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KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source 

The doorbell interrupt is only useful if the vcpu is blocked on WFI.
In all other cases, recieving a doorbell interrupt is just a waste
of cycles.

So let's only enable the doorbell if a vcpu is getting blocked,
and disable it when it is unblocked. This is very similar to
what we're doing for the background timer.

Reviewed-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2017-10-27 15:28:49 +01:00 committed by Christoffer Dall
parent bdb2d2ccac
commit df9ba95993
3 changed files with 23 additions and 0 deletions
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3
include/kvm/arm_vgic.h
View File

@ -381,4 +381,7 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq,
int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
struct kvm_kernel_irq_routing_entry *irq_entry);
void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu);
void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu);
#endif /* __KVM_ARM_VGIC_H */

2
virt/kvm/arm/arm.c
View File

@ -315,11 +315,13 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
{
kvm_timer_schedule(vcpu);
kvm_vgic_v4_enable_doorbell(vcpu);
}
void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
{
kvm_timer_unschedule(vcpu);
kvm_vgic_v4_disable_doorbell(vcpu);
}
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)

18
virt/kvm/arm/vgic/vgic-v4.c
View File

@ -233,3 +233,21 @@ out:
mutex_unlock(&its->its_lock);
return ret;
}
void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu)
{
if (vgic_supports_direct_msis(vcpu->kvm)) {
int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
if (irq)
enable_irq(irq);
}
}
void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu)
{
if (vgic_supports_direct_msis(vcpu->kvm)) {
int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
if (irq)
disable_irq(irq);
}
}