gmap_new
res = gmap_new(parent->kvm, limit);
new = gmap_new(parent->kvm, asce.r ? 1UL << (64 - PAGE_SHIFT) : asce_end(asce));
struct gmap *gmap_new(struct kvm *kvm, gfn_t limit);
kvm->arch.gmap = gmap_new(kvm, gpa_to_gfn(kvm->arch.mem_limit));