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KVM: switch irq injection/acking data structures to irq_lock

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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 <alex.williamson@hp.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Marcelo Tosatti 2009-06-04 15:08:24 -03:00 • committed by Avi Kivity
commit fa40a8214b
8 changed files with 58 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

4
virt/kvm/eventfd.c
View file

@ -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);
}
/*

34
virt/kvm/irq_comm.c
View file

@ -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;

16
virt/kvm/kvm_main.c
View file

@ -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)