From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 0A39411F5 for ; Thu, 10 Dec 2015 02:52:02 +0100 (CET) Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 1E6278E69C; Thu, 10 Dec 2015 01:52:01 +0000 (UTC) Received: from ul30vt.home (ovpn-113-98.phx2.redhat.com [10.3.113.98]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tBA1q0RP018325; Wed, 9 Dec 2015 20:52:00 -0500 Message-ID: <1449712320.15753.480.camel@redhat.com> From: Alex Williamson To: Stephen Hemminger Date: Wed, 09 Dec 2015 18:52:00 -0700 In-Reply-To: <20151209165216.778bf9e3@xeon-e3> References: <1449683756-13381-1-git-send-email-stephen@networkplumber.org> <2562631.e9AmeysRzG@xps13> <20151209135801.17965487@xeon-e3> <2072515.rqoGFgxSIN@xps13> <20151209151215.4d88b9d4@xeon-e3> <1449703334.15753.476.camel@redhat.com> <20151209165216.778bf9e3@xeon-e3> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Cc: dev@dpdk.org, Avi Kivity Subject: Re: [dpdk-dev] [PATCH] vfio: support iommu group zero X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Dec 2015 01:52:02 -0000 On Wed, 2015-12-09 at 16:52 -0800, Stephen Hemminger wrote: > On Wed, 09 Dec 2015 16:22:14 -0700 > Alex Williamson wrote: > > > On Wed, 2015-12-09 at 15:12 -0800, Stephen Hemminger wrote: > > > On Wed, 09 Dec 2015 23:49:59 +0100 > > > Thomas Monjalon wrote: > > > > > > > 2015-12-09 13:58, Stephen Hemminger: > > > > > On Wed, 09 Dec 2015 22:12:33 +0100 > > > > > Thomas Monjalon wrote: > > > > > > > > > > > 2015-12-09 09:55, Stephen Hemminger: > > > > > > > The current implementation of VFIO will not with the new no-IOMMU mode > > > > > > > in 4.4 kernel. The original code assumed that IOMMU group zero would > > > > > > > never be used. Group numbers are assigned starting at zero, and up > > > > > > > until now the group numbers came from the hardware which is likely > > > > > > > to use group 0 for system devices that are not used with DPDK. > > > > > > > > > > > > > > The fix is to allow 0 as a valid group and rearrange code > > > > > > > to split the return value from the group value. > > > > > > > > > > > > > > Signed-off-by: Stephen Hemminger > > > > > > > --- > > > > > > > Why was this ignored? It was originally sent on 26 Oct 15 back > > > > > > > when IOMMU discussion was lively. > > > > > > > > > > > > There was no review of this patch. > > > > > > The patch has been marked as deferred recently when it was too late > > > > > > to do such feature changes in DPDK code: > > > > > > http://dpdk.org/dev/patchwork/patch/8035/ > > > > > > > > > > This is why as a fallback the MAINTAINER has to review the patch > > > > > or direct a sub-maintainer to do it. I think almost 2 months is > > > > > plenty of time for review. > > > > > > > > 27 October was 3 days before the feature deadline. > > > > And you have not pinged about it since then. > > > > But that's true I have missed the importance of this patch. > > > > Would it help to have it integrated today? > > > > Are you sure it won't break something else? > > > > > > Could the original VFIO submitter from Intel review it. > > > > vfio group 0 has always been valid, but it's unlikely that you'd ever > > hit it in regular usage since it will typically be the root bus device. > > It's only with no-iommu mode in vfio that it's common, but that's > > getting reverted for Linux v4.4, so that may change your priorities > > about squeezing this in at the last minute. Thanks, > > Why, who objected? It was useful and working fine as far as I tested. > Really wanted to get to the per-queue stuff, but that was harder to > got working (even on regular IOMMU). I objected because nobody has spoken up for the month that I've been asking to be notified if a user has been tested. You can ask for it again in v4.5 with evidence showing that it works and meets your needs.