Auger Eric's latest patches about "ARM virt: Initial RAM expansion
and extended memory map"(https://patchwork.kernel.org/cover/10835377/)
paves the way to device memory, which is the foundation for NVDIMM and
memory hotplug.
This new feature on qemu kinds of depends on host kernel's new feature
on dynamic IPA range(https://lwn.net/Articles/750176/).
The availability of this feature is advertised by a new kvm cap
KVM_CAP_ARM_VM_IPA_SIZE. When supported, this capability returns the
maximum IPA shift supported by the host. The supported IPA size on
a host could be different from the system's PARange indicated
by the CPUs (e.g, kernel limit on the PA size).
Fixes: #1796
Signed-off-by: Penny Zheng <penny.zheng@arm.com>