diff options
| -rw-r--r-- | include/linux/kvm_host.h | 8 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 23 |
2 files changed, 25 insertions, 6 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 1c9c973a7dd9..63c6ab30bc81 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -371,7 +371,15 @@ struct kvm { struct srcu_struct srcu; struct srcu_struct irq_srcu; struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; + + /* + * created_vcpus is protected by kvm->lock, and is incremented + * at the beginning of KVM_CREATE_VCPU. online_vcpus is only + * incremented after storing the kvm_vcpu pointer in vcpus, + * and is accessed atomically. + */ atomic_t online_vcpus; + int created_vcpus; int last_boosted_vcpu; struct list_head vm_list; struct mutex lock; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 02e98f3131bd..15b757ae64e1 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2346,9 +2346,20 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) if (id >= KVM_MAX_VCPU_ID) return -EINVAL; + mutex_lock(&kvm->lock); + if (kvm->created_vcpus == KVM_MAX_VCPUS) { + mutex_unlock(&kvm->lock); + return -EINVAL; + } + + kvm->created_vcpus++; + mutex_unlock(&kvm->lock); + vcpu = kvm_arch_vcpu_create(kvm, id); - if (IS_ERR(vcpu)) - return PTR_ERR(vcpu); + if (IS_ERR(vcpu)) { + r = PTR_ERR(vcpu); + goto vcpu_decrement; + } preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); @@ -2361,10 +2372,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) r = -EINVAL; goto unlock_vcpu_destroy; } - if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) { - r = -EINVAL; - goto unlock_vcpu_destroy; - } if (kvm_get_vcpu_by_id(kvm, id)) { r = -EEXIST; goto unlock_vcpu_destroy; @@ -2397,6 +2404,10 @@ unlock_vcpu_destroy: mutex_unlock(&kvm->lock); vcpu_destroy: kvm_arch_vcpu_destroy(vcpu); +vcpu_decrement: + mutex_lock(&kvm->lock); + kvm->created_vcpus--; + mutex_unlock(&kvm->lock); return r; } |