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=-13.8 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 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 D36BBC433E0 for ; Thu, 18 Mar 2021 15:34:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A23164EF2 for ; Thu, 18 Mar 2021 15:34:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231761AbhCRPeO (ORCPT ); Thu, 18 Mar 2021 11:34:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbhCRPd7 (ORCPT ); Thu, 18 Mar 2021 11:33:59 -0400 Received: from theia.8bytes.org (8bytes.org [IPv6:2a01:238:4383:600:38bc:a715:4b6d:a889]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD943C06174A for ; Thu, 18 Mar 2021 08:33:59 -0700 (PDT) Received: by theia.8bytes.org (Postfix, from userid 1000) id 3EC7C2DA; Thu, 18 Mar 2021 16:33:56 +0100 (CET) Date: Thu, 18 Mar 2021 16:33:36 +0100 From: Joerg Roedel To: Suravee Suthikulpanit Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Jon.Grimm@amd.com, Wei.Huang2@amd.com Subject: Re: [RFC PATCH 6/7] iommu/amd: Introduce amd_iommu_pgtable command-line option Message-ID: References: <20210312090411.6030-1-suravee.suthikulpanit@amd.com> <20210312090411.6030-7-suravee.suthikulpanit@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210312090411.6030-7-suravee.suthikulpanit@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 12, 2021 at 03:04:10AM -0600, Suravee Suthikulpanit wrote: > To allow specification whether to use v1 or v2 IOMMU pagetable for > DMA remapping when calling kernel DMA-API. > > Signed-off-by: Suravee Suthikulpanit > --- > Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ > drivers/iommu/amd/init.c | 15 +++++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 04545725f187..466e807369ea 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -319,6 +319,12 @@ > This mode requires kvm-amd.avic=1. > (Default when IOMMU HW support is present.) > > + amd_iommu_pgtable= [HW,X86-64] > + Specifies one of the following AMD IOMMU page table to > + be used for DMA remapping for DMA-API: > + v1 - Use v1 page table (Default) > + v2 - Use v2 page table Any reason v2 can not be the default when it is supported by the IOMMU?