KVM: arm/arm64: vgic: Kick new VCPU on interrupt migration

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>

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index e74baec7636130c6e379c93c7312a0be70f97a59..4b6d72939c42859af1ac35153617f1efe67ea908 100644 (file)
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -594,6 +594,7 @@ 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);
 
@@ -664,11 +665,18 @@ 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;
        }