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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 86365C33CB1 for ; Fri, 17 Jan 2020 09:59:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63AAD22464 for ; Fri, 17 Jan 2020 09:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729017AbgAQJ75 (ORCPT ); Fri, 17 Jan 2020 04:59:57 -0500 Received: from 8bytes.org ([81.169.241.247]:60102 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727011AbgAQJ75 (ORCPT ); Fri, 17 Jan 2020 04:59:57 -0500 Received: by theia.8bytes.org (Postfix, from userid 1000) id AA481327; Fri, 17 Jan 2020 10:59:55 +0100 (CET) Date: Fri, 17 Jan 2020 10:59:54 +0100 From: Joerg Roedel To: Lu Baolu Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com, kevin.tian@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] iommu/vt-d: Remove unnecessary WARN_ON_ONCE() Message-ID: <20200117095953.GB15760@8bytes.org> References: <20200116015236.4458-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200116015236.4458-1-baolu.lu@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 16, 2020 at 09:52:36AM +0800, Lu Baolu wrote: > Address field in device TLB invalidation descriptor is qualified > by the S field. If S field is zero, a single page at page address > specified by address [63:12] is requested to be invalidated. If S > field is set, the least significant bit in the address field with > value 0b (say bit N) indicates the invalidation address range. The > spec doesn't require the address [N - 1, 0] to be cleared, hence > remove the unnecessary WARN_ON_ONCE(). > > Otherwise, the caller might set "mask = MAX_AGAW_PFN_WIDTH" in order > to invalidating all the cached mappings on an endpoint, and below > overflow error will be triggered. > > [...] > UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1354:3 > shift exponent 64 is too large for 64-bit type 'long long unsigned int' > [...] > > Reported-and-tested-by: Frank > Signed-off-by: Lu Baolu Does this need a Fixes and/or stable tag? Regards, Joerg