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 E9778C48BDF for ; Tue, 15 Jun 2021 07:06:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D40C5613BF for ; Tue, 15 Jun 2021 07:06:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230283AbhFOHJC (ORCPT ); Tue, 15 Jun 2021 03:09:02 -0400 Received: from mga11.intel.com ([192.55.52.93]:10848 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230238AbhFOHJA (ORCPT ); Tue, 15 Jun 2021 03:09:00 -0400 IronPort-SDR: myPEn0/Wn89407FVlKCLXGKDkslEetI5j4uzG1m6KBigaBSrHyaNk5PSGzHrRxrqsfkHOWgwiF VPCxFQvziO8g== X-IronPort-AV: E=McAfee;i="6200,9189,10015"; a="202912844" X-IronPort-AV: E=Sophos;i="5.83,275,1616482800"; d="scan'208";a="202912844" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2021 00:06:54 -0700 IronPort-SDR: mNrIp/+YQDnS3YmS1uGIMe/QxU0bRmTPEa/daQnYhi6UAm6CfU3GKyLCRi6wDdwP6+vNe1YmmA QnFLPH0A11CA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.83,275,1616482800"; d="scan'208";a="554354556" Received: from unknown (HELO [10.239.159.118]) ([10.239.159.118]) by fmsmga001.fm.intel.com with ESMTP; 15 Jun 2021 00:06:52 -0700 Cc: baolu.lu@linux.intel.com, will@kernel.org, john.garry@huawei.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu: Update "iommu.strict" documentation To: Robin Murphy , joro@8bytes.org References: <2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com> From: Lu Baolu Message-ID: Date: Tue, 15 Jun 2021 15:05:28 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/14/21 10:57 PM, Robin Murphy wrote: > Consolidating the flush queue logic also meant that the "iommu.strict" > option started taking effect on x86 as well. Make sure we document that. > > Fixes: a250c23f15c2 ("iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE") > Signed-off-by: Robin Murphy > --- > Documentation/admin-guide/kernel-parameters.txt | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index cb89dbdedc46..20a32de990ed 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1987,7 +1987,7 @@ > forcing Dual Address Cycle for PCI cards supporting > greater than 32-bit addressing. > > - iommu.strict= [ARM64] Configure TLB invalidation behaviour > + iommu.strict= [ARM64, X86] Configure TLB invalidation behaviour > Format: { "0" | "1" } > 0 - Lazy mode. > Request that DMA unmap operations use deferred > @@ -1998,6 +1998,10 @@ > 1 - Strict mode (default). > DMA unmap operations invalidate IOMMU hardware TLBs > synchronously. > + Note: on x86, the default behaviour depends on the > + equivalent driver-specific parameters, but a strict > + mode explicitly specified by either method takes > + precedence. > > iommu.passthrough= > [ARM64, X86] Configure DMA to bypass the IOMMU by default. > Reviewed-by: Lu Baolu Best regards, baolu