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 301F9EB64DA for ; Tue, 18 Jul 2023 09:18:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232231AbjGRJRv (ORCPT ); Tue, 18 Jul 2023 05:17:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229625AbjGRJRe (ORCPT ); Tue, 18 Jul 2023 05:17:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDD391985; Tue, 18 Jul 2023 02:17:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3026E614DC; Tue, 18 Jul 2023 09:16:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2729AC433C7; Tue, 18 Jul 2023 09:16:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689671815; bh=X1PB0DZ98HNXgcbNBNhLnxz+WT2Ttfz91vdZj8MqJdQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XEXVjd8A1wrHo2OdsLRY2qh7dp8JAFitJbD/0++C4IYmLBpgshjtfaQ+EanQBdDPS q6IWubOJ6X+Q+uXBW/hswlYp8i6EbnNRCjxx9MeSVi1X2+Xf2grZAfBcz3DaLuA7o+ tMXZ7c8l6PkTjQ9+MJIp4tLQIquKIKSURyu6eBsniqUnnMeepF3engRvmX9T+Gau6c pgxHDRnRcLSzoBDAaez5KndjZiFfDlirlhRGepgJyu/uWIqyez8VjNNO8UOTJ3rfUg aQiB8myN+2AUmHJ6dZMAFBd1EtvXIW65Ye+Auu4D9gDzqmsTOIlU2hVZt/oC/cI19N d6LKpVyXVm+Ug== Date: Tue, 18 Jul 2023 11:16:49 +0200 From: Lorenzo Pieralisi To: "guanghui.fgh" 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 Subject: Re: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in iort_node_get_rmr_info() Message-ID: References: <1689593625-45213-1-git-send-email-guanghuifeng@linux.alibaba.com> <8e2cfde3-15fa-4e5a-02bf-0763abf10821@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8e2cfde3-15fa-4e5a-02bf-0763abf10821@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 18, 2023 at 04:54:36PM +0800, guanghui.fgh wrote: > > > 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). Thank you, I wasn't asking you, it is comforting to know you tested the patch before sending it though. I asked Shameer to make sure the id_count check did not mask a bug in the platforms on which the RMR IORT implementation was initially tested - that's it, I don't want to merge a fix and revert it the next day. Thanks, Lorenzo