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,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 B4015C433E0 for ; Tue, 19 Jan 2021 19:45:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C81423138 for ; Tue, 19 Jan 2021 19:45:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729434AbhASTpE (ORCPT ); Tue, 19 Jan 2021 14:45:04 -0500 Received: from mga01.intel.com ([192.55.52.88]:50059 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730183AbhASTo6 (ORCPT ); Tue, 19 Jan 2021 14:44:58 -0500 IronPort-SDR: uMptGRmJsDifPK7HrEBn18xInBKa7Q4rng+0VDxbtHhkWw0L7u3U/tL7cqortXvrLn1FxjTQy+ FBx4p6MHLdOQ== X-IronPort-AV: E=McAfee;i="6000,8403,9869"; a="197700914" X-IronPort-AV: E=Sophos;i="5.79,359,1602572400"; d="scan'208";a="197700914" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2021 11:44:10 -0800 IronPort-SDR: tS99ZRoMcKD2HEn4uThzUqMw4f2RfoqhFCxR1WHmX3I6gjaflS1DNPyAlJue+tpwtM3nvLHSQ8 Th8up8lRIbFg== X-IronPort-AV: E=Sophos;i="5.79,359,1602572400"; d="scan'208";a="350648746" Received: from djiang5-mobl1.amr.corp.intel.com (HELO [10.213.191.188]) ([10.213.191.188]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2021 11:44:09 -0800 Subject: Re: [PATCH] dmaengine: idxd: add module parameter to force disable of SVA To: Vinod Koul Cc: dmaengine@vger.kernel.org References: <161074811013.2184257.13335125853932003159.stgit@djiang5-desk3.ch.intel.com> <20210117065115.GL2771@vkoul-mobl> <20210119163822.GC2771@vkoul-mobl> From: Dave Jiang Message-ID: <425267d2-dd13-5710-65b9-d98beff2b328@intel.com> Date: Tue, 19 Jan 2021 12:44:09 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210119163822.GC2771@vkoul-mobl> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 1/19/2021 9:38 AM, Vinod Koul wrote: > On 18-01-21, 10:06, Dave Jiang wrote: >> On 1/16/2021 11:51 PM, Vinod Koul wrote: >>> On 15-01-21, 15:01, Dave Jiang wrote: >>>> Add a module parameter that overrides the SVA feature enabling. This keeps >>>> the driver in legacy mode even when intel_iommu=sm_on is set. In this mode, >>>> the descriptor fields must be programmed with dma_addr_t from the Linux DMA >>>> API for source, destination, and completion descriptors. >>>> >>>> Signed-off-by: Dave Jiang >>>> --- >>>> drivers/dma/idxd/init.c | 8 +++++++- >>>> 1 file changed, 7 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c >>>> index 25cc947c6179..9687a24ff982 100644 >>>> --- a/drivers/dma/idxd/init.c >>>> +++ b/drivers/dma/idxd/init.c >>>> @@ -26,6 +26,10 @@ MODULE_VERSION(IDXD_DRIVER_VERSION); >>>> MODULE_LICENSE("GPL v2"); >>>> MODULE_AUTHOR("Intel Corporation"); >>>> +static bool sva = true; >>>> +module_param(sva, bool, 0644); >>>> +MODULE_PARM_DESC(sva, "Toggle SVA support on/off"); >>> Documentation for this please.. >> Just comments or is there somewhere specific for driver module parameter >> documentations? > All the parameters are supposed to be documented in Documentation/admin-guide/kernel-parameters.txt It seems to be for core kernel components and subsystems, and not specific device drivers. I'm not seeing any of the dmaengine driver module params being in this doc after grepping in drivers/dma. > > Thanks >