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

BugLink: http://bugs.launchpad.net/bugs/1794889
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 4980742410fa9b90dcbc95a4d4b060eb25933043..96a498871fa0fb19bbbe84b4439c04e8d9642105 100644 (file)
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -564,6 +564,7 @@ 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);
 
@@ -634,11 +635,18 @@ 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;
        }