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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CB4BC43334 for ; Fri, 10 Jun 2022 15:38:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240211AbiFJPiE (ORCPT ); Fri, 10 Jun 2022 11:38:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233903AbiFJPiD (ORCPT ); Fri, 10 Jun 2022 11:38:03 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0938326562F; Fri, 10 Jun 2022 08:37:58 -0700 (PDT) Received: from fraeml739-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LKQ2n144hz689ML; Fri, 10 Jun 2022 23:33:05 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml739-chm.china.huawei.com (10.206.15.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 10 Jun 2022 17:37:56 +0200 Received: from [10.47.88.201] (10.47.88.201) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 10 Jun 2022 16:37:55 +0100 Message-ID: Date: Fri, 10 Jun 2022 16:37:54 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits To: Bart Van Assche , , , , , , , , CC: , , , , , , , References: <1654507822-168026-1-git-send-email-john.garry@huawei.com> <1654507822-168026-4-git-send-email-john.garry@huawei.com> <31417477-953d-283e-808e-cf8701e820a8@huawei.com> <5b214e95-dd95-551a-496e-a2139a74e8eb@huawei.com> <9b1d155e-28cc-08dc-5a5a-8580132575e7@huawei.com> <23bf4427-41c3-bf1d-903a-75928bb47627@acm.org> From: John Garry In-Reply-To: <23bf4427-41c3-bf1d-903a-75928bb47627@acm.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.88.201] X-ClientProxiedBy: lhreml727-chm.china.huawei.com (10.201.108.78) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 09/06/2022 21:34, Bart Van Assche wrote: > On 6/9/22 10:54, John Garry wrote: >> ok, but do you have a system where the UFS host controller is behind >> an IOMMU? I had the impression that UFS controllers would be mostly >> found in embedded systems and IOMMUs are not as common on there. > > Modern phones have an IOMMU. Below one can find an example from a Pixel > 6 phone. The UFS storage controller is not controller by the IOMMU as > far as I can see but I wouldn't be surprised if the security team would > ask us one day to enable the IOMMU for the UFS controller. OK, then unfortunately it seems that you have no method to test. I might be able to test USB MSC but I am not even sure if I can even get DMA mappings who length exceeds the IOVA rcache limit there. Thanks, John