Re: [RFC PATCH 3/3] x86-64: Calgary IOMMU - hook it in

From: Jon Mason
Date: Tue Mar 14 2006 - 18:16:55 EST


On Wed, Mar 15, 2006 at 12:03:48AM +0100, Pavel Machek wrote:
> On ?t 14-03-06 10:26:34, Muli Ben-Yehuda wrote:
> > This patch hooks Calgary into the build and the x86-64 IOMMU
> > initialization paths.
> >
> > Signed-Off-By: Muli Ben-Yehuda <mulix@xxxxxxxxx>
> > Signed-Off-By: Jon Mason <jdmason@xxxxxxxxxx>
> >
> > diff -Naurp --exclude-from /home/muli/w/dontdiff iommu_detected/arch/x86_64/Kconfig linux/arch/x86_64/Kconfig
> > --- iommu_detected/arch/x86_64/Kconfig 2006-03-14 08:58:23.000000000 +0200
> > +++ linux/arch/x86_64/Kconfig 2006-03-12 10:49:04.000000000 +0200
> > @@ -372,6 +372,16 @@ config GART_IOMMU
> > and a software emulation used on other systems.
> > If unsure, say Y.
> >
> > +config CALGARY_IOMMU
> > + bool "IBM x366 server IOMMU"
> > + default y
> > + depends on PCI && MPSC && EXPERIMENTAL
> > + help
> > + Support for hardware IOMMUs in IBM's x366 server
> > + systems. The IOMMU can be turned off at runtime with the
> > + iommu=off parameter. Normally the kernel will make the right
>
> Runtime? I think you meant boottime.

Yes, thanks for pointing it out.

>
> > + choice by itself. If unsure, say Y.
>
> Eh? How common are those machines?

While this code is specific to IBM's xSeries systems, it will not hurt
to have it enabled on other systems. The code is intelligent enough to
detect the existence of Calgary chips and, if not there, will go down
the standard path of no-iommu (providing that swiotlb has not been
specified at boottime). If this isn't clear enough in the description,
I can remedy that.

Thanks,
Jon

> Pavel
>
> --
> 32: bw.Write( sbuffer );
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