KVM: Convert intx_mask_lock to spin lock
As kvm_notify_acked_irq calls kvm_assigned_dev_ack_irq under
rcu_read_lock, we cannot use a mutex in the latter function. Switch to a
spin lock to address this.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 08e0571..01f572c 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -77,11 +77,11 @@
{
if (unlikely(assigned_dev->irq_requested_type &
KVM_DEV_IRQ_GUEST_INTX)) {
- mutex_lock(&assigned_dev->intx_mask_lock);
+ spin_lock(&assigned_dev->intx_mask_lock);
if (!(assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX))
kvm_set_irq(assigned_dev->kvm,
assigned_dev->irq_source_id, vector, 1);
- mutex_unlock(&assigned_dev->intx_mask_lock);
+ spin_unlock(&assigned_dev->intx_mask_lock);
} else
kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
vector, 1);
@@ -141,7 +141,7 @@
kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);
- mutex_lock(&dev->intx_mask_lock);
+ spin_lock(&dev->intx_mask_lock);
if (!(dev->flags & KVM_DEV_ASSIGN_MASK_INTX)) {
bool reassert = false;
@@ -165,7 +165,7 @@
dev->guest_irq, 1);
}
- mutex_unlock(&dev->intx_mask_lock);
+ spin_unlock(&dev->intx_mask_lock);
}
static void deassign_guest_irq(struct kvm *kvm,
@@ -707,7 +707,7 @@
match->flags = assigned_dev->flags;
match->dev = dev;
spin_lock_init(&match->intx_lock);
- mutex_init(&match->intx_mask_lock);
+ spin_lock_init(&match->intx_mask_lock);
match->irq_source_id = -1;
match->kvm = kvm;
match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;
@@ -868,7 +868,7 @@
goto out;
}
- mutex_lock(&match->intx_mask_lock);
+ spin_lock(&match->intx_mask_lock);
match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;
match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;
@@ -895,7 +895,7 @@
}
}
- mutex_unlock(&match->intx_mask_lock);
+ spin_unlock(&match->intx_mask_lock);
out:
mutex_unlock(&kvm->lock);