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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 E1E79C4BA10 for ; Wed, 26 Feb 2020 08:45:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2EB2206E6 for ; Wed, 26 Feb 2020 08:45:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727097AbgBZIpN (ORCPT ); Wed, 26 Feb 2020 03:45:13 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:44650 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725872AbgBZIpN (ORCPT ); Wed, 26 Feb 2020 03:45:13 -0500 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 730B97C1AE6C45ED5204; Wed, 26 Feb 2020 16:44:54 +0800 (CST) Received: from [127.0.0.1] (10.67.101.242) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.439.0; Wed, 26 Feb 2020 16:44:53 +0800 Subject: Re: [PATCH v4 23/26] iommu/arm-smmu-v3: Add stall support for platform devices To: Jean-Philippe Brucker , , , , , References: <20200224182401.353359-1-jean-philippe@linaro.org> <20200224182401.353359-24-jean-philippe@linaro.org> CC: , , Jean-Philippe Brucker , , , , , , From: Xu Zaibo Message-ID: Date: Wed, 26 Feb 2020 16:44:53 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20200224182401.353359-24-jean-philippe@linaro.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.101.242] X-CFilter-Loop: Reflected Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi, On 2020/2/25 2:23, Jean-Philippe Brucker wrote: > From: Jean-Philippe Brucker > > The SMMU provides a Stall model for handling page faults in platform > devices. It is similar to PCI PRI, but doesn't require devices to have > their own translation cache. Instead, faulting transactions are parked and > the OS is given a chance to fix the page tables and retry the transaction. > > Enable stall for devices that support it (opt-in by firmware). When an > event corresponds to a translation error, call the IOMMU fault handler. If > the fault is recoverable, it will call us back to terminate or continue > the stall. > > Signed-off-by: Jean-Philippe Brucker > --- > drivers/iommu/arm-smmu-v3.c | 271 ++++++++++++++++++++++++++++++++++-- > drivers/iommu/of_iommu.c | 5 +- > include/linux/iommu.h | 2 + > 3 files changed, 269 insertions(+), 9 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 6a5987cce03f..da5dda5ba26a 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -374,6 +374,13 @@ > #define CMDQ_PRI_1_GRPID GENMASK_ULL(8, 0) > #define CMDQ_PRI_1_RESP GENMASK_ULL(13, 12) > [...] > +static int arm_smmu_page_response(struct device *dev, > + struct iommu_fault_event *unused, > + struct iommu_page_response *resp) > +{ > + struct arm_smmu_cmdq_ent cmd = {0}; > + struct arm_smmu_master *master = dev_iommu_fwspec_get(dev)->iommu_priv; Here can use 'dev_to_master' ? Cheers, Zaibo . > + int sid = master->streams[0].id; > + > + if (master->stall_enabled) { > + cmd.opcode = CMDQ_OP_RESUME; > + cmd.resume.sid = sid; > + cmd.resume.stag = resp->grpid; > + switch (resp->code) { > + case IOMMU_PAGE_RESP_INVALID: > + case IOMMU_PAGE_RESP_FAILURE: > + cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT; > + break; > + case IOMMU_PAGE_RESP_SUCCESS: > + cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY; > + break; > + default: > + return -EINVAL; > + } > + } else { > + /* TODO: insert PRI response here */ > + return -ENODEV; > + } > + > + arm_smmu_cmdq_issue_cmd(master->smmu, &cmd); > + /* > + * Don't send a SYNC, it doesn't do anything for RESUME or PRI_RESP. > + * RESUME consumption guarantees that the stalled transaction will be > + * terminated... at some point in the future. PRI_RESP is fire and > + * forget. > + */ > + > + return 0; > +} > + [...]