Entropy Stack update

[rivos-eblot]

This update contains mostly EDN IP update which has been heavily reworked based on HW simulation (Verilator traces) rather than on EDN documentation, as it has been done for the initial implementation.

It also contains several updates and fixes for the CSRNG and EntropySrc, but those IPs still require some updates, which will be delivered in a forth coming PR.

[rivos-eblot]

Updated EDN: GENERATE command header was not parsed in SW_PORT_MODE (as it's done for Boot and Auto mode), resulting of 0 expected entropy packet, deadlocking the CSRNG comm channel. Fixed.

[luismarques]

It's going to take me a while to mentally digest all of the changes in this PR, so a review from me might take a bit, but I don't want to delay this too much. Maybe we could occasionally do review meetings where we go over the code together?

[rivos-eblot]

Maybe we could occasionally do review meetings where we go over the code together?
Sure. I could take a couple of hours for such meetings, but I'm afraid it could not be much more, given how many IPs needs to be rewritten.

[rivos-eblot]

Some progress since last draft:

+----------------------------+---------+-----------+--------+----------------------------------------+
| Name                       |  Result |      Time | Icount |                                  Error |
+============================+=========+===========+========+========================================+
| csrng_edn_concurrency_test |    PASS | 145839 ms |      6 |                                        |
+----------------------------+---------+-----------+--------+----------------------------------------+
| csrng_kat_test             |    PASS |    267 ms |      6 |                                        |
+----------------------------+---------+-----------+--------+----------------------------------------+
| csrng_smoketest            |    PASS |    206 ms |      6 |                                        |
+----------------------------+---------+-----------+--------+----------------------------------------+
| edn_auto_mode              |    PASS |   9900 ms |      6 |                                        |
+----------------------------+---------+-----------+-------------------------------------------------+
| edn_boot_mode              |    FAIL |    200 ms |      6 | CHECK-STATUS-fail: Internal:["OBT";47] |
+----------------------------+---------+-----------+--------+----------------------------------------+
| edn_kat                    | TIMEOUT |  30002 ms |      6 |                                        |
+----------------------------+---------+-----------+--------+----------------------------------------+
| edn_sw_mode                |    PASS |   1505 ms |      6 |                                        |
+----------------------------+---------+-----------+--------+----------------------------------------+

edn_boot_mode failure is due to the OTBN not receiving the expected FIPS compliance status from the EDN, on the second round (first round is ok)

[rivos-eblot]

It might be worth splitting this PR once entropy test are passing. Entropy tests depend on so many IPs that is difficult to predict the proper set of IPs to update for now.

[rivos-eblot]

+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| Name                                                        |  Result |      Time | Icount |                                                                       Error |
+=============================================================+=========+===========+========+=============================================================================+
| aes_entropy_test                                            |    PASS |    307 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_force_prng_reseed_test                                  | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_idle_test                                               |    PASS |    315 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_masking_off_test                                        | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_prng_reseed_test                                        | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_smoketest                                               |    PASS |    374 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| aes_stall_test                                              |    FAIL |    339 ms |      6 | CHECK-fail: ERROR: AES module not STALLED as expected after loading block 1 |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| csrng_edn_concurrency_test                                  |    PASS | 171378 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| csrng_kat_test                                              |    PASS |    268 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| csrng_smoketest                                             |    PASS |    207 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| edn_auto_mode                                               |    PASS |  14308 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| edn_boot_mode                                               |    PASS |    846 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| edn_kat                                                     | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| edn_sw_mode                                                 |    PASS |   1463 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_ast_rng_req_test                                |    PASS |    429 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_bypass_mode_health_test                         | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_csrng_test                                      | TIMEOUT |  10001 ms |        |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_edn_reqs_test                                   |   ERROR |    413 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_fw_observe_many_contiguous_test                 |    FAIL |   4097 ms |      6 |                              CHECK-STATUS-fail: DeadlineExceeded:["RVC";25] |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_fw_override_test                                | TIMEOUT |  10002 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_fw_ovr_test                                     |    PASS |    395 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_kat_test                                        |    FAIL |    284 ms |      6 |                            CHECK-fail: fail_count < kKatTestTimeoutAttempts |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| entropy_src_smoketest                                       | TIMEOUT |  10001 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| hmac_enc_idle_test                                          |    PASS |    393 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| hmac_enc_test                                               |    PASS |    371 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| hmac_secure_wipe_test                                       |    PASS |    405 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| hmac_smoketest                                              |    PASS |    580 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_irq_test                                               |    PASS |    282 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_isa_test                                               |    PASS |   1121 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_mem_scramble                                           |    FAIL |    539 ms |      6 |              CHECK-fail: Expecting at least 48 IMEM integrity errors; got 0 |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_randomness_test                                        |    PASS |    589 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_rsa_test                                               |    PASS |   2042 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+
| otbn_smoketest_silicon_creator                              |    PASS |    286 ms |      6 |                                                                             |
+-------------------------------------------------------------+---------+-----------+--------+-----------------------------------------------------------------------------+

[AlexJones0]

I'm not very familiar with the EDN and CSRNG and so can't provide a thorough review on the implementation specifics (I did find the CSRNG changes easier to review though); I've left some comments on things I noticed going over the code. On the whole the changes all look great, however, and it's nice to see more EDN/CSRNG tests passing.

Aside: it is surprising to me to see entropy_src_kat_test failing, since I have it noted as passing - I went and ran it on master on OpenTitan and to my surprise it is failing! Going back to an older OpenTitan commit 32b1337496 and running ./bazelisk.sh test //sw/device/tests:entropy_src_kat_test_sim_qemu_rom_with_fake_keys it clearly is passing, so there has been a regression at some point, though not in this PR (so it shouldn't block merging). I would guess that the implementation of this test changed during the Multitop top-level-test porting efforts, in a way that is incompatible with the QEMU model (or maybe QEMU was bumped since then and a previous change broke this)?

[rivos-eblot]

#153 (comment) not yet addressed (TBD next week).
Thanks for the review @AlexJones0 The EDN has been a large rewrite and comes as a very large change, which is not easy to read. There were some many changes to do that did not found a way to split it into coherent, small change commits.

[rivos-eblot]

#153 (comment) not yet addressed (TBD next week).

It turns out that the generation identifier is no longer needed with the latest Entropy Src IP.
I'll remove the whole thing, as it simplifies both the API and the error management.

[AlexJones0]

This looks good to me, thank you! I'm not familiar with the hardware enough to thoroughly review all the EDN changes but the code all seems reasonable and more tests are passing, so this is definitely an improvement.