We get a warning when build kernel W=1: arch/x86/kvm/../../../virt/kvm/eventfd.c:48:1: warning: no previous prototype for ‘kvm_arch_irqfd_allowed’ [-Wmissing-prototypes] kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args) ^ The reason is kvm_arch_irqfd_allowed() is declared in arch/x86/kvm/irq.h, which is not included by eventfd.c. Considering kvm_arch_irqfd_allowed() is a weakly defined function in eventfd.c, remove the declaration to kvm_host.h can fix this. Signed-off-by: Yi Wang <wang.yi59@xxxxxxxxxx> Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> --- v2: add comments about the reason. --- arch/x86/kvm/irq.h | 1 - include/linux/kvm_host.h | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h index d6519a3..7c6233d 100644 --- a/arch/x86/kvm/irq.h +++ b/arch/x86/kvm/irq.h @@ -102,7 +102,6 @@ static inline int irqchip_in_kernel(struct kvm *kvm) return mode != KVM_IRQCHIP_NONE; } -bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args); void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu); void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu); void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d1ad38a..5f04005 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -990,6 +990,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm, struct kvm_irq_ack_notifier *kian); int kvm_request_irq_source_id(struct kvm *kvm); void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id); +bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args); /* * search_memslots() and __gfn_to_memslot() are here because they are -- 1.8.3.1