Re: [RFC PATCH v3 0/4] x86: Add exception fixup for SGX ENCLU

From: Josh Triplett
Date: Mon Dec 10 2018 - 18:26:20 EST

On Mon, Dec 10, 2018 at 03:21:37PM -0800, Sean Christopherson wrote:
> At that point I realized it's a hell of a lot easier to simply provide
> an IOCTL via /dev/sgx that allows userspace to register a per-process
> ENCLU exception handler. At a high level, the basic idea is the same
> as the vDSO approach: provide a hardcoded fixup handler for ENCLU and
> attempt to fixup select unhandled exceptions that occurred in user code.

So, on the one hand, this is *absolutely* much cleaner than the VDSO
approach. On the other hand, this is global process state and has some
of the same problems as a signal handler as a result.