diff options
| -rw-r--r-- | virt/kvm/eventfd.c | 98 |
1 files changed, 55 insertions, 43 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 7b7c5269cf18..170a67aad983 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -245,9 +245,32 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) return ret; } +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; + + lockdep_assert_held(&kvm->irqfds.lock); + + 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); +} + struct kvm_irqfd_pt { struct kvm_kernel_irqfd *irqfd; + struct kvm *kvm; poll_table pt; + int ret; }; static void kvm_irqfd_register(struct file *file, wait_queue_head_t *wqh, @@ -255,6 +278,25 @@ static void kvm_irqfd_register(struct file *file, wait_queue_head_t *wqh, { struct kvm_irqfd_pt *p = container_of(pt, struct kvm_irqfd_pt, pt); struct kvm_kernel_irqfd *irqfd = p->irqfd; + struct kvm_kernel_irqfd *tmp; + struct kvm *kvm = p->kvm; + + spin_lock_irq(&kvm->irqfds.lock); + + list_for_each_entry(tmp, &kvm->irqfds.items, list) { + if (irqfd->eventfd != tmp->eventfd) + continue; + /* This fd is used for another irq already. */ + p->ret = -EBUSY; + spin_unlock_irq(&kvm->irqfds.lock); + return; + } + + irqfd_update(kvm, irqfd); + + list_add_tail(&irqfd->list, &kvm->irqfds.items); + + spin_unlock_irq(&kvm->irqfds.lock); /* * Add the irqfd as a priority waiter on the eventfd, with a custom @@ -264,26 +306,7 @@ static void kvm_irqfd_register(struct file *file, wait_queue_head_t *wqh, init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); 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); + p->ret = 0; } #if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS) @@ -308,7 +331,7 @@ void __weak kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd, static int kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) { - struct kvm_kernel_irqfd *irqfd, *tmp; + struct kvm_kernel_irqfd *irqfd; struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; struct kvm_irqfd_pt irqfd_pt; int ret; @@ -407,32 +430,22 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) */ idx = srcu_read_lock(&kvm->irq_srcu); - 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; - goto fail_duplicate; - } - - irqfd_update(kvm, irqfd); - - list_add_tail(&irqfd->list, &kvm->irqfds.items); - - spin_unlock_irq(&kvm->irqfds.lock); - /* - * Register the irqfd with the eventfd by polling on the eventfd. If - * there was en event pending on the eventfd prior to registering, - * manually trigger IRQ injection. + * Register the irqfd with the eventfd by polling on the eventfd, and + * simultaneously and the irqfd to KVM's list. If there was en event + * pending on the eventfd prior to registering, manually trigger IRQ + * injection. */ irqfd_pt.irqfd = irqfd; + irqfd_pt.kvm = kvm; init_poll_funcptr(&irqfd_pt.pt, kvm_irqfd_register); events = vfs_poll(fd_file(f), &irqfd_pt.pt); + + ret = irqfd_pt.ret; + if (ret) + goto fail_poll; + if (events & EPOLLIN) schedule_work(&irqfd->inject); @@ -452,8 +465,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) srcu_read_unlock(&kvm->irq_srcu, idx); return 0; -fail_duplicate: - spin_unlock_irq(&kvm->irqfds.lock); +fail_poll: srcu_read_unlock(&kvm->irq_srcu, idx); fail: if (irqfd->resampler) |