KVM: ARM: vgic: abstract VMCR access

Instead of directly messing with with the GICH_VMCR bits for the CPU
interface save/restore code, add accessors that encode/decode the
entire set of registers exposed by VMCR.

Not the most efficient thing, but given that this code is only used
by the save/restore code, performance is far from being critical.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index cdfa5d9..f515800 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -81,6 +81,13 @@
 	u8	state;
 };
 
+struct vgic_vmcr {
+	u32	ctlr;
+	u32	abpr;
+	u32	bpr;
+	u32	pmr;
+};
+
 struct vgic_ops {
 	struct vgic_lr	(*get_lr)(const struct kvm_vcpu *, int);
 	void	(*set_lr)(struct kvm_vcpu *, int, struct vgic_lr);
@@ -90,6 +97,8 @@
 	u32	(*get_interrupt_status)(const struct kvm_vcpu *vcpu);
 	void	(*enable_underflow)(struct kvm_vcpu *vcpu);
 	void	(*disable_underflow)(struct kvm_vcpu *vcpu);
+	void	(*get_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
+	void	(*set_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 };
 
 struct vgic_dist {