Intel Software Defined Silicon (SDSi) is a post manufacturing mechanism for
activating additional silicon features. Features are enabled through a
license activation process.  The SDSi driver provides a per socket, sysfs
attribute interface for applications to perform 3 main provisioning
functions:

1. Provision an Authentication Key Certificate (AKC), a key written to
   internal NVRAM that is used to authenticate a capability specific
   activation payload.

2. Provision a Capability Activation Payload (CAP), a token authenticated
   using the AKC and applied to the CPU configuration to activate a new
   feature.

3. Read the SDSi State Certificate, containing the CPU configuration
   state.

The operations perform function specific mailbox commands that forward the
requests to SDSi hardware to perform authentication of the payloads and
enable the silicon configuration (to be made available after power
cycling).

The SDSi device itself is enumerated as an auxiliary device from the
intel_vsec driver and as such has a build dependency on CONFIG_INTEL_VSEC.

Link: https://github.com/intel/intel-sdsiSigned-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mark Gross <markgross@kernel.org>
Link: https://lore.kernel.org/r/20220212013252.1293396-2-david.e.box@linux.intel.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>