On Mon, Nov 08, 2021, Like Xu wrote: > On 5/11/2021 11:48 pm, Sean Christopherson wrote: > > On Wed, Nov 03, 2021, Like Xu wrote: > > > diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c > > > index 0db1887137d9..b6f08c719125 100644 > > > --- a/arch/x86/kvm/pmu.c > > > +++ b/arch/x86/kvm/pmu.c > > > @@ -50,6 +50,13 @@ > > > struct kvm_pmu_ops kvm_pmu_ops __read_mostly; > > > EXPORT_SYMBOL_GPL(kvm_pmu_ops); > > > +#define KVM_X86_PMU_OP(func) \ > > > + DEFINE_STATIC_CALL_NULL(kvm_x86_pmu_##func, \ > > > + *(((struct kvm_pmu_ops *)0)->func)) > > > +#define KVM_X86_PMU_OP_NULL KVM_X86_PMU_OP > > > > More of a question for the existing code, what's the point of KVM_X86_OP_NULL? > > The comment says: > > * KVM_X86_OP_NULL() can leave a NULL definition for the > * case where there is no definition or a function name that > * doesn't match the typical naming convention is supplied. > > Does it help ? No. I understand the original intent of KVM_X86_OP_NULL, but unless there's some form of enforcement, it does more harm than good because it can very easily become stale, e.g. see get_cs_db_l_bits(). I guess "what's the point of KVM_X86_OP_NULL?" was somewhat of a rhetorical question. > > AFAICT, it always resolves to KVM_X86_OP. Unless there's some magic I'm missing, > > I vote we remove KVM_X86_OP_NULL and then not introduce KVM_X86_PMU_OP_NULL. > > And I'm pretty sure it's useless, e.g. get_cs_db_l_bits is defined with the NULL
