intc/arm_gic: Add the virtualization extensions to the GIC state

intc/arm_gic: Add the virtualization extensions to the GIC state

Add the necessary parts of the virtualization extensions state to the
GIC state. We choose to increase the size of the CPU interfaces state to
add space for the vCPU interfaces (the GIC_NCPU_VCPU macro). This way,
we'll be able to reuse most of the CPU interface code for the vCPUs.

The only exception is the APR value, which is stored in h_apr in the
virtual interface state for vCPUs. This is due to some complications
with the GIC VMState, for which we don't want to break backward
compatibility. APRs being stored in 2D arrays, increasing the second
dimension would lead to some ugly VMState description. To avoid
that, we keep it in h_apr for vCPUs.

The vCPUs are numbered from GIC_NCPU to (GIC_NCPU * 2) - 1. The
`gic_is_vcpu` function help to determine if a given CPU id correspond to
a physical CPU or a virtual one.

For the in-kernel KVM VGIC, since the exposed VGIC does not implement
the virtualization extensions, we report an error if the corresponding
property is set to true.

Signed-off-by: Luc Michel <luc.michel@greensocs.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20180727095421.386-6-luc.michel@greensocs.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>