On Tue, Dec 11, 2018 at 08:53:39AM -0600, Dr. Greg wrote: > On Mon, Dec 10, 2018 at 03:24:50PM -0800, Josh Triplett wrote: > > Good morning to everyone, I hope the week is progressing well. > > > 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. > > Sean's architecture is very simple and straight forward and thus has a > lot going for it. > > As Sean's approach indicates, by linking the exception handler to > current->mm, SGX is very much a per memory map concept. The issue is > that there can be multiple enclaves loaded and excecuting in a > processes memory map, the problem is, execution and thus exception > handling, is very much at the per thread level. Right, but is there a need to have a per-thread code page? The handler isn't per-process any more than the AEP is per-process.
