[libvirt] ivshmem server

[Cam Macdonell]

On Tue, Dec 4, 2012 at 3:57 AM, Andrew Jones <drjones at redhat.com> wrote:
> Cam,
>
> ping
>
> Please let us know your opinion on integrating ivshmem-server
> into libvirt. Also, please confirm the licensing would allow it.
>
> Thanks,
> Drew

Hi,

Apologies for missing this until now, I'll make sure to keep an eye
here more often.  I'm happy to release it under the GPL and work
towards integrating it into libvirt.

Sincerely,
Cam

>
> ----- Original Message -----
>>
>>
>> ----- Original Message -----
>> > On Tue, Nov 20, 2012 at 01:16:56PM -0500, Andrew Jones wrote:
>> > >
>> > > This mail is meant to get a discussion started. Please keep me on
>> > > cc
>> > > for the discussion, as I'm not subscribed to libvir-list.
>> > >
>> > > ivshmem is an implementation of an inter-VM communication
>> > > channel.
>> > > Support for this has been in qemu since v0.14.0 and libvirt
>> > > patches
>> > > have been recently posted[1]. What's still missing is the ivshmem
>> > > server. The ivshmem server is needed when one would like to use
>> > > interrupts with ivshmem. The server manages a set of eventfds
>> > > to send/recv those interrupts. There is currently only one
>> > > implementation of this server that I'm aware of, which is
>> > > available
>> > > from this git repo [2] in the ivshmem-server directory. My
>> > > suggestion
>> > > for libvirt is that this code be integrated into libvirt, rather
>> > > than managed by libvirt, for the following reasons
>> > >
>> > > 1. libvirt should keep track of the socket path in order to build
>> > >    ivshmem's command line anyway.
>> > > 2. the current ivshmem server code is ~300 lines, so it shouldn't
>> > > be
>> > >    a large integration effort.
>> > > 3. keeping ivhsmem server separate increases the package
>> > > management
>> > >    that distributions need to do. afaik, it isn't currently
>> > >    packaged
>> > >    for any distribution.
>> > >
>> > > One concern I have with the git repo [2] is that I don't see any
>> > > license for ivshmem-server. I've cc'ed Cam for his input.
>> >
>> > I guess my main question would be how much more, if any, is the
>> > ivshmem-server expected to grow over time ? I wouldn't want to
>> > get into a fork-situation if people are planning to do much more
>> > dev work on the current ivshmem-server code.
>>
>> Here's the entire git log for ivshmem-server
>>
>> Date:   Thu Sep 6 11:36:33 2012 -0600
>>     Error clean-up
>>     Fixed a warning and cleaned up two error message
>> Date:   Tue Nov 16 11:11:16 2010 -0700
>>     just a few fixups
>> Date:   Tue Jun 15 14:43:01 2010 -0600
>>     Adding the ivshmem server here - Cam
>>
>> So there was an initial drop, then nothing for two years, and then
>> some recent cleanups. I believe that it serves a simple enough
>> purpose that there shouldn't be any more growth.
>>
>> >
>> > NB, if the code is integrated into libvirt, I think it would
>> > still have to run in a separate daemon. The reason is that we
>> > want to ensure that guests remain fully functional, even when
>> > libvirtd is stopped (whether for RPM upgrade, or due to crash)
>> >
>> > I've no particular strong opinion either way on your proposal.
>> > On the surface it seems reasonable to me.
>> >
>> > Daniel
>> > --
>> > |: http://berrange.com      -o-
>> > |   http://www.flickr.com/photos/dberrange/ :|
>> > |: http://libvirt.org              -o-
>> > |            http://virt-manager.org :|
>> > |: http://autobuild.org       -o-
>> > |        http://search.cpan.org/~danberr/ :|
>> > |: http://entangle-photo.org       -o-
>> > |      http://live.gnome.org/gtk-vnc :|
>> >
>>
>