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/kvm_main.c b/virt/kvm/kvm_main.c
index d47e660..0d481b2 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 @@
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 @@
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 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)