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 BA10FEB64DA for ; Tue, 18 Jul 2023 08:55:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230260AbjGRIz2 (ORCPT ); Tue, 18 Jul 2023 04:55:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232049AbjGRIzY (ORCPT ); Tue, 18 Jul 2023 04:55:24 -0400 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 524E81982; Tue, 18 Jul 2023 01:55:00 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=guanghuifeng@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0Vnh4bmV_1689670476; Received: from 30.221.158.235(mailfrom:guanghuifeng@linux.alibaba.com fp:SMTPD_---0Vnh4bmV_1689670476) by smtp.aliyun-inc.com; Tue, 18 Jul 2023 16:54:50 +0800 Message-ID: <8e2cfde3-15fa-4e5a-02bf-0763abf10821@linux.alibaba.com> Date: Tue, 18 Jul 2023 16:54:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in iort_node_get_rmr_info() To: Lorenzo Pieralisi Cc: guohanjun@huawei.com, sudeep.holla@arm.com, rafael@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, baolin.wang@linux.alibaba.com, alikernel-developer@linux.alibaba.com, will@kernel.org, catalin.marinas@arm.com, shameerali.kolothum.thodi@huawei.com References: <1689593625-45213-1-git-send-email-guanghuifeng@linux.alibaba.com> From: "guanghui.fgh" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org 在 2023/7/18 15:52, Lorenzo Pieralisi 写道: > [+Catalin, Will, Shameer] > > On Mon, Jul 17, 2023 at 07:33:45PM +0800, Guanghui Feng wrote: >> According to the ARM IORT specifications DEN 0049 issue E, >> the "Number of IDs" field in the ID mapping format reports >> the number of IDs in the mapping range minus one. >> >> In iort_node_get_rmr_info(), we erroneously skip ID mappings >> whose "Number of IDs" equal to 0, resulting in valid mapping >> nodes with a single ID to map being skipped, which is wrong. >> >> Fix iort_node_get_rmr_info() by removing the bogus id_count >> check. >> >> Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR reserved regions") >> Signed-off-by: Guanghui Feng >> --- >> drivers/acpi/arm64/iort.c | 3 --- >> 1 file changed, 3 deletions(-) >> >> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c >> index 3631230..56d8873 100644 >> --- a/drivers/acpi/arm64/iort.c >> +++ b/drivers/acpi/arm64/iort.c >> @@ -1007,9 +1007,6 @@ static void iort_node_get_rmr_info(struct acpi_iort_node *node, >> for (i = 0; i < node->mapping_count; i++, map++) { >> struct acpi_iort_node *parent; >> >> - if (!map->id_count) >> - continue; >> - >> parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, >> map->output_reference); >> if (parent != iommu) > > Shameer, I know this may look like overkill since the hunk we are > removing is buggy but can you please test this patch on platforms > with RMR to make sure we are not triggering regressions by removing > it (by the specs that's what should be done but current firmware > is always something to reckon with) ? > > Thanks, > Lorenzo Thanks for your response. Firstly, I have tested iort rmr with one ID mapping and works well. Secondly, When there is more than two id mappings, the buggly id_count check has no effect(for the id_count is larger than zero).