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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 D16D1C43381 for ; Wed, 20 Feb 2019 19:54:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DEC72086A for ; Wed, 20 Feb 2019 19:54:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725806AbfBTTye (ORCPT ); Wed, 20 Feb 2019 14:54:34 -0500 Received: from mail-ua1-f66.google.com ([209.85.222.66]:44865 "EHLO mail-ua1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbfBTTye (ORCPT ); Wed, 20 Feb 2019 14:54:34 -0500 Received: by mail-ua1-f66.google.com with SMTP id v9so8663172uar.11 for ; Wed, 20 Feb 2019 11:54:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TUzowNOEMvtJzG78eSaKZiRNXsPark9DdbpYihCbK10=; b=LdlW481+WzQNlQV0EK9iB8yfJZePj3RsryRy5bznI/0KcTO/i0f8fQlS2m0r9gsm+I pRJ+4JW42AJX3CwaNPzGsPqq3fAeGsPeFLYaB9lu/msxj1d0hkMZFrzXBQhyo48GAbDS BKZOwUn39H6hEIMUvtr75nx38TNVgoK6+YRtM3MlaPSIjLKzdm49pfw2CK6/Wgr5DHSc lGGiv+FxYiREO9/KETSRxM3yN0h76UvMHjqKYg4IHpW40Ibj3T/07WA0KDc8FFQpL7qV jEWi3/lKf03i/Nb5yN/ekbUwRit6C2i5UH82/OmK1v1CH6b3ef6jlXiBn6bXFzX6wked 14QQ== X-Gm-Message-State: AHQUAuZHMzGkSN8OAdaOfN91tyQsRgspohv1WJh05Ab65mOPCw5zHwXF WuvS5SX0u7wzhTC4Ttl5yqqISWPLsO5blVE5DLA= X-Google-Smtp-Source: AHgI3IavH6VKZT6jCqqFWVS4oJv2RE2HPYAY990+zjp8ciRSW3ILa4+aXXx3eFjN2Y9q5C3HH/wEmAGyVCD7yLKJI54= X-Received: by 2002:a9f:30dc:: with SMTP id k28mr11826773uab.75.1550692473183; Wed, 20 Feb 2019 11:54:33 -0800 (PST) MIME-Version: 1.0 References: <155067454871.15971.12157033067057246708.sendpatchset@octo> <155067457726.15971.1787990365004385103.sendpatchset@octo> In-Reply-To: <155067457726.15971.1787990365004385103.sendpatchset@octo> From: Geert Uytterhoeven Date: Wed, 20 Feb 2019 20:54:21 +0100 Message-ID: Subject: Re: [PATCH/RFC 03/09] iommu/ipmmu-vmsa: Introduce keepipmmu boot parameter To: Magnus Damm Cc: Linux-Renesas Content-Type: text/plain; charset="UTF-8" Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Magnus, On Wed, Feb 20, 2019 at 3:55 PM Magnus Damm wrote: > From: Magnus Damm > > Introduce a keepipmmu boot paramenter to let the user override. > > Not-Yet-Signed-off-by: Magnus Damm > --- > > drivers/iommu/ipmmu-vmsa.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > --- 0004/drivers/iommu/ipmmu-vmsa.c > +++ work/drivers/iommu/ipmmu-vmsa.c 2019-02-20 23:17:54.038850305 +0900 > @@ -759,6 +759,17 @@ static int ipmmu_init_platform_device(st > return 0; > } > > + > +static int keep_ipmmu; > + > +static int __init keepipmmu_setup(char *__unused) > +{ > + keep_ipmmu = 1; > + return 1; > +} > + > +__setup("keepipmmu", keepipmmu_setup); Documentation/admin-guide/kernel-parameters.txt shows other IOMMUs implement binary parameters, which allow to override the default, to disable or enable the IOMMU. Perhaps you want the default to be enabled when running in HYP mode, so the IPMMU can be used for KVM+VFIO device pass-through? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds