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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 32332C2D0DB for ; Thu, 23 Jan 2020 16:08:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 144B620684 for ; Thu, 23 Jan 2020 16:08:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728911AbgAWQIJ (ORCPT ); Thu, 23 Jan 2020 11:08:09 -0500 Received: from foss.arm.com ([217.140.110.172]:41568 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726231AbgAWQII (ORCPT ); Thu, 23 Jan 2020 11:08:08 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B471B1007; Thu, 23 Jan 2020 08:08:07 -0800 (PST) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 801503F881; Thu, 23 Jan 2020 08:08:06 -0800 (PST) Date: Thu, 23 Jan 2020 16:08:01 +0000 From: Lorenzo Pieralisi To: Bjorn Helgaas Cc: Jon Derrick , linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig , Keith Busch , Joerg Roedel , David Woodhouse , Lu Baolu Subject: Re: [PATCH v5 3/7] PCI: Introduce pci_real_dma_dev() Message-ID: <20200123160800.GA7302@e121166-lin.cambridge.arm.com> References: <1579613871-301529-4-git-send-email-jonathan.derrick@intel.com> <20200122211259.GA19172@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200122211259.GA19172@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jan 22, 2020 at 03:12:59PM -0600, Bjorn Helgaas wrote: > On Tue, Jan 21, 2020 at 06:37:47AM -0700, Jon Derrick wrote: > > The current DMA alias implementation requires the aliased device be on > > the same PCI bus as the requester ID. This introduces an arch-specific > > mechanism to point to another PCI device when doing mapping and > > PCI DMA alias search. The default case returns the actual device. > > > > CC: Christoph Hellwig > > Signed-off-by: Jon Derrick > > Acked-by: Bjorn Helgaas > > Looks like a nice cleanup to me. > > Lorenzo, let me know if you want me to take this. Hi Bjorn, I think it makes sense for you to take the series given that it is mostly core/x86 changes. FWIW I Acked the relevant patch (6) even though Jon forgot to carry it to v5. Thanks, Lorenzo > > arch/x86/pci/common.c | 10 ++++++++++ > > drivers/pci/pci.c | 19 ++++++++++++++++++- > > drivers/pci/search.c | 6 ++++++ > > include/linux/pci.h | 1 + > > 4 files changed, 35 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c > > index 1e59df0..fe21a5c 100644 > > --- a/arch/x86/pci/common.c > > +++ b/arch/x86/pci/common.c > > @@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void) > > else > > return 0; > > } > > + > > +#if IS_ENABLED(CONFIG_VMD) > > +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev) > > +{ > > + if (is_vmd(dev->bus)) > > + return to_pci_sysdata(dev->bus)->vmd_dev; > > + > > + return dev; > > +} > > +#endif > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 581b177..36d24f2 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -6048,7 +6048,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2) > > return (dev1->dma_alias_mask && > > test_bit(dev2->devfn, dev1->dma_alias_mask)) || > > (dev2->dma_alias_mask && > > - test_bit(dev1->devfn, dev2->dma_alias_mask)); > > + test_bit(dev1->devfn, dev2->dma_alias_mask)) || > > + pci_real_dma_dev(dev1) == dev2 || > > + pci_real_dma_dev(dev2) == dev1; > > } > > > > bool pci_device_is_present(struct pci_dev *pdev) > > @@ -6072,6 +6074,21 @@ void pci_ignore_hotplug(struct pci_dev *dev) > > } > > EXPORT_SYMBOL_GPL(pci_ignore_hotplug); > > > > +/** > > + * pci_real_dma_dev - Get PCI DMA device for PCI device > > + * @dev: the PCI device that may have a PCI DMA alias > > + * > > + * Permits the platform to provide architecture-specific functionality to > > + * devices needing to alias DMA to another PCI device on another PCI bus. If > > + * the PCI device is on the same bus, it is recommended to use > > + * pci_add_dma_alias(). This is the default implementation. Architecture > > + * implementations can override this. > > + */ > > +struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev) > > +{ > > + return dev; > > +} > > + > > resource_size_t __weak pcibios_default_alignment(void) > > { > > return 0; > > diff --git a/drivers/pci/search.c b/drivers/pci/search.c > > index e4dbdef..2061672 100644 > > --- a/drivers/pci/search.c > > +++ b/drivers/pci/search.c > > @@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, > > struct pci_bus *bus; > > int ret; > > > > + /* > > + * The device may have an explicit alias requester ID for DMA where the > > + * requester is on another PCI bus. > > + */ > > + pdev = pci_real_dma_dev(pdev); > > ret = fn(pdev, pci_dev_id(pdev), data); > > if (ret) > > return ret; > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > index 930fab2..3840a54 100644 > > --- a/include/linux/pci.h > > +++ b/include/linux/pci.h > > @@ -1202,6 +1202,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, > > int pci_select_bars(struct pci_dev *dev, unsigned long flags); > > bool pci_device_is_present(struct pci_dev *pdev); > > void pci_ignore_hotplug(struct pci_dev *dev); > > +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev); > > > > int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr, > > irq_handler_t handler, irq_handler_t thread_fn, void *dev_id, > > -- > > 1.8.3.1 > >