With the newest release of wolfSSL, you can now set the Intel CPU ID flags rather than let them be discovered. The CPU ID flags indicate which instructions are implemented in the CPU. wolfSSL uses this information to decide which is the fastest optimized implementation that will execute!
wolfSSL’s normal discovery works just fine when running on physical CPUs, but emulation in virtual environments does not always report the true state. In these cases users can call cpuid_set_flag() to enable the flag that is needed. Bugs do occur in CPU implementations and in these cases turning off a flag with cpuid_clear_flag() enables switching to different implementations across potentially a number of different cryptographic algorithms. Alternatively, the exact list of flags that you want can be selected with cpuid_select_flags().
If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.