[PATCH v6 18/39] KVM: arm64: gic: Introduce queue_irq_unlock to irq_ops

Sascha Bischoff
2026-03-17T11:45:49Z

There are times when the default behaviour of vgic_queue_irq_unlock()
is undesirable. This is because some GICs, such a GICv5 which is the
main driver for this change, handle the majority of the interrupt
lifecycle in hardware. In this case, there is no need for a per-VCPU
AP list as the interrupt can be made pending directly. This is done
either via the ICH_PPI_x_EL2 registers for PPIs, or with the VDPEND
system instruction for SPIs and LPIs.

The vgic_queue_irq_unlock() function is made overridable using a new
function pointer in struct irq_ops. vgic_queue_irq_unlock() is
overridden if the function pointer is non-null.

This new irq_op is unused in this change - it is purely providing the
infrastructure itself. The subsequent PPI injection changes provide a
demonstration of the usage of the queue_irq_unlock irq_op.

Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
---
arch/arm64/kvm/vgic/vgic.c | 3 +++
include/kvm/arm_vgic.h | 8 ++++++++
2 files changed, 11 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 6df03d0d55078..f3677535200ff 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -404,6 +404,9 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,

lockdep_assert_held(&irq->irq_lock);

+ if (irq->ops && irq->ops->queue_irq_unlock)
+ return irq->ops->queue_irq_unlock(kvm, irq, flags);
+
retry:
vcpu = vgic_target_oracle(irq);
if (irq->vcpu || !vcpu) {
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index fdad0263499ba..e9797c5dbbf0c 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -189,6 +189,8 @@ enum vgic_irq_config {
VGIC_CONFIG_LEVEL
};

+struct vgic_irq;
+
/*
* Per-irq ops overriding some common behavious.
*
@@ -207,6 +209,12 @@ struct irq_ops {
* peaking into the physical GIC.
*/
bool (*get_input_level)(int vintid);
+
+ /*
+ * Function pointer to override the queuing of an IRQ.
+ */
+ bool (*queue_irq_unlock)(struct kvm *kvm, struct vgic_irq *irq,
+ unsigned long flags) __releases(&irq->irq_lock);
};

struct vgic_irq {
--
2.34.1