[PATCH 4.7 16/31] KVM: arm/arm64: vgic: Dont flush/sync without a working vgic

From: Greg Kroah-Hartman
Date: Fri Oct 14 2016 - 09:36:04 EST


4.7-stable review patch. If anyone has any objections, please let me know.

------------------

From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>

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.

Fixes: 0919e84c0fc1 ("KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework")
Reported-by: Alexander Graf <agraf@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -553,6 +553,9 @@ 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);
@@ -561,6 +564,9 @@ 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);