From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH 2/5] iommu/amd: Implement DOMAIN_ATTR_GEOMETRY attribute Date: Thu, 26 Jan 2012 12:25:32 -0600 Message-ID: <4F219A9C.8000400@freescale.com> References: <1326983405-319-1-git-send-email-joerg.roedel@amd.com> <1326983405-319-3-git-send-email-joerg.roedel@amd.com> <20120120160344.GG2205@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120120160344.GG2205@amd.com> Sender: linux-kernel-owner@vger.kernel.org To: Joerg Roedel Cc: Sethi Varun-B16395 , "iommu@lists.linux-foundation.org" , Ohad Ben-Cohen , Tony Lindgren , Hiroshi DOYU , "linux-kernel@vger.kernel.org" , Laurent Pinchart , Wood Scott-B07421 , David Brown , David Woodhouse List-Id: iommu@lists.linux-foundation.org On 01/20/2012 10:03 AM, Joerg Roedel wrote: > On Thu, Jan 19, 2012 at 05:16:48PM +0000, Sethi Varun-B16395 wrote: >>> struct iommu_domain { >>> struct iommu_ops *ops; >>> void *priv; >>> iommu_fault_handler_t handler; >>> + struct iommu_domain_geometry geometry; >>> }; >> In case of our iommu implementation the iommu_domain_geometry would >> include additional attributes. Why can't we let the geometry be >> Implementation dependent? > > Because the values in this generic geometry-struct make sense for more > than one IOMMU (short-term for Tegra GART and Freescale PAMU). If you > have additional vendor-specific ones you could add them via a > vendor-specific attribute. Freescale PAMU is the IOMMU that Varun is talking about, that needs additional geometry attributes (in particular, subwindow count). How should a PAMU driver interpret "force_aperture"? When would DMA ever be allowed outside the specified range? What does the range mean in that case? -Scott