Re: [PATCH] kvm: x86: remove vmx_vm_has_apicv() outside of hwapic_isr_update()

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/12/2014 10:28, Tiejun Chen wrote:
> In most cases calling hwapic_isr_update(), actually we always
> check if kvm_apic_vid_enabled() == 1, and also actually,
> kvm_apic_vid_enabled()
>     -> kvm_x86_ops->vm_has_apicv()
>         -> vmx_vm_has_apicv() or '0' in svm case
> 
> So its unnecessary to recall this inside hwapic_isr_update(), here
> just remove vmx_vm_has_apicv() out and follow others.

If you want to do this, please NULL out the function pointer instead, as
KVM already does for hwapic_irr_update.

Paolo

> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
>  arch/x86/kvm/lapic.c | 3 ++-
>  arch/x86/kvm/vmx.c   | 3 ---
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index e0e5642..2ddc426 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1739,7 +1739,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
>  	if (kvm_x86_ops->hwapic_irr_update)
>  		kvm_x86_ops->hwapic_irr_update(vcpu,
>  				apic_find_highest_irr(apic));
> -	kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
> +	if (kvm_apic_vid_enabled(vcpu->kvm))
> +	    kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
>  	kvm_make_request(KVM_REQ_EVENT, vcpu);
>  	kvm_rtc_eoi_tracking_restore_one(vcpu);
>  }
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 6a951d8..f0c16a9 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7406,9 +7406,6 @@ static void vmx_hwapic_isr_update(struct kvm *kvm, int isr)
>  	u16 status;
>  	u8 old;
>  
> -	if (!vmx_vm_has_apicv(kvm))
> -		return;
> -
>  	if (isr == -1)
>  		isr = 0;
>  
>