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: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Link: https://lore.kernel.org/r/20191107160412.30301-2-maz@kernel.org
This commit is contained in:
Marc Zyngier 2019-11-07 16:04:11 +00:00
parent 9090825fa9
commit 5bd90b0989
4 changed files with 8 additions and 0 deletions

View File

@ -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;

View File

@ -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

View File

@ -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);
}

View File

@ -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);
}