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,USER_AGENT_SANE_2 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 5AFD3C38A2A for ; Thu, 7 May 2020 16:25:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 350412083B for ; Thu, 7 May 2020 16:25:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726495AbgEGQZp (ORCPT ); Thu, 7 May 2020 12:25:45 -0400 Received: from mga11.intel.com ([192.55.52.93]:21311 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726470AbgEGQZp (ORCPT ); Thu, 7 May 2020 12:25:45 -0400 IronPort-SDR: dx3xesLci+fKG1o5vNeaJDaI7mzsELKq/xcLU16yRnXtFQsCozExJxOuBCMmtUdnBMG/5NmP6w SbUgNO+Q9pzg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2020 09:25:44 -0700 IronPort-SDR: UI2DdPDFZfRj74OALBpuW41w58LXZwgsjf3LGqDj+vALiCsEHXQU/Sa9YbL1TRdZwaxVQulhgj S1oqukCmHM3Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,364,1583222400"; d="scan'208";a="278651044" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga002.jf.intel.com with ESMTP; 07 May 2020 09:25:43 -0700 Date: Thu, 7 May 2020 09:31:50 -0700 From: Jacob Pan To: Jean-Philippe Brucker Cc: iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, joro@8bytes.org, catalin.marinas@arm.com, will@kernel.org, robin.murphy@arm.com, kevin.tian@intel.com, baolu.lu@linux.intel.com, Jonathan.Cameron@huawei.com, christian.koenig@amd.com, felix.kuehling@amd.com, zhangfei.gao@linaro.org, jgg@ziepe.ca, xuzaibo@huawei.com, fenghua.yu@intel.com, hch@infradead.org, jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v6 17/25] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Message-ID: <20200507093150.6da9d6fb@jacob-builder> In-Reply-To: <20200505091531.GA203922@myrica> References: <20200430143424.2787566-1-jean-philippe@linaro.org> <20200430143424.2787566-18-jean-philippe@linaro.org> <20200430141617.6ad4be4c@jacob-builder> <20200504164351.GJ170104@myrica> <20200504134723.54e2ebcd@jacob-builder> <20200505091531.GA203922@myrica> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, 5 May 2020 11:15:31 +0200 Jean-Philippe Brucker wrote: > On Mon, May 04, 2020 at 01:47:23PM -0700, Jacob Pan wrote: > > > > > + arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, > > > > > &invalid_cd); + > > > > > + arm_smmu_tlb_inv_asid(smmu_domain->smmu, > > > > > smmu_mn->cd->asid); > > > > > + /* TODO: invalidate ATS */ > > > > > + > > > > If mm release is called after tlb invalidate range, is it still > > > > necessary to invalidate again? > > > > > > No, provided all mappings from the address space are unmapped and > > > invalidated. I'll double check, but in my tests invalidate range > > > didn't seem to be called for all mappings on mm exit, so I > > > believe we do need this. > > > > > I think it is safe to invalidate again. There was a concern that mm > > release may delete IOMMU driver from the notification list and miss > > tlb invalidate range. I had a hard time to confirm that with ftrace > > while killing a process, many lost events. > > > > If it helps, I have a test that generates small DMA transactions on a > SMMU model. This is the trace for a job on a 8kB mmap'd buffer: > > smmu_bind_alloc: dev=0000:00:03.0 pasid=1 > dev_fault: IOMMU:0000:00:03.0 type=2 reason=0 > addr=0x0000ffff860e6000 pasid=1 group=74 flags=3 prot=2 > dev_page_response: IOMMU:0000:00:03.0 code=0 pasid=1 group=74 > dev_fault: IOMMU:0000:00:03.0 type=2 reason=0 addr=0x0000ffff860e7000 > pasid=1 group=143 flags=3 prot=2 dev_page_response: > IOMMU:0000:00:03.0 code=0 pasid=1 group=143 smmu_mm_invalidate: > pasid=1 start=0xffff860e6000 end=0xffff860e8000 smmu_mm_invalidate: > pasid=1 start=0xffff860e6000 end=0xffff860e8000 smmu_mm_invalidate: > pasid=1 start=0xffff860e8000 end=0xffff860ea000 smmu_mm_invalidate: > pasid=1 start=0xffff860e8000 end=0xffff860ea000 smmu_unbind_free: > dev=0000:00:03.0 pasid=1 > > And this is the same job, but the process immediately kills itself > after launching it. > > smmu_bind_alloc: dev=0000:00:03.0 pasid=1 > dev_fault: IOMMU:0000:00:03.0 type=2 reason=0 > addr=0x0000ffffb9d15000 pasid=1 group=259 flags=3 prot=2 > smmu_mm_release: pasid=1 dev_page_response: IOMMU:0000:00:03.0 code=0 > pasid=1 group=259 dev_fault: IOMMU:0000:00:03.0 type=2 reason=0 > addr=0x0000ffffb9d15000 pasid=1 group=383 flags=3 prot=2 > dev_page_response: IOMMU:0000:00:03.0 code=1 pasid=1 group=383 > smmu_unbind_free: dev=0000:00:03.0 pasid=1 > > We don't get any invalidate_range notification in this case. > Thanks for the confirmation. We do need to invalidate here. > Thanks, > Jean [Jacob Pan]