From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Friesen Subject: Re: [E1000-devel] discussion questions: SR-IOV, virtualization, and bonding Date: Fri, 10 Aug 2012 12:41:40 -0600 Message-ID: <502555E4.6060705@genband.com> References: <501AD33E.5090308@genband.com> <17679.1343939453@death.nxdomain> <501AFEAD.10001@genband.com> <501B0037.1010804@genband.com> <20421.1343948491@death.nxdomain> <501B587E.6040703@intel.com> <1344016163.2610.9.camel@bwh-desktop.uk.solarflarecom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: John Fastabend , Jay Vosburgh , "e1000-devel@lists.sourceforge.net" , netdev To: Ben Hutchings Return-path: Received: from exprod7og121.obsmtp.com ([64.18.2.20]:40350 "EHLO exprod7og121.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754673Ab2HJSl6 (ORCPT ); Fri, 10 Aug 2012 14:41:58 -0400 In-Reply-To: <1344016163.2610.9.camel@bwh-desktop.uk.solarflarecom.com> Sender: netdev-owner@vger.kernel.org List-ID: On 08/03/2012 11:49 AM, Ben Hutchings wrote: > On Thu, 2012-08-02 at 21:50 -0700, John Fastabend wrote: >> Perhaps one argument against this is if the hardware supports loopback >> modes or the edge relay in the hardware is acting like a VEB it may >> still be possible to support VF to VF traffic even if the external link >> is down. Not sure how useful this is though or if any existing hardware >> even supports it. > [...] > > It seems to me that VF to VF traffic ought to still work. If it doesn't > then that's an unfortunate regression when moving from software bridging > and virtio to hardware-supported network virtualisation. (But hybrid > network virtualisation may help to solve that.) I would have thought this to be desirable as well. Apparently the Intel engineers disagreed. The 82599 datasheet has the following: "Loopback is disabled when the network link is disconnected. It is expected (but not required) that system software (including VMs) does not post packets for transmission when the link is disconnected. Note that packets posted by system software for transmission when the link is down are buffered." Chris