From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH] vfio: Include No-IOMMU mode Date: Wed, 02 Dec 2015 17:19:18 +0100 Message-ID: <1473285.yZJWhu9CPo@xps13> References: <20151028211309.14155.23867.stgit@gimli.home> <564A0E70.4030409@scylladb.com> <1449070123.15753.35.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1449070123.15753.35.camel@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" To: Alex Williamson Cc: Avi Kivity , gleb@scylladb.com, corbet@lwn.net, dev@dpdk.org, gregkh@linuxfoundation.org, mst@redhat.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, hjk@hansjkoch.de List-Id: iommu@lists.linux-foundation.org Hi, 2015-12-02 08:28, Alex Williamson: > On Mon, 2015-11-16 at 19:12 +0200, Avi Kivity wrote: > > On 11/16/2015 07:06 PM, Alex Williamson wrote: > > > FYI, this is now in v4.4-rc1 (the slightly modified v2 version). I want > > > to give fair warning though that while we seem to agree on this idea, it > > > hasn't been proven with a userspace driver port. I've opted to include > > > it in this merge window rather than delaying it until v4.5, but I really > > > need to see a user for this before the end of the v4.4 cycle or I think > > > we'll need to revert and revisit for v4.5 anyway. I don't really have > > > any interest in adding and maintaining code that has no users. Please > > > keep me informed of progress with a dpdk port. Thanks, > > > > Thanks Alex. Copying the dpdk mailing list, where the users live. > > > > dpdk-ers: vfio-noiommu is a replacement for uio_pci_generic and > > uio_igb. It supports MSI-X and so can be used on SR/IOV VF devices. > > The intent is that you can use dpdk without an external module, using > > vfio, whether you are on bare metal with an iommu, bare metal without an > > iommu, or virtualized. However, dpdk needs modification to support this. > > Still no users for this that I'm aware of. I'm going to revert this in > rc5 unless something changes. Thanks, Removing needs for out-of-tree modules is a really nice achievement. Yes, we (in the DPDK project) should check how to use this no-iommu VFIO and to replace igb_uio. I'm sorry we failed to catch your email and follow up. Is it really too late? What is the risk of keeping it in Linux 4.4? Advertising a new feature and removing it would be frustrating. Have you tried this VFIO mode with DPDK? How complex would be the patch to support it? Thanks From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758894AbbLBQUd (ORCPT ); Wed, 2 Dec 2015 11:20:33 -0500 Received: from mail-wm0-f46.google.com ([74.125.82.46]:35283 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869AbbLBQUa (ORCPT ); Wed, 2 Dec 2015 11:20:30 -0500 From: Thomas Monjalon To: Alex Williamson Cc: dev@dpdk.org, Avi Kivity , gleb@scylladb.com, mst@redhat.com, corbet@lwn.net, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, hjk@hansjkoch.de, gregkh@linuxfoundation.org Subject: Re: [dpdk-dev] [PATCH] vfio: Include No-IOMMU mode Date: Wed, 02 Dec 2015 17:19:18 +0100 Message-ID: <1473285.yZJWhu9CPo@xps13> Organization: 6WIND User-Agent: KMail/4.14.10 (Linux/4.1.6-1-ARCH; KDE/4.14.11; x86_64; ; ) In-Reply-To: <1449070123.15753.35.camel@redhat.com> References: <20151028211309.14155.23867.stgit@gimli.home> <564A0E70.4030409@scylladb.com> <1449070123.15753.35.camel@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, 2015-12-02 08:28, Alex Williamson: > On Mon, 2015-11-16 at 19:12 +0200, Avi Kivity wrote: > > On 11/16/2015 07:06 PM, Alex Williamson wrote: > > > FYI, this is now in v4.4-rc1 (the slightly modified v2 version). I want > > > to give fair warning though that while we seem to agree on this idea, it > > > hasn't been proven with a userspace driver port. I've opted to include > > > it in this merge window rather than delaying it until v4.5, but I really > > > need to see a user for this before the end of the v4.4 cycle or I think > > > we'll need to revert and revisit for v4.5 anyway. I don't really have > > > any interest in adding and maintaining code that has no users. Please > > > keep me informed of progress with a dpdk port. Thanks, > > > > Thanks Alex. Copying the dpdk mailing list, where the users live. > > > > dpdk-ers: vfio-noiommu is a replacement for uio_pci_generic and > > uio_igb. It supports MSI-X and so can be used on SR/IOV VF devices. > > The intent is that you can use dpdk without an external module, using > > vfio, whether you are on bare metal with an iommu, bare metal without an > > iommu, or virtualized. However, dpdk needs modification to support this. > > Still no users for this that I'm aware of. I'm going to revert this in > rc5 unless something changes. Thanks, Removing needs for out-of-tree modules is a really nice achievement. Yes, we (in the DPDK project) should check how to use this no-iommu VFIO and to replace igb_uio. I'm sorry we failed to catch your email and follow up. Is it really too late? What is the risk of keeping it in Linux 4.4? Advertising a new feature and removing it would be frustrating. Have you tried this VFIO mode with DPDK? How complex would be the patch to support it? Thanks