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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A9DC5C433DF for ; Fri, 15 May 2020 14:20:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 895B720671 for ; Fri, 15 May 2020 14:20:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726228AbgEOOUv (ORCPT ); Fri, 15 May 2020 10:20:51 -0400 Received: from 8bytes.org ([81.169.241.247]:43486 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbgEOOUv (ORCPT ); Fri, 15 May 2020 10:20:51 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 792053C3; Fri, 15 May 2020 16:20:49 +0200 (CEST) Date: Fri, 15 May 2020 16:20:48 +0200 From: Joerg Roedel To: Lu Baolu Cc: iommu@lists.linux-foundation.org, jroedel@suse.de, linux-kernel@vger.kernel.org, Tom Murphy Subject: Re: [PATCH] iommu: Implement deferred domain attachment Message-ID: <20200515142047.GX18353@8bytes.org> References: <20200515094519.20338-1-joro@8bytes.org> <8ce93a10-2ce0-e5a0-88a0-5d21d7003c0f@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8ce93a10-2ce0-e5a0-88a0-5d21d7003c0f@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 15, 2020 at 09:51:03PM +0800, Lu Baolu wrote: > On 2020/5/15 17:45, Joerg Roedel wrote: > > struct iommu_domain *iommu_get_dma_domain(struct device *dev) > > { > > - return dev->iommu_group->default_domain; > > + struct iommu_domain *domain = dev->iommu_group->default_domain; > > + > > + if (__iommu_is_attach_deferred(domain, dev)) > > + __iommu_attach_device_no_defer(domain, dev); > > It seems that the return value needs to be checked. The default domain > is invalid if attach() failed. True, I looked at that, the callers can't handle returning NULL here, so I kept it this way for now. The outcome is that DMA will fail, but otherwise we'd see a NULL-ptr dereference really quickly after returning from that function. Bottom line: This needs to be cleaned up separatly. Regards, Joerg 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 B7328C433E0 for ; Fri, 15 May 2020 14:21:01 +0000 (UTC) Received: from whitealder.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 mail.kernel.org (Postfix) with ESMTPS id 7DCD020671 for ; Fri, 15 May 2020 14:21:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7DCD020671 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 41EDF88DB4; Fri, 15 May 2020 14:21:01 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id K7J7pycOOq0L; Fri, 15 May 2020 14:20:56 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 9365588021; Fri, 15 May 2020 14:20:56 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 77C6CC0178; Fri, 15 May 2020 14:20:56 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 80E4CC016F for ; Fri, 15 May 2020 14:20:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 68FA1899F5 for ; Fri, 15 May 2020 14:20:55 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id S1YLf29WUoHi for ; Fri, 15 May 2020 14:20:53 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by hemlock.osuosl.org (Postfix) with ESMTPS id B69DC899EB for ; Fri, 15 May 2020 14:20:53 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id 792053C3; Fri, 15 May 2020 16:20:49 +0200 (CEST) Date: Fri, 15 May 2020 16:20:48 +0200 From: Joerg Roedel To: Lu Baolu Subject: Re: [PATCH] iommu: Implement deferred domain attachment Message-ID: <20200515142047.GX18353@8bytes.org> References: <20200515094519.20338-1-joro@8bytes.org> <8ce93a10-2ce0-e5a0-88a0-5d21d7003c0f@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8ce93a10-2ce0-e5a0-88a0-5d21d7003c0f@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: iommu@lists.linux-foundation.org, jroedel@suse.de, linux-kernel@vger.kernel.org, Tom 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 Fri, May 15, 2020 at 09:51:03PM +0800, Lu Baolu wrote: > On 2020/5/15 17:45, Joerg Roedel wrote: > > struct iommu_domain *iommu_get_dma_domain(struct device *dev) > > { > > - return dev->iommu_group->default_domain; > > + struct iommu_domain *domain = dev->iommu_group->default_domain; > > + > > + if (__iommu_is_attach_deferred(domain, dev)) > > + __iommu_attach_device_no_defer(domain, dev); > > It seems that the return value needs to be checked. The default domain > is invalid if attach() failed. True, I looked at that, the callers can't handle returning NULL here, so I kept it this way for now. The outcome is that DMA will fail, but otherwise we'd see a NULL-ptr dereference really quickly after returning from that function. Bottom line: This needs to be cleaned up separatly. Regards, Joerg _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu