diff options
Diffstat (limited to 'virt/kvm/eventfd.c')
| -rw-r--r-- | virt/kvm/eventfd.c | 154 |
1 files changed, 114 insertions, 40 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 64ee720b75c7..71ed39941b9c 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -31,11 +31,14 @@ #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 <trace/events/kvm.h> #include "iodev.h" -#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING +#ifdef CONFIG_HAVE_KVM_IRQFD /* * -------------------------------------------------------------------- * irqfd: Allows an fd to be used to inject an interrupt to the guest @@ -74,7 +77,8 @@ struct _irqfd { struct kvm *kvm; wait_queue_t wait; /* Update side is protected by irqfds.lock */ - struct kvm_kernel_irq_routing_entry __rcu *irq_entry; + struct kvm_kernel_irq_routing_entry irq_entry; + seqcount_t irq_entry_sc; /* Used for level IRQ fast-path */ int gsi; struct work_struct inject; @@ -118,19 +122,22 @@ static void irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) { struct _irqfd_resampler *resampler; + struct kvm *kvm; struct _irqfd *irqfd; + int idx; resampler = container_of(kian, struct _irqfd_resampler, notifier); + kvm = resampler->kvm; - kvm_set_irq(resampler->kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, + kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, resampler->notifier.gsi, 0, false); - rcu_read_lock(); + idx = srcu_read_lock(&kvm->irq_srcu); list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link) eventfd_signal(irqfd->resamplefd, 1); - rcu_read_unlock(); + srcu_read_unlock(&kvm->irq_srcu, idx); } static void @@ -142,7 +149,7 @@ irqfd_resampler_shutdown(struct _irqfd *irqfd) mutex_lock(&kvm->irqfds.resampler_lock); list_del_rcu(&irqfd->resampler_link); - synchronize_rcu(); + synchronize_srcu(&kvm->irq_srcu); if (list_empty(&resampler->list)) { list_del(&resampler->link); @@ -219,19 +226,24 @@ 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_kernel_irq_routing_entry irq; struct kvm *kvm = irqfd->kvm; + unsigned seq; + int idx; if (flags & POLLIN) { - rcu_read_lock(); - irq = rcu_dereference(irqfd->irq_entry); + 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 (irq) - kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, + if (irq.type == KVM_IRQ_ROUTING_MSI) + kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false); else schedule_work(&irqfd->inject); - rcu_read_unlock(); + srcu_read_unlock(&kvm->irq_srcu, idx); } if (flags & POLLHUP) { @@ -267,34 +279,37 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, } /* Must be called under irqfds.lock */ -static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd, - struct kvm_irq_routing_table *irq_rt) +static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd) { struct kvm_kernel_irq_routing_entry *e; + struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; + int i, n_entries; - if (irqfd->gsi >= irq_rt->nr_rt_entries) { - rcu_assign_pointer(irqfd->irq_entry, NULL); - return; - } + n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); + + write_seqcount_begin(&irqfd->irq_entry_sc); + + irqfd->irq_entry.type = 0; - hlist_for_each_entry(e, &irq_rt->map[irqfd->gsi], link) { + e = entries; + for (i = 0; i < n_entries; ++i, ++e) { /* 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); + irqfd->irq_entry = *e; } + + write_seqcount_end(&irqfd->irq_entry_sc); } static int kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) { - struct kvm_irq_routing_table *irq_rt; struct _irqfd *irqfd, *tmp; struct file *file = NULL; struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; int ret; unsigned int events; + int idx; irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); if (!irqfd) @@ -305,6 +320,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) INIT_LIST_HEAD(&irqfd->list); INIT_WORK(&irqfd->inject, irqfd_inject); INIT_WORK(&irqfd->shutdown, irqfd_shutdown); + seqcount_init(&irqfd->irq_entry_sc); file = eventfd_fget(args->fd); if (IS_ERR(file)) { @@ -363,7 +379,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) } list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); - synchronize_rcu(); + synchronize_srcu(&kvm->irq_srcu); mutex_unlock(&kvm->irqfds.resampler_lock); } @@ -387,9 +403,9 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) goto fail; } - irq_rt = rcu_dereference_protected(kvm->irq_routing, - lockdep_is_held(&kvm->irqfds.lock)); - irqfd_update(kvm, irqfd, irq_rt); + idx = srcu_read_lock(&kvm->irq_srcu); + irqfd_update(kvm, irqfd); + srcu_read_unlock(&kvm->irq_srcu, idx); events = file->f_op->poll(file, &irqfd->pt); @@ -428,12 +444,73 @@ fail: 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_rcu(kian, &kvm->irq_ack_notifier_list, + link) + 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_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) +{ + struct kvm_irq_ack_notifier *kian; + 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) + hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, + link) + if (kian->gsi == gsi) + kian->irq_acked(kian); + 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); +#ifdef __KVM_HAVE_IOAPIC + kvm_vcpu_request_scan_ioapic(kvm); +#endif +} + +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); +#ifdef __KVM_HAVE_IOAPIC + kvm_vcpu_request_scan_ioapic(kvm); +#endif +} #endif void kvm_eventfd_init(struct kvm *kvm) { -#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING +#ifdef CONFIG_HAVE_KVM_IRQFD spin_lock_init(&kvm->irqfds.lock); INIT_LIST_HEAD(&kvm->irqfds.items); INIT_LIST_HEAD(&kvm->irqfds.resampler_list); @@ -442,7 +519,7 @@ kvm_eventfd_init(struct kvm *kvm) INIT_LIST_HEAD(&kvm->ioeventfds); } -#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING +#ifdef CONFIG_HAVE_KVM_IRQFD /* * shutdown any irqfd's that match fd+gsi */ @@ -461,14 +538,14 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) { /* - * This rcu_assign_pointer is needed for when + * 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). - * It is paired with synchronize_rcu done by caller - * of that function. */ - rcu_assign_pointer(irqfd->irq_entry, NULL); + write_seqcount_begin(&irqfd->irq_entry_sc); + irqfd->irq_entry.type = 0; + write_seqcount_end(&irqfd->irq_entry_sc); irqfd_deactivate(irqfd); } } @@ -523,20 +600,17 @@ kvm_irqfd_release(struct kvm *kvm) } /* - * Change irq_routing and irqfd. - * Caller must invoke synchronize_rcu afterwards. + * 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_irq_routing_table *irq_rt) +void kvm_irq_routing_update(struct kvm *kvm) { 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); + irqfd_update(kvm, irqfd); spin_unlock_irq(&kvm->irqfds.lock); } |