Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 13efc29..0026829 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -838,6 +838,18 @@ void kvm_put_kvm(struct kvm *kvm)
 }
 EXPORT_SYMBOL_GPL(kvm_put_kvm);
 
+/*
+ * Used to put a reference that was taken on behalf of an object associated
+ * with a user-visible file descriptor, e.g. a vcpu or device, if installation
+ * of the new file descriptor fails and the reference cannot be transferred to
+ * its final owner.  In such cases, the caller is still actively using @kvm and
+ * will fail miserably if the refcount unexpectedly hits zero.
+ */
+void kvm_put_kvm_no_destroy(struct kvm *kvm)
+{
+       WARN_ON(refcount_dec_and_test(&kvm->users_count));
+}
+EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
 
 static int kvm_vm_release(struct inode *inode, struct file *filp)
 {
@@ -2739,17 +2751,18 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
                goto unlock_vcpu_destroy;
        }
 
-       BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
+       vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
+       BUG_ON(kvm->vcpus[vcpu->vcpu_idx]);
 
        /* Now it's all set up, let userspace reach it */
        kvm_get_kvm(kvm);
        r = create_vcpu_fd(vcpu);
        if (r < 0) {
-               kvm_put_kvm(kvm);
+               kvm_put_kvm_no_destroy(kvm);
                goto unlock_vcpu_destroy;
        }
 
-       kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
+       kvm->vcpus[vcpu->vcpu_idx] = vcpu;
 
        /*
         * Pairs with smp_rmb() in kvm_get_vcpu.  Write kvm->vcpus
@@ -3115,14 +3128,14 @@ struct kvm_device *kvm_device_from_filp(struct file *filp)
        return filp->private_data;
 }
 
-static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
+static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
 #ifdef CONFIG_KVM_MPIC
        [KVM_DEV_TYPE_FSL_MPIC_20]      = &kvm_mpic_ops,
        [KVM_DEV_TYPE_FSL_MPIC_42]      = &kvm_mpic_ops,
 #endif
 };
 
-int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
+int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type)
 {
        if (type >= ARRAY_SIZE(kvm_device_ops_table))
                return -ENOSPC;
@@ -3143,7 +3156,7 @@ void kvm_unregister_device_ops(u32 type)
 static int kvm_ioctl_create_device(struct kvm *kvm,
                                   struct kvm_create_device *cd)
 {
-       struct kvm_device_ops *ops = NULL;
+       const struct kvm_device_ops *ops = NULL;
        struct kvm_device *dev;
        bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
        int type;
@@ -3183,7 +3196,7 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
        kvm_get_kvm(kvm);
        ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
        if (ret < 0) {
-               kvm_put_kvm(kvm);
+               kvm_put_kvm_no_destroy(kvm);
                mutex_lock(&kvm->lock);
                list_del(&dev->vm_node);
                mutex_unlock(&kvm->lock);
@@ -4341,12 +4354,12 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 
        r = kvm_arch_hardware_setup();
        if (r < 0)
-               goto out_free_0a;
+               goto out_free_1;
 
        for_each_online_cpu(cpu) {
                smp_call_function_single(cpu, check_processor_compat, &r, 1);
                if (r < 0)
-                       goto out_free_1;
+                       goto out_free_2;
        }
 
        r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_STARTING, "kvm/cpu:starting",
@@ -4403,9 +4416,8 @@ out_free_3:
        unregister_reboot_notifier(&kvm_reboot_notifier);
        cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);
 out_free_2:
-out_free_1:
        kvm_arch_hardware_unsetup();
-out_free_0a:
+out_free_1:
        free_cpumask_var(cpus_hardware_enabled);
 out_free_0:
        kvm_irqfd_exit();