arch: official support for RISC-V (riscv64)

[wcz0910]

Title: Support for RISC-V 64-bit architecture (riscv64)

Description:
As the RISC-V ecosystem is rapidly expanding in data centers and edge computing, providing official support for Envoy on riscv64 has become increasingly important.

I have successfully compiled and verified Envoy v1.26.4 on a native RISC-V machine. Here are the environment details:

• OS/Kernel: Linux 6.6.0.mlu370 riscv64
• Architecture: riscv64
• Envoy Version: v1.26.4

Questions:

1. Does the Envoy community have an official roadmap for RISC-V support?
2. What are the requirements (e.g., CI infrastructure, maintenance commitment) to start the process of upstreaming RISC-V support?

I am interested in contributing the necessary patches and build configuration changes to the upstream repository. I would love to discuss how to move this forward.

[yanavlasov]

We do not have a roadmap for RISC-V. The main issue is that there is no RISC-V support on AWS, or GCP where we have CI capacity. As such we can not build and test RISC-V binaries. The best you can do at this point is to build Envoy releases using your own resources and publish your own RISC-V Envoy binaries. If it helps you can submit build setting you need.

[wcz0910]

@yanavlasov
Thank you for the feedback. I understand the current limitations regarding CI infrastructure on AWS/GCP.

To move this forward, I plan to port the changes and patches I've verified on v1.26.4 to the current main branch. I will use my native RISC-V environment to perform the build and run tests to ensure compatibility with the latest upstream code.

Once I have successfully verified the build and test results on the main branch, I will submit a PR with the necessary build configurations and patches. This should provide a foundation for the community to support RISC-V even if official CI is not yet available.