Re: [Qemu-devel] KVM call for 2017-03-14

[Peter Maydell]

On 12 March 2017 at 21:45, Juan Quintela <address@hidden> wrote:
>
>
> Hi
>
> Please, send any topic that you are interested in covering.
>
> So far the agenda is:
>
> - Direction of QEMU and toolstack in light of Google Cloud blog:
>   
> https://cloudplatform.googleblog.com/2017/01/7-ways-we-harden-our-KVM-hypervisor-at-Google-Cloud-security-in-plaintext.html


Ah, I'd forgotten that this was on the call agenda. I actually
had an interesting conversation with Alex Graf last week about
some similar topics, which I guess you could generally summarize
as "what are the issues we need to address as a project in order
to not become irrelevant in five years time". Since I wrote them
up for an internal "what I did on my holi^Wconference trip" report
I might as well repost them here:

  - on the "VM support" side, QEMU is more used because it's the only
    production-quality option in this space, rather than because its
    users love it. (cf the Google choice to replace it.) It's also got
    a pretty poor security record. It wouldn't be too surprising if
    some time in the next five years somebody writes a replacement in
    a safer language (perhaps also targeting only the VM support role)
    and it got enough mindshare and takeup to eclipse QEMU.
    [Is it too early/daft to think about prototyping being able to
     write QEMU device emulation in Rust ?]
    If the "VM support" usecase moves to another project then QEMU
    will become a very quiet backwater...
  - on the "emulation" side, nobody is clearly articulating a purpose
    for QEMU, a reason why you should use it rather than other modelling
    technologies (or rather than using real hardware). As a result the
    efforts applied to QEMU are somewhat unfocused. Are we trying to be:
    . a dev platform before easy h/w availability?
      [not easy for QEMU for several reasons]
    . a dev tool that provides better introspection into guest
      behaviour than running on h/w?
      [if so we should put more work into improving our introspection
       and guest tracing capabilities!]
    . primarily a tool for doing automated CI testing and one-off
      developer smoke-testing that's easier to set up and scale than
      trying to test on real h/w?
    . something else?
      [your idea goes here!]
  - in all areas our legacy code and back-compatibility requirements
    are threatening to choke forward progress if we don't make serious
    efforts to get on top of them
  - there's no easy way for people to use parts of QEMU like the CPU
    emulation, or to add their own devices without having to write lots
    of C code (we're firmly in a "one monolithic blob of code" setup
    right now and disentangling and setting clear API dividing lines
    will be a lot of work)
    [Making QEMU more modular would help with defeating the legacy
    and back-compat dragons, though]

thanks
-- PMM