[PATCH 31/43] KVM: arm64: gic: Introduce set_pending_state() to irq_op

[Sascha Bischoff]

There are times, such as with GICv5 SPIs and LPIs, where the hardware
itself handles the interrupt lifecycle. This means that interrupt
state can be directly communicated to the hardware, and no AP lists or
similar are required to do so. This means that such interrupts don't
fit into the existing flows.

In order to accommodate cases where the hardware handles pending state
directly, a new function is added via a function pointer:
set_pending_state(). The intent is for this to be used to directly set
the pending state in hardware, and can be used when the hardware
itself is able to handle the lifecycle of an interrupt (for example,
for GICv5's SPIs).

This new function is plumbed into kvm_vgic_inject_irq(), and is only
called if irq_ops are provided and this function pointer is explicitly
set. In the general case, this has no effect.

This is part of preparatory work for GICv5 SPI support in KVM.

Signed-off-by: Sascha Bischoff <sascha.bischoff at arm.com>
---
 arch/arm64/kvm/vgic/vgic.c | 3 +++
 include/kvm/arm_vgic.h     | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index d628eea4cfa4e..b35833a4e2bf9 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -565,6 +565,9 @@ int kvm_vgic_inject_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
 	else
 		irq->pending_latch = true;
 
+	if (irq->ops && irq->ops->set_pending_state)
+		WARN_ON_ONCE(!irq->ops->set_pending_state(vcpu, irq));
+
 	vgic_queue_irq_unlock(kvm, irq, flags);
 	vgic_put_irq(kvm, irq);
 
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 812ad325b01be..a47e5c742aac8 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -217,6 +217,12 @@ struct irq_ops {
 	 */
 	bool (*get_input_level)(int vintid);
 
+	/*
+	 * Function pointer to directly set the pending state for interrupts
+	 * that don't need to be enqueued on AP lists (for example, GICv5 PPIs).
+	 */
+	bool (*set_pending_state)(struct kvm_vcpu *vcpu, struct vgic_irq *irq);
+
 	/*
 	 * Function pointer to override the queuing of an IRQ.
 	 */
-- 
2.34.1