[RFC PATCH v2 3/4] KVM: arm64: GICv4.1: Restore VLPI's pending state to physical side

[Shenming Lu]

From: Zenghui Yu <yuzenghui@xxxxxxxxxx>

When setting the forwarding path of a VLPI (switch to the HW mode),
we could also transfer the pending state from irq->pending_latch to
VPT (especially in migration, the pending states of VLPIs are restored
into kvm’s vgic first). And we currently send "INT+VSYNC" to trigger
a VLPI to pending.

Signed-off-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Signed-off-by: Shenming Lu <lushenming@xxxxxxxxxx>
---
 arch/arm64/kvm/vgic/vgic-v4.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c
index f211a7c32704..7945d6d09cdd 100644
--- a/arch/arm64/kvm/vgic/vgic-v4.c
+++ b/arch/arm64/kvm/vgic/vgic-v4.c
@@ -454,6 +454,18 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
 	irq->host_irq	= virq;
 	atomic_inc(&map.vpe->vlpi_count);
 
+	/* Transfer pending state */
+	ret = irq_set_irqchip_state(irq->host_irq,
+				    IRQCHIP_STATE_PENDING,
+				    irq->pending_latch);
+	WARN_RATELIMIT(ret, "IRQ %d", irq->host_irq);
+
+	/*
+	 * Let it be pruned from ap_list later and don't bother
+	 * the List Register.
+	 */
+	irq->pending_latch = false;
+
 out:
 	mutex_unlock(&its->its_lock);
 	return ret;
-- 
2.19.1