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=-13.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 1D4F4C2D0DC for ; Thu, 2 Jan 2020 11:18:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE434215A4 for ; Thu, 2 Jan 2020 11:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728147AbgABLSW (ORCPT ); Thu, 2 Jan 2020 06:18:22 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2219 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728111AbgABLSW (ORCPT ); Thu, 2 Jan 2020 06:18:22 -0500 Received: from LHREML712-CAH.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id E3A86358BA1AB7826A05; Thu, 2 Jan 2020 11:18:20 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML712-CAH.china.huawei.com (10.201.108.35) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 2 Jan 2020 11:18:20 +0000 Received: from [127.0.0.1] (10.202.226.43) 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 15.1.1713.5; Thu, 2 Jan 2020 11:18:20 +0000 Subject: Re: [PATCH v1] ACPI/IORT: Workaround for IORT ID count "minus one" issue To: "Guohanjun (Hanjun Guo)" , Lorenzo Pieralisi , Sudeep Holla , "Rafael J. Wysocki" , Pankaj Bansal CC: "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linuxarm , Shameer Kolothum , Robert Richter References: <1577708824-4873-1-git-send-email-guohanjun@huawei.com> From: John Garry Message-ID: <639f61ab-e692-caaf-9b4e-b848b05caee2@huawei.com> Date: Thu, 2 Jan 2020 11:18:19 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <1577708824-4873-1-git-send-email-guohanjun@huawei.com> Content-Type: text/plain; charset="gbk"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.43] X-ClientProxiedBy: lhreml710-chm.china.huawei.com (10.201.108.61) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org + On 30/12/2019 12:27, Guohanjun (Hanjun Guo) wrote: > The IORT spec [0] says Number of IDs = The number of IDs in the range minus > one, it is confusing but it was written down in the first version of the > IORT spec. But the IORT ID mapping function iort_id_map() did something > wrong from the start, which bails out if: > > the request ID >= the input base + number of IDs > > This is wrong because it ignored the "minus one", and breaks some valid > usecases such as ID mapping to contain single device mapping without > single mapping flag set. > > Pankaj Bansal proposed a solution to fix the issue [1], which bails > out if: > > the request ID > the input base + number of IDs > > This works as the spec defined, unfortunately some firmware didn't > minus one for the number of IDs in the range, and the propoased > solution will break those systems in this way: > > PCI hostbridge mapping entry 1: > Input base: 0x1000 > ID Count: 0x100 > Output base: 0x1000 > Output reference: 0xC4 //ITS reference > > PCI hostbridge mapping entry 2: > Input base: 0x1100 > ID Count: 0x100 > Output base: 0x2000 > Output reference: 0xD4 //ITS reference > > Two mapping entries which the second entry's Input base = the first > entry's Input base + ID count, so for requester ID 0x1100 will map > to ITS 0xC4 not 0xD4 if we update '>=' to '>'. > > So introduce a workaround to match the IORT's OEM information for > the broken firmware, also update the logic of the ID mapping for > firmwares report the number of IDs as the IORT spec defined, to > make the code compatible for both kinds of system. > > I checked the ACPI tables in the tianocore/edk2-platforms [2], Hi Hanjun, only > HiSilicon HIP07/08 did wrong, so just add HIP07/08 to the workaround > info table, Are you asserting that other platforms are ok on the basis that NumIds = large power of 2 - 1, e.g. 0xffff? Is this strictly proper? if we break other platforms, we can add that later. > I think that it would be better to audit others now as well as best as reasonably possible. There is somewhat limited coverage in [2]. Thanks, John > [0]: http://infocenter.arm.com/help/topic/com.arm.doc.den0049d/DEN0049D_IO_Remapping_Table.pdf > [1]: https://patchwork.kernel.org/patch/11292823/ > [2]: https://github.com/tianocore/edk2-platforms > > Cc: Pankaj Bansal > Cc: Lorenzo Pieralisi > Signed-off-by: Hanjun Guo > --- > > RFC->v1: > - Print warning when matched the workaround info, suggested by Pankaj. > > drivers/acpi/arm64/iort.c | 55 ++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 52 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > index 33f7198..60eb10d 100644 > --- a/drivers/acpi/arm64/iort.c > +++ b/drivers/acpi/arm64/iort.c > @@ -298,6 +298,42 @@ static acpi_status iort_match_node_callback(struct acpi_iort_node *node, > return status; > } > > +struct iort_workaround_oem_info { > + char oem_id[ACPI_OEM_ID_SIZE + 1]; > + char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1]; > + u32 oem_revision; > +}; > + > +static bool apply_id_count_workaround; > + > +static struct iort_workaround_oem_info wa_info[] __initdata = { > + { > + .oem_id = "HISI ", > + .oem_table_id = "HIP07 ", > + .oem_revision = 0, > + }, { > + .oem_id = "HISI ", > + .oem_table_id = "HIP08 ", > + .oem_revision = 0, > + } > +}; > + > +static void __init > +iort_check_id_count_workaround(struct acpi_table_header *tbl) > +{ > + int i; > + > + for (i = 0; i < ARRAY_SIZE(wa_info); i++) { > + if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) && > + !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) && > + wa_info[i].oem_revision == tbl->oem_revision) { > + apply_id_count_workaround = true; > + pr_warn(FW_BUG "ID count for ID mapping entry is wrong, applying workaround\n"); > + break; > + } > + } > +} > + > static int iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in, > u32 *rid_out) > { > @@ -314,9 +350,21 @@ static int iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in, > return -ENXIO; > } > > - if (rid_in < map->input_base || > - (rid_in >= map->input_base + map->id_count)) > - return -ENXIO; > + /* > + * IORT spec says Number of IDs = The number of IDs in the range minus > + * one, but the IORT code ingored the "minus one", and some firmware > + * did that too, so apply a workaround here to keep compatible with > + * both new and old versions of the firmware. > + */ > + if (apply_id_count_workaround) { > + if (rid_in < map->input_base || > + (rid_in >= map->input_base + map->id_count)) > + return -ENXIO; > + } else { > + if (rid_in < map->input_base || > + (rid_in > map->input_base + map->id_count)) > + return -ENXIO; > + } > > *rid_out = map->output_base + (rid_in - map->input_base); > return 0; > @@ -1631,5 +1679,6 @@ void __init acpi_iort_init(void) > return; > } > > + iort_check_id_count_workaround(iort_table); > iort_init_platform_devices(); > } >