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,URIBL_BLOCKED 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 D238EC46464 for ; Tue, 14 Aug 2018 01:49:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2449F216E3 for ; Tue, 14 Aug 2018 01:49:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2449F216E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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 S1730318AbeHNEeQ (ORCPT ); Tue, 14 Aug 2018 00:34:16 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:10717 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725829AbeHNEeP (ORCPT ); Tue, 14 Aug 2018 00:34:15 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id B09171645CFC2; Tue, 14 Aug 2018 09:49:20 +0800 (CST) Received: from [127.0.0.1] (10.177.23.164) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.399.0; Tue, 14 Aug 2018 09:49:12 +0800 Subject: Re: [PATCH v4 4/5] iommu/arm-smmu-v3: add support for non-strict mode To: Robin Murphy , Will Deacon , Joerg Roedel , linux-arm-kernel , iommu , linux-kernel References: <1533558424-16748-1-git-send-email-thunder.leizhen@huawei.com> <1533558424-16748-5-git-send-email-thunder.leizhen@huawei.com> <94c88d9e-818e-f893-9ee2-7a0cf425bd9a@arm.com> CC: LinuxArm , Hanjun Guo , Libin From: "Leizhen (ThunderTown)" Message-ID: <5B723517.3010603@huawei.com> Date: Tue, 14 Aug 2018 09:49:11 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <94c88d9e-818e-f893-9ee2-7a0cf425bd9a@arm.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.23.164] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/8/9 19:06, Robin Murphy wrote: > 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. OK, I will try it. > > Robin. > >> __arm_smmu_tlb_sync(smmu); >> } >> >> -- >> 1.8.3 >> >> > > . > -- Thanks! BestRegards