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=-15.3 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=unavailable 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 6FD3AC433E6 for ; Tue, 26 Jan 2021 12:15:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 438AE2223D for ; Tue, 26 Jan 2021 12:15:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392096AbhAZMPL (ORCPT ); Tue, 26 Jan 2021 07:15:11 -0500 Received: from foss.arm.com ([217.140.110.172]:36582 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405044AbhAZMNP (ORCPT ); Tue, 26 Jan 2021 07:13:15 -0500 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 4F88F101E; Tue, 26 Jan 2021 04:12:29 -0800 (PST) Received: from [10.57.43.46] (unknown [10.57.43.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3EE783F66B; Tue, 26 Jan 2021 04:12:28 -0800 (PST) Subject: Re: [PATCH v3 2/2] iommu: use the __iommu_attach_device() directly for deferred attach To: Lianbo Jiang , linux-kernel@vger.kernel.org Cc: thomas.lendacky@amd.com, will@kernel.org, hch@infradead.org, iommu@lists.linux-foundation.org References: <20210126115337.20068-1-lijiang@redhat.com> <20210126115337.20068-3-lijiang@redhat.com> From: Robin Murphy Message-ID: <378fce27-cea4-8a98-0adb-89192fa8e302@arm.com> Date: Tue, 26 Jan 2021 12:12:27 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210126115337.20068-3-lijiang@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-01-26 11:53, Lianbo Jiang wrote: > Currently, because domain attach allows to be deferred from iommu > driver to device driver, and when iommu initializes, the devices > on the bus will be scanned and the default groups will be allocated. > > Due to the above changes, some devices could be added to the same > group as below: > > [ 3.859417] pci 0000:01:00.0: Adding to iommu group 16 > [ 3.864572] pci 0000:01:00.1: Adding to iommu group 16 > [ 3.869738] pci 0000:02:00.0: Adding to iommu group 17 > [ 3.874892] pci 0000:02:00.1: Adding to iommu group 17 > > But when attaching these devices, it doesn't allow that a group has > more than one device, otherwise it will return an error. This conflicts > with the deferred attaching. Unfortunately, it has two devices in the > same group for my side, for example: > > [ 9.627014] iommu_group_device_count(): device name[0]:0000:01:00.0 > [ 9.633545] iommu_group_device_count(): device name[1]:0000:01:00.1 > ... > [ 10.255609] iommu_group_device_count(): device name[0]:0000:02:00.0 > [ 10.262144] iommu_group_device_count(): device name[1]:0000:02:00.1 > > Finally, which caused the failure of tg3 driver when tg3 driver calls > the dma_alloc_coherent() to allocate coherent memory in the tg3_test_dma(). > > [ 9.660310] tg3 0000:01:00.0: DMA engine test failed, aborting > [ 9.754085] tg3: probe of 0000:01:00.0 failed with error -12 > [ 9.997512] tg3 0000:01:00.1: DMA engine test failed, aborting > [ 10.043053] tg3: probe of 0000:01:00.1 failed with error -12 > [ 10.288905] tg3 0000:02:00.0: DMA engine test failed, aborting > [ 10.334070] tg3: probe of 0000:02:00.0 failed with error -12 > [ 10.578303] tg3 0000:02:00.1: DMA engine test failed, aborting > [ 10.622629] tg3: probe of 0000:02:00.1 failed with error -12 > > In addition, the similar situations also occur in other drivers such > as the bnxt_en driver. That can be reproduced easily in kdump kernel > when SME is active. > > Let's move the handling currently in iommu_dma_deferred_attach() into > the iommu core code so that it can call the __iommu_attach_device() > directly instead of the iommu_attach_device(). The external interface > iommu_attach_device() is not suitable for handling this situation. No objection to the cosmetic change - arguably parsing "attach" as a verb rather than a noun is more normal anyway :) Thus my previous review still stands: Reviewed-by: Robin Murphy > Signed-off-by: Lianbo Jiang > --- > drivers/iommu/dma-iommu.c | 18 +++--------------- > drivers/iommu/iommu.c | 10 ++++++++++ > include/linux/iommu.h | 1 + > 3 files changed, 14 insertions(+), 15 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index c80056f6c9f9..f659395e7959 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -380,18 +380,6 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, > return iova_reserve_iommu_regions(dev, domain); > } > > -static int iommu_dma_deferred_attach(struct device *dev, > - struct iommu_domain *domain) > -{ > - const struct iommu_ops *ops = domain->ops; > - > - if (unlikely(ops->is_attach_deferred && > - ops->is_attach_deferred(domain, dev))) > - return iommu_attach_device(domain, dev); > - > - return 0; > -} > - > /** > * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API > * page flags. > @@ -535,7 +523,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, > dma_addr_t iova; > > if (static_branch_unlikely(&iommu_deferred_attach_enabled) && > - iommu_dma_deferred_attach(dev, domain)) > + iommu_deferred_attach(dev, domain)) > return DMA_MAPPING_ERROR; > > size = iova_align(iovad, size + iova_off); > @@ -694,7 +682,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, > *dma_handle = DMA_MAPPING_ERROR; > > if (static_branch_unlikely(&iommu_deferred_attach_enabled) && > - iommu_dma_deferred_attach(dev, domain)) > + iommu_deferred_attach(dev, domain)) > return NULL; > > min_size = alloc_sizes & -alloc_sizes; > @@ -978,7 +966,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, > int i; > > if (static_branch_unlikely(&iommu_deferred_attach_enabled) && > - iommu_dma_deferred_attach(dev, domain)) > + iommu_deferred_attach(dev, domain)) > return 0; > > if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index ffeebda8d6de..15b5fd6bd554 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1980,6 +1980,16 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev) > } > EXPORT_SYMBOL_GPL(iommu_attach_device); > > +int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain) > +{ > + const struct iommu_ops *ops = domain->ops; > + > + if (ops->is_attach_deferred && ops->is_attach_deferred(domain, dev)) > + return __iommu_attach_device(domain, dev); > + > + return 0; > +} > + > /* > * Check flags and other user provided data for valid combinations. We also > * make sure no reserved fields or unused flags are set. This is to ensure > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index b3f0e2018c62..92ee9b56f118 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -376,6 +376,7 @@ int iommu_device_sysfs_add(struct iommu_device *iommu, > void iommu_device_sysfs_remove(struct iommu_device *iommu); > int iommu_device_link(struct iommu_device *iommu, struct device *link); > void iommu_device_unlink(struct iommu_device *iommu, struct device *link); > +int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain); > > static inline void __iommu_device_set_ops(struct iommu_device *iommu, > const struct iommu_ops *ops) >