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 <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>
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index ddc17f0..08a9a49 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -62,6 +62,8 @@
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 @@
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 @@
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_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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;