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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 61517C4320A for ; Thu, 5 Aug 2021 13:54:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4808D60F58 for ; Thu, 5 Aug 2021 13:54:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241235AbhHENyN (ORCPT ); Thu, 5 Aug 2021 09:54:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:42238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241778AbhHENyM (ORCPT ); Thu, 5 Aug 2021 09:54:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9C4CE61157; Thu, 5 Aug 2021 13:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628171638; bh=ZalQG662IXTcyh3MsfHL5bDf1isxgd8l9UI/IjdZ6B4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aiY7GdTjJKfhSf96A3bqXb/p1a43jtGaD4oiZT6yst961vXXAgj/EaQNGjjTIyoam EQc6U5whqoMp0u6D8u/ZFO50NTQDpoYKymUIowzlLCpZazcqIDp1FyRvRC44DOXeTc qILxLyZNc6XUetrGlUzcY+iaCr+v1x6ccHBKijgC1SBTuMHezRF8p2yIUwH+XwSZSH 1ZBT1dx1/7ixHmQNCwYibl/+ITrQK3t5g09CPT8LWbKyQ8Zk5dCLHSUjlSFZcwI8NR Yhtmn3ywcUl8YBWc92+LJB3Kz38azkkin/HrSOxmtiqLdvDpO4nHfhYHa84UCu7bQN kYeckWD4v9+ww== Date: Thu, 5 Aug 2021 16:53:54 +0300 From: Leon Romanovsky To: Dongdong Liu Cc: Logan Gunthorpe , helgaas@kernel.org, hch@infradead.org, kw@linux.com, linux-pci@vger.kernel.org, rajur@chelsio.com, hverkuil-cisco@xs4all.nl, linux-media@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH V7 7/9] PCI/sysfs: Add a 10-Bit Tag sysfs file Message-ID: References: <1628084828-119542-1-git-send-email-liudongdong3@huawei.com> <1628084828-119542-8-git-send-email-liudongdong3@huawei.com> <75243571-3213-6ae2-040f-ae1b1f799e42@deltatee.com> <8758a42b-233b-eb73-dce4-493e0ce8eed5@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8758a42b-233b-eb73-dce4-493e0ce8eed5@huawei.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Aug 05, 2021 at 09:14:50PM +0800, Dongdong Liu wrote: > On 2021/8/4 23:51, Logan Gunthorpe wrote: > > > > > > > > On 2021-08-04 7:47 a.m., Dongdong Liu wrote: > > > PCIe spec 5.0 r1.0 section 2.2.6.2 says that if an Endpoint supports > > > sending Requests to other Endpoints (as opposed to host memory), the > > > Endpoint must not send 10-Bit Tag Requests to another given Endpoint > > > unless an implementation-specific mechanism determines that the Endpoint > > > supports 10-Bit Tag Completer capability. Add a 10bit_tag sysfs file, > > > write 0 to disable 10-Bit Tag Requester when the driver does not bind > > > the device if the peer device does not support the 10-Bit Tag Completer. > > > This will make P2P traffic safe. the 10bit_tag file content indicate > > > current 10-Bit Tag Requester Enable status. > > > > Can we not have both the sysfs file and the command line parameter? If > > the user wants to disable it always for a specific device this sysfs > > parameter is fairly awkward. A script at boot to unbind the driver, set > > the sysfs file and rebind the driver is not trivial and the command line > > parameter offers additional options for users. > Does the command line parameter as "[PATCH V6 7/8] PCI: Add > "pci=disable_10bit_tag=" parameter for peer-to-peer support" does? > > Do we also need such command line if we already had sysfs file? > I think we may not need. I think the same. > > Thanks, > Dongdong > > > > Logan > > . > >