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From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: Ohad Ben-Cohen <ohad@wizery.com>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	David Woodhouse <dwmw2@infradead.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	David Brown <davidb@codeaurora.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Stepan Moskovchenko <stepanm@codeaurora.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Hiroshi Doyu <hdoyu@nvidia.com>
Subject: Re: [PATCH v3 1/6] iommu/core: split mapping to page sizes as supported by the hardware
Date: Tue, 11 Oct 2011 12:19:36 +0200	[thread overview]
Message-ID: <20111011101936.GD2138@amd.com> (raw)
In-Reply-To: <CAK=WgbYR_qx53Z7s3R=q29KYo8ebYCH9H9=2OrrWXWMv6=-iOQ@mail.gmail.com>

Hi Ohad,

On Mon, Oct 10, 2011 at 01:02:46PM -0400, Ohad Ben-Cohen wrote:
> On Mon, Oct 10, 2011 at 5:36 PM, Roedel, Joerg <Joerg.Roedel@amd.com> wrote:
> > Yes, somthing like that. Probably the iommu_ops->unmap function should
> > be turned into a unmap_page function call which only takes an iova and
> > no size parameter. The iommu-driver unmaps the page pointing to that
> > iova and returns the size of the page unmapped. This still allows the
> > simple implementation for the unmap-call.
> 
> Yes, exactly. It will take some time to migrate all drivers (today we
> have 4 drivers, each of which is implementing a slightly different
> ->unmap() semantics), but at least let's not accept any new driver
> that doesn't adhere to this, otherwise it's going to be even harder
> for the API to evolve.

Agreed. We should change the existing drivers one-by-one.

> > We don't need to really enforce the calls to be symetric. But we can
> > define that we only give the guarantee about what will be unmapped
> > when the calls are symetric.
> 
> Sounds good to me. I'll add this to the kernel doc patch (which I'll
> submit after this patch set materializes), and when/if we move to
> symmetric only, we will update it.

Great. So if no one disagrees with this direction (this means all the
other people on Cc :) ) it is the way to.

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632


  parent reply	other threads:[~2011-10-11 10:20 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-16 17:51 [PATCH v3 0/6] iommu: split mapping to page sizes as supported by the hardware Ohad Ben-Cohen
2011-09-16 17:51 ` [PATCH v3 1/6] iommu/core: " Ohad Ben-Cohen
2011-09-27 10:05   ` Roedel, Joerg
2011-09-27 12:26     ` Ohad Ben-Cohen
2011-09-27 13:12       ` Roedel, Joerg
2011-09-27 13:28         ` Ohad Ben-Cohen
2011-09-27 18:14           ` Roedel, Joerg
2011-10-02 15:58             ` Ohad Ben-Cohen
2011-10-10  7:40               ` Ohad Ben-Cohen
2011-10-10  9:47               ` Roedel, Joerg
2011-10-10 13:59                 ` Ohad Ben-Cohen
2011-10-10 15:36                   ` Roedel, Joerg
2011-10-10 17:02                     ` Ohad Ben-Cohen
2011-10-10 22:01                       ` Ohad Ben-Cohen
2011-10-11 10:21                         ` Roedel, Joerg
2011-10-11 10:19                       ` Roedel, Joerg [this message]
2011-10-10 22:49                     ` Ohad Ben-Cohen
2011-10-11 10:38                       ` Roedel, Joerg
2011-10-11 17:01                         ` Ohad Ben-Cohen
2011-10-14 13:35                           ` Roedel, Joerg
2011-10-14 17:03                             ` Ohad Ben-Cohen
2011-10-14 17:05                               ` Ohad Ben-Cohen
2011-10-17  8:05                               ` Ohad Ben-Cohen
2011-10-17  9:28                                 ` Roedel, Joerg
2011-10-17  9:55                                   ` Ohad Ben-Cohen
2011-10-11 14:59                       ` KyongHo Cho
2011-10-11 17:04                         ` Ohad Ben-Cohen
2011-10-10 12:52               ` KyongHo Cho
2011-10-10 14:00                 ` Ohad Ben-Cohen
2011-09-16 17:51 ` [PATCH v3 2/6] iommu/omap: announce supported page sizes Ohad Ben-Cohen
2011-09-16 17:51 ` [PATCH v3 3/6] iommu/msm: " Ohad Ben-Cohen
2011-09-25  5:03   ` David Brown
2011-09-16 17:51 ` [PATCH v3 4/6] iommu/amd: " Ohad Ben-Cohen
2011-09-16 17:51 ` [PATCH v3 5/6] iommu/intel: " Ohad Ben-Cohen
2011-09-16 17:51 ` [PATCH v3 6/6] iommu/core: remove the temporary register_iommu_pgsize API Ohad Ben-Cohen
2011-09-27  8:56 ` [PATCH v3 0/6] iommu: split mapping to page sizes as supported by the hardware Ohad Ben-Cohen

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