From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Wed, 14 Mar 2012 10:02:11 +0000 (+0100)
Subject: KVM: Convert intx_mask_lock to spin lock
X-Git-Tag: MMI-PSA29.97-13-9~17141^2
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=cf9eeac46350b8b43730b7dc5e999757bed089a4;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

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/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ec171c1d0878..40bb1c661a6e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -556,7 +556,7 @@ struct kvm_assigned_dev_kernel {
 	struct pci_dev *dev;
 	struct kvm *kvm;
 	spinlock_t intx_lock;
-	struct mutex intx_mask_lock;
+	spinlock_t intx_mask_lock;
 	char irq_name[32];
 	struct pci_saved_state *pci_saved_state;
 };
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 08e05715df72..01f572c10c71 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -77,11 +77,11 @@ kvm_assigned_dev_raise_guest_irq(struct kvm_assigned_dev_kernel *assigned_dev,
 {
 	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 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
 
 	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 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
 				    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 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 	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 @@ static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
 		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 @@ static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
 		}
 	}
 
-	mutex_unlock(&match->intx_mask_lock);
+	spin_unlock(&match->intx_mask_lock);
 
 out:
 	mutex_unlock(&kvm->lock);