Commit 5bd90b09 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: vgic-v4: Track the number of VLPIs per vcpu 



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: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarZenghui Yu <yuzenghui@huawei.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Link: https://lore.kernel.org/r/20191107160412.30301-2-maz@kernel.org
parent 9090825f

include/linux/irqchip/arm-gic-v4.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

virt/kvm/arm/vgic/vgic-init.c

+1 −0
Original line number Diff line number Diff line
@@ -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

virt/kvm/arm/vgic/vgic-its.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

	}

virt/kvm/arm/vgic/vgic-v4.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

	}

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