
|
|
bus_idx = ioeventfd_bus_from_flags(args->flags); |
|
/* must be natural-word sized, or 0 to ignore length */ |
|
switch (args->len) { |
|
case 0: |
|
case 1: |
|
case 2: |
|
case 4: |
|
case 8: |
|
break; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
/* check for range overflow */ |
|
if (args->addr + args->len < args->addr) |
|
return -EINVAL; |
|
|
|
/* check for extra flags that we don't understand */ |
|
if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) |
|
return -EINVAL; |
|
|
|
/* ioeventfd with no length can't be combined with DATAMATCH */ |
|
if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)) |
|
return -EINVAL; |
|
|
|
ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args); |
|
if (ret) |
|
goto fail; |
|
|
|
/* When length is ignored, MMIO is also put on a separate bus, for |
|
* faster lookups. |
|
*/ |
|
if (!args->len && bus_idx == KVM_MMIO_BUS) { |
|
ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); |
|
if (ret < 0) |
|
goto fast_fail; |
|
} |
|
|
|
return 0; |
|
|
|
fast_fail: |
|
kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); |
|
fail: |
|
return ret; |
|
} |
|
|
|
int |
|
kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) |
|
{ |
|
if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN) |
|
return kvm_deassign_ioeventfd(kvm, args); |
|
|
|
return kvm_assign_ioeventfd(kvm, args); |
|
}
|
|
|