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From: Stefan Hajnoczi <>
To: Stefano Garzarella <>
Cc:,,, "Michael S. Tsirkin" <>,
	Dexuan Cui <>,,,
	Stefan Hajnoczi <>,
	"David S. Miller" <>,
	Jorgen Hansen <>
Subject: Re: [RFC PATCH 0/3] vsock: support network namespace
Date: Tue, 3 Dec 2019 09:26:49 +0000
Message-ID: <20191203092649.GB153510@stefanha-x1.localdomain> (raw)
In-Reply-To: <>

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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.

> 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.

> 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.

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  parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28 17:15 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 ` Stefan Hajnoczi [this message]
2019-12-03 11:17   ` [RFC PATCH 0/3] vsock: support network namespace Stefano Garzarella

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