RE: [PATCH 1/2] fpga: mgr: Adds secure BitStream loading support

[Nava kishore Manne <navam@xilinx.com>]

Hi Moritz,

	Thanks for providing the review comments.
Please find my response inline.

> -----Original Message-----
> From: Moritz Fischer <mdf@kernel.org>
> Sent: Thursday, March 4, 2021 4:42 AM
> To: Moritz Fischer <mdf@kernel.org>
> Cc: Nava kishore Manne <navam@xilinx.com>; trix@redhat.com;
> robh+dt@kernel.org; Michal Simek <michals@xilinx.com>; linux-
> fpga@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git
> <git@xilinx.com>; chinnikishore369@gmail.com
> Subject: Re: [PATCH 1/2] fpga: mgr: Adds secure BitStream loading support
> 
> Hi Nava,
> 
> On Thu, Jan 21, 2021 at 09:17:10PM -0800, Moritz Fischer wrote:
> > On Mon, Jan 18, 2021 at 08:20:57AM +0530, Nava kishore Manne wrote:
> > > This commit adds secure flags to the framework to support secure
> > > BitStream Loading.
> > >
> > > Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
> > > ---
> > >  drivers/fpga/of-fpga-region.c | 10 ++++++++++
> > > include/linux/fpga/fpga-mgr.h | 12 ++++++++++++
> > >  2 files changed, 22 insertions(+)
> > >
> > > diff --git a/drivers/fpga/of-fpga-region.c
> > > b/drivers/fpga/of-fpga-region.c index e405309baadc..3a5eb4808888
> > > 100644
> > > --- a/drivers/fpga/of-fpga-region.c
> > > +++ b/drivers/fpga/of-fpga-region.c
> > > @@ -228,6 +228,16 @@ static struct fpga_image_info
> *of_fpga_region_parse_ov(
> > >  	if (of_property_read_bool(overlay, "encrypted-fpga-config"))
> > >  		info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
> > >
> > > +	if (of_property_read_bool(overlay, "userkey-encrypted-fpga-
> config"))
> > > +		info->flags |=
> FPGA_MGR_USERKEY_ENCRYPTED_BITSTREAM;
> >
> > Can this just be encrypted-fpga-config/FPGA_MGR_ENCRYPTED?
> > > +
> > > +	if (of_property_read_bool(overlay, "ddrmem-authenticated-fpga-
> config"))
> > > +		info->flags |= FPGA_MGR_DDR_MEM_AUTH_BITSTREAM;
> > > +
> > > +	if (of_property_read_bool(overlay,
> > > +				  "securemem-authenticated-fpga-config"))
> > > +		info->flags |= FPGA_MGR_SECURE_MEM_AUTH_BITSTREAM;
> Shouldn't all these get binding docs? I remember Richard adding
> authentication support for an Intel platform, too and I'd like to avoid adding
> random bindings per vendor.
> 
> Would it be possible to have an 'authentication method / type' that is more
> extensible with different methods maybe?
> 
Yes, I agree this flags should not be a vendor specific we should make it as generic.
can we have flags something like below .
1) authenticated-fpga-config --> By default it uses kernel memory(DDR) to authenticate the image(FPGA_MGR_MEM_AUTH_BITSTREAM)
2) authenticated-onchip-fpga-config --> It uses the On chip memory to authenticate the image ( FPGA_MGR_AUTH_ON_CHIP_BITSTREAM)

if you have any other thoughts let me know will try to adopt the same...


Regards,
Navakishore.