From: Joerg Roedel <joro@8bytes.org>
To: Zach Pfeffer <zpfeffer@codeaurora.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: Sat, 10 Jul 2010 16:54:00 +0200 [thread overview]
Message-ID: <20100710145400.GB10080@8bytes.org> (raw)
In-Reply-To: <4C2D0FF1.6010206@codeaurora.org>
On Thu, Jul 01, 2010 at 03:00:17PM -0700, Zach Pfeffer wrote:
> Additionally, the current IOMMU interface does not allow users to
> associate one page table with multiple IOMMUs [...]
Thats not true. Multiple IOMMUs are completly handled by the IOMMU
drivers. In the case of the IOMMU-API backend drivers this also includes
the ability to use page-tables on multiple IOMMUs.
> Since the particular topology is run-time configurable all of these
> use-cases and more can be expressed without pushing the topology into
> the low-level IOMMU driver.
The IOMMU driver has to know about the topology anyway because it needs
to know which IOMMU it needs to program for a particular device.
> Already, there are ~20 different IOMMU map implementations in the
> kernel. Had the Linux kernel had the VCMM, many of those
> implementations could have leveraged the mapping and topology
> management of a VCMM, while focusing on a few key hardware specific
> functions (map this physical address, program the page table base
> register).
I partially agree here. All the IOMMU implementations in the Linux
kernel have a lot of functionality in common where code could be
shared. Work to share code has been done in the past by Fujita Tomonori
but there are more places to work on. I am just not sure if a new
front-end API is the right way to do this.
Joerg
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next prev parent reply other threads:[~2010-07-10 14:54 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
2010-07-03 6:36 ` Zach Pfeffer
2010-07-10 14:54 ` Joerg Roedel [this message]
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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