From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id F34487D922 for ; Mon, 19 Aug 2019 13:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727611AbfHSNXU (ORCPT ); Mon, 19 Aug 2019 09:23:20 -0400 Received: from 8bytes.org ([81.169.241.247]:50418 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727716AbfHSNXC (ORCPT ); Mon, 19 Aug 2019 09:23:02 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 745E2712; Mon, 19 Aug 2019 15:23:00 +0200 (CEST) From: Joerg Roedel To: Joerg Roedel Cc: corbet@lwn.net, tony.luck@intel.com, fenghua.yu@intel.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Thomas.Lendacky@amd.com, Suravee.Suthikulpanit@amd.com, Joerg Roedel Subject: [PATCH 10/11] iommu: Disable passthrough mode when SME is active Date: Mon, 19 Aug 2019 15:22:55 +0200 Message-Id: <20190819132256.14436-11-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190819132256.14436-1-joro@8bytes.org> References: <20190819132256.14436-1-joro@8bytes.org> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Joerg Roedel Using Passthrough mode when SME is active causes certain devices to use the SWIOTLB bounce buffer. The bounce buffer code has an upper limit of 256kb for the size of DMA allocations, which is too small for certain devices and causes them to fail. With this patch we enable IOMMU by default when SME is active in the system, making the default configuration work for more systems than it does now. Users that don't want IOMMUs to be enabled still can disable them with kernel parameters. Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 01759d4ac70b..ec18c9630e93 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -119,6 +119,11 @@ static int __init iommu_subsys_init(void) iommu_set_default_passthrough(false); else iommu_set_default_translated(false); + + if (iommu_default_passthrough() && sme_active()) { + pr_info("SME detected - Disabling default IOMMU Passthrough\n"); + iommu_set_default_translated(false); + } } pr_info("Default domain type: %s %s\n", -- 2.16.4