ff000000 ffbfffff Reserved for future expansion of DMA
mapping region.
+fee00000 feffffff Mapping of PCI I/O space. This is a static
+ mapping within the vmalloc space.
+
VMALLOC_START VMALLOC_END-1 vmalloc() / ioremap() space.
Memory returned by vmalloc/ioremap will
be dynamically placed in this region.