| Message ID | 20191107160412.30301-2-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Reduce occurence of GICv4 doorbells on non-oversubscribed systems | expand |
Hi Marc, On 2019/11/8 0:04, Marc Zyngier wrote: > In order to find out whether a vcpu is likely to be the target of > VLPIs (and to further optimize the way we deal with those), let's > track the number of VLPIs a vcpu can receive. > > This gets implemented with an atomic variable that gets incremented > or decremented on map, unmap and move of a VLPI. > > Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h index ab1396afe08a..5dbcfc65f21e 100644 --- a/include/linux/irqchip/arm-gic-v4.h +++ b/include/linux/irqchip/arm-gic-v4.h @@ -32,6 +32,8 @@ struct its_vm { struct its_vpe { struct page *vpt_page; struct its_vm *its_vm; + /* per-vPE VLPI tracking */ + atomic_t vlpi_count; /* Doorbell interrupt */ int irq; irq_hw_number_t vpe_db_lpi; diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index 6f50c429196d..b3c5de48064c 100644 --- a/virt/kvm/arm/vgic/vgic-init.c +++ b/virt/kvm/arm/vgic/vgic-init.c @@ -203,6 +203,7 @@ int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu) INIT_LIST_HEAD(&vgic_cpu->ap_list_head); raw_spin_lock_init(&vgic_cpu->ap_list_lock); + atomic_set(&vgic_cpu->vgic_v3.its_vpe.vlpi_count, 0); /* * Enable and configure all SGIs to be edge-triggered and diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 2be6b66b3856..98c7360d9fb7 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -360,7 +360,10 @@ static int update_affinity(struct vgic_irq *irq, struct kvm_vcpu *vcpu) if (ret) return ret; + if (map.vpe) + atomic_dec(&map.vpe->vlpi_count); map.vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe; + atomic_inc(&map.vpe->vlpi_count); ret = its_map_vlpi(irq->host_irq, &map); } diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c index 7e1f3202968a..7e227033ab8e 100644 --- a/virt/kvm/arm/vgic/vgic-v4.c +++ b/virt/kvm/arm/vgic/vgic-v4.c @@ -309,6 +309,7 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, irq->hw = true; irq->host_irq = virq; + atomic_inc(&map.vpe->vlpi_count); out: mutex_unlock(&its->its_lock); @@ -342,6 +343,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq, WARN_ON(!(irq->hw && irq->host_irq == virq)); if (irq->hw) { + atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count); irq->hw = false; ret = its_unmap_vlpi(virq); }
In order to find out whether a vcpu is likely to be the target of VLPIs (and to further optimize the way we deal with those), let's track the number of VLPIs a vcpu can receive. This gets implemented with an atomic variable that gets incremented or decremented on map, unmap and move of a VLPI. Signed-off-by: Marc Zyngier <maz@kernel.org> --- include/linux/irqchip/arm-gic-v4.h | 2 ++ virt/kvm/arm/vgic/vgic-init.c | 1 + virt/kvm/arm/vgic/vgic-its.c | 3 +++ virt/kvm/arm/vgic/vgic-v4.c | 2 ++ 4 files changed, 8 insertions(+)