On 11.07.2013, at 14:37, Benjamin Herrenschmidt wrote:

On Thu, 2013-07-11 at 11:52 +0200, Alexander Graf wrote:

quoted

quoted

Where exactly (it is rather SPAPR_TCE_IOMMU but does not really

matter)?

quoted

Select it on KVM_BOOK3S_64? CONFIG_KVM_BOOK3S_64_HV?
CONFIG_KVM_BOOK3S_64_PR? PPC_BOOK3S_64?

=20
I'd say the most logical choice would be to check the Makefile and =

see

quoted

when it gets compiled. For those cases we want it enabled.

=20
What *what* gets compiled ? You know our Makefile, it's crap :-)
=20
We enable built-in things when CONFIG_KVM=3Dm (which means you cannot =

take

a kernel build with CONFIG_KVM not set, enable CONFIG_KVM=3Dm, and =

just

build the module, it won't work).
=20
We could use KVM_BOOK3S_64 maybe ?

If either a =3Dm or a =3Dy option selects a =3Dy option, it gets =
selected regardless, no? So it shouldn't really matter where we attach =
it FWIW.

=20

quoted

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I am trying to imagine a configuration where we really do not want
IOMMU_API. Ben mentioned PPC32 and embedded PPC64 and that's it so

any of

quoted

BOOK3S (KVM_BOOK3S_64 is the best) should be fine, no?

=20
book3s_32 doesn't want this, but any book3s_64 implementation could
potentially use it, yes. That's pretty much what the Makefile tells
you too :).

=20
Not really no. But that would do. You could have give a more useful
answer in the first place though rather than stringing him along.

Sorry, I figured it was obvious.


Alex