From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Cun Li <cun.jia.li@gmail.com>
Cc: seanjc@google.com, wanpengli@tencent.com, jmattson@google.com,
joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, Cun Li <cun.jia.li@gmail.com>,
pbonzini@redhat.com
Subject: Re: [PATCH] KVM: update depracated jump label API
Date: Mon, 11 Jan 2021 18:15:43 +0100 [thread overview]
Message-ID: <87h7nn8ke8.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20210111152435.50275-1-cun.jia.li@gmail.com>
Cun Li <cun.jia.li@gmail.com> writes:
> The use of 'struct static_key' and 'static_key_false' is
> deprecated. Use the new API.
>
> Signed-off-by: Cun Li <cun.jia.li@gmail.com>
> ---
> arch/x86/kvm/lapic.h | 6 +++---
> arch/x86/kvm/mmu/mmu_audit.c | 4 ++--
> arch/x86/kvm/x86.c | 2 +-
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 4fb86e3a9dd3..b7aa76e2678e 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -176,7 +176,7 @@ extern struct static_key kvm_no_apic_vcpu;
>
> static inline bool lapic_in_kernel(struct kvm_vcpu *vcpu)
> {
> - if (static_key_false(&kvm_no_apic_vcpu))
> + if (static_branch_unlikely(&kvm_no_apic_vcpu))
> return vcpu->arch.apic;
> return true;
> }
> @@ -185,7 +185,7 @@ extern struct static_key_deferred apic_hw_disabled;
>
> static inline int kvm_apic_hw_enabled(struct kvm_lapic *apic)
> {
> - if (static_key_false(&apic_hw_disabled.key))
> + if (static_branch_unlikely(&apic_hw_disabled.key))
> return apic->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE;
> return MSR_IA32_APICBASE_ENABLE;
> }
> @@ -194,7 +194,7 @@ extern struct static_key_deferred apic_sw_disabled;
>
> static inline bool kvm_apic_sw_enabled(struct kvm_lapic *apic)
> {
> - if (static_key_false(&apic_sw_disabled.key))
> + if (static_branch_unlikely(&apic_sw_disabled.key))
> return apic->sw_enabled;
> return true;
> }
> diff --git a/arch/x86/kvm/mmu/mmu_audit.c b/arch/x86/kvm/mmu/mmu_audit.c
> index c8d51a37e2ce..8a4b3510151a 100644
> --- a/arch/x86/kvm/mmu/mmu_audit.c
> +++ b/arch/x86/kvm/mmu/mmu_audit.c
> @@ -234,7 +234,7 @@ static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
> }
>
> static bool mmu_audit;
> -static struct static_key mmu_audit_key;
> +static DEFINE_STATIC_KEY_FALSE(mmu_audit_key);
>
> static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
> {
> @@ -250,7 +250,7 @@ static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
>
> static inline void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
> {
> - if (static_key_false((&mmu_audit_key)))
> + if (static_branch_unlikely((&mmu_audit_key)))
> __kvm_mmu_audit(vcpu, point);
> }
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9a8969a6dd06..b8c05ef26942 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -10339,7 +10339,7 @@ bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)
> return (vcpu->arch.apic_base & MSR_IA32_APICBASE_BSP) != 0;
> }
>
> -struct static_key kvm_no_apic_vcpu __read_mostly;
> +__read_mostly DEFINE_STATIC_KEY_FALSE(kvm_no_apic_vcpu);
> EXPORT_SYMBOL_GPL(kvm_no_apic_vcpu);
>
> void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu)
mmu_audit_key can only be true or false so it would also be nice to use
static_branch_enable()/static_branch_disable() for it and not
static_key_slow_inc()/static_key_slow_dec() we currently use (as it
sounds weird to increment 'false').
kvm_no_apic_vcpu is different, we actually need to increase it with
every vCPU which doesn't have LAPIC but maybe we can at least switch to
static_branch_inc()/static_branch_dec(). It is still weird we initialize
it to 'false' but it seems to be a documented behavior. From
include/linux/jump_label.h:
"... Thus, static_branch_inc() can be thought of as a 'make more true'
and static_branch_dec() as a 'make more false'"
so .. oh well.
--
Vitaly
next prev parent reply other threads:[~2021-01-11 17:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 15:24 [PATCH] KVM: update depracated jump label API Cun Li
2021-01-11 17:15 ` Vitaly Kuznetsov [this message]
2021-01-16 5:41 ` Cun Li
2021-01-16 5:50 ` [PATCH] KVM: update depracated and inappropriate " Cun Li
2021-01-19 20:46 ` Sean Christopherson
2021-01-26 17:57 ` [PATCH] KVM: update depracated " Paolo Bonzini
2021-01-26 18:51 ` Sean Christopherson
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