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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7BBA3C2B9F4 for ; Mon, 14 Jun 2021 14:57:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 646D66124B for ; Mon, 14 Jun 2021 14:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233184AbhFNO7h (ORCPT ); Mon, 14 Jun 2021 10:59:37 -0400 Received: from foss.arm.com ([217.140.110.172]:37998 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233087AbhFNO7g (ORCPT ); Mon, 14 Jun 2021 10:59:36 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 05DB01FB; Mon, 14 Jun 2021 07:57:33 -0700 (PDT) Received: from 010265703453.arm.com (unknown [10.57.9.136]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E17EF3F70D; Mon, 14 Jun 2021 07:57:31 -0700 (PDT) From: Robin Murphy To: joro@8bytes.org Cc: will@kernel.org, john.garry@huawei.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, baolu.lu@linux.intel.com Subject: [PATCH] iommu: Update "iommu.strict" documentation Date: Mon, 14 Jun 2021 15:57:26 +0100 Message-Id: <2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- 2.25.1