releases/4.16.17/kvm-arm-arm64-vgic-kick-new-vcpu-on-interrupt-migration.patch

From foo@baz Sun Jun 17 12:07:33 CEST 2018
From: Andre Przywara <andre.przywara@arm.com>
Date: Tue, 17 Apr 2018 11:23:49 +0100
Subject: KVM: arm/arm64: vgic: Kick new VCPU on interrupt migration

From: Andre Przywara <andre.przywara@arm.com>

[ Upstream commit bf9a41377d14f565764022470e14aae72559589a ]

When vgic_prune_ap_list() finds an interrupt that needs to be migrated
to a new VCPU, we should notify this VCPU of the pending interrupt,
since it requires immediate action.
Kick this VCPU once we have added the new IRQ to the list, but only
after dropping the locks.

Reported-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 virt/kvm/arm/vgic/vgic.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -599,6 +599,7 @@ retry:
 
 	list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
 		struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
+		bool target_vcpu_needs_kick = false;
 
 		spin_lock(&irq->irq_lock);
 
@@ -669,11 +670,18 @@ retry:
 			list_del(&irq->ap_list);
 			irq->vcpu = target_vcpu;
 			list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
+			target_vcpu_needs_kick = true;
 		}
 
 		spin_unlock(&irq->irq_lock);
 		spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
 		spin_unlock_irqrestore(&vcpuA->arch.vgic_cpu.ap_list_lock, flags);
+
+		if (target_vcpu_needs_kick) {
+			kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
+			kvm_vcpu_kick(target_vcpu);
+		}
+
 		goto retry;
 	}