From: Zach Pfeffer <zpfeffer@codeaurora.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Daniel Walker <dwalker@codeaurora.org>,
Randy Dunlap <randy.dunlap@oracle.com>,
mel@csn.ul.ie, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org, linux-omap@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 3/3] mm: iommu: The Virtual Contiguous Memory Manager
Date: Mon, 12 Jul 2010 22:52:43 -0700 [thread overview]
Message-ID: <4C3BFF2B.40006@codeaurora.org> (raw)
In-Reply-To: <20100710151111.GD10080@8bytes.org>
Joerg Roedel wrote:
> On Thu, Jul 01, 2010 at 11:17:34PM -0700, Zach Pfeffer wrote:
>> Andi Kleen wrote:
>
>>> Hmm? dma_map_* does not change any CPU mappings. It only sets up
>>> DMA mapping(s).
>> Sure, but I was saying that iommu_map() doesn't just set up the IOMMU
>> mappings, its sets up both the iommu and kernel buffer mappings.
>
> What do you mean by kernel buffer mappings?
In-kernel mappings whose addresses can be dereferenced.
>
>
>>> That assumes that all the IOMMUs on the system support the same page table
>>> format, right?
>> Actually no. Since the VCMM abstracts a page-table as a Virtual
>> Contiguous Region (VCM) a VCM can be associated with any device,
>> regardless of their individual page table format.
>
> The IOMMU-API abstracts a page-table as a domain which can also be
> associated with any device (behind an iommu).
It does, but only by convention. The domain member is just a big
catchall void *. It would be more useful to factor out a VCM
abstraction, with associated ops. As it stands all IOMMU device driver
writters have to re-invent IOMMU virtual address management.
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next prev parent reply other threads:[~2010-07-13 5:52 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-30 5:55 [RFC 1/3] mm: iommu: An API to unify IOMMU, CPU and device memory management Zach Pfeffer
2010-06-30 5:55 ` [RFC 2/3] mm: iommu: A physical allocator for the VCMM Zach Pfeffer
2010-06-30 5:55 ` [RFC 3/3] mm: iommu: The Virtual Contiguous Memory Manager Zach Pfeffer
2010-07-01 17:17 ` Randy Dunlap
2010-07-01 18:02 ` Andi Kleen
2010-07-01 19:28 ` Daniel Walker
2010-07-01 19:38 ` Andi Kleen
2010-07-01 19:42 ` Daniel Walker
2010-07-01 22:15 ` Hari Kanigeri
2010-07-02 7:09 ` Zach Pfeffer
2010-07-10 14:36 ` Joerg Roedel
2010-07-13 5:21 ` Zach Pfeffer
2010-07-14 19:34 ` Joerg Roedel
2010-07-15 1:18 ` Zach Pfeffer
2010-07-01 22:00 ` Zach Pfeffer
2010-07-01 22:05 ` Daniel Walker
2010-07-02 7:33 ` Zach Pfeffer
2010-07-10 14:56 ` Joerg Roedel
2010-07-13 5:46 ` Zach Pfeffer
2010-07-13 5:59 ` FUJITA Tomonori
2010-07-13 8:20 ` Alan Cox
2010-07-13 8:30 ` FUJITA Tomonori
2010-07-13 8:42 ` Alan Cox
2010-07-13 8:45 ` FUJITA Tomonori
2010-07-13 9:02 ` Russell King - ARM Linux
2010-07-14 1:59 ` FUJITA Tomonori
2010-07-22 3:50 ` Zach Pfeffer
2010-07-22 4:47 ` FUJITA Tomonori
2010-07-22 16:33 ` Zach Pfeffer
2010-07-22 7:51 ` Russell King - ARM Linux
2010-07-22 16:13 ` Zach Pfeffer
2010-07-13 12:06 ` Zach Pfeffer
2010-07-01 22:51 ` Hari Kanigeri
2010-07-02 7:29 ` Zach Pfeffer
2010-07-01 23:00 ` Andi Kleen
2010-07-02 6:17 ` Zach Pfeffer
2010-07-02 8:22 ` Andi Kleen
2010-07-02 18:42 ` Zach Pfeffer
2010-07-10 15:11 ` Joerg Roedel
2010-07-13 5:52 ` Zach Pfeffer [this message]
2010-07-03 6:36 ` Zach Pfeffer
2010-07-10 14:54 ` Joerg Roedel
2010-07-13 5:27 ` Zach Pfeffer
2010-07-01 20:59 ` Paul Walmsley
2010-07-01 21:48 ` Randy Dunlap
2010-06-30 23:40 ` [RFC 1/3] mm: iommu: An API to unify IOMMU, CPU and device memory management Randy Dunlap
2010-07-01 7:16 ` Zach Pfeffer
2010-07-02 7:00 ` Paul Mundt
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