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=-15.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 D6705C4338F for ; Mon, 26 Jul 2021 08:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD81B604DC for ; Mon, 26 Jul 2021 08:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232987AbhGZHqm (ORCPT ); Mon, 26 Jul 2021 03:46:42 -0400 Received: from foss.arm.com ([217.140.110.172]:47450 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232818AbhGZHql (ORCPT ); Mon, 26 Jul 2021 03:46:41 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 787E3106F; Mon, 26 Jul 2021 01:27:09 -0700 (PDT) Received: from [10.57.36.146] (unknown [10.57.36.146]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 615CD3F66F; Mon, 26 Jul 2021 01:27:07 -0700 (PDT) Subject: Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type To: Lu Baolu , joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, suravee.suthikulpanit@amd.com, john.garry@huawei.com, dianders@chromium.org References: <37708e21b55e17eb074ef145afc2157cd0192abe.1626888445.git.robin.murphy@arm.com> From: Robin Murphy Message-ID: <77057c4b-479b-c5b8-4666-f16e294552d1@arm.com> Date: Mon, 26 Jul 2021 09:27:01 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-07-24 06:29, Lu Baolu wrote: > Hi Robin, > > On 2021/7/22 2:20, Robin Murphy wrote: >> Eliminate the iommu_get_dma_strict() indirection and pipe the >> information through the domain type from the beginning. Besides >> the flow simplification this also has several nice side-effects: >> >>   - Automatically implies strict mode for untrusted devices by >>     virtue of their IOMMU_DOMAIN_DMA override. >>   - Ensures that we only ends up using flush queues for drivers >>     which are aware of them and can actually benefit. > > Is this expressed by vendor iommu driver has ops->flush_iotlb_all? No, it's literally whether ->domain_alloc accepts the DMA_DOMAIN_FQ type or not. >>   - Allows us to handle flush queue init failure by falling back >>     to strict mode instead of leaving it to possibly blow up later. >> >> Signed-off-by: Robin Murphy >> --- >>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  2 +- >>   drivers/iommu/arm/arm-smmu/arm-smmu.c       |  2 +- >>   drivers/iommu/dma-iommu.c                   | 10 ++++++---- >>   drivers/iommu/iommu.c                       | 14 ++++---------- >>   include/linux/iommu.h                       |  1 - >>   5 files changed, 12 insertions(+), 17 deletions(-) >> >> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> index fa41026d272e..260b560d0075 100644 >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> @@ -2175,7 +2175,7 @@ static int arm_smmu_domain_finalise(struct >> iommu_domain *domain, >>           .iommu_dev    = smmu->dev, >>       }; >> -    if (!iommu_get_dma_strict(domain)) >> +    if (domain->type == IOMMU_DOMAIN_DMA_FQ) >>           pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; >>       pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain); >> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c >> b/drivers/iommu/arm/arm-smmu/arm-smmu.c >> index dbc14c265b15..2c717f3be056 100644 >> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c >> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c >> @@ -765,7 +765,7 @@ static int arm_smmu_init_domain_context(struct >> iommu_domain *domain, >>           .iommu_dev    = smmu->dev, >>       }; >> -    if (!iommu_get_dma_strict(domain)) >> +    if (domain->type == IOMMU_DOMAIN_DMA_FQ) >>           pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; >>       if (smmu->impl && smmu->impl->init_context) { >> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c >> index b1af1ff324c5..a114a7ad88ec 100644 >> --- a/drivers/iommu/dma-iommu.c >> +++ b/drivers/iommu/dma-iommu.c >> @@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct >> iommu_domain *domain, dma_addr_t base, >>       init_iova_domain(iovad, 1UL << order, base_pfn); >> -    if (!cookie->fq_domain && !dev_is_untrusted(dev) && >> -        domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) { >> +    if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain && >> +        domain->ops->flush_iotlb_all) { >>           if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, >> -                      iommu_dma_entry_dtor)) >> +                      iommu_dma_entry_dtor)) { >>               pr_warn("iova flush queue initialization failed\n"); >> -        else >> +            domain->type = IOMMU_DOMAIN_DMA; >> +        } else { >>               cookie->fq_domain = domain; >> +        } >>       } >>       return iova_reserve_iommu_regions(dev, domain); >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 8333c334891e..d7eaacae0944 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -135,6 +135,9 @@ static int __init iommu_subsys_init(void) >>           } >>       } >> +    if (!iommu_default_passthrough() && !iommu_dma_strict) >> +        iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ; >> + >>       pr_info("Default domain type: %s %s\n", >>           iommu_domain_type_str(iommu_def_domain_type), >>           (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ? >> @@ -352,15 +355,6 @@ void iommu_set_dma_strict(bool strict) >>           iommu_dma_strict = strict; >>   } >> -bool iommu_get_dma_strict(struct iommu_domain *domain) >> -{ >> -    /* only allow lazy flushing for DMA domains */ >> -    if (domain->type == IOMMU_DOMAIN_DMA) >> -        return iommu_dma_strict; >> -    return true; >> -} >> -EXPORT_SYMBOL_GPL(iommu_get_dma_strict); >> - >>   static ssize_t iommu_group_attr_show(struct kobject *kobj, >>                        struct attribute *__attr, char *buf) >>   { >> @@ -764,7 +758,7 @@ static int >> iommu_create_device_direct_mappings(struct iommu_group *group, >>       unsigned long pg_size; >>       int ret = 0; >> -    if (!domain || domain->type != IOMMU_DOMAIN_DMA) >> +    if (!domain || !(domain->type & __IOMMU_DOMAIN_DMA_API)) > > Nit: probably move above change to patch 14? Indeed I'm not sure why this one ended up here, good catch! Thanks, Robin. >>           return 0; >>       BUG_ON(!domain->pgsize_bitmap); >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 56519110d43f..557c4c12e2cf 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -484,7 +484,6 @@ int iommu_set_pgtable_quirks(struct iommu_domain >> *domain, >>           unsigned long quirks); >>   void iommu_set_dma_strict(bool val); >> -bool iommu_get_dma_strict(struct iommu_domain *domain); >>   extern int report_iommu_fault(struct iommu_domain *domain, struct >> device *dev, >>                     unsigned long iova, int flags); >> > > Best regards, > baolu