Status at a glance:

• Current  Definition-of-Done Status:  Stable
• Next  Definition-of-Done Status::  Freeze
  • (allows start of formal public review period)

Scalar Crypto Specification:

Lightweight instruction set extensions for RV32 and RV64 HARTs.  Proposed extensions:

• Extensions fully defined in the Scalar Crypto Specification:  K, Zkn, Zks, Zkr, Zkne, Zknd, Zknh, Zksed, Zksh
• Shared with the Bit-Manipulation Specification: Zkg, Zkb

Specification

• Latest Draft Scalar Crypto Specification (v0.9.1)
• Stable in asciidoc form now.
• Some consistency review feedback which will be applied in subsequent functional releases:
  
  • aes32* and sm4* encodings will change to remove the `rt` field.
  • Change aes64ks1i "rcon" immediate to "rnum".
  • Remove packu[w] since they aren't needed for our usecase of packing bytes into words. We can use other pack instructions.
  • Break Zbk into smaller units: (Zbkc: clmul*, Zbkx: xperm.*, Zbkb: everything else)
  • Entropy source changes, including configurable access to the entropy source from S mode.

Encoding/OpCode consistency review

• Opcodes and encodings proposed
• Instruction extensions (instruction groupings) proposed
• Submitted to review task group
• The Bit-Manipulation shared subsets are being reviewed first as part of Bit-Manipulation specification review
  • Proposed as Zkg (clmul) and Zkb (specific crypto-required bit-manipulation commands)
• The Proposed Scalar Crypto-unique subsets are next in line for review:
  
  • K (Krypto): 
    • Zkn (full NIST Suite):  ZKne (NIST encrypt suite), ZKnd (NIST decrypt suite), ZKnh (NIST hash suite), Zkg, Zkb (see above)
    • Zkr (random entropy source)
  • Zks (full ShangMi Suite):  Zksed (SM4 encrypt/decrypt suite), Zksh (SM3 hash suite), Zkg, Zkb (see above)

• OpCode and Consistency Review page
• What's next:  Respond to OpCode and Consistency Review comments, once available, and achieve consensus on any changes.
• We need to discuss the aes32* and sm4* rt encodings.
  
  • Comments from others and Andrew particularly suggest that having distinct rd/rs1/rs2 is acceptable and that we over-estimated the importance of minimising encoding cost.
  • We will likely be reverting to the original form of these instructions, with separate rd/rs1/rs2 before public review.

Architecture Tests

• Test plan for the scalar-crypto specific instructions is available.
• Imperas have a complete set of tests, written to the existing test plan, for the scalar crypto instructions and the bitmanip instructions we borrow.
  • These have been merged into the main test suite as of PR#177, with many thanks to Imperas for the contribution.
    • Spike, OVPSim and Sail all agree on the test signatures.
  • They form a base we can use to develop prototype implementations / Spike / SAIL / QEMU very easily and quickly.
• Upstream Spike support for enabling it to work with the K test suite is being added in PR#687.
• IIT Madras are also looking at writing the scalar crypto tests for integration into the official architectural tests repo as well.
  • Agreed SoW for IITM
  • They are re-implementing the tests as part of the blessed coverage and test generation tooling.
    • Making good progress with the simple test patterns for scalar-crypto specific instructions A/O April 7'th '21
  • We then switch over to using the IIT tests when they are finished, since they will be easier to maintain/extend going forward than the Imperas tests.
• YAML config changes for K have been merged in. See here.
• Status from IIT Madras as on 20-May:
  • Real world test cases as per the test plan has been generated.
  • Currently waiting for the fixed toolchain with K extension from PLCT to test the generated test cases. All the test cases are working fine when we run against the patched toolchain
  • A PR has been raised with a pull request for this suite to be reviewed and merged in the riscv-arch tests github repo.
• Status from IIT Madras as on 12-May:
  • Coverage report for all developed cases in CTG/ISAC has been generated and it is reported as 100%
  • Currently real world test cases are being developed as per test plan and will be completed and send for review by beginning of next week
• Status from IIT Madras as on 05-May:
  • Resolved issues in running the rv64ik toolchain after interacting with PLCT and compile the relevant tests generated from CTG and run them on spike
  • Currently resolving issues in the running the rv64ibk toolchain. Once this is done, will generate the coverage report of the test cases built till now and share with team.
• Status from IIT Madras as on 26-Apr:
  • Completed the coverage points specification for all 32-bit and 64-bit instructions
  • Generated test cases from the coverage points
  • Currently working on trying to install the scalar crypto enabled toolchain.

Compilers / Toolchains

Imperas maintain pre-built toolchains for various in-progress RISC-V extensions here. See the "rvk-*" branches for scalar crypto.

GCC and Binutils

• Experimental / development toolchain available in the riscv-crypto repository.
  
  • This cannot be up-streamed, but can be used for development work for now.
• Intrinsics proposal from Markku
• PLCT lab have developed complete Binutils and GCC patches.
  • The pull requests into the main RISC-V repos can be found here:
    • Binutils pull request: https://github.com/riscv/riscv-binutils-gdb/pull/254
    • GCC pull request: https://github.com/riscv/riscv-gcc/pull/250 (merged)
  • The PLCT lab continuous integration server can be found here:
    • https://ci.rvperf.org/view/Krypto-Scalar/
    • This is a good place to start for re-producing the PLCT builds of GCC/Binutils
  • Some small changes will be needed as we move to v1.0 of scalar crypto around encodings.

LLVM

• Work will be done by PLTC lab under the group contributor model.
  • Github repository
  • Continuous integration status
• Slides from PLCT Update Weds 10'th Feb
• As of 21'st April '21, LLVM work is mostly complete, waiting on PLCT lab for an update about merging things upstream.
  • Some small changes will be needed as we move to v1.0 of scalar crypto around encodings.

Simulators

Though all listed under "simulators", these are actually a collection of formal model / virtual machine / architectural simulators / DV simulators etc.

SAIL

• Currently working on getting support merged in upstream in PR#80
  • Support for all scalar-crypto dedicated instructions is present.
  • Support for the entropy source is still the main point of discussion.
  • No support for Bitmanip. The Bitmanip TG is waiting until after the opcode and consistency review to start writing SAIL code.
  • This PR is "paused" until the next release of the scalar crypto spec, which will bring some functional changes to the `aes32*` and `sm4*` instructions.

Spike

• Upstream support has been merged in as of PR#635
  • Support for all of scalar crypto specific instructions and entropy source.
  • The only feature left is to enable the right Bitmanip instructions when K is enabled. Currently, one must include "b" in the spike "–isa=" argument.
  • PR#649 has now been merged. Support now consistent with v0.9.0.

riscvOVPSimPlus

• Imperas Commercial Simulator
• Freeware version
• Support for:
  • Crypto-scalar v0.7.2, v0.81 + Bitmanip subsets
  • Bitmanip 0.92, 0.93
  • Functional coverage collection.

QEMU

• Work will be done by PLTC lab under the group contributor model.
  • Github repository
  • Continuous integration status
  • Waiting to hear back from PLCT on status.

Proof-of-Concept implementations

Hardware

• We still need RV64 implementations. 
• Barry Spinney has offered to do advanced node synthesis runs for open source implementations.
  • I (Ben) intend to take him up on this when I get time. No idea when that will be.

Software

ABI Extensions

• None required