From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FDBCC3A5A3 for ; Thu, 29 Aug 2019 14:14:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63E782070B for ; Thu, 29 Aug 2019 14:14:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727675AbfH2OO6 (ORCPT ); Thu, 29 Aug 2019 10:14:58 -0400 Received: from verein.lst.de ([213.95.11.211]:46641 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726852AbfH2OO5 (ORCPT ); Thu, 29 Aug 2019 10:14:57 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 2351F68B20; Thu, 29 Aug 2019 16:14:54 +0200 (CEST) Date: Thu, 29 Aug 2019 16:14:53 +0200 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , "Derrick, Jonathan" , "x86@kernel.org" , "joro@8bytes.org" , "linux-pci@vger.kernel.org" , "bhelgaas@google.com" , "dwmw2@infradead.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 4/5] PCI/vmd: Stop overriding dma_map_ops Message-ID: <20190829141453.GC18677@lst.de> References: <20190828141443.5253-1-hch@lst.de> <20190828141443.5253-5-hch@lst.de> <20190828150106.GD23412@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190828150106.GD23412@localhost.localdomain> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 28, 2019 at 09:01:06AM -0600, Keith Busch wrote: > On Wed, Aug 28, 2019 at 07:14:42AM -0700, Christoph Hellwig wrote: > > With a little tweak to the intel-iommu code we should be able to work > > around the VMD mess for the requester IDs without having to create giant > > amounts of boilerplate DMA ops wrapping code. The other advantage of > > this scheme is that we can respect the real DMA masks for the actual > > devices, and I bet it will only be a matter of time until we'll see the > > first DMA challeneged NVMe devices. > > This tests out fine on VMD hardware, but it's quite different than the > previous patch. In v1, the original dev was used in iommu_need_mapping(), > but this time it's the vmd device. Is this still using the actual device's > DMA mask then? True. But then again I think the old one was broken as well, as it will pass the wrong dev to identity_mapping() or iommu_request_dma_domain_for_dev. So I guess I'll need to respin it a bit to do the work in iommu_need_mapping again, and then factor that one to make it obvious what device we deal with.