From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: [PATCH 0/9][RFC] KVM virtio_net performance Date: Sun, 27 Jul 2008 09:17:57 -0400 Message-ID: <488C7585.2050804@tmr.com> References: <1216899979-32532-1-git-send-email-markmc@redhat.com> <4888EC61.8050208@codemonkey.ws> <488B7668.7090605@tmr.com> <488C292C.7020609@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Mark McLoughlin , kvm@vger.kernel.org, Herbert Xu , Rusty Russell To: Avi Kivity Return-path: Received: from mail.tmr.com ([64.65.253.246]:40625 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbYG0NPg (ORCPT ); Sun, 27 Jul 2008 09:15:36 -0400 In-Reply-To: <488C292C.7020609@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Bill Davidsen wrote: >> >> I have been discussing this (on this list) in another thread. Putting >> tcpdump on the eth0 device in the VM, the br0 device in the host, and >> the eth0 (physical NIC) in the host, you can see that when the VM >> generates a DHCP request it shows up on the br0 in the host, but >> never gets sent on the wire by eth0. >> >> That's the point of failure, at least using RHEL5/FC6/kvm-66 as the >> environment. > > Does playing with the bridge forward delay ('brctl setfd') help? > Update: Redhat has a user chain in iptables shared between INPUT and FORWARD (bad idea) which doesn't pass bootp packets by default. Adding the following rules to that table solved the DHCP for me. ACCEPT udp -- anywhere anywhere udp spt:bootps dpt:bootpc ACCEPT udp -- anywhere anywhere udp spt:bootpc dpt:bootps This seems to solve my problem, I just have to make it part of my "start kvm" procedure. -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark