1 files changed, 20 insertions, 24 deletions

diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index f56ff1cf52ec..ceeda7e04a4d 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -313,36 +313,30 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 
 	spin_lock_irqsave(&irq->irq_lock, flags);
 
-	/*
-	 * If this virtual IRQ was written into a list register, we
-	 * have to make sure the CPU that runs the VCPU thread has
-	 * synced back the LR state to the struct vgic_irq.
-	 *
-	 * As long as the conditions below are true, we know the VCPU thread
-	 * may be on its way back from the guest (we kicked the VCPU thread in
-	 * vgic_change_active_prepare)  and still has to sync back this IRQ,
-	 * so we release and re-acquire the spin_lock to let the other thread
-	 * sync back the IRQ.
-	 *
-	 * When accessing VGIC state from user space, requester_vcpu is
-	 * NULL, which is fine, because we guarantee that no VCPUs are running
-	 * when accessing VGIC state from user space so irq->vcpu->cpu is
-	 * always -1.
-	 */
-	while (irq->vcpu && /* IRQ may have state in an LR somewhere */
-	       irq->vcpu != requester_vcpu && /* Current thread is not the VCPU thread */
-	       irq->vcpu->cpu != -1) /* VCPU thread is running */
-		cond_resched_lock(&irq->irq_lock);
-
 	if (irq->hw) {
 		vgic_hw_irq_change_active(vcpu, irq, active, !requester_vcpu);
 	} else {
 		u32 model = vcpu->kvm->arch.vgic.vgic_model;
+		u8 active_source;
 
 		irq->active = active;
+
+		/*
+		 * The GICv2 architecture indicates that the source CPUID for
+		 * an SGI should be provided during an EOI which implies that
+		 * the active state is stored somewhere, but at the same time
+		 * this state is not architecturally exposed anywhere and we
+		 * have no way of knowing the right source.
+		 *
+		 * This may lead to a VCPU not being able to receive
+		 * additional instances of a particular SGI after migration
+		 * for a GICv2 VM on some GIC implementations.  Oh well.
+		 */
+		active_source = (requester_vcpu) ? requester_vcpu->vcpu_id : 0;
+
 		if (model == KVM_DEV_TYPE_ARM_VGIC_V2 &&
 		    active && vgic_irq_is_sgi(irq->intid))
-			irq->active_source = requester_vcpu->vcpu_id;
+			irq->active_source = active_source;
 	}
 
 	if (irq->active)
@@ -368,14 +362,16 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
  */
 static void vgic_change_active_prepare(struct kvm_vcpu *vcpu, u32 intid)
 {
-	if (intid > VGIC_NR_PRIVATE_IRQS)
+	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3 ||
+	    intid > VGIC_NR_PRIVATE_IRQS)
 		kvm_arm_halt_guest(vcpu->kvm);
 }
 
 /* See vgic_change_active_prepare */
 static void vgic_change_active_finish(struct kvm_vcpu *vcpu, u32 intid)
 {
-	if (intid > VGIC_NR_PRIVATE_IRQS)
+	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3 ||
+	    intid > VGIC_NR_PRIVATE_IRQS)
 		kvm_arm_resume_guest(vcpu->kvm);
 }