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 Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1D729C433EF for ; Wed, 15 Jun 2022 09:53:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id B15CB831A7; Wed, 15 Jun 2022 09:53:29 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nh8oDFHtO7Qo; Wed, 15 Jun 2022 09:53:28 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp1.osuosl.org (Postfix) with ESMTPS id 6EC5982DDE; Wed, 15 Jun 2022 09:53:28 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3122EC0039; Wed, 15 Jun 2022 09:53:28 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id E3A51C002D for ; Wed, 15 Jun 2022 09:53:26 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id C4C4B606C0 for ; Wed, 15 Jun 2022 09:53:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xj0_QTK6kDFK for ; Wed, 15 Jun 2022 09:53:25 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp3.osuosl.org (Postfix) with ESMTP id 88B45605D8 for ; Wed, 15 Jun 2022 09:53:25 +0000 (UTC) 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 B68F7152B; Wed, 15 Jun 2022 02:53:24 -0700 (PDT) Received: from [10.57.7.82] (unknown [10.57.7.82]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3BD563F792; Wed, 15 Jun 2022 02:53:23 -0700 (PDT) Message-ID: <10eaa3b1-4cf7-a7b6-a7f6-111a486a343a@arm.com> Date: Wed, 15 Jun 2022 10:53:21 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 From: Steven Price Subject: Re: [RESEND PATCH v8 01/11] iommu: Add DMA ownership management interfaces To: Lu Baolu , Joerg Roedel References: <20220418005000.897664-1-baolu.lu@linux.intel.com> <20220418005000.897664-2-baolu.lu@linux.intel.com> Content-Language: en-GB In-Reply-To: <20220418005000.897664-2-baolu.lu@linux.intel.com> Cc: Kevin Tian , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Jason Gunthorpe , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 18/04/2022 01:49, Lu Baolu wrote: > Multiple devices may be placed in the same IOMMU group because they > cannot be isolated from each other. These devices must either be > entirely under kernel control or userspace control, never a mixture. > > This adds dma ownership management in iommu core and exposes several > interfaces for the device drivers and the device userspace assignment > framework (i.e. VFIO), so that any conflict between user and kernel > controlled dma could be detected at the beginning. > > The device driver oriented interfaces are, > > int iommu_device_use_default_domain(struct device *dev); > void iommu_device_unuse_default_domain(struct device *dev); > > By calling iommu_device_use_default_domain(), the device driver tells > the iommu layer that the device dma is handled through the kernel DMA > APIs. The iommu layer will manage the IOVA and use the default domain > for DMA address translation. > > The device user-space assignment framework oriented interfaces are, > > int iommu_group_claim_dma_owner(struct iommu_group *group, > void *owner); > void iommu_group_release_dma_owner(struct iommu_group *group); > bool iommu_group_dma_owner_claimed(struct iommu_group *group); > > The device userspace assignment must be disallowed if the DMA owner > claiming interface returns failure. > > Signed-off-by: Jason Gunthorpe > Signed-off-by: Kevin Tian > Signed-off-by: Lu Baolu > Reviewed-by: Robin Murphy I'm seeing a regression that I've bisected to this commit on a Firefly RK3288 board. The display driver fails to probe properly because __iommu_attach_group() returns -EBUSY. This causes long hangs and splats as the display flips timeout. The call stack to __iommu_attach_group() is: __iommu_attach_group from iommu_attach_device+0x64/0xb4 iommu_attach_device from rockchip_drm_dma_attach_device+0x20/0x50 rockchip_drm_dma_attach_device from vop_crtc_atomic_enable+0x10c/0xa64 vop_crtc_atomic_enable from drm_atomic_helper_commit_modeset_enables+0xa8/0x290 drm_atomic_helper_commit_modeset_enables from drm_atomic_helper_commit_tail_rpm+0x44/0x8c drm_atomic_helper_commit_tail_rpm from commit_tail+0x9c/0x180 commit_tail from drm_atomic_helper_commit+0x164/0x18c drm_atomic_helper_commit from drm_atomic_commit+0xac/0xe4 drm_atomic_commit from drm_client_modeset_commit_atomic+0x23c/0x284 drm_client_modeset_commit_atomic from drm_client_modeset_commit_locked+0x60/0x1c8 drm_client_modeset_commit_locked from drm_client_modeset_commit+0x24/0x40 drm_client_modeset_commit from drm_fb_helper_set_par+0xb8/0xf8 drm_fb_helper_set_par from drm_fb_helper_hotplug_event.part.0+0xa8/0xc0 drm_fb_helper_hotplug_event.part.0 from output_poll_execute+0xb8/0x224 > @@ -2109,7 +2115,7 @@ static int __iommu_attach_group(struct iommu_domain *domain, > { > int ret; > > - if (group->default_domain && group->domain != group->default_domain) > + if (group->domain && group->domain != group->default_domain) > return -EBUSY; > > ret = __iommu_group_for_each_dev(group, domain, Reverting this 'fixes' the problem for me. The follow up 0286300e6045 ("iommu: iommu_group_claim_dma_owner() must always assign a domain") doesn't help. Adding some debug printks I can see that domain is a valid pointer, but both default_domain and blocking_domain are NULL. I'm using the DTB from the kernel tree (rk3288-firefly.dtb). Any ideas? Thanks, Steve _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu