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=-10.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 16B56C433DB for ; Fri, 26 Feb 2021 09:45:04 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 9BE6E64E85 for ; Fri, 26 Feb 2021 09:45:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BE6E64E85 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=hisilicon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4Fi6dhE2ixh3oa9MbcySp9FwSJwJY64lFvRvV/6Stvw=; b=0yjKcRaCBAY2Hi0Fc11mbos+m FAIGSg/3FBGwxpJXltP2PFUJqHDGpHtnebOf6kLhYFh6IU0uITn+nQca0ZJZdBF0XTVOP6VEV/7yO wqP2rAIE7UZ2BPfq/E6W+CIMvi38vgl234CnR+78SoSN2GczGf79Ne5tc8RiGaOifKKUim5JD5anD DOAo/pEqm3R6PT2sUYbK2V8GVhuVFh/OS/ToRz4yKmaEttrgIaY7uT/+tqIGiZh6EiZQfPpbQkcw/ 5H/QEfHaM3uUusxbom78tRFZrS42oSWgiDYCS2tnc5oEEExE6wY/MFUwoT93iKPgmMXeD6o7R/kqT /sSBjKePw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lFZf5-0005qf-9H; Fri, 26 Feb 2021 09:43:51 +0000 Received: from szxga04-in.huawei.com ([45.249.212.190]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lFZf3-0005ps-1J for linux-arm-kernel@lists.infradead.org; Fri, 26 Feb 2021 09:43:50 +0000 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4Dn4S81Wj2z16D0R; Fri, 26 Feb 2021 17:42:00 +0800 (CST) Received: from [127.0.0.1] (10.40.188.87) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.498.0; Fri, 26 Feb 2021 17:43:27 +0800 Subject: Re: [PATCH v12 10/10] iommu/arm-smmu-v3: Add stall support for platform devices To: Jean-Philippe Brucker References: <20210127154322.3959196-1-jean-philippe@linaro.org> <20210127154322.3959196-11-jean-philippe@linaro.org> <8adc79cc-7afb-dfe8-4f7b-07fa6dc5b905@hisilicon.com> From: Zhou Wang Message-ID: Date: Fri, 26 Feb 2021 17:43:27 +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: X-Originating-IP: [10.40.188.87] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210226_044349_820577_74EF3BC5 X-CRM114-Status: GOOD ( 15.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, kevin.tian@intel.com, linux-acpi@vger.kernel.org, robin.murphy@arm.com, joro@8bytes.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vivek.gautam@arm.com, iommu@lists.linux-foundation.org, robh+dt@kernel.org, linux-accelerators@lists.ozlabs.org, guohanjun@huawei.com, zhangfei.gao@linaro.org, will@kernel.org, linux-arm-kernel@lists.infradead.org, lenb@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2021/2/1 19:14, Jean-Philippe Brucker wrote: > Hi Zhou, > > On Mon, Feb 01, 2021 at 09:18:42AM +0800, Zhou Wang wrote: >>> @@ -1033,8 +1076,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, >>> FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) | >>> CTXDESC_CD_0_V; >>> >>> - /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */ >>> - if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE) >>> + if (smmu_domain->stall_enabled) >> >> Could we add ssid checking here? like: if (smmu_domain->stall_enabled && ssid). >> The reason is if not CD.S will also be set when ssid is 0, which is not needed. > > Some drivers may want to get stall events on SSID 0: > https://lore.kernel.org/kvm/20210125090402.1429-1-lushenming@huawei.com/#t > > Are you seeing an issue with stall events on ssid 0? Normally there > shouldn't be any fault on this context, but if they happen and no handler > is registered, the SMMU driver will just abort them and report them like a > non-stall event. Hi Jean, I notice that there is problem. In my case, I expect that CD0 is for kernel and other CDs are for user space. Normally there shouldn't be any fault in kernel, however, we have RAS case which is for some reason there may has invalid address access from hardware device. So at least there are two different address access failures: 1. hardware RAS problem; 2. software fault fail(e.g. kill process when doing DMA). Handlings for these two are different: for 1, we should reset hardware device; for 2, stop related DMA is enough. Currently if SMMU returns the same signal(by SMMU resume abort), master device driver can not tell these two kinds of cases. >From the basic concept, if a CD is used for kernel, its S bit should not be set. How about we add iommu domain check here too, if DMA domain we do not set S bit for CD0, if unmanaged domain we set S bit for all CDs? Thanks, Zhou > > Thanks, > Jean > > . > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel