Disable AVX / AVX2 on Openssl

[quantropi-RYANTOTH]

Hello,

I'm trying to disable AVX / AVX2 instructions. I've researched online and throughout the repo, and found the following command to try but it didn't seem to work after executing it and recompiling.

env OPENSSL_ia32cap=:0 apps/openssl

I'm looking for any suggestions that might help me achieve this functionality. Thank you!

[baentsch]

This looks like a general (upstream) OpenSSL question. Further looking at the command above, the ":" seems odd: Are you sure that syntax is right? Lastly, if you compile OpenSSL on a platform without AVX(2) support, those instructions should not be compiled in, right?

[quantropi-RYANTOTH]

Thanks for the quick response -- I went ahead and asked the question in OpenSSL.

You are right in that if the platform doesn't support AVX(2), it won't be executed.

The solution I used was just commenting out the AVX(2) calling functions in liboqs (since my machine had AVX(2) enabled).

[baentsch]

Just out of curiosity: What is the reason you'd like to disable AVX(2) if your machine supports it? If you'd like to create "distributable" liboqs object code (e.g., in docker images) then you probably simply want to set OQS_DIST_BUILD=ON and OQS_OPT_TARGET=generic when running cmake.