From patchwork Mon Jul 23 22:16:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 10541219 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AFB7891E for ; Mon, 23 Jul 2018 22:16:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0CB328536 for ; Mon, 23 Jul 2018 22:16:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 93A922855D; Mon, 23 Jul 2018 22:16:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ED00028536 for ; Mon, 23 Jul 2018 22:16:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388161AbeGWXT5 (ORCPT ); Mon, 23 Jul 2018 19:19:57 -0400 Received: from foss.arm.com ([217.140.101.70]:40062 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388052AbeGWXT5 (ORCPT ); Mon, 23 Jul 2018 19:19:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 21698ED1; Mon, 23 Jul 2018 15:16:39 -0700 (PDT) Received: from e110467-lin.cambridge.arm.com (e110467-lin.Emea.Arm.com [10.4.12.131]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E19953F5D0; Mon, 23 Jul 2018 15:16:36 -0700 (PDT) From: Robin Murphy To: hch@lst.de, m.szyprowski@samsung.com Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, x86@kernel.org, lorenzo.pieralisi@arm.com, hanjun.guo@linaro.org, sudeep.holla@arm.com, joro@8bytes.org, robh+dt@kernel.org, frowand.list@gmail.com, gregkh@linuxfoundation.org Subject: [PATCH v2 5/7] iommu/dma: Respect bus DMA limit for IOVAs Date: Mon, 23 Jul 2018 23:16:10 +0100 Message-Id: X-Mailer: git-send-email 2.17.1.dirty In-Reply-To: References: Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Take the new bus limit into account (when present) for IOVA allocations, to accommodate those SoCs which integrate off-the-shelf IP blocks with narrower interconnects such that the link between a device output and an IOMMU input can truncate DMA addresses to even fewer bits than the native size of either block's interface would imply. Eventually it might make sense for the DMA core to apply this constraint up-front in dma_set_mask() and friends, but for now this seems like the least risky approach. CC: Joerg Roedel Signed-off-by: Robin Murphy --- Bonus question: Now that we're collecing DMA API code in kernel/dma/ do we want to reevaluate dma-iommu? On the one hand it's the bulk of a dma_ops implementation so should perhaps move, but on the other it's entirely IOMMU-specific code so should perhaps stay where it is... :/ drivers/iommu/dma-iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index ddcbbdb5d658..511ff9a1d6d9 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -367,6 +367,9 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1))) iova_len = roundup_pow_of_two(iova_len); + if (dev->bus_dma_mask) + dma_limit &= dev->bus_dma_mask; + if (domain->geometry.force_aperture) dma_limit = min(dma_limit, domain->geometry.aperture_end);