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 08:58:09 +0200
Message-ID: <201104180858.09828.arnd@arndb.de>
References: <4DABD5BC.2040204@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>
Return-path: <kvm-owner@vger.kernel.org>
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On Monday 18 April 2011, Asias He wrote:
> 
> Hi, folks
> 
> I am trying to use qemu/qemu-kvm with macvtap using following commands:
> 
> # ip link add link eth0 name v0 type macvtap mode {vepa,bridge,private}
> # ip link set v0 address da:4e:17:88:42:b1 up
> # idx=`ip link show v0 | grep mtu| awk -F":" '{print $1}'`
> # kvm -net nic,macaddr=da:4e:17:88:42:b1 -net tap,fd=3 -hda
> /home/asias/qemu-stuff/sid.img  3<>/dev/tap${idx}
> 
> I found that guest can access other hosts on the LAN except the host
> where guest lives, and host where guest lives can not access guest.
> 
> My question is: Does macvtap support host(hypervisor host) to guest
> communication?
> 

You can communicate between macvtap and macvlan devices when they are in
bridge mode, but these devices cannot communicate with clients that
run on the underlying device.

Just add a macvlan device to your hardware interface and use that in
the host instead of running on the low-level device directly.

The other option is to use a vepa enabled bridge, but these are relatively
rare.

	Arnd