Subject: Re: kvm PCI assignment & VFIO ramblings

From: "Roedel, Joerg" <[email-masked]>
Date: Thu, 25 Aug 2011 18:46:01 +0200

On Thu, Aug 25, 2011 at 11:38:09AM -0400, Don Dutile wrote:

> On 08/25/2011 06:54 AM, Roedel, Joerg wrote:
> > We need to solve this differently. ARM is starting to use the iommu-api
> > too and this definitly does not work there. One possible solution might
> > be to make the iommu-ops per-bus.
> >
> When you think of a system where there isn't just one bus-type
> with iommu support, it makes more sense.
> Additionally, it also allows the long-term architecture to use different types
> of IOMMUs on each bus segment -- think per-PCIe-switch/bridge IOMMUs --
> esp. 'tuned' IOMMUs -- ones better geared for networks, ones better geared
> for direct-attach disk hba's.

Not sure how likely it is to have different types of IOMMUs within a
given bus-type. But if they become reality we can multiplex in the
iommu-api without much hassle :)
For now, something like bus_set_iommu() or bus_register_iommu() would
provide a nice way to do bus-specific setups for a given iommu
implementation.

Joerg

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