From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Horman Subject: Re: copyless virtio net thoughts? Date: Thu, 19 Feb 2009 10:31:42 +1100 Message-ID: <20090218233126.GA3105@verge.net.au> References: <20090205020732.GA27684@sequoia.sous-sol.org> <200902182208.00843.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chris Wright , Arnd Bergmann , Herbert Xu , kvm@vger.kernel.org To: Rusty Russell Return-path: Received: from kirsty.vergenet.net ([202.4.237.240]:42124 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753307AbZBSAh4 (ORCPT ); Wed, 18 Feb 2009 19:37:56 -0500 Content-Disposition: inline In-Reply-To: <200902182208.00843.rusty@rustcorp.com.au> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Feb 18, 2009 at 10:08:00PM +1030, Rusty Russell wrote: > > 2) Direct NIC attachment This is particularly interesting with SR-IOV or > other multiqueue nics, but for boutique cases or benchmarks, could be for > normal NICs. So far I have some very sketched-out patches: for the > attached nic dev_alloc_skb() gets an skb from the guest (which supplies > them via some kind of AIO interface), and a branch in netif_receive_skb() > which returned it to the guest. This bypasses all firewalling in the > host though; we're basically having the guest process drive the NIC > directly. Hi Rusty, Can I clarify that the idea with utilising SR-IOV would be to assign virtual functions to guests? That is, something conceptually similar to PCI pass-through in Xen (although I'm not sure that anyone has virtual function pass-through working yet). If so, wouldn't this also be useful on machines that have multiple NICs? -- Simon Horman VA Linux Systems Japan K.K., Sydney, Australia Satellite Office H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en