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 597ECC001DC for ; Wed, 19 Jul 2023 09:13:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230406AbjGSJNS (ORCPT ); Wed, 19 Jul 2023 05:13:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229823AbjGSJNQ (ORCPT ); Wed, 19 Jul 2023 05:13:16 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEC0F10B; Wed, 19 Jul 2023 02:13:14 -0700 (PDT) Received: from dggpemm500002.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4R5VT71yWZzrRr5; Wed, 19 Jul 2023 17:12:27 +0800 (CST) Received: from [10.174.178.247] (10.174.178.247) by dggpemm500002.china.huawei.com (7.185.36.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Wed, 19 Jul 2023 17:13:11 +0800 Subject: Re: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in iort_node_get_rmr_info() To: Shameerali Kolothum Thodi , Lorenzo Pieralisi , Guanghui Feng CC: "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" References: <1689593625-45213-1-git-send-email-guanghuifeng@linux.alibaba.com> <597f481b0e5149dabe4821ca618af6b3@huawei.com> From: Hanjun Guo Message-ID: <613da2c3-d515-b49c-4ff3-cf94836b2acf@huawei.com> Date: Wed, 19 Jul 2023 17:13:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <597f481b0e5149dabe4821ca618af6b3@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.247] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/7/18 16:56, Shameerali Kolothum Thodi wrote: >> [+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) ? > Yes, that is a valid fix. Unlikely it will be a problem. Anyway, I have requested > Hanjun to help with the testing as I don't have a test setup with me now. Valid fix for me as well, we had a firmware bug which reported the numbers of ID as 1 when we only have one ID mapping, so remove the check is fine for the old firmware, but to make it sure, we need some test before give it a pass. > > Hanjun, please help. I need some time to get it properly tested on two versions of firmware, and get the test machine properly setup, please allow me give the feedback next week. Thanks Hanjun