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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 B6E6EC46464 for ; Thu, 9 Aug 2018 11:06:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A37021D5B for ; Thu, 9 Aug 2018 11:06:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A37021D5B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730760AbeHINax (ORCPT ); Thu, 9 Aug 2018 09:30:53 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:52204 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727768AbeHINax (ORCPT ); Thu, 9 Aug 2018 09:30:53 -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 BA13D18A; Thu, 9 Aug 2018 04:06:32 -0700 (PDT) Received: from [10.4.12.131] (e110467-lin.Emea.Arm.com [10.4.12.131]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3D6513F5D4; Thu, 9 Aug 2018 04:06:31 -0700 (PDT) Subject: Re: [PATCH v4 4/5] iommu/arm-smmu-v3: add support for non-strict mode To: Zhen Lei , Will Deacon , Joerg Roedel , linux-arm-kernel , iommu , linux-kernel Cc: LinuxArm , Hanjun Guo , Libin References: <1533558424-16748-1-git-send-email-thunder.leizhen@huawei.com> <1533558424-16748-5-git-send-email-thunder.leizhen@huawei.com> From: Robin Murphy Message-ID: <94c88d9e-818e-f893-9ee2-7a0cf425bd9a@arm.com> Date: Thu, 9 Aug 2018 12:06:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1533558424-16748-5-git-send-email-thunder.leizhen@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/08/18 13:27, Zhen Lei wrote: > Dynamically choose strict or non-strict mode for page table config based > on the iommu domain type. > > Signed-off-by: Zhen Lei > --- > drivers/iommu/arm-smmu-v3.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 2f1304b..904bc1e 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -1622,6 +1622,11 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain) > if (smmu->features & ARM_SMMU_FEAT_COHERENCY) > pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA; > > + if (domain->type == IOMMU_DOMAIN_DMA) { > + domain->non_strict = 1; > + pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > + } > + > pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain); > if (!pgtbl_ops) > return -ENOMEM; > @@ -1782,7 +1787,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain) > { > struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu; > > - if (smmu) > + if (smmu && !domain->non_strict) That doesn't smell right - even in non-strict domains we still need stuff like walk cache invalidations for non-leaf unmaps to be synchronous, so we can't just ignore all sync operations at the driver level. I think the right thing to do to elide the "normal" sync on unmap is to first convert __iommu_dma_unmap to use iommu_unmap_fast()/iommu_tlb_sync(), then make it not issue that sync at all for non-strict domains. Robin. > __arm_smmu_tlb_sync(smmu); > } > > -- > 1.8.3 > >