[PATCH 4.8 16/37] KVM: arm/arm64: vgic: Dont flush/sync without a working vgic

From: Greg Kroah-Hartman
Date: Fri Oct 14 2016 - 08:28:09 EST

4.8-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

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
@@ -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;
@@ -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;