Re: [libvirt] [Qemu-arm] [PATCH v6 2/4] arm: enhance kvm_arm_create_scratch_host_vcpu

On 23/03/16 08:32, Peter Xu wrote: > diff --git a/target-arm/kvm.c b/target-arm/kvm.c > index 969ab0b..0a7f9a6 100644 > --- a/target-arm/kvm.c > +++ b/target-arm/kvm.c > @@ -62,13 +62,17 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t *cpus_to_try, > goto err; > } > > + if (!init) { > + goto finish; > + } > + > ret = ioctl(vmfd, KVM_ARM_PREFERRED_TARGET, init); > if (ret >= 0) { > ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, init); > if (ret < 0) { > goto err; > } > - } else { > + } else if (cpus_to_try) { > /* Old kernel which doesn't know about the > * PREFERRED_TARGET ioctl: we know it will only support > * creating one kind of guest CPU which is its preferred > @@ -85,8 +89,12 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t *cpus_to_try, > if (ret < 0) { > goto err; > } > + } else { > + /* Not providing cpus_to_try, do nothing. */ > + ; I think it's probably not the best idea to skip CPU initialization here. I'd rather raise an error in such case. If we supplied non-NULL init argument then we need VCPU been initialized, don't we? If we pass NULL as init then we actually skip this code.