The basic idea of virtio-mem is to provide a flexible, cross-architecture
memory hot plug and hot unplug solution that avoids many limitations
imposed by existing technologies, architectures, and interfaces. More
details can be found in https://lkml.org/lkml/2019/12/12/681.
This commit add virtio-mem device.
Signed-off-by: Hui Zhu <teawater@antfin.com>
