Messages in this thread | | | Date | Thu, 7 Nov 2019 01:34:36 -0800 | From | Christoph Hellwig <> | Subject | Re: [PATCH 1/1] iommu/vt-d: Add Kconfig option to enable/disable scalable mode |
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On Wed, Nov 06, 2019 at 01:11:30PM +0800, Lu Baolu wrote: > This adds a Kconfig option INTEL_IOMMU_SCALABLE_MODE_ON to make > it easier for distributions to enable or disable the Intel IOMMU > scalable mode during kernel build.
> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > drivers/iommu/Kconfig | 10 ++++++++++ > drivers/iommu/intel-iommu.c | 5 +++++ > 2 files changed, 15 insertions(+) > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index e3842eabcfdd..32f30e27791c 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -242,6 +242,16 @@ config INTEL_IOMMU_FLOPPY_WA > workaround will setup a 1:1 mapping for the first > 16MiB to make floppy (an ISA device) work. > > +config INTEL_IOMMU_SCALABLE_MODE_ON
That should have a DEFAULT in the name as it is a default.
> + def_bool n
n is the default default, so this can just be bool.
> +#ifdef CONFIG_INTEL_IOMMU_SCALABLE_MODE_ON > +int intel_iommu_sm = 1; > +#else > int intel_iommu_sm; > +#endif /* CONFIG_INTEL_IOMMU_SCALABLE_MODE_ON */
This can use IS_ENABLED().
But then again the distro can just add iommu=sm_on to CONFIG_CMDLINE and have the same effect, so I don't really get the point of the whole patch.
Or why we can't just enable it by default for that matter.
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