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 0842ECA9EC5 for ; Wed, 30 Oct 2019 17:55:59 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8FB592087F for ; Wed, 30 Oct 2019 17:55:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8FB592087F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 473GMv6NF8zF4cm for ; Thu, 31 Oct 2019 04:55:55 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 473GKT4YYszF4Wx for ; Thu, 31 Oct 2019 04:53:47 +1100 (AEDT) Received: by verein.lst.de (Postfix, from userid 2407) id 4E59F68C7B; Wed, 30 Oct 2019 18:53:41 +0100 (CET) Date: Wed, 30 Oct 2019 18:53:41 +0100 From: Christoph Hellwig To: Reza Arbab Subject: Re: [PATCH 00/11] powerpv/powernv: Restore pnv_npu_try_dma_set_bypass() Message-ID: <20191030175341.GA19166@lst.de> References: <1572454800-17976-1-git-send-email-arbab@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1572454800-17976-1-git-send-email-arbab@linux.ibm.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Donnellan , Alexey Kardashevskiy , Paul Mackerras , Alistair Popple , Oliver O'Halloran , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, Christoph Hellwig Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Oct 30, 2019 at 11:59:49AM -0500, Reza Arbab wrote: > With recent kernels, TCE tables for NPU devices are no longer being > configured. That task was performed by pnv_npu_try_dma_set_bypass(), a > function that got swept away in recent overhauling of dma code. > > Patches 1-4 here bring the lost function back and reintegrate it with > the updated generic iommu bypass infrastructure. > > Patch 5 fixes a regression in behavior when a requested dma mask can not > be fulfilled. > > Patches 6-8 are cleanup. I put these later in the set because they > aren't bisectable until after the restored code is wired back in. > > Patches 9-11 refactor pnv_pci_ioda_iommu_bypass_supported(). It seems > wrong for a boolean *_supported() function to have side effects. They > reintroduce a pci controller based dma_set_mask() hook. If that's > undesirable, these last three patches can be dropped. How do you even use this code? Nothing in the kernel even calls dma_set_mask for NPU devices, as we only suport vfio pass through.