From: Yu Zhao Subject: Re: [PATCH 0/16 v6] PCI: Linux kernel SR-IOV support Date: Mon, 17 Nov 2008 20:01:55 +0800 Message-ID: <49215D33.4010607@uniscape.net> References: <20081106154351.GA30459@kroah.com> <20081107061700.GD3860@kroah.com> <4913F2AA.90405@intel.com> <200811111048.45242.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Zhao, Yu" , Greg KH , Anthony Liguori , "Leonid.Grossman@neterion.com" , Matthew Wilcox , H L , "randy.dunlap@oracle.com" , "grundler@parisc-linux.org" , "achiang@hp.com" , "linux-pci@vger.kernel.org" , "rdreier@cisco.com" , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "mingo@elte.hu" , Chris Wright To: Rusty Russell Return-path: Received: from outbound-mail-08.bluehost.com ([69.89.17.208]:36574 "HELO outbound-mail-08.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753859AbYKQMDY (ORCPT ); Mon, 17 Nov 2008 07:03:24 -0500 In-Reply-To: <200811111048.45242.rusty@rustcorp.com.au> Sender: kvm-owner@vger.kernel.org List-ID: Rusty Russell wrote: > On Friday 07 November 2008 18:17:54 Zhao, Yu wrote: > > Greg KH wrote: > > > On Thu, Nov 06, 2008 at 04:40:21PM -0600, Anthony Liguori wrote: > > >> Greg KH wrote: > > >>> On Thu, Nov 06, 2008 at 10:47:41AM -0700, Matthew Wilcox wrote: > > >>>> I don't think we really know what the One True Usage model is for VF > > >>>> devices. Chris Wright has some ideas, I have some ideas and Yu Zhao > > >>>> has some ideas. I bet there's other people who have other ideas too. > > >>> > > >>> I'd love to hear those ideas. > > >> > > >> We've been talking about avoiding hardware passthrough entirely and > > >> just backing a virtio-net backend driver by a dedicated VF in the > > >> host. That avoids a huge amount of guest-facing complexity, let's > > >> migration Just Work, and should give the same level of performance. > > > > This can be commonly used not only with VF -- devices that have multiple > > DMA queues (e.g., Intel VMDq, Neterion Xframe) and even traditional > > devices can also take the advantage of this. > > > > CC Rusty Russel in case he has more comments. > > Yes, even dumb devices could use this mechanism if you wanted to bind an > entire device solely to one guest. > > We don't have network infrastructure for this today, but my thought was > to do something in dev_alloc_skb and dev_kfree_skb et al. Is there any discussion about this on the netdev? Any prototype available? If not, I'd like to create one and evaluate the performance of virtio-net solution again the hardware passthrough. Thanks, Yu