Messages in this thread | | | Date | Mon, 8 Nov 2021 17:31:17 +0800 | Subject | Re: [PATCH 2/3] KVM: x86: Introduce definitions to support static calls for kvm_pmu_ops | From | Like Xu <> |
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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 ?
> 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
This transitions will not be included in the next version. Open to you.
> variant, but it's never NULL and its calls aren't guarded with anything. And if > KVM_X86_OP_NULL is intended to aid in documenting behavior, it's doing a pretty > miserable job of that :-) > >> +#include <asm/kvm-x86-pmu-ops.h> >> +EXPORT_STATIC_CALL_GPL(kvm_x86_pmu_is_valid_msr); > > I'll double down on my nVMX suggestion so that this export can be avoided.
Fine to me.
> >> static void kvm_pmi_trigger_fn(struct irq_work *irq_work) >> { >> struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work); >> diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h >> index b2fe135d395a..e5550d4acf14 100644 >> --- a/arch/x86/kvm/pmu.h >> +++ b/arch/x86/kvm/pmu.h >> @@ -3,6 +3,8 @@ >> #define __KVM_X86_PMU_H >> >> #include <linux/nospec.h> >> +#include <linux/static_call_types.h> >> +#include <linux/static_call.h> >> >> #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu) >> #define pmu_to_vcpu(pmu) (container_of((pmu), struct kvm_vcpu, arch.pmu)) >> @@ -45,6 +47,19 @@ struct kvm_pmu_ops { >> void (*cleanup)(struct kvm_vcpu *vcpu); >> }; >> >> +#define KVM_X86_PMU_OP(func) \ >> + DECLARE_STATIC_CALL(kvm_x86_pmu_##func, *(((struct kvm_pmu_ops *)0)->func)) >> +#define KVM_X86_PMU_OP_NULL KVM_X86_PMU_OP >> +#include <asm/kvm-x86-pmu-ops.h> >> + >> +static inline void kvm_pmu_ops_static_call_update(void) >> +{ >> +#define KVM_X86_PMU_OP(func) \ >> + static_call_update(kvm_x86_pmu_##func, kvm_pmu_ops.func) >> +#define KVM_X86_PMU_OP_NULL KVM_X86_PMU_OP >> +#include <asm/kvm-x86-pmu-ops.h> >> +} > > As alluded to in patch 01, I'd prefer these go in kvm_ops_static_call_update() > to keep the static call magic somewhat contained.
Thank and applied.
> >> + >> static inline u64 pmc_bitmask(struct kvm_pmc *pmc) >> { >> struct kvm_pmu *pmu = pmc_to_pmu(pmc); >> -- >> 2.33.0 >> >
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