Re: [PATCH v5 17/23] KVM: arm64: GICv4.1: Let doorbells be auto-enabled

Auger Eric
2020-03-17T11:04:37Z

Hi Marc,

On 3/4/20 9:33 PM, Marc Zyngier wrote:
> As GICv4.1 understands the life cycle of doorbells (instead of
> just randomly firing them at the most inconvenient time), just
> enable them at irq_request time, and be done with it.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric

> ---
> virt/kvm/arm/vgic/vgic-v4.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
> index 1eb0f8c76219..c2fcde104ea2 100644
> --- a/virt/kvm/arm/vgic/vgic-v4.c
> +++ b/virt/kvm/arm/vgic/vgic-v4.c
> @@ -141,6 +141,7 @@ int vgic_v4_init(struct kvm *kvm)
>
> kvm_for_each_vcpu(i, vcpu, kvm) {
> int irq = dist->its_vm.vpes[i]->irq;
> + unsigned long irq_flags = DB_IRQ_FLAGS;
>
> /*
> * Don't automatically enable the doorbell, as we're
> @@ -148,8 +149,14 @@ int vgic_v4_init(struct kvm *kvm)
> * blocked. Also disable the lazy disabling, as the
> * doorbell could kick us out of the guest too
> * early...
> + *
> + * On GICv4.1, the doorbell is managed in HW and must
> + * be left enabled.
> */
> - irq_set_status_flags(irq, DB_IRQ_FLAGS);
> + if (kvm_vgic_global_state.has_gicv4_1)
> + irq_flags &= ~IRQ_NOAUTOEN;
> + irq_set_status_flags(irq, irq_flags);
> +
> ret = request_irq(irq, vgic_v4_doorbell_handler,
> 0, "vcpu", vcpu);
> if (ret) {
>