kvm: destroy emulated devices on VM exit
Scott Wood [Thu, 25 Apr 2013 14:11:23 +0000 (14:11 +0000)]
The hassle of getting refcounting right was greater than the hassle
of keeping a list of devices to destroy on VM exit.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/mpic.c
include/linux/kvm_host.h
virt/kvm/kvm_main.c

index 89fe1d6..795ca0c 100644 (file)
@@ -1781,7 +1781,6 @@ int kvmppc_mpic_connect_vcpu(struct kvm_device *dev, struct kvm_vcpu *vcpu,
        if (opp->mpic_mode_mask == GCR_MODE_PROXY)
                vcpu->arch.epr_flags |= KVMPPC_EPR_KERNEL;
 
-       kvm_device_get(dev);
 out:
        spin_unlock_irq(&opp->lock);
        return ret;
@@ -1797,7 +1796,6 @@ void kvmppc_mpic_disconnect_vcpu(struct openpic *opp, struct kvm_vcpu *vcpu)
        BUG_ON(!opp->dst[vcpu->arch.irq_cpu_id].vcpu);
 
        opp->dst[vcpu->arch.irq_cpu_id].vcpu = NULL;
-       kvm_device_put(opp->dev);
 }
 
 /*
index feffbda..36c9776 100644 (file)
@@ -393,6 +393,7 @@ struct kvm {
        long mmu_notifier_count;
 #endif
        long tlbs_dirty;
+       struct list_head devices;
 };
 
 #define kvm_err(fmt, ...) \
@@ -1069,8 +1070,8 @@ struct kvm_device_ops;
 struct kvm_device {
        struct kvm_device_ops *ops;
        struct kvm *kvm;
-       atomic_t users;
        void *private;
+       struct list_head vm_node;
 };
 
 /* create, destroy, and name are mandatory */
index f6cd14d..5da9f02 100644 (file)
@@ -504,6 +504,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
        mutex_init(&kvm->irq_lock);
        mutex_init(&kvm->slots_lock);
        atomic_set(&kvm->users_count, 1);
+       INIT_LIST_HEAD(&kvm->devices);
 
        r = kvm_init_mmu_notifier(kvm);
        if (r)
@@ -581,6 +582,19 @@ void kvm_free_physmem(struct kvm *kvm)
        kfree(kvm->memslots);
 }
 
+static void kvm_destroy_devices(struct kvm *kvm)
+{
+       struct list_head *node, *tmp;
+
+       list_for_each_safe(node, tmp, &kvm->devices) {
+               struct kvm_device *dev =
+                       list_entry(node, struct kvm_device, vm_node);
+
+               list_del(node);
+               dev->ops->destroy(dev);
+       }
+}
+
 static void kvm_destroy_vm(struct kvm *kvm)
 {
        int i;
@@ -600,6 +614,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
        kvm_arch_flush_shadow_all(kvm);
 #endif
        kvm_arch_destroy_vm(kvm);
+       kvm_destroy_devices(kvm);
        kvm_free_physmem(kvm);
        cleanup_srcu_struct(&kvm->srcu);
        kvm_arch_free_vm(kvm);
@@ -2195,23 +2210,11 @@ static long kvm_device_ioctl(struct file *filp, unsigned int ioctl,
        }
 }
 
-void kvm_device_get(struct kvm_device *dev)
-{
-       atomic_inc(&dev->users);
-}
-
-void kvm_device_put(struct kvm_device *dev)
-{
-       if (atomic_dec_and_test(&dev->users))
-               dev->ops->destroy(dev);
-}
-
 static int kvm_device_release(struct inode *inode, struct file *filp)
 {
        struct kvm_device *dev = filp->private_data;
        struct kvm *kvm = dev->kvm;
 
-       kvm_device_put(dev);
        kvm_put_kvm(kvm);
        return 0;
 }
@@ -2257,7 +2260,6 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
 
        dev->ops = ops;
        dev->kvm = kvm;
-       atomic_set(&dev->users, 1);
 
        ret = ops->create(dev, cd->type);
        if (ret < 0) {
@@ -2271,6 +2273,7 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
                return ret;
        }
 
+       list_add(&dev->vm_node, &kvm->devices);
        kvm_get_kvm(kvm);
        cd->fd = ret;
        return 0;