Add the definitions and utility functions for the PVSECRET-HMAC key type.
A PVSECRET-HMAC key token contains the secret id of a protected
virtualization secret. It does not contain the key material, just a
reference to the key in the ultravisor.
When such a key token is used to perform HMAC operations later on, the
PHMAC kernel cipher will obtain the protected key belonging to this secret
id with the help of the pkey kernel module.
Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Finn Callies <fcallies@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>