diff options
Diffstat (limited to 'virt/kvm/eventfd.c')
| -rw-r--r-- | virt/kvm/eventfd.c | 91 |
1 files changed, 79 insertions, 12 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index c1f1e3c6298..2ca4535f4fb 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -44,14 +44,19 @@ */ struct _irqfd { - struct kvm *kvm; - struct eventfd_ctx *eventfd; - int gsi; - struct list_head list; - poll_table pt; - wait_queue_t wait; - struct work_struct inject; - struct work_struct shutdown; + /* Used for MSI fast-path */ + struct kvm *kvm; + wait_queue_t wait; + /* Update side is protected by irqfds.lock */ + struct kvm_kernel_irq_routing_entry __rcu *irq_entry; + /* Used for level IRQ fast-path */ + int gsi; + struct work_struct inject; + /* Used for setup/shutdown */ + struct eventfd_ctx *eventfd; + struct list_head list; + poll_table pt; + struct work_struct shutdown; }; static struct workqueue_struct *irqfd_cleanup_wq; @@ -125,14 +130,22 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key) { struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait); unsigned long flags = (unsigned long)key; + struct kvm_kernel_irq_routing_entry *irq; + struct kvm *kvm = irqfd->kvm; - if (flags & POLLIN) + if (flags & POLLIN) { + rcu_read_lock(); + irq = rcu_dereference(irqfd->irq_entry); /* An event has been signaled, inject an interrupt */ - schedule_work(&irqfd->inject); + if (irq) + kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1); + else + schedule_work(&irqfd->inject); + rcu_read_unlock(); + } if (flags & POLLHUP) { /* The eventfd is closing, detach from KVM */ - struct kvm *kvm = irqfd->kvm; unsigned long flags; spin_lock_irqsave(&kvm->irqfds.lock, flags); @@ -163,9 +176,31 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, add_wait_queue(wqh, &irqfd->wait); } +/* Must be called under irqfds.lock */ +static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd, + struct kvm_irq_routing_table *irq_rt) +{ + struct kvm_kernel_irq_routing_entry *e; + struct hlist_node *n; + + if (irqfd->gsi >= irq_rt->nr_rt_entries) { + rcu_assign_pointer(irqfd->irq_entry, NULL); + return; + } + + hlist_for_each_entry(e, n, &irq_rt->map[irqfd->gsi], link) { + /* Only fast-path MSI. */ + if (e->type == KVM_IRQ_ROUTING_MSI) + rcu_assign_pointer(irqfd->irq_entry, e); + else + rcu_assign_pointer(irqfd->irq_entry, NULL); + } +} + static int kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi) { + struct kvm_irq_routing_table *irq_rt; struct _irqfd *irqfd, *tmp; struct file *file = NULL; struct eventfd_ctx *eventfd = NULL; @@ -215,6 +250,10 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi) goto fail; } + irq_rt = rcu_dereference_protected(kvm->irq_routing, + lockdep_is_held(&kvm->irqfds.lock)); + irqfd_update(kvm, irqfd, irq_rt); + events = file->f_op->poll(file, &irqfd->pt); list_add_tail(&irqfd->list, &kvm->irqfds.items); @@ -271,8 +310,17 @@ kvm_irqfd_deassign(struct kvm *kvm, int fd, int gsi) spin_lock_irq(&kvm->irqfds.lock); list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { - if (irqfd->eventfd == eventfd && irqfd->gsi == gsi) + if (irqfd->eventfd == eventfd && irqfd->gsi == gsi) { + /* + * This rcu_assign_pointer is needed for when + * another thread calls kvm_irqfd_update before + * we flush workqueue below. + * It is paired with synchronize_rcu done by caller + * of that function. + */ + rcu_assign_pointer(irqfd->irq_entry, NULL); irqfd_deactivate(irqfd); + } } spin_unlock_irq(&kvm->irqfds.lock); @@ -322,6 +370,25 @@ kvm_irqfd_release(struct kvm *kvm) } /* + * Change irq_routing and irqfd. + * Caller must invoke synchronize_rcu afterwards. + */ +void kvm_irq_routing_update(struct kvm *kvm, + struct kvm_irq_routing_table *irq_rt) +{ + struct _irqfd *irqfd; + + spin_lock_irq(&kvm->irqfds.lock); + + rcu_assign_pointer(kvm->irq_routing, irq_rt); + + list_for_each_entry(irqfd, &kvm->irqfds.items, list) + irqfd_update(kvm, irqfd, irq_rt); + + 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 single-thread * queue to prevent deadlock against flushing the normal work-queue. |