On Thu, Feb 13, 2025 at 04:17:56PM -0600, Stuart Yoder wrote: > > > On 2/13/25 4:11 PM, Jarkko Sakkinen wrote: > > On Wed, Feb 12, 2025 at 04:05:48PM -0600, Stuart Yoder wrote: > > > Add documentation providing details of how the CRB driver interacts > > > with FF-A. > > > > > > Signed-off-by: Stuart Yoder <stuart.yoder@xxxxxxx> > > > --- > > > Documentation/security/tpm/tpm_ffa_crb.rst | 65 ++++++++++++++++++++++ > > > 1 file changed, 65 insertions(+) > > > create mode 100644 Documentation/security/tpm/tpm_ffa_crb.rst > > > > > > diff --git a/Documentation/security/tpm/tpm_ffa_crb.rst b/Documentation/security/tpm/tpm_ffa_crb.rst > > > new file mode 100644 > > > index 000000000000..c70f8904a93d > > > --- /dev/null > > > +++ b/Documentation/security/tpm/tpm_ffa_crb.rst > > > @@ -0,0 +1,65 @@ > > > +.. SPDX-License-Identifier: GPL-2.0 > > > + > > > +======================== > > > +TPM CRB over FF-A Driver > > > +======================== > > > + > > > +The TPM Command Response Buffer (CRB) interface is a standard TPM interface > > > +defined in the TCG PC Client Platform TPM Profile (PTP) Specification [1]_. > > > +The CRB provides a structured set of control registers a client uses when > > > +interacting with a TPM as well as a data buffer for storing TPM commands and > > > +responses. A CRB interface can be implemented in: > > > + > > > +- hardware registers in a discrete TPM chip > > > + > > > +- in memory for a TPM running in isolated environment where shared memory > > > + allows a client to interact with the TPM > > > + > > > +The Firmware Framework for Arm A-profile (FF-A) [2]_ is a specification > > > +that defines interfaces and protocols for the following purposes: > > > + > > > +- Compartmentalize firmware into software partitions that run in the Arm > > > + Secure world environment (also know as TrustZone) > > > > Does that also cover ARM CCA? Just a question (not a review question). > > No, CCA is for confidential VMs which is a separate trusted execution > environment and FF-A is not used there. OK, cool, just plain interested :-) > > Thanks, > Stuart BR, Jarkko
