On 03/07/18 22:26, Christoffer Dall wrote: > The vgic_init function can race with kvm_arch_vcpu_create() which does > not hold kvm_lock() and we therefore have no synchronization primitives > to ensure we're doing the right thing. > > As the user is trying to initialize or run the VM while at the same time > creating more VCPUs, we just have to refuse to initialize the VGIC in > this case rather than silently failing with a broken VCPU. > > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxx> > --- > virt/kvm/arm/vgic/vgic-init.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c > index 9406eaf..c0c0b88 100644 > --- a/virt/kvm/arm/vgic/vgic-init.c > +++ b/virt/kvm/arm/vgic/vgic-init.c > @@ -286,6 +286,10 @@ int vgic_init(struct kvm *kvm) > if (vgic_initialized(kvm)) > return 0; > > + /* Are we also in the middle of creating a VCPU? */ > + if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus)) > + return -EBUSY; > + > /* freeze the number of spis */ > if (!dist->nr_spis) > dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS; > Applied to queue. Thanks, M. -- Jazz is not dead. It just smells funny...
