From fa40a8214bb9bcae8d49c234c19d8b4a6c1f37ff Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Thu, 4 Jun 2009 15:08:24 -0300 Subject: KVM: switch irq injection/acking data structures to irq_lock Protect irq injection/acking data structures with a separate irq_lock mutex. This fixes the following deadlock: CPU A CPU B kvm_vm_ioctl_deassign_dev_irq() mutex_lock(&kvm->lock); worker_thread() -> kvm_deassign_irq() -> kvm_assigned_dev_interrupt_work_handler() -> deassign_host_irq() mutex_lock(&kvm->lock); -> cancel_work_sync() [blocked] [gleb: fix ia64 path] Reported-by: Alex Williamson Signed-off-by: Marcelo Tosatti Signed-off-by: Gleb Natapov Signed-off-by: Avi Kivity --- virt/kvm/eventfd.c | 4 ++-- virt/kvm/irq_comm.c | 34 ++++++++++++++++++++++++++++------ virt/kvm/kvm_main.c | 16 +++++++++------- 3 files changed, 39 insertions(+), 15 deletions(-) (limited to 'virt') diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 314012323afe..4092b8dcd510 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -57,10 +57,10 @@ irqfd_inject(struct work_struct *work) struct _irqfd *irqfd = container_of(work, struct _irqfd, inject); struct kvm *kvm = irqfd->kvm; - mutex_lock(&kvm->lock); + mutex_lock(&kvm->irq_lock); kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1); kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0); - mutex_unlock(&kvm->lock); + mutex_unlock(&kvm->irq_lock); } /* diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c index ddc17f0e2f35..08a9a49481b2 100644 --- a/virt/kvm/irq_comm.c +++ b/virt/kvm/irq_comm.c @@ -62,6 +62,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, int i, r = -1; struct kvm_vcpu *vcpu, *lowest = NULL; + WARN_ON(!mutex_is_locked(&kvm->irq_lock)); + if (irq->dest_mode == 0 && irq->dest_id == 0xff && kvm_is_dm_lowest_prio(irq)) printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); @@ -113,7 +115,7 @@ static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, return kvm_irq_delivery_to_apic(kvm, NULL, &irq); } -/* This should be called with the kvm->lock mutex held +/* This should be called with the kvm->irq_lock mutex held * Return value: * < 0 Interrupt was ignored (masked or not delivered for other reasons) * = 0 Interrupt was coalesced (previous irq is still pending) @@ -125,6 +127,8 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level) unsigned long *irq_state, sig_level; int ret = -1; + WARN_ON(!mutex_is_locked(&kvm->irq_lock)); + if (irq < KVM_IOAPIC_NUM_PINS) { irq_state = (unsigned long *)&kvm->arch.irq_states[irq]; @@ -175,19 +179,26 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) void kvm_register_irq_ack_notifier(struct kvm *kvm, struct kvm_irq_ack_notifier *kian) { + mutex_lock(&kvm->irq_lock); hlist_add_head(&kian->link, &kvm->arch.irq_ack_notifier_list); + mutex_unlock(&kvm->irq_lock); } -void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian) +void kvm_unregister_irq_ack_notifier(struct kvm *kvm, + struct kvm_irq_ack_notifier *kian) { + mutex_lock(&kvm->irq_lock); hlist_del_init(&kian->link); + mutex_unlock(&kvm->irq_lock); } -/* The caller must hold kvm->lock mutex */ int kvm_request_irq_source_id(struct kvm *kvm) { unsigned long *bitmap = &kvm->arch.irq_sources_bitmap; - int irq_source_id = find_first_zero_bit(bitmap, + int irq_source_id; + + mutex_lock(&kvm->irq_lock); + irq_source_id = find_first_zero_bit(bitmap, sizeof(kvm->arch.irq_sources_bitmap)); if (irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) { @@ -197,6 +208,7 @@ int kvm_request_irq_source_id(struct kvm *kvm) ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID); set_bit(irq_source_id, bitmap); + mutex_unlock(&kvm->irq_lock); return irq_source_id; } @@ -207,6 +219,7 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id) ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID); + mutex_lock(&kvm->irq_lock); if (irq_source_id < 0 || irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) { printk(KERN_ERR "kvm: IRQ source ID out of range!\n"); @@ -215,19 +228,24 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id) for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++) clear_bit(irq_source_id, &kvm->arch.irq_states[i]); clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap); + mutex_unlock(&kvm->irq_lock); } void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq, struct kvm_irq_mask_notifier *kimn) { + mutex_lock(&kvm->irq_lock); kimn->irq = irq; hlist_add_head(&kimn->link, &kvm->mask_notifier_list); + mutex_unlock(&kvm->irq_lock); } void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq, struct kvm_irq_mask_notifier *kimn) { + mutex_lock(&kvm->irq_lock); hlist_del(&kimn->link); + mutex_unlock(&kvm->irq_lock); } void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask) @@ -235,6 +253,8 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask) struct kvm_irq_mask_notifier *kimn; struct hlist_node *n; + WARN_ON(!mutex_is_locked(&kvm->irq_lock)); + hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link) if (kimn->irq == irq) kimn->func(kimn, mask); @@ -250,7 +270,9 @@ static void __kvm_free_irq_routing(struct list_head *irq_routing) void kvm_free_irq_routing(struct kvm *kvm) { + mutex_lock(&kvm->irq_lock); __kvm_free_irq_routing(&kvm->irq_routing); + mutex_unlock(&kvm->irq_lock); } static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e, @@ -325,13 +347,13 @@ int kvm_set_irq_routing(struct kvm *kvm, e = NULL; } - mutex_lock(&kvm->lock); + mutex_lock(&kvm->irq_lock); list_splice(&kvm->irq_routing, &tmp); INIT_LIST_HEAD(&kvm->irq_routing); list_splice(&irq_list, &kvm->irq_routing); INIT_LIST_HEAD(&irq_list); list_splice(&tmp, &irq_list); - mutex_unlock(&kvm->lock); + mutex_unlock(&kvm->irq_lock); r = 0; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d47e660fb709..0d481b282448 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -62,6 +62,12 @@ MODULE_AUTHOR("Qumranet"); MODULE_LICENSE("GPL"); +/* + * Ordering of locks: + * + * kvm->lock --> kvm->irq_lock + */ + DEFINE_SPINLOCK(kvm_lock); LIST_HEAD(vm_list); @@ -126,11 +132,7 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work) interrupt_work); kvm = assigned_dev->kvm; - /* This is taken to safely inject irq inside the guest. When - * the interrupt injection (or the ioapic code) uses a - * finer-grained lock, update this - */ - mutex_lock(&kvm->lock); + mutex_lock(&kvm->irq_lock); spin_lock_irq(&assigned_dev->assigned_dev_lock); if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) { struct kvm_guest_msix_entry *guest_entries = @@ -149,7 +151,7 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work) assigned_dev->guest_irq, 1); spin_unlock_irq(&assigned_dev->assigned_dev_lock); - mutex_unlock(&assigned_dev->kvm->lock); + mutex_unlock(&assigned_dev->kvm->irq_lock); } static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id) @@ -207,7 +209,7 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian) static void deassign_guest_irq(struct kvm *kvm, struct kvm_assigned_dev_kernel *assigned_dev) { - kvm_unregister_irq_ack_notifier(&assigned_dev->ack_notifier); + kvm_unregister_irq_ack_notifier(kvm, &assigned_dev->ack_notifier); assigned_dev->ack_notifier.gsi = -1; if (assigned_dev->irq_source_id != -1) -- cgit v1.2.1