From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] macvlan: Introduce 'passthru' mode to takeover the underlying device Date: Sat, 30 Oct 2010 18:57:50 +0200 Message-ID: <20101030165750.GB17210@redhat.com> References: <1288307450.30131.82.camel@sridhar.beaverton.ibm.com> <201010291545.17910.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sridhar Samudrala , Patrick McHardy , Stephen Hemminger , netdev , "kvm@vger.kernel.org" To: Arnd Bergmann Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754632Ab0J3Q6F (ORCPT ); Sat, 30 Oct 2010 12:58:05 -0400 Content-Disposition: inline In-Reply-To: <201010291545.17910.arnd@arndb.de> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Oct 29, 2010 at 03:45:17PM +0200, Arnd Bergmann wrote: > On Friday 29 October 2010, Sridhar Samudrala wrote: > > With the current default 'vepa' mode, a KVM guest using virtio with > > macvtap backend has the following limitations. > > - cannot change/add a mac address on the guest virtio-net > > I believe this could be changed if there is a neeed, but I actually > consider it one of the design points of macvlan that the guest > is not able to change the mac address. With 802.1Qbg you rely on > the switch being able to identify the guest by its MAC address, > which the host kernel must ensure. > > > - cannot create a vlan device on the guest virtio-net > > Why not? If this doesn't work, it's probably a bug! > Why does the passthru mode enable it if it doesn't work > already? > > > - cannot enable promiscuous mode on guest virtio-net > > Could you elaborate why such a setup would be useful? > > Arnd E.g. to support bridging in the guest. -- MST