On Wed, Dec 01, 2021 at 11:23:00AM -0800, Reinette Chatre wrote: > The SGX ENCLS instruction uses EAX to specify an SGX function and > may require additional registers, depending on the SGX function. > ENCLS invokes the specified privileged SGX function for managing > and debugging enclaves. Several macros are used to wrap the ENCLS > functionality. > > Add ENCLS wrappers for the SGX2 EMODPR, EMODT, and EAUG functions > that can make changes to pages of an initialized SGX enclave. The > EMODPR function is used to restrict enclave page permissions > as maintained within the enclave (Enclave Page Cache Map (EPCM) > permissions). The EMODT function is used to change the type of an > enclave page. The EAUG function is used to dynamically add enclave > pages to an initialized enclave. > > EMODPR and EMODT accepts two parameters and can fault as well as return > an SGX error code. EAUG also accepts two parameters but does not return > an SGX error code. Use existing macros for all new functions. > > Expand enum sgx_return_code with the possible EMODPR and EMODT > return codes. These implementation details only obfuscate this commit message, and it is way too high-level to be useful e.g. for kernel maintenance. I'd replace it with something like: " Add wrappers for ENCLS leaf functions EAUG, EMODT and EMODPR, which roughly take two steps: 1. EAUG creates a new EPCM entry. EMODT and EMODPR modify an existing EPCM entry. 2. Set either .PR = 1 (EMODPR), .MODIFY = 1 (EMODT) or .PENDING = 1 (AUG). The bit is reset by the enclave by invoking ENCLU leaf function EACCEPT or EACCEPTCOPY, which will result the EPCM change becoming effective. " The current commit message is also not addressing these: 1. What happens if enclaves accesses a memory address with either .PR, .MODIFY or .PENDING set in EPCM, other than by the means of EACCEPT or EACCEPTCOPY? 2. The calling conditions (e.g. concerning TLB's and ETRACK/IPI/etc dance related to it). If this information was properly contained here, discussing about the following commits would be much easier. /Jarkko
