Major change in Linux kernel may hit virtualization

Anthony Liguori, Software Engineer at IBM Linux Technology Center and Xen developer for a long time, published on his personal blog a note about upcoming changes decided for Linux kernel:

It was decided today on LKML that starting in January 2008, binary modules are no longer going to be loadable in the Linux kernel. This has some rather major consequences for a number of virtualization technologies.

Parallels, Win4Lin, kqemu, and VMware rely on binary modules for their Linux products. I suspect all of these products will have a hard time moving their code out of kernel space seeing that it’s performance sensitive. So what are they all going to do?

I see three possible options:

  1. drop Linux support (Win4lin and kqemu disappear completely)
  2. build a minimal kernel interface to privilege state and try to develop fast userspace interfaces. I can’t see how one could do a fast userspace shadow paging implementation though.
  3. open source the kernel bits

Read the whole article at source.