Re: [PATCH v14 1/4] fpga: m10bmc-sec: create max10 bmc secure update driver

From: Xu Yilun
Date: Mon Sep 13 2021 - 21:21:40 EST


On Mon, Sep 13, 2021 at 05:12:32AM -0700, Tom Rix wrote:
>
> On 9/12/21 10:37 PM, Xu Yilun wrote:
> > On Sat, Sep 11, 2021 at 12:04:07PM -0700, Tom Rix wrote:
> > > On 9/10/21 1:27 PM, Russ Weight wrote:
> > > > On 9/10/21 8:13 AM, Xu Yilun wrote:
> > > > > On Thu, Sep 09, 2021 at 04:33:01PM -0700, Russ Weight wrote:
> > > > > > Create a sub driver for the FPGA Card BMC in order to support secure
> > > > > > updates. This sub-driver will invoke an instance of the FPGA Image Load
> > > > > > class driver for the image load portion of the update.
> > > > > >
> > > > > > This patch creates the MAX10 BMC Secure Update driver and provides sysfs
> > > > > > files for displaying the current root entry hashes for the FPGA static
> > > > > > region, the FPGA PR region, and the MAX10 BMC.
> > > > > >
> > > > > > Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > > > > Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
> > > > > > ---
> > > > > > v14:
> > > > > > - Changed symbol and text references to reflect the renaming of the
> > > > > > Security Manager Class driver to FPGA Image Load.
> > > > > > v13:
> > > > > > - Updated copyright to 2021
> > > > > > - Updated ABI documentation date and kernel version
> > > > > > - Call updated fpga_sec_mgr_register() and fpga_sec_mgr_unregister()
> > > > > > functions instead of devm_fpga_sec_mgr_create() and
> > > > > > devm_fpga_sec_mgr_register().
> > > > > > v12:
> > > > > > - Updated Date and KernelVersion fields in ABI documentation
> > > > > > v11:
> > > > > > - Added Reviewed-by tag
> > > > > > v10:
> > > > > > - Changed the path expressions in the sysfs documentation to
> > > > > > replace the n3000 reference with something more generic to
> > > > > > accomodate other devices that use the same driver.
> > > > > > v9:
> > > > > > - Rebased to 5.12-rc2 next
> > > > > > - Updated Date and KernelVersion in ABI documentation
> > > > > > v8:
> > > > > > - Previously patch 2/6, otherwise no change
> > > > > > v7:
> > > > > > - Updated Date and KernelVersion in ABI documentation
> > > > > > v6:
> > > > > > - Added WARN_ON() call for (sha_num_bytes / stride) to assert
> > > > > > that the proper count is passed to regmap_bulk_read().
> > > > > > v5:
> > > > > > - No change
> > > > > > v4:
> > > > > > - Moved sysfs files for displaying the root entry hashes (REH)
> > > > > > from the FPGA Security Manager class driver to here. The
> > > > > > m10bmc_reh() and m10bmc_reh_size() functions are removed and
> > > > > > the functionality from these functions is moved into a
> > > > > > show_root_entry_hash() function for displaying the REHs.
> > > > > > - Added ABI documentation for the new sysfs entries:
> > > > > > sysfs-driver-intel-m10-bmc-secure
> > > > > > - Updated the MAINTAINERS file to add the new ABI documentation
> > > > > > file: sysfs-driver-intel-m10-bmc-secure
> > > > > > - Removed unnecessary ret variable from m10bmc_secure_probe()
> > > > > > - Incorporated new devm_fpga_sec_mgr_register() function into
> > > > > > m10bmc_secure_probe() and removed the m10bmc_secure_remove()
> > > > > > function.
> > > > > > v3:
> > > > > > - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
> > > > > > - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
> > > > > > - Changed "MAX10 BMC Secure Engine driver" to "MAX10 BMC Secure
> > > > > > Update driver"
> > > > > > - Removed wrapper functions (m10bmc_raw_*, m10bmc_sys_*). The
> > > > > > underlying functions are now called directly.
> > > > > > - Changed "_root_entry_hash" to "_reh", with a comment explaining
> > > > > > what reh is.
> > > > > > v2:
> > > > > > - Added drivers/fpga/intel-m10-bmc-secure.c file to MAINTAINERS.
> > > > > > - Switched to GENMASK(31, 16) for a couple of mask definitions.
> > > > > > - Moved MAX10 BMC address and function definitions to a separate
> > > > > > patch.
> > > > > > - Replaced small function-creation macros with explicit function
> > > > > > declarations.
> > > > > > - Removed ifpga_sec_mgr_init() and ifpga_sec_mgr_uinit() functions.
> > > > > > - Adapted to changes in the Intel FPGA Security Manager by splitting
> > > > > > the single call to ifpga_sec_mgr_register() into two function
> > > > > > calls: devm_ifpga_sec_mgr_create() and ifpga_sec_mgr_register().
> > > > > > ---
> > > > > > .../testing/sysfs-driver-intel-m10-bmc-secure | 29 ++++
> > > > > > MAINTAINERS | 2 +
> > > > > > drivers/fpga/Kconfig | 11 ++
> > > > > > drivers/fpga/Makefile | 3 +
> > > > > > drivers/fpga/intel-m10-bmc-secure.c | 145 ++++++++++++++++++
> > > > > > 5 files changed, 190 insertions(+)
> > > > > > create mode 100644 Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> > > > > > create mode 100644 drivers/fpga/intel-m10-bmc-secure.c
> > > > > >
> > > > > > diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> > > > > > new file mode 100644
> > > > > > index 000000000000..363403ce992d
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> > > > > > @@ -0,0 +1,29 @@
> > > > > > +What: /sys/bus/platform/drivers/intel-m10bmc-secure/.../security/sr_root_entry_hash
> > > > > > +Date: Aug 2021
> > > > > > +KernelVersion: 5.15
> > > > > > +Contact: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > > > > +Description: Read only. Returns the root entry hash for the static
> > > > > > + region if one is programmed, else it returns the
> > > > > > + string: "hash not programmed". This file is only
> > > > > > + visible if the underlying device supports it.
> > > > > > + Format: "0x%x".
> > > > > > +
> > > > > > +What: /sys/bus/platform/drivers/intel-m10bmc-secure/.../security/pr_root_entry_hash
> > > > > > +Date: Aug 2021
> > > > > > +KernelVersion: 5.15
> > > > > > +Contact: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > > > > +Description: Read only. Returns the root entry hash for the partial
> > > > > > + reconfiguration region if one is programmed, else it
> > > > > > + returns the string: "hash not programmed". This file
> > > > > > + is only visible if the underlying device supports it.
> > > > > > + Format: "0x%x".
> > > > > > +
> > > > > > +What: /sys/bus/platform/drivers/intel-m10bmc-secure/.../security/bmc_root_entry_hash
> > > > > > +Date: Aug 2021
> > > > > > +KernelVersion: 5.15
> > > > > > +Contact: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > > > > +Description: Read only. Returns the root entry hash for the BMC image
> > > > > > + if one is programmed, else it returns the string:
> > > > > > + "hash not programmed". This file is only visible if the
> > > > > > + underlying device supports it.
> > > > > > + Format: "0x%x".
> > > > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > > > index e3fbc1bde9bc..cf93835b4775 100644
> > > > > > --- a/MAINTAINERS
> > > > > > +++ b/MAINTAINERS
> > > > > > @@ -7363,8 +7363,10 @@ M: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > > > > L: linux-fpga@xxxxxxxxxxxxxxx
> > > > > > S: Maintained
> > > > > > F: Documentation/ABI/testing/sysfs-class-fpga-image-load
> > > > > > +F: Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
> > > > > Should we change the name of the driver? Some keywords like "image load"
> > > > > or "firmware update" should be in the name.
> > > > I considered that. The image-upload functionality is a subset of  this
> > > > driver. It also exposes security collateral via sysfs, and the image-load
> > > > triggers and power-on-image sysfs files will probably end up in this
> > > > driver too.
> > > >
> > > > The current driver name is intel-m10-bmc-secure. Do we need to keep
> > > > "intel-m10-bmc" in the name?
> > > >
> > > > intel-m10-bmc-sec-fw-update?
> > > > intel-m10-bmc-sec-update?
> > > >
> > > > What do you think? Any other suggestions?
> > The single word "secure" is quite indistinct to me. I think
> > intel-m10-bmc-sec-update is much better.
>
> This fine.
>
> Should it move to mfd/ ?

I think not. The mfd folder only contains MFD parent device drivers. The
subdev drivers are placed in various class folder according to their own
functionality.

Thanks,
Yilun

>
> Tom
>
> >
> > > The prefix intel-m10-bmc-sec is clunky and confuses me because I think of
> > > mfd/intel-m10-bmc.c
> > The secure update engine is now implemented in MAX10 bmc. The driver
> > code also assumes it is always a sub device of MAX10 bmc. So my
> > preference is we keep the prefix.
> >
> > > How about
> > >
> > > dfl-image-load ?
> > There may be several secure update engines for DFL based FPGAs. So we
> > may be more specific.
> >
> > Thanks,
> > Yilun
> >