[sival/aes] Add aes_prng_reseed,aes_prng_force_reseed

This commit introduces the AES PRNG reseed test (chip_sw_aes_prng_reseed) and (chip_sw_aes_force_prng_reseed) and AES FORCE PRNG reseed, to handle the reseed process by disabling entrpy complex and triggering PRNG reseed accordingly to test the actual behavior of the AES module's PRNG reseeding in ECB mode. - Updated the test plan descriptions in `chip_aes_testplan.hjson` to match the implemented tests. Added missing test feature. - Resoloved latest code suggestions provided in PR #24574 and updated code with suggestions from other thread (using TRY and remove .c suffix in bazel tag). - Single commit for a cleaner history. - Resolve multiple commits. See: hw/top_earlgrey/data/ip/chip_aes_testplan.hjson Closes Issue #24857 Closes Issue #24899 PR #24574 Signed-off-by: Varunkumar Trivedi <[email protected]>
lowRISC · Nov 21, 2024 · 036c58a · 036c58a
1 parent 096be43
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diff --git a/hw/top_earlgrey/data/ip/chip_aes_testplan.hjson b/hw/top_earlgrey/data/ip/chip_aes_testplan.hjson
@@ -144,34 +144,65 @@
     }
     {
       name: chip_sw_aes_prng_reseed
-      desc: '''Verify that PRNG reseeding is triggered
-
-            This test should start encryption, disable the EDN, and verify that the
-            encryption stalls when reseed is required. Afterwards it should verify that AES
-            finishes encryption after EDN is re-enabled.
+      desc: ''' Verify that the AES module halts when a PRNG reseed is
+            required but the entropy complex is disabled, and resumes
+            encryption once the entropy complex is re-enabled.
 
             Procedure:
-            -Configure encryption using the ECB mode, desired key length, and set the engine to
-            automatic operation.
-                -Set the mask_reseeding to once per 64 blocks (kDifAesReseedPer64Block)
-            -Using dif_aes_process_data() encrypt some number of blocks (fewer than 64).
-            -Disable the EDN using dif_edn_stop().
-            -Encrypt more blocks and verify that encryption stalls after 64 blocks.
-                -Once the first 64 blocks are encrypted, a reseed request will be sent to EDN.
-                Since the EDN should be disabled at this point, this should cause encryption
-                to stall.
-            -Re-enable EDN. In order to do this it is required to first disable and re-enable the
-             CSRNG. In order to re-enable CSRNG, it is required to first disable and re-enable
-             the entropy source. The following sequence of steps should be used:
-                -Disable CSRNG
-                -Disable Entropy Source
-                -Enable Entropy Source
-                -Enable CSRNG
-                -Enable EDN
-            -Verify that the AES completes encryption of the remaining blocks.
+            - After proper initialization of the AES and entropy modules,
+              configure the AES encryption operation to process a number of
+              blocks with:
+              - Operation: Encrypt
+              - Mode: ECB
+              - Key Length: 128 bits
+              - Key Provider: Software-provided key
+              - Manual Operation: Disabled (Automatic operation)
+              - Mask Reseeding: Reseed per 64 blocks
+                (`kDifAesReseedPer64Block`)
+              - Reseed on Key Change: Enabled
+              - Force Masks: Disabled
+
+            - Generate AES key.
+
+            - Initialize the AES module and start the AES operation using
+              `dif_aes_start()`.
+
+            - Process blocks using the following steps:
+              - Disable entropy for a block fewer than 64.
+              - For each block,
+                  - Continue encrypting blocks (fewer than 64 blocks)
+                  - Once processing reaches the block where the entropy complex
+                    is disabled
+                    - Disable the entire entropy complex using
+                      `entropy_testutils_stop_all()`.
+                    - This will halt the AES module when a PRNG reseed is
+                      required (i.e after 64 blocks).
+                  - Re-enable the entropy complex to resume encryption:
+                    - Verify that the AES module is halted by checking that
+                      `kDifAesStatusOutputValid` is not set for the 63rd block
+                    - Re-enable the entropy complex using
+                      `entropy_testutils_auto_mode_init()`.
+                    - Wait for some time for the entropy complex to stabilize.
+                    - Wait for the AES module to produce output valid
+                      (`kDifAesStatusOutputValid`).
+                    - Read the encrypted output data using
+                      `dif_aes_read_output()`.
+
+            - Finish the AES encryption operation by calling `dif_aes_end()`.
 
-            -Repeat the test for a reseed rate kDifAesReseedPer8kBlock and a message longer than 8K
-            blocks.
+            - Verify that the AES module is idle at the end of the encryption
+              operation (`kDifAesStatusIdle`).
+            - Repeat the test for a reseed rate kDifAesReseedPer8kBlock and
+              a message longer than 8K blocks.
+
+            Expected Outcome:
+            - The AES module halts when a PRNG reseed is required but the
+              entropy complex is disabled.
+            - After re-enabling the entropy complex, the AES module resumes
+              encryption and produces the expected output.
+            - The test verifies that the AES module correctly handles halting
+              and resuming based on the availability of entropy and the
+              configured mask reseeding rate.
             '''
       features: [
         "AES.MODE.ECB",
@@ -180,32 +211,54 @@
       stage: V2
       si_stage: SV3
       lc_states: ["PROD"]
-      tests: []
-      bazel: []
+      tests: ["chip_sw_aes_prng_reseed"]
+      bazel: ["//sw/device/tests:aes_prng_reseed_test"]
     }
     {
       name: chip_sw_aes_force_prng_reseed
-      desc: '''Verify that when KEY_TOUCH_FORCES_RESEED is set, the PRNG reseed is
-               triggered every time a key changes
+      desc: '''Verify that the AES module stalls/halts when the entropy
+            complex is disabled before starting encryption and enables
+            output of encryption once the entropy complex is re-enabled.
 
             Procedure:
-            -Configures the auxiliary options for AES to enable KEY_TOUCH_FORCES_RESEED
-            -Disable the EDN using dif_edn_stop()
-            -Configure the encryption operation, mode, key length, and set the engine to manual
-             operation.
-            -Set up encryption using aes_testutils_setup_encryption()
-              -At this point dif_aes_start() will write the key register which will trigger reseed
-               request. This request will stall the encryption until EDN is re-enabled.
-            -Verify that the encryption stalls.
-            -Re-enable EDN. In order to do this it is required to first disable and re-enable the
-             CSRNG. In order to re-enable CSRNG, it is required to first disable and re-enable
-             the entropy source. The following sequence of steps should be used:
-                -Disable CSRNG
-                -Disable Entropy Source
-                -Enable Entropy Source
-                -Enable CSRNG
-                -Enable EDN
-            -Verify that the AES completes encryption.
+            - After proper initialization of AES and entropy modules, disable
+              the entire entropy complex using `entropy_testutils_stop_all()`.
+              - Configure the AES encryption operation to process some number of
+                blocks with:
+                - Operation: Encrypt
+                - Mode: ECB
+                - Key Length: 128 bits
+                - Key Provider: Software-provided key
+                - Manual Operation: Enabled
+                - Mask Reseeding: Reseed per block
+                - Reseed on Key Change: Enabled (When KEY_TOUCH_FORCES_RESEED is
+                  set, the PRNG reseed is triggered every time a key changes)
+                - Force Masks: Enabled
+              - Generate AES key.
+              - At this point dif_aes_start() will write the key register which
+                will trigger reseed request.
+              - This request will stall the output of the encrypted data until
+                entropy is re-enabled.
+              - Verify that the AES module is halted by checking that
+                `kDifAesStatusOutputValid` is not set.
+              - Re-enable the entropy complex using
+                `entropy_testutils_auto_mode_init()`.
+              - Wait for some time for the entropy complex to stabilize.
+              - Wait for the AES module to produce output valid
+                (`kDifAesStatusOutputValid`).
+              - Read the encrypted output data using `dif_aes_read_output()`.
+              - Process all the blocks and ensure AES completes encryption
+                operation.
+                - Verify that the AES module is idle at the end of encryption
+                  operation (`kDifAesStatusIdle`).
+
+              Expected Outcome:
+              - The AES module halts output when the entropy complex is disabled
+                before starting encryption.
+              - After re-enabling the entropy complex, the AES module resumes
+                encryption and produces the expected output.
+              - The test verifies that the AES module correctly handles halting
+                and resuming based on the availability of entropy.
             '''
       features: [
         "AES.MODE.ECB",
@@ -214,8 +267,8 @@
       stage: V2
       si_stage: SV3
       lc_states: ["PROD"]
-      tests: []
-      bazel: []
+      tests: ["chip_sw_aes_force_prng_reseed"]
+      bazel: ["//sw/device/tests:aes_force_prng_reseed_test"]
     }
     {
       name: chip_sw_aes_idle

diff --git a/sw/device/tests/BUILD b/sw/device/tests/BUILD
@@ -177,6 +177,72 @@ opentitan_test(
     ],
 )
 
+opentitan_test(
+    name = "aes_force_prng_reseed_test",
+    srcs = ["aes_force_prng_reseed_test.c"],
+    exec_env = dicts.add(
+        EARLGREY_TEST_ENVS,
+        EARLGREY_SILICON_OWNER_ROM_EXT_ENVS,
+        {
+            "//hw/top_earlgrey:fpga_cw310_sival": None,
+            "//hw/top_earlgrey:sim_verilator": None,
+            "//hw/top_earlgrey:fpga_cw340_sival": None,
+            "//hw/top_earlgrey:silicon_creator": None,
+        },
+    ),
+    verilator = verilator_params(
+        timeout = "long",
+    ),
+    deps = [
+        "//hw/ip/aes:model",
+        "//hw/top_earlgrey/sw/autogen:top_earlgrey",
+        "//sw/device/lib/base:memory",
+        "//sw/device/lib/base:mmio",
+        "//sw/device/lib/dif:aes",
+        "//sw/device/lib/dif:edn",
+        "//sw/device/lib/dif:entropy_src",
+        "//sw/device/lib/runtime:log",
+        "//sw/device/lib/testing:aes_testutils",
+        "//sw/device/lib/testing:entropy_testutils",
+        "//sw/device/lib/testing/test_framework:ottf_main",
+        "//sw/device/sca/lib:simple_serial",
+    ],
+)
+
+opentitan_test(
+    name = "aes_prng_reseed_test",
+    srcs = ["aes_prng_reseed_test.c"],
+    exec_env = dicts.add(
+        EARLGREY_TEST_ENVS,
+        EARLGREY_SILICON_OWNER_ROM_EXT_ENVS,
+        {
+            "//hw/top_earlgrey:fpga_cw310_sival": None,
+            "//hw/top_earlgrey:sim_verilator": None,
+            "//hw/top_earlgrey:fpga_cw340_sival": None,
+            "//hw/top_earlgrey:silicon_creator": None,
+        },
+    ),
+    verilator = verilator_params(
+        timeout = "long",
+    ),
+    deps = [
+        "//hw/ip/aes:model",
+        "//hw/top_earlgrey/sw/autogen:top_earlgrey",
+        "//sw/device/lib/base:memory",
+        "//sw/device/lib/base:mmio",
+        "//sw/device/lib/dif:aes",
+        "//sw/device/lib/dif:edn",
+        "//sw/device/lib/dif:entropy_src",
+        "//sw/device/lib/runtime:log",
+        "//sw/device/lib/testing:aes_testutils",
+        "//sw/device/lib/testing:entropy_testutils",
+        "//sw/device/lib/testing/test_framework:check",
+        "//sw/device/lib/testing/test_framework:ottf_main",
+        "//sw/device/lib/testing/test_framework:ottf_utils",
+        "//sw/device/sca/lib:simple_serial",
+    ],
+)
+
 opentitan_test(
     name = "alert_handler_ping_timeout_test",
     srcs = ["alert_handler_ping_timeout_test.c"],