Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757562Ab0HCSnv (ORCPT ); Tue, 3 Aug 2010 14:43:51 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:21761 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757174Ab0HCSns (ORCPT ); Tue, 3 Aug 2010 14:43:48 -0400 X-IronPort-AV: E=McAfee;i="5400,1158,6063"; a="49611771" Message-ID: <4C586348.2050209@codeaurora.org> Date: Tue, 03 Aug 2010 11:43:20 -0700 From: Stepan Moskovchenko User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.7) Gecko/20100713 Thunderbird/3.1.1 MIME-Version: 1.0 To: "Roedel, Joerg" CC: Zach Pfeffer , FUJITA Tomonori , "arnd@arndb.de" , "linux-arm-kernel@lists.infradead.org" , "linux-arm-msm@vger.kernel.org" , "dwalker@codeaurora.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2] arm: msm: Add System MMU support. References: <20100729123512Y.fujita.tomonori@lab.ntt.co.jp> <201007291026.55928.arnd@arndb.de> <20100729084018.GM26098@amd.com> <20100729174621W.fujita.tomonori@lab.ntt.co.jp> <20100729090607.GN26098@amd.com> <20100802075802.GN24084@amd.com> <20100802202935.GA26214@codeaurora.org> <20100803092325.GD18307@amd.com> In-Reply-To: <20100803092325.GD18307@amd.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2309 Lines: 49 On 8/3/2010 2:23 AM, Roedel, Joerg wrote: > On Mon, Aug 02, 2010 at 04:29:38PM -0400, Zach Pfeffer wrote: >> On Mon, Aug 02, 2010 at 09:58:02AM +0200, Roedel, Joerg wrote: >>> In the means of the IOMMU-API the domain is the abstraction of an >>> address space (in other words a page table). The IOMMU(s) which this domain >>> is later assigned to are determined by the iommu_attach_device calls. >>> I think the right way to go here is to create the concept of a >>> device-context in the IOMMU-API and add functions like >>> >>> iommu_attach_context(struct iommu_domain *domain, >>> struct iommu_context *ctxt); >>> iommu_detach_context(struct iommu_context *ctxt); >>> >>> This would work if you can determine in your iommu-driver which iommu >>> you need to program for which device. What do you think? >>> >> Joerg, I'd like to make sure I understand this. A domain is an address >> space separate from the actual page-tables that may be part of an >> iommu_context, correct? After I iommu_attach_context the ctxt will >> reflect the address space of the domain, correct? > A domain is defined by a single page-table which can be modified using > the iommu_map/iommu_unmap function calls. I am not completly sure what > you mean by an iommu_context. Can you describe what it means in your > context? > > Joerg > Joerg, I think with some rework, all my use cases can be handled by your existing iommu API. If the domain is treated basically a page table, there will be some changes, but I think it can be done. I will push a new version of my driver in a few days. One thing that may be helpful for the future, however, is maybe something like adding iommu_tlb_flush to the ops. I suppose this would either have to take a device, or the domain would need to keep a list of devices it had been attached to (so that their TLBs can be invalidated). But I suppose on the other hand, iommu_map/unmap may be able to just implicitly invalidate the TLB also, since TLB invalidation often follows map/unmap. What are your thoughts? Thanks Steve -- 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/