From: Vincent JARDIN <vincent.jardin@6wind.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: Henning Schild <henning.schild@siemens.com>,
David Marchand <david.marchand@6wind.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: Why I advise against using ivshmem
Date: Thu, 12 Jun 2014 18:02:17 +0200 [thread overview]
Message-ID: <5399CF09.8030803__11699.5815224529$1402588950$gmane$org@6wind.com> (raw)
In-Reply-To: <87vbs6qjhj.fsf_-_@blackfin.pond.sub.org>
Markus,
see inline (I am not on all mailing list, please, keep the cc list).
> Sure! The reasons for my dislike range from practical to
> philosophical.
>
> My practical concerns include:
>
> 1. ivshmem code needs work, but has no maintainer
See David's contributions:
http://patchwork.ozlabs.org/patch/358750/
> 2. There is no libvirt support
One can use qemu without libvivrt.
> 3. Out-of-tree server program required for full functionality
We have the source code, it provides the documentation to write our own
better server program.
> 4. Out-of-tree kernel uio driver required
No, it is optional.
> These concerns are all fixable, but it'll take serious work, and time.
> Something like:
>
> * Find a maintainer for the device model
I guess, we can find it into the DPDK.org community.
> * Review and fix its code
>
> * Get the required kernel module upstream
which module? uio, it is not required.
> * Get all the required parts outside QEMU packaged in major distros, or
> absorbed into QEMU
Redhat did disable it. why? it is there in QEMU.
> In short, create a viable community around ivshmem, either within the
> QEMU community, or separately but cooperating.
At least, DPDK.org community is a community using it.
> On to the more philosophical ones.
>
> 5. Out-of-tree interface required
>
> Paraphrasing an old quip: Some people, when confronted with a
> problem, think "I know, I'll use shared memory." Now they have two
> problems.
>
> Shared memory is not an interface. It's at best something you can
> use to build an interface.
>
> I'd rather have us offer something with a little bit more structure.
> Very fast guest-to-guest networking perhaps.
It is not just networking, you have other use cases like HPC, sharing
in-memory databases.
>
> 6. Device models belong into QEMU
>
> Say you build an actual interface on top of ivshmem. Then ivshmem in
> QEMU together with the supporting host code outside QEMU (see 3.) and
> the lower layer of the code using it in guests (kernel + user space)
> provide something that to me very much looks like a device model.
>
> Device models belong into QEMU. It's what QEMU does.
See my previous statement, it is not just device model.
Best regards,
Vincent
next prev parent reply other threads:[~2014-06-12 16:02 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-10 16:48 Using virtio for inter-VM communication Henning Schild
2014-06-10 16:48 ` [Qemu-devel] " Henning Schild
2014-06-10 22:15 ` Vincent JARDIN
2014-06-10 22:15 ` Vincent JARDIN
2014-06-10 22:15 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 6:48 ` Markus Armbruster
2014-06-12 6:48 ` Markus Armbruster
2014-06-12 6:48 ` [Qemu-devel] " Markus Armbruster
2014-06-12 7:44 ` Henning Schild
2014-06-12 7:44 ` [Qemu-devel] " Henning Schild
2014-06-12 9:31 ` Vincent JARDIN
2014-06-12 9:31 ` Vincent JARDIN
2014-06-12 9:31 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 12:55 ` Markus Armbruster
2014-06-12 14:40 ` Why I advise against using ivshmem (was: [Qemu-devel] Using virtio for inter-VM communication) Markus Armbruster
2014-06-12 14:40 ` Markus Armbruster
2014-06-12 14:40 ` [Qemu-devel] Why I advise against using ivshmem (was: " Markus Armbruster
2014-06-12 16:02 ` Why I advise against using ivshmem Vincent JARDIN
2014-06-12 16:02 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 16:54 ` Paolo Bonzini
2014-06-12 16:54 ` [Qemu-devel] " Paolo Bonzini
2014-06-13 8:46 ` Markus Armbruster
2014-06-13 9:26 ` Vincent JARDIN
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 10:09 ` Paolo Bonzini
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 14:10 ` Paolo Bonzini
2014-06-13 14:10 ` Paolo Bonzini
2014-06-14 18:01 ` Vincent JARDIN
2014-06-14 18:01 ` Vincent JARDIN
2014-06-17 2:54 ` Stefan Hajnoczi
2014-06-17 9:03 ` David Marchand
2014-06-17 9:03 ` David Marchand
2014-06-17 9:44 ` Paolo Bonzini
2014-06-18 10:48 ` Stefan Hajnoczi
2014-06-18 10:48 ` Stefan Hajnoczi
2014-06-18 14:57 ` David Marchand
2014-06-18 14:57 ` David Marchand
2014-06-18 14:57 ` David Marchand
2014-06-18 15:10 ` Paolo Bonzini
2014-06-21 9:34 ` Stefan Hajnoczi
2014-06-26 20:02 ` Cam Macdonell
2014-06-26 20:02 ` Cam Macdonell
2014-06-18 15:01 ` Andreas Färber
2014-06-18 15:01 ` Andreas Färber
2014-06-19 8:25 ` David Marchand
2014-06-19 8:25 ` David Marchand
2014-06-19 8:25 ` David Marchand
2014-06-18 15:01 ` Andreas Färber
2014-06-30 11:10 ` Markus Armbruster
2014-06-30 11:10 ` Markus Armbruster
2014-06-30 11:10 ` Markus Armbruster
2014-06-18 10:51 ` Stefan Hajnoczi
2014-06-18 10:51 ` Stefan Hajnoczi
2014-06-18 14:58 ` David Marchand
2014-06-18 14:58 ` David Marchand
2014-06-18 14:58 ` David Marchand
2014-06-18 14:22 ` Claudio Fontana
2014-06-17 9:03 ` David Marchand
2014-06-13 9:29 ` Jobin Raju George
2014-06-13 9:29 ` [Qemu-devel] " Jobin Raju George
2014-06-13 9:29 ` Jobin Raju George
2014-06-12 16:02 ` Vincent JARDIN [this message]
2014-06-12 2:27 ` Using virtio for inter-VM communication Rusty Russell
2014-06-12 2:27 ` Rusty Russell
2014-06-12 2:27 ` [Qemu-devel] " Rusty Russell
2014-06-12 5:32 ` Jan Kiszka
2014-06-12 5:32 ` [Qemu-devel] " Jan Kiszka
2014-06-13 0:47 ` Rusty Russell
2014-06-13 0:47 ` [Qemu-devel] " Rusty Russell
2014-06-13 6:23 ` Jan Kiszka
2014-06-13 6:23 ` [Qemu-devel] " Jan Kiszka
2014-06-13 8:45 ` Paolo Bonzini
2014-06-13 8:45 ` [Qemu-devel] " Paolo Bonzini
2014-06-15 6:20 ` Jan Kiszka
2014-06-15 6:20 ` Jan Kiszka
2014-06-15 6:20 ` [Qemu-devel] " Jan Kiszka
2014-06-17 5:24 ` Paolo Bonzini
2014-06-17 5:24 ` [Qemu-devel] " Paolo Bonzini
2014-06-17 5:57 ` Jan Kiszka
2014-06-17 5:57 ` Jan Kiszka
2014-06-17 5:57 ` [Qemu-devel] " Jan Kiszka
2014-06-17 5:24 ` Paolo Bonzini
2014-06-12 5:32 ` Jan Kiszka
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