From: Stefano Garzarella <sgarzare@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: netdev@vger.kernel.org, linux-hyperv@vger.kernel.org,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
Dexuan Cui <decui@microsoft.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Stefan Hajnoczi <stefanha@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Jorgen Hansen <jhansen@vmware.com>
Subject: Re: [RFC PATCH 0/3] vsock: support network namespace
Date: Tue, 3 Dec 2019 12:17:39 +0100 [thread overview]
Message-ID: <20191203111739.jbxptcpmvtwg7j2g@steredhat> (raw)
In-Reply-To: <20191203092649.GB153510@stefanha-x1.localdomain>
On Tue, Dec 03, 2019 at 09:26:49AM +0000, Stefan Hajnoczi wrote:
> On Thu, Nov 28, 2019 at 06:15:16PM +0100, Stefano Garzarella wrote:
> > Hi,
> > now that we have multi-transport upstream, I started to take a look to
> > support network namespace (netns) in vsock.
> >
> > As we partially discussed in the multi-transport proposal [1], it could
> > be nice to support network namespace in vsock to reach the following
> > goals:
> > - isolate host applications from guest applications using the same ports
> > with CID_ANY
> > - assign the same CID of VMs running in different network namespaces
> > - partition VMs between VMMs or at finer granularity
> >
> > This preliminary implementation provides the following behavior:
> > - packets received from the host (received by G2H transports) are
> > assigned to the default netns (init_net)
> > - packets received from the guest (received by H2G - vhost-vsock) are
> > assigned to the netns of the process that opens /dev/vhost-vsock
> > (usually the VMM, qemu in my tests, opens the /dev/vhost-vsock)
> > - for vmci I need some suggestions, because I don't know how to do
> > and test the same in the vmci driver, for now vmci uses the
> > init_net
> > - loopback packets are exchanged only in the same netns
> >
> > Questions:
> > 1. Should we make configurable the netns (now it is init_net) where
> > packets from the host should be delivered?
>
> Yes, it should be possible to have multiple G2H (e.g. virtio-vsock)
> devices and to assign them to different net namespaces. Something like
> net/core/dev.c:dev_change_net_namespace() will eventually be needed.
>
Make sense, but for now we support only one G2H.
How we can provide this feature to the userspace?
Should we interface vsock with ip-link(8)?
I don't know if initially we can provide through sysfs a way to set the
netns of the only G2H loaded.
> > 2. Should we provide an ioctl in vhost-vsock to configure the netns
> > to use? (instead of using the netns of the process that opens
> > /dev/vhost-vsock)
>
> Creating the vhost-vsock instance in the process' net namespace makes
> sense. Maybe wait for a use case before adding an ioctl.
>
Agree.
> > 3. Should we provide a way to disable the netns support in vsock?
>
> The code should follow CONFIG_NET_NS semantics. I'm not sure what they
> are exactly since struct net is always defined, regardless of whether
> network namespaces are enabled.
I think that if CONFIG_NET_NS is not defined, all sockets and processes
are assigned to init_net and this RFC should work in this case, but I'll
try this case before v1.
I was thinking about the Kata's use case, I don't know if they launch the
VM in a netns and even the runtime in the host runs inside the same netns.
I'll send an e-mail to kata mailing list.
Thanks,
Stefano
prev parent reply other threads:[~2019-12-03 11:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 17:15 [RFC PATCH 0/3] vsock: support network namespace Stefano Garzarella
2019-11-28 17:15 ` [RFC PATCH 1/3] vsock: add network namespace support Stefano Garzarella
2019-11-28 17:15 ` [RFC PATCH 2/3] vsock/virtio_transport_common: handle netns of received packets Stefano Garzarella
2019-11-28 17:15 ` [RFC PATCH 3/3] vhost/vsock: use netns of process that opens the vhost-vsock device Stefano Garzarella
2019-12-03 9:26 ` [RFC PATCH 0/3] vsock: support network namespace Stefan Hajnoczi
2019-12-03 11:17 ` Stefano Garzarella [this message]
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