Re: [Xen-devel] [PATCH 3/6] arm: make it possible to disable the SMMU driver

[Julien Grall <julien.grall@xxxxxxx>]

On 19/04/18 16:44, Julien Grall wrote:
> Hi,
>
> On 18/04/18 23:15, Stefano Stabellini wrote:
> > Introduce a Kconfig option for the ARM SMMUv2 driver.
> The driver is handling both SMMUv1 and SMMUv2.
I forgot to mention that by disabling the driver, you are going to 
end-up giving the SMMU to Dom0. I don't think we want that to happen.
So you need to find a way to blacklist all the SMMUs.

> > Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > CC: jbeulich@xxxxxxxx
> > ---
> >   xen/drivers/passthrough/Kconfig      | 2 ++
> >   xen/drivers/passthrough/arm/Kconfig  | 7 +++++++
> >   xen/drivers/passthrough/arm/Makefile | 2 +-
> >   3 files changed, 10 insertions(+), 1 deletion(-)
> >   create mode 100644 xen/drivers/passthrough/arm/Kconfig
> >
> > diff --git a/xen/drivers/passthrough/Kconfig 
> > b/xen/drivers/passthrough/Kconfig
> > index 8d90b67..2fe94fa 100644
> > --- a/xen/drivers/passthrough/Kconfig
> > +++ b/xen/drivers/passthrough/Kconfig
> > @@ -1,3 +1,5 @@
> >   config HAS_PASSTHROUGH
> >       bool
> > +
> > +source "drivers/passthrough/arm/Kconfig"
> Can't we load arm/Kconfig only when arm is selected? This would avoid 
> weird option on x86.
> > diff --git a/xen/drivers/passthrough/arm/Kconfig 
> > b/xen/drivers/passthrough/arm/Kconfig
> > new file mode 100644
> > index 0000000..98318d9
> > --- /dev/null
> > +++ b/xen/drivers/passthrough/arm/Kconfig
> > @@ -0,0 +1,7 @@
> > +
> > +config HAS_SMMUv2
> > +    bool "ARM SMMUv2 driver"
> > +    default y
> > +    depends on ARM
> > +    ---help---
> > +      Driver for the ARM SMMU version 2, a popular IOMMU by ARM.
> > diff --git a/xen/drivers/passthrough/arm/Makefile 
> > b/xen/drivers/passthrough/arm/Makefile
> > index f4cd26e..4db273a 100644
> > --- a/xen/drivers/passthrough/arm/Makefile
> > +++ b/xen/drivers/passthrough/arm/Makefile
> > @@ -1,2 +1,2 @@
> >   obj-y += iommu.o
> > -obj-y += smmu.o
> > +obj-$(HAS_SMMUv2) += smmu.o
> Cheers,
--
Julien Grall

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