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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 85070C433E0 for ; Fri, 15 Jan 2021 10:13:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35D19235F9 for ; Fri, 15 Jan 2021 10:13:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731744AbhAOKMy (ORCPT ); Fri, 15 Jan 2021 05:12:54 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2354 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728260AbhAOKMv (ORCPT ); Fri, 15 Jan 2021 05:12:51 -0500 Received: from fraeml740-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DHH1m2w1Dz67bP3; Fri, 15 Jan 2021 18:08:12 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml740-chm.china.huawei.com (10.206.15.221) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Fri, 15 Jan 2021 11:12:10 +0100 Received: from [10.47.4.21] (10.47.4.21) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2106.2; Fri, 15 Jan 2021 10:12:08 +0000 Subject: Re: [PATCH] lib/logic_pio: Fix overlap check for pio registery To: Jiahui Cen , CC: Wei Xu , Arnd Bergmann , "Bjorn Helgaas" , Andy Shevchenko , , "linuxarm@openeuler.org" References: <20201218062335.5320-1-cenjiahui@huawei.com> <2cde14cd-91da-aae4-70aa-656d629259e6@huawei.com> <006ad6ce-d6b2-59cb-8209-aca3f6e53fec@huawei.com> <5df9663b-7c6a-6652-2561-9d3889ff94bc@huawei.com> From: John Garry Message-ID: <643b5c84-3e94-4029-721b-34b79c1b3589@huawei.com> Date: Fri, 15 Jan 2021 10:10:58 +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: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.47.4.21] X-ClientProxiedBy: lhreml708-chm.china.huawei.com (10.201.108.57) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/12/2020 13:04, Jiahui Cen wrote: >> On 21/12/2020 03:24, Jiahui Cen wrote: >>> Hi John, >>> >>> On 2020/12/18 18:40, John Garry wrote: >>>> On 18/12/2020 06:23, Jiahui Cen wrote: >>>>> Since the [start, end) is a half-open interval, a range with the end equal >>>>> to the start of another range should not be considered as overlapped. >>>>> >>>>> Signed-off-by: Jiahui Cen >>>>> --- >>>>>    lib/logic_pio.c | 2 +- >>>>>    1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/lib/logic_pio.c b/lib/logic_pio.c >>>>> index f32fe481b492..445d611f1dc1 100644 >>>>> --- a/lib/logic_pio.c >>>>> +++ b/lib/logic_pio.c >>>>> @@ -57,7 +57,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range) >>>>>                new_range->flags == LOGIC_PIO_CPU_MMIO) { >>>>>                /* for MMIO ranges we need to check for overlap */ >>>>>                if (start >= range->hw_start + range->size || >>>>> -                end < range->hw_start) { >>>>> +                end <= range->hw_start) { >>>> It looks like your change is correct, but should not really have an impact in practice since: >>>> a: BIOSes generally list ascending IO port CPU addresses >>>> b. there is space between IO port CPU address regions >>>> >>>> Have you seen a problem here? >>>> >>> No serious problem. I found it just when I was working on adding support of >>> pci expander bridge for Arm in QEMU. I found the IO window of some extended >>> root bus could not be registered when I inserted the extended buses' _CRS >>> info into DSDT table in the x86 way, which does not sort the buses. >>> >>> Though root buses should be sorted in QEMU, would it be better to accept >>> those non-ascending IO windows? >>> >> ok, so it seems that you have seen a real problem, and this issue is not just detected by code analysis. >> >>> BTW, for b, it seems to be no space between IO windows of different root buses >>> generated by EDK2. Or maybe I missed something obvious. >> I don't know about that. Anyway, your change looks ok. >> >> Reviewed-by: John Garry >> >> BTW, for your virt env, will there be requirement to unregister PCI MMIO ranges? Currently we don't see that in non-virt world. >> > Thanks for your review. > > And currently there is no such a requirement in my virt env. > I am not sure what happened to this patch, but I plan on sending some patches in this area soon - do you want me to include this one? Thanks, John