Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755719Ab2K0XA5 (ORCPT ); Tue, 27 Nov 2012 18:00:57 -0500 Received: from mail-oa0-f46.google.com ([209.85.219.46]:55148 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754159Ab2K0XAz convert rfc822-to-8bit (ORCPT ); Tue, 27 Nov 2012 18:00:55 -0500 MIME-Version: 1.0 In-Reply-To: <50B4A483.8030305@nvidia.com> References: <1353935954-13763-1-git-send-email-tbergstrom@nvidia.com> <1353935954-13763-9-git-send-email-tbergstrom@nvidia.com> <50B46336.8030605@nvidia.com> <50B476E1.4070403@nvidia.com> <50B47DA8.60609@nvidia.com> <1354011776.1479.31.camel@tellur> <20121127103739.GA3329@avionic-0098.adnet.avionic-design.de> <50B4A483.8030305@nvidia.com> Date: Wed, 28 Nov 2012 09:00:54 +1000 Message-ID: Subject: Re: [RFC v2 8/8] drm: tegra: Add gr2d device From: Dave Airlie To: =?ISO-8859-1?Q?Terje_Bergstr=F6m?= Cc: Thierry Reding , Lucas Stach , "linux-tegra@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , Arto Merilainen Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1158 Lines: 26 On Tue, Nov 27, 2012 at 9:31 PM, Terje Bergstr?m wrote: > On 27.11.2012 12:37, Thierry Reding wrote: >> But in that case it should be made mandatory at first until proper IOMMU >> support is enabled on Tegra30. Then it can be checked at driver probe >> time whether or not to enable the extra checks. That way we don't need a >> special Kconfig option and we still get all the security that we need, >> right? > > I guess it depends on the level of security. > > If we want to only protect kernel and user space memory, this would be > sufficient and no firewall is needed if IOMMU is turned on. > > If we want to protect 2D buffers from each other, this is not sufficient. We generally aim for the first, to stop the gpu from reading/writing any memory it hasn't been granted access to, the second is nice to have though, but really requires a GPU with VM to implement properly. Dave. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/