From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: [PATCH v3 52/59] KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source Date: Mon, 31 Jul 2017 18:26:30 +0100 Message-ID: <20170731172637.29355-53-marc.zyngier@arm.com> References: <20170731172637.29355-1-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jason Cooper , Thomas Gleixner To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Return-path: In-Reply-To: <20170731172637.29355-1-marc.zyngier@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org 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. Signed-off-by: Marc Zyngier --- include/kvm/arm_vgic.h | 3 +++ virt/kvm/arm/arm.c | 2 ++ virt/kvm/arm/vgic/vgic-v4.c | 32 +++++++++++++++++++++++++++++++- 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 050f78d4fb42..7b1cc7ff5b42 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -375,4 +375,7 @@ 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 */ diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index 6803ea27c47d..5dbc8dc8fbf4 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -316,11 +316,13 @@ 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) diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c index 6af3cde6d7d4..50721c4e3da5 100644 --- a/virt/kvm/arm/vgic/vgic-v4.c +++ b/virt/kvm/arm/vgic/vgic-v4.c @@ -16,6 +16,7 @@ */ #include +#include #include #include @@ -73,6 +74,14 @@ int vgic_v4_init(struct kvm *kvm) kvm_for_each_vcpu(i, vcpu, kvm) { int irq = dist->its_vm.vpes[i]->irq; + /* + * Don't automatically enable the doorbell, as we're + * flipping it back and forth when the vcpu gets + * blocked. Also disable the lazy disabling, as the + * doorbell could kick us out of the guest too + * early... + */ + irq_set_status_flags(irq, IRQ_NOAUTOEN | IRQ_DISABLE_UNLAZY); ret = request_irq(irq, vgic_v4_doorbell_handler, 0, "vcpu", vcpu); if (ret) { @@ -98,7 +107,10 @@ void vgic_v4_teardown(struct kvm *kvm) for (i = 0; i < its_vm->nr_vpes; i++) { struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i); - free_irq(its_vm->vpes[i]->irq, vcpu); + int irq = its_vm->vpes[i]->irq; + + irq_clear_status_flags(irq, IRQ_NOAUTOEN | IRQ_DISABLE_UNLAZY); + free_irq(irq, vcpu); } its_free_vcpu_irqs(its_vm); @@ -211,3 +223,21 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq, mutex_unlock(&its->its_lock); return ret; } + +void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu) +{ + if (vgic_is_v4_capable(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_is_v4_capable(vcpu->kvm)) { + int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq; + if (irq) + disable_irq(irq); + } +} -- 2.11.0