Re: [PATCH v8 2/2] iommu/amd: Add basic debugfs infrastructure for AMD IOMMU

[Gary R Hook]

On 06/04/2018 08:23 PM, Randy Dunlap wrote:
> On 05/29/2018 11:39 AM, Greg KH wrote:
> > On Tue, May 29, 2018 at 01:23:23PM -0500, Gary R Hook wrote:
> > > Implement a skeleton framework for debugfs support in the
> > > AMD IOMMU. Add a hidden boolean to Kconfig that is defined
> > > for the AMD IOMMU when general IOMMY DebugFS support is
> > > enabled.
> > >
> > > Signed-off-by: Gary R Hook <gary.hook@xxxxxxx>
> > > ---
> > >   drivers/iommu/Kconfig             |    4 ++++
> > >   drivers/iommu/Makefile            |    1 +
> > >   drivers/iommu/amd_iommu_debugfs.c |   39 +++++++++++++++++++++++++++++++++++++
> > >   drivers/iommu/amd_iommu_init.c    |    6 ++++--
> > >   drivers/iommu/amd_iommu_proto.h   |    6 ++++++
> > >   drivers/iommu/amd_iommu_types.h   |    5 +++++
> > >   6 files changed, 59 insertions(+), 2 deletions(-)
> > >   create mode 100644 drivers/iommu/amd_iommu_debugfs.c
> > >
> > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > > index f9af25ac409f..ec223f6f4ad4 100644
> > > --- a/drivers/iommu/Kconfig
> > > +++ b/drivers/iommu/Kconfig
> > > @@ -137,6 +137,10 @@ config AMD_IOMMU
> > >   	  your BIOS for an option to enable it or if you have an IVRS ACPI
> > >   	  table.
> > >   
> > > +config AMD_IOMMU_DEBUGFS
> > > +	def_bool y
> >
> > Why default y?  Can you not boot a box without this?  If not, it should
> > not be Y.
> >
> > > +	depends on AMD_IOMMU && IOMMU_DEBUGFS
> > > +
> > >   config AMD_IOMMU_V2
> > >   	tristate "AMD IOMMU Version 2 driver"
> > >   	depends on AMD_IOMMU
>
> Gary,
>
> By far, most driver-debugfs additions are optional and include a user Kconfig prompt
> so that user's can choose whether to enable it or not.
>
> I suggest that the way forward is to fix Greg's debugfs_() api comments
> and to add a prompt string to AMD_IOMMU_DEBUGFS.

Roger. I think we have that all worked out. Will send another version soon.

Thanks.