Patch "KVM: arm/arm64: vgic: Don't flush/sync without a working vgic" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

KVM: arm/arm64: vgic: Don't flush/sync without a working vgic

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kvm-arm-arm64-vgic-don-t-flush-sync-without-a-working-vgic.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Christoffer Dall <[email protected]>
Date: Tue, 27 Sep 2016 18:53:35 +0200
Subject: KVM: arm/arm64: vgic: Don't flush/sync without a working vgic

From: Christoffer Dall <[email protected]>

commit 0099b7701f5296a758d9e6b945ec96f96847cc2f upstream.

If the vgic hasn't been created and initialized, we shouldn't attempt to look at its data structures or flush/sync anything to the GIC hardware.

This fixes an issue reported by Alexander Graf when using a userspace irqchip.

---
 virt/kvm/arm/vgic/vgic.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -645,6 +645,9 @@ next:
 /* Sync back the hardware VGIC state into our emulation after a guest's run. */
 void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
+	if (unlikely(!vgic_initialized(vcpu->kvm)))
+		return;
+
 	vgic_process_maintenance_interrupt(vcpu);
 	vgic_fold_lr_state(vcpu);
 	vgic_prune_ap_list(vcpu);

@@ -653,6 +656,9 @@ void kvm_vgic_sync_hwstate(struct kvm_vc
 /* Flush our emulation state into the GIC hardware before entering the guest. */
 void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 {
+	if (unlikely(!vgic_initialized(vcpu->kvm)))
+		return;
+
 	spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
 	vgic_flush_lr_state(vcpu);
 	spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/kvm-arm64-require-in-kernel-irqchip-for-pmu-support.patch queue-4.8/kvm-arm-arm64-vgic-don-t-flush-sync-without-a-working-vgic.patch