From patchwork Thu Apr 7 15:47:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 12805578 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96186C43219 for ; Thu, 7 Apr 2022 17:28:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346264AbiDGR35 (ORCPT ); Thu, 7 Apr 2022 13:29:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346380AbiDGR1T (ORCPT ); Thu, 7 Apr 2022 13:27:19 -0400 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93BD4E33BD; Thu, 7 Apr 2022 10:23:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:MIME-Version:References:In-Reply-To: Message-Id:Date:Cc:To:From:content-disposition; bh=Kj/SB7arPoOJg6cQxRfaeWMDbv4G2wYTNapPOj3Wwdw=; b=NT9H+hlZ+KIP/WMXMQWNKkhN/L f6WTtGH3C69fwh98cKtrQOJSxMKFgb60ulndEzepoDRlaoXp2MAdZ60WhPpvGb2dLEhbM3qmNH7SI HjdiGVTAqIPFZxkt2rRCB51WoI27d3M3cky6msJTw7hAzx7CPaaceN+3PPA1OLUTux27R4BmZsBoJ xVmBFtArkFf2/a4Qn5jDJ3ifCiD7q8htyu0jAuQ6hxkAs8jPqGkcQtIwpTltjlkbiOErsHe2wW1+O dTE/wDwY9PpiWjzFr+beyW958mdpG8ZRAzU97p9rIhokLPvL7UXjQX82d+DPVjHNM8JAUdjDvDOy9 NIjGFazg==; Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ncUMM-002BBh-2c; Thu, 07 Apr 2022 09:47:46 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.94.2) (envelope-from ) id 1ncUMC-00021W-5f; Thu, 07 Apr 2022 09:47:36 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org Cc: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?utf-8?q?Christian_K=C3=B6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni , Ralph Campbell , Logan Gunthorpe Date: Thu, 7 Apr 2022 09:47:02 -0600 Message-Id: <20220407154717.7695-7-logang@deltatee.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220407154717.7695-1-logang@deltatee.com> References: <20220407154717.7695-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, sbates@raithlin.com, hch@lst.de, jgg@ziepe.ca, christian.koenig@amd.com, ddutile@redhat.com, willy@infradead.org, daniel.vetter@ffwll.ch, jason@jlekstrand.net, dave.hansen@linux.intel.com, helgaas@kernel.org, dan.j.williams@intel.com, andrzej.jakowski@intel.com, dave.b.minturn@intel.com, jianxin.xiong@intel.com, ira.weiny@intel.com, robin.murphy@arm.com, martin.oliveira@eideticom.com, ckulkarnilinux@gmail.com, jhubbard@nvidia.com, rcampbell@nvidia.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v6 06/21] dma-direct: support PCI P2PDMA pages in dma-direct map_sg X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Add PCI P2PDMA support for dma_direct_map_sg() so that it can map PCI P2PDMA pages directly without a hack in the callers. This allows for heterogeneous SGLs that contain both P2PDMA and regular pages. A P2PDMA page may have three possible outcomes when being mapped: 1) If the data path between the two devices doesn't go through the root port, then it should be mapped with a PCI bus address 2) If the data path goes through the host bridge, it should be mapped normally, as though it were a CPU physical address 3) It is not possible for the two devices to communicate and thus the mapping operation should fail (and it will return -EREMOTEIO). SGL segments that contain PCI bus addresses are marked with sg_dma_mark_pci_p2pdma() and are ignored when unmapped. P2PDMA mappings are also failed if swiotlb needs to be used on the mapping. Signed-off-by: Logan Gunthorpe --- kernel/dma/direct.c | 43 +++++++++++++++++++++++++++++++++++++------ kernel/dma/direct.h | 8 +++++++- 2 files changed, 44 insertions(+), 7 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 9743c6ccce1a..33b838a3ccb2 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -461,29 +461,60 @@ void dma_direct_sync_sg_for_cpu(struct device *dev, arch_sync_dma_for_cpu_all(); } +/* + * Unmaps segments, except for ones marked as pci_p2pdma which do not + * require any further action as they contain a bus address. + */ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir, unsigned long attrs) { struct scatterlist *sg; int i; - for_each_sg(sgl, sg, nents, i) - dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir, - attrs); + for_each_sg(sgl, sg, nents, i) { + if (sg_is_dma_bus_address(sg)) + sg_dma_unmark_bus_address(sg); + else + dma_direct_unmap_page(dev, sg->dma_address, + sg_dma_len(sg), dir, attrs); + } } #endif int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir, unsigned long attrs) { - int i; + struct pci_p2pdma_map_state p2pdma_state = {}; + enum pci_p2pdma_map_type map; struct scatterlist *sg; + int i, ret; for_each_sg(sgl, sg, nents, i) { + if (is_pci_p2pdma_page(sg_page(sg))) { + map = pci_p2pdma_map_segment(&p2pdma_state, dev, sg); + switch (map) { + case PCI_P2PDMA_MAP_BUS_ADDR: + continue; + case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: + /* + * Any P2P mapping that traverses the PCI + * host bridge must be mapped with CPU physical + * address and not PCI bus addresses. This is + * done with dma_direct_map_page() below. + */ + break; + default: + ret = -EREMOTEIO; + goto out_unmap; + } + } + sg->dma_address = dma_direct_map_page(dev, sg_page(sg), sg->offset, sg->length, dir, attrs); - if (sg->dma_address == DMA_MAPPING_ERROR) + if (sg->dma_address == DMA_MAPPING_ERROR) { + ret = -EIO; goto out_unmap; + } sg_dma_len(sg) = sg->length; } @@ -491,7 +522,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, out_unmap: dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC); - return -EIO; + return ret; } dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr, diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index 4632b0f4f72e..81b213409ce8 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -8,6 +8,7 @@ #define _KERNEL_DMA_DIRECT_H #include +#include int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, @@ -87,10 +88,15 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (is_swiotlb_force_bounce(dev)) + if (is_swiotlb_force_bounce(dev)) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; return swiotlb_map(dev, phys, size, dir, attrs); + } if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; if (swiotlb_force != SWIOTLB_NO_FORCE) return swiotlb_map(dev, phys, size, dir, attrs);