[PATCH 34/35] KVM: arm64: GICv4.1: Configure SGIs as HW interrupts

[Marc Zyngier <maz@kernel.org>]

To enable HW delivery of SGIs, set their hw flag to true, link them
to the corresponding Linux interrupt, which is then activated.

This configures the SGIs at the ITS level, and put the show
on the road!

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 virt/kvm/arm/vgic/vgic-v4.c | 42 +++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
index e61c7a149515..0ff6dac16cba 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -97,6 +97,46 @@ static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
 	return IRQ_HANDLED;
 }
 
+static void vgic_v4_sync_sgi_config(struct its_vpe *vpe, struct vgic_irq *irq)
+{
+	vpe->sgi_config[irq->intid].enabled	= irq->enabled;
+	vpe->sgi_config[irq->intid].group 	= irq->group;
+	vpe->sgi_config[irq->intid].priority	= irq->priority;
+}
+
+static void vgic_v4_init_vsgis(struct kvm_vcpu *vcpu)
+{
+	struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+	int i;
+
+	if (!kvm_vgic_global_state.has_gicv4_1)
+		return;
+
+	/*
+	 * With GICv4.1, every virtual SGI can be directly injected. So
+	 * let's pretend that they are HW interrupts, tied to a host
+	 * IRQ. The SGI code will do its magic.
+	 */
+	for (i = 0; i < VGIC_NR_SGIS; i++) {
+		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, i);
+		struct irq_desc *desc;
+		int ret;
+
+		irq->hw = true;
+		irq->host_irq = irq_find_mapping(vpe->sgi_domain, i);
+		vgic_v4_sync_sgi_config(vpe, irq);
+		/*
+		 * SGIs are initialised as disabled. Enable them if
+		 * required by the rest of the VGIC init code.
+		 */
+		desc = irq_to_desc(irq->host_irq);
+		ret = irq_domain_activate_irq(irq_desc_get_irq_data(desc),
+					      false);
+		WARN_ON(ret);
+		vgic_put_irq(vcpu->kvm, irq);
+	}
+}
+
 /**
  * vgic_v4_init - Initialize the GICv4 data structures
  * @kvm:	Pointer to the VM being initialized
@@ -168,6 +208,8 @@ int vgic_v4_init(struct kvm *kvm)
 			dist->its_vm.nr_vpes = i;
 			break;
 		}
+
+		vgic_v4_init_vsgis(vcpu);
 	}
 
 	if (ret)
-- 
2.20.1