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Subject: Re: [PATCH net-next 0/3] vsock: support network namespace
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     davem@davemloft.net, Stefan Hajnoczi <stefanha@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        linux-kernel@vger.kernel.org, Jorgen Hansen <jhansen@vmware.com>,
        kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        linux-hyperv@vger.kernel.org, Dexuan Cui <decui@microsoft.com>,
        netdev@vger.kernel.org
References: <20200116172428.311437-1-sgarzare@redhat.com>
 <20200427142518.uwssa6dtasrp3bfc@steredhat>
 <224cdc10-1532-7ddc-f113-676d43d8f322@redhat.com>
 <20200428160052.o3ihui4262xogyg4@steredhat>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <6dc937e4-0ef9-617d-c9c8-8b1f8c428d90@redhat.com>
Date:   Wed, 29 Apr 2020 17:21:42 +0800
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On 2020/4/29 =E4=B8=8A=E5=8D=8812:00, Stefano Garzarella wrote:
> On Tue, Apr 28, 2020 at 04:13:22PM +0800, Jason Wang wrote:
>> On 2020/4/27 =E4=B8=8B=E5=8D=8810:25, Stefano Garzarella wrote:
>>> Hi David, Michael, Stefan,
>>> I'm restarting to work on this topic since Kata guys are interested t=
o
>>> have that, especially on the guest side.
>>>
>>> While working on the v2 I had few doubts, and I'd like to have your
>>> suggestions:
>>>
>>>    1. netns assigned to the device inside the guest
>>>
>>>      Currently I assigned this device to 'init_net'. Maybe it is bett=
er
>>>      if we allow the user to decide which netns assign to the device
>>>      or to disable this new feature to have the same behavior as befo=
re
>>>      (host reachable from any netns).
>>>      I think we can handle this in the vsock core and not in the sing=
le
>>>      transports.
>>>
>>>      The simplest way that I found, is to add a new
>>>      IOCTL_VM_SOCKETS_ASSIGN_G2H_NETNS to /dev/vsock to enable the fe=
ature
>>>      and assign the device to the same netns of the process that do t=
he
>>>      ioctl(), but I'm not sure it is clean enough.
>>>
>>>      Maybe it is better to add new rtnetlink messages, but I'm not su=
re if
>>>      it is feasible since we don't have a netdev device.
>>>
>>>      What do you suggest?
>> As we've discussed, it should be a netdev probably in either guest or =
host
>> side. And it would be much simpler if we want do implement namespace t=
hen.
>> No new API is needed.
>>
> Thanks Jason!
>
> It would be cool, but I don't have much experience on netdev.
> Do you see any particular obstacles?


I don't see but if there's we can try to find a solution or ask for=20
netdev experts for that. I do hear from somebody that is interested in=20
having netdev in the past.


>
> I'll take a look to understand how to do it, surely in the guest would
> be very useful to have the vsock device as a netdev and maybe also in t=
he host.


Yes, it's worth to have a try then we will have a unified management=20
interface and we will benefit from it in the future.

Starting form guest is good idea which should be less complicated than ho=
st.

Thanks


>
> Stefano
>