Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1501125 > unrolled thread

[PATCH 4/5] KVM: x86: remove unnecessary sync_pir_to_irr

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH 4/5] KVM: x86: remove unnecessary sync_pir_to_irr Paolo Bonzini <pbonzini@redhat.com> - 2016-10-14 20:30 +0200
    Re: [PATCH 4/5] KVM: x86: remove unnecessary sync_pir_to_irr Radim Krčmář <rkrcmar@redhat.com> - 2016-10-26 22:30 +0200

#1501125 — [PATCH 4/5] KVM: x86: remove unnecessary sync_pir_to_irr

Synchronizing PIR to IRR is not needed in most callers of
apic_find_highest_irr.  Move it to the one place that matters,
interrupt acknowledgement.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/lapic.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index c0928173b2e3..255b5e1658f6 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -382,8 +382,6 @@ static inline int apic_find_highest_irr(struct kvm_lapic *apic)
 	if (!apic->irr_pending)
 		return -1;
 
-	if (apic->vcpu->arch.apicv_active)
-		kvm_x86_ops->sync_pir_to_irr(apic->vcpu);
 	result = apic_search_irr(apic);
 	ASSERT(result == -1 || result >= 16);
 
@@ -1973,6 +1971,9 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
 		return -1;
 
 	apic_update_ppr(apic);
+
+	if (apic->vcpu->arch.apicv_active)
+		kvm_x86_ops->sync_pir_to_irr(apic->vcpu);
 	highest_irr = apic_find_highest_irr(apic);
 	if ((highest_irr == -1) ||
 	    ((highest_irr & 0xF0) <= kvm_lapic_get_reg(apic, APIC_PROCPRI)))
@@ -2206,6 +2207,11 @@ void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu)
 	if (!test_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention))
 		return;
 
+	/* We don't get here when APICv is active, since that blocks
+	 * TPR access vmexits.
+	 */
+	WARN_ON_ONCE(vcpu->arch.apicv_active);
+
 	tpr = kvm_lapic_get_reg(apic, APIC_TASKPRI) & 0xff;
 	max_irr = apic_find_highest_irr(apic);
 	if (max_irr < 0)
-- 
1.8.3.1

[toc] | [next] | [standalone]

#1509795

2016-10-14 20:21+0200, Paolo Bonzini:
> Synchronizing PIR to IRR is not needed in most callers of
> apic_find_highest_irr.  Move it to the one place that matters,
> interrupt acknowledgement.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>

> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> @@ -1973,6 +1971,9 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
>  		return -1;
>  
>  	apic_update_ppr(apic);
> +
> +	if (apic->vcpu->arch.apicv_active)
> +		kvm_x86_ops->sync_pir_to_irr(apic->vcpu);

Btw. do all callers of kvm_apic_has_interrupt() need it?

Thanks.

>  	highest_irr = apic_find_highest_irr(apic);
>  	if ((highest_irr == -1) ||
>  	    ((highest_irr & 0xF0) <= kvm_lapic_get_reg(apic, APIC_PROCPRI)))

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web