[PATCH 4.9 120/164] KVM: arm/arm64: vgic-v3: Do not use Active+Pending state for a HW interrupt

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 3d6e77ad1489650afa20da92bb589c8778baa8da upstream.

When an interrupt is injected with the HW bit set (indicating that
deactivation should be propagated to the physical distributor),
special care must be taken so that we never mark the corresponding
LR with the Active+Pending state (as the pending state is kept in
the physycal distributor).

Fixes: 59529f69f504 ("KVM: arm/arm64: vgic-new: Add GICv3 world switch backend")
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Reviewed-by: Christoffer Dall <cdall@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <cdall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 virt/kvm/arm/vgic/vgic-v3.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -151,6 +151,13 @@ void vgic_v3_populate_lr(struct kvm_vcpu
 	if (irq->hw) {
 		val |= ICH_LR_HW;
 		val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT;
+		/*
+		 * Never set pending+active on a HW interrupt, as the
+		 * pending state is kept at the physical distributor
+		 * level.
+		 */
+		if (irq->active && irq_is_pending(irq))
+			val &= ~ICH_LR_PENDING_BIT;
 	} else {
 		if (irq->config == VGIC_CONFIG_LEVEL)
 			val |= ICH_LR_EOI;