[PATCH v4 5/6] KVM: arm64: GICv4.1: Restore VLPI pending state to physical side

[Shenming Lu]

From: Zenghui Yu <yuzenghui at huawei.com>

When setting the forwarding path of a VLPI (switch to the HW mode),
we can 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 at huawei.com>
Signed-off-by: Shenming Lu <lushenming at huawei.com>
---
 arch/arm64/kvm/vgic/vgic-v4.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c
index ac029ba3d337..3b82ab80c2f3 100644
--- a/arch/arm64/kvm/vgic/vgic-v4.c
+++ b/arch/arm64/kvm/vgic/vgic-v4.c
@@ -449,6 +449,24 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
 	irq->host_irq	= virq;
 	atomic_inc(&map.vpe->vlpi_count);
 
+	/* Transfer pending state */
+	if (irq->pending_latch) {
+		unsigned long flags;
+
+		ret = irq_set_irqchip_state(irq->host_irq,
+					    IRQCHIP_STATE_PENDING,
+					    irq->pending_latch);
+		WARN_RATELIMIT(ret, "IRQ %d", irq->host_irq);
+
+		/*
+		 * Clear pending_latch and communicate this state
+		 * change via vgic_queue_irq_unlock.
+		 */
+		raw_spin_lock_irqsave(&irq->irq_lock, flags);
+		irq->pending_latch = false;
+		vgic_queue_irq_unlock(kvm, irq, flags);
+	}
+
 out:
 	mutex_unlock(&its->its_lock);
 	return ret;
-- 
2.19.1