[$] Live migration of virtual machines over CXL

Virtual-machine hosting can be a fickle business; once a virtual machine
has been placed on a physical host, there may arise a desire to move it to
a different host. The problem with migrating virtual machines, though, is
that there is a period during which the machine is not running; that can be
disruptive even if it is brief. At the 2023 Linux Storage, Filesystem,
Memory-Management and BPF Summit, Dragan Stancevic, presenting
remotely, showed how CXL
shared memory can be used to migrate virtual machines with no offline time.