From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: help? need to enable VT-d for 2.6.27 Date: Tue, 30 Aug 2011 12:31:04 -0600 Message-ID: <4E5D2C68.2050801@gmail.com> References: <4E5D0FF3.6030705@genband.com> <4E5D23F5.3070905@gmail.com> <4E5D27B5.8090004@genband.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , mtosatti@redhat.com, kvm@vger.kernel.org To: Chris Friesen Return-path: Received: from mail-gy0-f174.google.com ([209.85.160.174]:38273 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755971Ab1H3SbI (ORCPT ); Tue, 30 Aug 2011 14:31:08 -0400 Received: by gya6 with SMTP id 6so5860617gya.19 for ; Tue, 30 Aug 2011 11:31:07 -0700 (PDT) In-Reply-To: <4E5D27B5.8090004@genband.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/30/2011 12:11 PM, Chris Friesen wrote: > On 08/30/2011 11:55 AM, David Ahern wrote: >> On 08/30/2011 10:29 AM, Chris Friesen wrote: >>> >>> I'm in a bit of an odd situation. We run an embedded version of linux >>> on many different boards with different vendor agreements so it's >>> painful to upgrade kernel versions. >>> >>> I've been asked to provide VT-d support for KVM on our kernel (primarily >>> for mapping NIC VFs into the guests), and I'm trying to figure out my >>> best option to get a working implementation. >> >> I've had pains with VF passthrough with as late as a Fedora 14 kernel >> (2.6.35). Ended up punting and moving to 2.6.39. > > Ouch. Not good news, but not entirely unexpected. Are you doing > anything complicated, or was this just basic functionality that wasn't > working? In my case I am setting the MAC address for the VFs in the host at boot; they are getting reset on passthrough so the VM driver creates a random one. A backport of commit a6b5ea3 fixes one aspect. Looking at the code for the igb driver I think commit 8fa7e0f fixes the other reset problem. On the plus side I can tell you that the VF driver for the VM http://sourceforge.net/projects/e1000/files/igbvf%20stable/ compiles cleaning against WRL3 and appears to work fine (limited testing with benchmarks). kernel module wise I ran some basic KVM tests with kvm-kmod-2.6.32.27; I have not tried VF passthrough. This is on my radar as well, so I would be interested in what you learn. David > >>> Looking at the kvm git tree, kvm-77 seems to be based off 2.6.27. Should >>> I look at porting that? >> >> By 2.6.27 do you mean WRL3 or something else? > > Yes, that's correct. (Wind River Linux 3, for the non-embedded types > out there.) > > Chris >