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Re: [Qemu-devel] updated: kvm networking todo wiki
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] updated: kvm networking todo wiki |
Date: |
Thu, 30 May 2013 08:40:47 -0500 |
User-agent: |
Notmuch/0.15.2+77~g661dcf8 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Stefan Hajnoczi <address@hidden> writes:
> On Thu, May 30, 2013 at 7:23 AM, Rusty Russell <address@hidden> wrote:
>> Anthony Liguori <address@hidden> writes:
>>> Rusty Russell <address@hidden> writes:
>>>> On Fri, May 24, 2013 at 08:47:58AM -0500, Anthony Liguori wrote:
>>>>> FWIW, I think what's more interesting is using vhost-net as a networking
>>>>> backend with virtio-net in QEMU being what's guest facing.
>>>>>
>>>>> In theory, this gives you the best of both worlds: QEMU acts as a first
>>>>> line of defense against a malicious guest while still getting the
>>>>> performance advantages of vhost-net (zero-copy).
>>>>>
>>>> It would be an interesting idea if we didn't already have the vhost
>>>> model where we don't need the userspace bounce.
>>>
>>> The model is very interesting for QEMU because then we can use vhost as
>>> a backend for other types of network adapters (like vmxnet3 or even
>>> e1000).
>>>
>>> It also helps for things like fault tolerance where we need to be able
>>> to control packet flow within QEMU.
>>
>> (CC's reduced, context added, Dmitry Fleytman added for vmxnet3 thoughts).
>>
>> Then I'm really confused as to what this would look like. A zero copy
>> sendmsg? We should be able to implement that today.
>>
>> On the receive side, what can we do better than readv? If we need to
>> return to userspace to tell the guest that we've got a new packet, we
>> don't win on latency. We might reduce syscall overhead with a
>> multi-dimensional readv to read multiple packets at once?
>
> Sounds like recvmmsg(2).
Could we map this to mergable rx buffers though?
Regards,
Anthony Liguori
>
> Stefan
- Re: [Qemu-devel] updated: kvm networking todo wiki, (continued)
- Re: [Qemu-devel] updated: kvm networking todo wiki, Jason Wang, 2013/05/24
- Re: [Qemu-devel] updated: kvm networking todo wiki, Michael S. Tsirkin, 2013/05/24
- Re: [Qemu-devel] updated: kvm networking todo wiki, Anthony Liguori, 2013/05/24
- Re: [Qemu-devel] updated: kvm networking todo wiki, Michael S. Tsirkin, 2013/05/24
- Re: [Qemu-devel] updated: kvm networking todo wiki, Rusty Russell, 2013/05/29
- Re: [Qemu-devel] updated: kvm networking todo wiki, Anthony Liguori, 2013/05/29
- Re: [Qemu-devel] updated: kvm networking todo wiki, Michael S. Tsirkin, 2013/05/29
- Re: [Qemu-devel] updated: kvm networking todo wiki, Rusty Russell, 2013/05/30
- Re: [Qemu-devel] updated: kvm networking todo wiki, Stefan Hajnoczi, 2013/05/30
- Re: [Qemu-devel] updated: kvm networking todo wiki, Rusty Russell, 2013/05/30
- Re: [Qemu-devel] updated: kvm networking todo wiki,
Anthony Liguori <=
- Re: [Qemu-devel] updated: kvm networking todo wiki, Michael S. Tsirkin, 2013/05/30
- Re: [Qemu-devel] updated: kvm networking todo wiki, Anthony Liguori, 2013/05/30
- Re: [Qemu-devel] updated: kvm networking todo wiki, Anthony Liguori, 2013/05/30