From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd@arndb.de>
Subject: Re: Does macvtap support host to guest communication?
Date: Mon, 18 Apr 2011 12:53:06 +0200
Message-ID: <201104181253.07023.arnd@arndb.de>
References: <4DABD5BC.2040204@gmail.com> <201104180858.09828.arnd@arndb.de> <4DAC109F.1060807@gmail.com>
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Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Pekka Enberg <penberg@kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Amos Kong <akong@redhat.com>, kvm@vger.kernel.org
To: Asias He <asias.hejun@gmail.com>
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On Monday 18 April 2011, Asias He wrote:
> (1) Is it possible to add an interface to macvtap like /dev/net/tun,
> eg, /dev/net/macvtap. Currently, it is hard to use macvtap programmatically.

I decided against having a multiplexor device because it makes permission
handling rather hard. One chardev per network interface makes it possible
to handle permissions in multiuser setups.

> (2) Adding another macvlan device(e.g., macvlan0) to the hardware
> interface(e.g., eth0) and using it as the old eth0 make the process of
> using macvtap complicate. One has to reconfigure the network. This is
> not optimal from the user perspective. Is it possible to leave the
> low-level device as is when using the macvtap device?

Only in VEPA mode. Note that a similar restriction applies when using
the bridge device, for the same technical reasons.

	Arnd