[svsm-devel] Questions about crypto support

[Gerd Hoffmann]

> > Q3) What libc implementation should we use to build OpenSSL and other CPL3
> > modules?
> 
> What amount of libc does openssl need? Or how much is it beyond
> malloc/free? Whatever libc we chose, some porting efforts to the SVSM
> syscall interface will be needed.

edk2 essentially has the same problem, and it is solved by building with
--taget=UEFI plus a combination of #defines and stubs and efi-specific
implementations.

Details are here:
 * https://github.com/tianocore/edk2/tree/master/CryptoPkg/Library/Include
   (where CrtLibSupport.h is the most interesting file)
 * https://github.com/tianocore/edk2/blob/master/CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c
 * https://github.com/tianocore/edk2/tree/master/CryptoPkg/Library/OpensslLib/OpensslStub

There also is
https://github.com/tianocore/edk2/tree/master/CryptoPkg/Library/IntrinsicLib
to provide an implementation for the compiler intrinsics generated by
gcc.

take care,
  Gerd