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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 3F265C4338F for ; Fri, 30 Jul 2021 09:27:03 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0DF226054F for ; Fri, 30 Jul 2021 09:27:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0DF226054F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:CC:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BaGfLwFFj5/mW5PvLI4FWxF1cnmE4vRuV9//BS1ujOw=; b=B7VpIubKeND0eWt72rYSMUwOST 4ZVkNSk1o61x1x5u8SBAFxNKQ4RVX7/XFk7jD4f5fOQ8t8Kr0gBPeOobtjrG75I58MaUKKOyeFwGj m6tlDF4a5sEh+F3F/jvJ3pszWYoyCCVpbAh27XQWWc5xpmpkXuxZ3GE614BG81z6PJV0uIZ+3u7WP bLMHONTaIM7tVQQejs5VzhtkQWVJB83IMb7c1XERsNCVzPvv+Y4D7mK3OReOGtp0+Y3qAWbFbymvx Dj8n/seXMcF+V28zpkwgQOPJnC6hMDOuFlEbH1hLBImN0lk+rMBesdmq8r+p9jGt/FdYisRJkKyVA 8VQ3gUIQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9OlD-007rdF-HQ; Fri, 30 Jul 2021 09:24:56 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m9Ol7-007raG-0j for linux-arm-kernel@lists.infradead.org; Fri, 30 Jul 2021 09:24:51 +0000 Received: from fraeml710-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GbhZN6Bmyz6G9MK; Fri, 30 Jul 2021 17:15:24 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml710-chm.china.huawei.com (10.206.15.59) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 30 Jul 2021 11:24:44 +0200 Received: from [10.47.25.95] (10.47.25.95) 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 15.1.2176.2; Fri, 30 Jul 2021 10:24:43 +0100 Subject: Re: [PATCH v2 22/24] iommu: Allow enabling non-strict mode dynamically To: Robin Murphy , , CC: , , , , , References: From: John Garry Message-ID: <985c0a86-21d9-8d4b-0c33-c00b94e41bb9@huawei.com> Date: Fri, 30 Jul 2021 10:24:24 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Originating-IP: [10.47.25.95] X-ClientProxiedBy: lhreml735-chm.china.huawei.com (10.201.108.86) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210730_022449_270777_66CE38DE X-CRM114-Status: GOOD ( 11.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 28/07/2021 16:58, Robin Murphy wrote: > Allocating and enabling a flush queue is in fact something we can > reasonably do while a DMA domain is active, without having to rebuild it > from scratch. Thus we can allow a strict -> non-strict transition from > sysfs without requiring to unbind the device's driver, which is of > particular interest to users who want to make selective relaxations to > critical devices like the one serving their root filesystem. > > Disabling and draining a queue also seems technically possible to > achieve without rebuilding the whole domain, but would certainly be more > involved. Furthermore there's not such a clear use-case for tightening > up security*after* the device may already have done whatever it is that > you don't trust it not to do, so we only consider the relaxation case. > > Signed-off-by: Robin Murphy Reviewed-by: John Garry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel