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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 ACA0CC31E44 for ; Wed, 12 Jun 2019 02:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B3AA20866 for ; Wed, 12 Jun 2019 02:11:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408385AbfFLCLI (ORCPT ); Tue, 11 Jun 2019 22:11:08 -0400 Received: from mga07.intel.com ([134.134.136.100]:26277 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406579AbfFLCLI (ORCPT ); Tue, 11 Jun 2019 22:11:08 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Jun 2019 19:11:07 -0700 X-ExtLoop1: 1 Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga004.jf.intel.com with ESMTP; 11 Jun 2019 19:11:01 -0700 Cc: baolu.lu@linux.intel.com, David Woodhouse , Joerg Roedel , Bjorn Helgaas , Christoph Hellwig , ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, Ingo Molnar , Greg Kroah-Hartman , pengfei.xu@intel.com, Marek Szyprowski , Robin Murphy , Jonathan Corbet , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Steven Rostedt , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jacob Pan , Mika Westerberg Subject: Re: [PATCH v4 5/9] iommu/vt-d: Don't switch off swiotlb if use direct dma To: Konrad Rzeszutek Wilk References: <20190603011620.31999-1-baolu.lu@linux.intel.com> <20190603011620.31999-6-baolu.lu@linux.intel.com> <20190610155451.GU28796@char.us.oracle.com> From: Lu Baolu Message-ID: <23c85769-b529-663b-a55d-d8ddc5f9c28c@linux.intel.com> Date: Wed, 12 Jun 2019 10:03:52 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190610155451.GU28796@char.us.oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 6/10/19 11:54 PM, Konrad Rzeszutek Wilk wrote: > On Mon, Jun 03, 2019 at 09:16:16AM +0800, Lu Baolu wrote: >> The direct dma implementation depends on swiotlb. Hence, don't >> switch of swiotlb since direct dma interfaces are used in this > > s/of/off/ Yes. > >> driver. > > But I think you really want to leave the code as is but change > the #ifdef to check for IOMMU_BOUNCE_PAGE and not CONFIG_SWIOTLB. > > As one could disable IOMMU_BOUNCE_PAGE. SWIOTLB is not only used when IOMMU_BOUCE_PAGE is enabled. Please check this code: static dma_addr_t intel_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long attrs) { if (iommu_need_mapping(dev)) return __intel_map_single(dev, page_to_phys(page) + offset, size, dir, *dev->dma_mask); return dma_direct_map_page(dev, page, offset, size, dir, attrs); } The dma_direct_map_page() will eventually call swiotlb_map() if the buffer is beyond the address capability of the device. Best regards, Baolu >> >> Cc: Ashok Raj >> Cc: Jacob Pan >> Cc: Kevin Tian >> Cc: Mika Westerberg >> Signed-off-by: Lu Baolu >> --- >> drivers/iommu/intel-iommu.c | 6 ------ >> 1 file changed, 6 deletions(-) >> >> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c >> index d5a6c8064c56..235837c50719 100644 >> --- a/drivers/iommu/intel-iommu.c >> +++ b/drivers/iommu/intel-iommu.c >> @@ -4625,9 +4625,6 @@ static int __init platform_optin_force_iommu(void) >> iommu_identity_mapping |= IDENTMAP_ALL; >> >> dmar_disabled = 0; >> -#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB) >> - swiotlb = 0; >> -#endif >> no_iommu = 0; >> >> return 1; >> @@ -4765,9 +4762,6 @@ int __init intel_iommu_init(void) >> } >> up_write(&dmar_global_lock); >> >> -#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB) >> - swiotlb = 0; >> -#endif >> dma_ops = &intel_dma_ops; >> >> init_iommu_pm_ops(); >> -- >> 2.17.1 >> >