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 999CAC46460 for ; Thu, 9 Aug 2018 11:08:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 519062151C for ; Thu, 9 Aug 2018 11:08:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 519062151C 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 S1730680AbeHINdC (ORCPT ); Thu, 9 Aug 2018 09:33:02 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:52256 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727786AbeHINdC (ORCPT ); Thu, 9 Aug 2018 09:33:02 -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 5BE8B18A; Thu, 9 Aug 2018 04:08:40 -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 8D93C3F5D4; Thu, 9 Aug 2018 04:08:37 -0700 (PDT) Subject: Re: [PATCH v4 5/5] iommu/arm-smmu-v3: add bootup option "arm_iommu" 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> <1533558424-16748-6-git-send-email-thunder.leizhen@huawei.com> From: Robin Murphy Message-ID: Date: Thu, 9 Aug 2018 12:08:36 +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: <1533558424-16748-6-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: > Add a bootup option to make the system manager can choose which mode to > be used. The default mode is strict. > > Signed-off-by: Zhen Lei > --- > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ > drivers/iommu/arm-smmu-v3.c | 17 ++++++++++++++++- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 533ff5c..426e989 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1720,6 +1720,15 @@ > nobypass [PPC/POWERNV] > Disable IOMMU bypass, using IOMMU for PCI devices. > > + arm_iommu= [ARM64] > + non-strict [Default Off] Again, I'd much rather have "iommu.non_strict= { "0" | "1" }" in line with the passthrough option. Robin. > + Put off TLBs invalidation and release memory first. > + It's good for scatter-gather performance but lacks full > + isolation, an untrusted device can access the reused > + memory because the TLBs may still valid. Please take > + full consideration before choosing this mode. > + Note that, VFIO will always use strict mode. > + > iommu.passthrough= > [ARM64] Configure DMA to bypass the IOMMU by default. > Format: { "0" | "1" } > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 904bc1e..9a30892 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -631,6 +631,21 @@ struct arm_smmu_option_prop { > { 0, NULL}, > }; > > +static u32 smmu_non_strict __read_mostly; > + > +static int __init arm_smmu_setup(char *str) > +{ > + if (!strncmp(str, "non-strict", 10)) { > + smmu_non_strict = 1; > + pr_warn("WARNING: iommu non-strict mode is chosen.\n" > + "It's good for scatter-gather performance but lacks full isolation\n"); > + add_taint(TAINT_WARN, LOCKDEP_STILL_OK); > + } > + > + return 0; > +} > +early_param("arm_iommu", arm_smmu_setup); > + > static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset, > struct arm_smmu_device *smmu) > { > @@ -1622,7 +1637,7 @@ 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) { > + if ((domain->type == IOMMU_DOMAIN_DMA) && smmu_non_strict) { > domain->non_strict = 1; > pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > } > -- > 1.8.3 > > From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Thu, 9 Aug 2018 12:08:36 +0100 Subject: [PATCH v4 5/5] iommu/arm-smmu-v3: add bootup option "arm_iommu" In-Reply-To: <1533558424-16748-6-git-send-email-thunder.leizhen@huawei.com> References: <1533558424-16748-1-git-send-email-thunder.leizhen@huawei.com> <1533558424-16748-6-git-send-email-thunder.leizhen@huawei.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 06/08/18 13:27, Zhen Lei wrote: > Add a bootup option to make the system manager can choose which mode to > be used. The default mode is strict. > > Signed-off-by: Zhen Lei > --- > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ > drivers/iommu/arm-smmu-v3.c | 17 ++++++++++++++++- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 533ff5c..426e989 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1720,6 +1720,15 @@ > nobypass [PPC/POWERNV] > Disable IOMMU bypass, using IOMMU for PCI devices. > > + arm_iommu= [ARM64] > + non-strict [Default Off] Again, I'd much rather have "iommu.non_strict= { "0" | "1" }" in line with the passthrough option. Robin. > + Put off TLBs invalidation and release memory first. > + It's good for scatter-gather performance but lacks full > + isolation, an untrusted device can access the reused > + memory because the TLBs may still valid. Please take > + full consideration before choosing this mode. > + Note that, VFIO will always use strict mode. > + > iommu.passthrough= > [ARM64] Configure DMA to bypass the IOMMU by default. > Format: { "0" | "1" } > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 904bc1e..9a30892 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -631,6 +631,21 @@ struct arm_smmu_option_prop { > { 0, NULL}, > }; > > +static u32 smmu_non_strict __read_mostly; > + > +static int __init arm_smmu_setup(char *str) > +{ > + if (!strncmp(str, "non-strict", 10)) { > + smmu_non_strict = 1; > + pr_warn("WARNING: iommu non-strict mode is chosen.\n" > + "It's good for scatter-gather performance but lacks full isolation\n"); > + add_taint(TAINT_WARN, LOCKDEP_STILL_OK); > + } > + > + return 0; > +} > +early_param("arm_iommu", arm_smmu_setup); > + > static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset, > struct arm_smmu_device *smmu) > { > @@ -1622,7 +1637,7 @@ 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) { > + if ((domain->type == IOMMU_DOMAIN_DMA) && smmu_non_strict) { > domain->non_strict = 1; > pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > } > -- > 1.8.3 > >