From: Nikita Leshenko <nikita.leshchenko@oracle.com>

Date: Sun, 5 Nov 2017 15:52:30 +0200

Subject: KVM: x86: ioapic: Don't fire level irq when Remote IRR set

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Patch-mainline: v4.15-rc2

Git-commit: da3fe7bdfada217bf02ecd0477fcdb55da50944c

References: bsc#1077761

Avoid firing a level-triggered interrupt that has the Remote IRR bit set,

because that means that some CPU is already processing it. The Remote

IRR bit will be cleared after an EOI and the interrupt will refire

if the irq line is still asserted.

This behavior is aligned with QEMU's IOAPIC implementation that was

introduced by commit f99b86b94987

("x86: ioapic: ignore level irq during processing") in QEMU.

Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>

Reviewed-by: Liran Alon <liran.alon@oracle.com>

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

Acked-by: Alexander Graf <agraf@suse.de>

---

 arch/x86/kvm/ioapic.c |    4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/ioapic.c

+++ b/arch/x86/kvm/ioapic.c

@@ -323,7 +323,9 @@

 	struct kvm_lapic_irq irqe;

 	int ret;

-	if (entry->fields.mask)

+	if (entry->fields.mask ||

+	    (entry->fields.trig_mode == IOAPIC_LEVEL_TRIG &&

+	    entry->fields.remote_irr))

 		return -1;

 	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "