[PATCH v5 3/6] KVM: x86: ioapic: Preserve irr_delivered for duplicate edge interrupts

[Hao Zhang <hao_zhang_kdev@163.com>]

From: Hao Zhang <zhanghao1@kylinos.cn>

For edge-triggered interrupts, ioapic_set_irq() clears irr_delivered
before checking whether the new edge is a duplicate.  A duplicate edge
is then coalesced without being serviced, leaving the interrupt visible
in KVM_GET_IRQCHIP state even though the original interrupt was already
delivered.

Move the state update after the duplicate-edge check so duplicate edges
do not make a delivered interrupt appear pending during VM migration.

Signed-off-by: Hao Zhang <zhanghao1@kylinos.cn>
---
 arch/x86/kvm/ioapic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index 24a7cc3b8b7e..676effd674f9 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -230,11 +230,11 @@ static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq,
 	old_irr = ioapic->irr;
 	ioapic->irr |= mask;
 	if (edge) {
-		ioapic->irr_delivered &= ~mask;
 		if (old_irr == ioapic->irr) {
 			ret = 0;
 			goto out;
 		}
+		ioapic->irr_delivered &= ~mask;
 	}
 
 	ret = ioapic_service(ioapic, irq, line_status);
-- 
2.15.0