Re: [PATCH v2 20/36] KVM: arm64: gic-v5: Init Private IRQs (PPIs) for GICv5

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Fri, 19 Dec 2025 15:52:42 +0000
Sascha Bischoff <Sascha.Bischoff@arm.com> wrote:

> Initialise the private interrupts (PPIs, only) for GICv5. This means
> that a GICv5-style intid is generated (which encodes the PPI type in
> the top bits) instead of the 0-based index that is used for older
> GICs.
> 
> Additionally, set all of the GICv5 PPIs to use Level for the handling
> mode, with the exception of the SW_PPI which uses Edge. This matches
> the architecturally-defined set in the GICv5 specification (the CTIIRQ
> handling mode is IMPDEF, so pick Level has been picked for that).

so Level has been

> 
> Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>

Trivial comment inline, which you can feel free to ignore if you like

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> ---
>  arch/arm64/kvm/vgic/vgic-init.c    | 41 +++++++++++++++++++++++-------
>  include/linux/irqchip/arm-gic-v5.h |  2 ++
>  2 files changed, 34 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
> index bcc2c79f7833c..03f45816464b0 100644
> --- a/arch/arm64/kvm/vgic/vgic-init.c
> +++ b/arch/arm64/kvm/vgic/vgic-init.c

> @@ -280,22 +286,39 @@ static int vgic_allocate_private_irqs_locked(struct kvm_vcpu *vcpu, u32 type)
>  	 * Enable and configure all SGIs to be edge-triggered and
>  	 * configure all PPIs as level-triggered.
>  	 */
> -	for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
> +	for (i = 0; i < num_private_irqs; i++) {
>  		struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
>  
>  		INIT_LIST_HEAD(&irq->ap_list);
>  		raw_spin_lock_init(&irq->irq_lock);
> -		irq->intid = i;
>  		irq->vcpu = NULL;
>  		irq->target_vcpu = vcpu;
>  		refcount_set(&irq->refcount, 0);
> -		if (vgic_irq_is_sgi(i)) {
> -			/* SGIs */
> -			irq->enabled = 1;
> -			irq->config = VGIC_CONFIG_EDGE;
> +		if (!vgic_is_v5(vcpu->kvm)) {
> +			irq->intid = i;
> +			if (vgic_irq_is_sgi(i)) {
> +				/* SGIs */
> +				irq->enabled = 1;
> +				irq->config = VGIC_CONFIG_EDGE;
> +			} else {
> +				/* PPIs */
> +				irq->config = VGIC_CONFIG_LEVEL;
> +			}
>  		} else {
> -			/* PPIs */
> -			irq->config = VGIC_CONFIG_LEVEL;
> +			irq->intid = i | FIELD_PREP(GICV5_HWIRQ_TYPE,
> +						    GICV5_HWIRQ_TYPE_PPI);
Trivial:
I'd use FIELD_PREP() even for the ID part.  Makes no difference other than
making it explicit that it's a field that doesn't overlap with the type
one.