On Fri, Apr 15, 2022, Sean Christopherson wrote: > > It's safe to invoke kvm_arch_vcpu_precreate() within the protection of > > kvm->lock directly rather than take into account in the implementation for > > each architecture. > > This absolutely needs to explain _why_ it's safe, e.g. only arm64, x86, and s390 > have non-nop implementations and they're all simple and short with no tendrils > into other code that might take kvm->lock. > > And as before, I suspect arm64 needs this protection, the vgic_initialized() > check looks racy. Though it's hard to tell if doing the check under kvm->lock > actually fixes anything. Ah, I bet this code in vgic_init() provides the necessary protection. /* Are we also in the middle of creating a VCPU? */ if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus)) return -EBUSY;
