KVM, QEMU, and kernel project management

“The KVM virtualization subsystem is seen as one of the great
success stories of contemporary kernel development. KVM came from
nowhere into a situation with a number of established players –
both free and proprietary – and promptly found a home in the kernel
and in the marketing plans of a number of Linux companies. Both the
code and its development model are seen as conforming much more
closely to the Linux way of doing things than the alternatives; KVM
is expected to be the long-term virtualization solution for Linux.
So, one might well wonder, why has KVM been the topic of one of the
more massive and less pleasant linux-kernel discussions in some
time?

“Yanmin Zhang was probably not expecting to set off a flame war
with the posting of a patch adding a set of KVM-related commands to
the “perf” tool. The value of this patch seems obvious: beyond
allowing a host to collect performance statistics on a running
guest, it enables the profiling of the host/guest combination as a
whole. One can imagine that there would be value to being able to
see how the two systems interact.

“The problem, it seems, is that this feature requires that the
host have access to specific information from the running KVM
guest: at a minimum, it needs the guest kernel’s symbol table. More
involved profiling will require access to files in the guest’s
namespaces. To this end, Ingo Molnar suggested that life would be
easier if the host could mount (read-only) all of the filesystems
which were active in the guest. It would also be nice, he said
elsewhere, if the host could easily enumerate running guests and
assign names to them.”

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