arm64: Add SVE support This patch enables the Scalable Vector Extension for the guest when the host supports it. This requires use of the new KVM_ARM_VCPU_FINALIZE ioctl before the vcpu is runnable, so a new hook kvm_cpu__configure_features() is added to provide an appropriate place to do this work. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Will Deacon <will@kernel.org>