KVM: Don't destroy vcpu in case vcpu_setup fails

One of vcpu_setup responsibilities is to do mmu initialization.
However, in case we fail in kvm_arch_vcpu_reset, before we get the
chance to init mmu. OTOH, vcpu_destroy will attempt to destroy mmu,
triggering a bug. Keeping track of whether or not mmu is initialized
would unnecessarily complicate things. Rather, we just make return,
making sure any needed uninitialization is done before we return, in
case we fail.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cd34f73513d3633b8ef1ad772ddc1650e5bde74f..ef9a121bbd1366b98a85ee239bf07d65578dbe8a 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1089,12 +1089,11 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
 
        r = kvm_arch_vcpu_setup(vcpu);
        if (r)
-               goto vcpu_destroy;
+               return r;
 
        mutex_lock(&kvm->lock);
        if (kvm->vcpus[n]) {
                r = -EEXIST;
-               mutex_unlock(&kvm->lock);
                goto vcpu_destroy;
        }
        kvm->vcpus[n] = vcpu;
@@ -1110,8 +1109,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
 unlink:
        mutex_lock(&kvm->lock);
        kvm->vcpus[n] = NULL;
-       mutex_unlock(&kvm->lock);
 vcpu_destroy:
+       mutex_unlock(&kvm->lock);
        kvm_arch_vcpu_destroy(vcpu);
        return r;
 }