From: Joerg Roedel <joro@8bytes.org>
To: Don Dutile <ddutile@redhat.com>
Cc: Greg KH <gregkh@suse.de>, Ohad Ben-Cohen <ohad@wizery.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org,
David Brown <davidb@codeaurora.org>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH 02/10] Driver core: Add iommu_ops to bus_type
Date: Thu, 8 Sep 2011 10:58:42 +0200 [thread overview]
Message-ID: <20110908085842.GD31674@8bytes.org> (raw)
In-Reply-To: <4E67D5F7.6070103@redhat.com>
On Wed, Sep 07, 2011 at 04:37:11PM -0400, Don Dutile wrote:
> On 09/07/2011 03:44 PM, Greg KH wrote:
>> Why are you pushing this down into the driver core? What other busses
>> becides PCI use/need this?
>>
>> If you can have a different IOMMU driver on the same bus, then wouldn't
>> this be a per-device thing instead of a per-bus thing?
>>
> And given the dma api takes a struct device *, it'd be more efficient
> to be tied into the device structure.
More efficient in what way? Currently no dma-api implementation uses the
iommu-api directly. It is planned to change that, of course. But the
dma-api implementation will use the iommu_map/iommu_unmap functions which
get an iommu_domain parameter and no device structure. Thats why the
domain structure keeps an iommu_ops pointer too.
> Device structure would get iommu ops set by parent(bus);
> if a bus (segment) doesn't provide a unique/different/layered IOMMU
> then the parent bus, it inherits the parent's iommu-ops.
> setting the iommu-ops in the root bus struct, seeds the iommu-ops
> for the (PCI) tree.
>
> For intel & amd IOMMUs, in early pci (bios,root?) init, you would
> seed the pci root busses with appropriate IOMMU support (based on
> dmar/drhd & ivrs/ivhd data structures, respectively), and
> then modify the PCI code to do the inheritence (PPB code inherits
> unless specific device driver for a given PPB vid-did loads a
> different iommu-ops for that segment/branch).
>
> This would enable different types of IOMMUs for different devices
> (or PCI segments, or branches of PCI trees) that are designed for
> different tasks -- simple IOMMUs for legacy devices; complicated, io-page-faulting
> IOMMUs for plug-in, high-end devices on virtualizing servers for PCI (SRIOV) endpoints.
This only works for pci, but the iommu-api is not pci-only.
> and as Greg indicates, is only relevant to PCI.
We already have non-pci iommu drivers implementing the iommu-api. So
this is certainly relevant outside pci too.
Joerg
next prev parent reply other threads:[~2011-09-08 8:58 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-07 15:41 [PATCH 0/10] IOMMU: Make iommu_ops per-bus_type Joerg Roedel
2011-09-07 15:41 ` [PATCH 01/10] iommu/core: Define iommu_ops and register_iommu only with CONFIG_IOMMU_API Joerg Roedel
2011-09-07 15:41 ` [PATCH 02/10] Driver core: Add iommu_ops to bus_type Joerg Roedel
2011-09-07 18:47 ` Greg KH
2011-09-07 19:19 ` Joerg Roedel
2011-09-07 19:44 ` Greg KH
2011-09-07 20:37 ` Don Dutile
2011-09-08 8:58 ` Joerg Roedel [this message]
2011-09-08 8:41 ` Joerg Roedel
2011-09-12 11:40 ` Sethi Varun-B16395
2011-09-13 14:54 ` Roedel, Joerg
2011-09-13 14:58 ` Greg KH
2011-09-13 15:15 ` Roedel, Joerg
2011-09-13 15:38 ` Roedel, Joerg
2011-09-13 16:21 ` Greg KH
2011-09-14 12:46 ` Roedel, Joerg
2011-09-12 12:08 ` Sethi Varun-B16395
2011-09-12 12:35 ` Roedel, Joerg
2011-09-15 12:45 ` Sethi Varun-B16395
2011-09-15 13:13 ` Roedel, Joerg
2011-09-07 15:41 ` [PATCH 03/10] iommu/core: Add bus_type parameter to iommu_domain_alloc Joerg Roedel
2011-09-12 11:50 ` Sethi Varun-B16395
2011-09-12 12:37 ` Roedel, Joerg
2011-09-07 15:41 ` [PATCH 04/10] iommu/core: Convert iommu_found to iommu_present Joerg Roedel
2011-09-07 15:41 ` [PATCH 05/10] iommu/core: Use bus->iommu_ops in the iommu-api Joerg Roedel
2011-09-07 15:41 ` [PATCH 06/10] iommu/amd: Use bus_set_iommu instead of register_iommu Joerg Roedel
2011-09-07 15:41 ` [PATCH 07/10] iommu/vt-d: " Joerg Roedel
2011-09-07 15:41 ` [PATCH 08/10] iommu/omap: " Joerg Roedel
2011-09-07 15:41 ` [PATCH 09/10] iommu/msm: " Joerg Roedel
2011-09-07 15:41 ` [PATCH 10/10] iommu/core: Remove global iommu_ops and register_iommu Joerg Roedel
2011-09-07 18:48 ` [PATCH 0/10] IOMMU: Make iommu_ops per-bus_type Greg KH
2011-09-07 19:29 ` Joerg Roedel
-- strict thread matches above, loose matches on Subject: below --
2011-09-22 16:14 [PATCH 0/10 v2] " Joerg Roedel
2011-09-22 16:14 ` [PATCH 02/10] Driver core: Add iommu_ops to bus_type Joerg Roedel
2011-09-22 20:11 ` Greg KH
2011-09-23 15:19 ` Roedel, Joerg
2011-09-23 15:45 [PATCH 0/10 v3] IOMMU: Make iommu_ops per-bus_type Joerg Roedel
2011-09-23 15:45 ` [PATCH 02/10] Driver core: Add iommu_ops to bus_type Joerg Roedel
2011-09-29 20:05 ` Greg KH
2011-09-30 6:24 ` Joerg Roedel
2011-09-30 13:58 ` Greg KH
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