On Mon, Aug 10, 2020 at 04:08:46PM -0700, Andy Lutomirski wrote: > On Thu, Aug 6, 2020 at 7:55 AM Nathaniel McCallum <npmccallum@xxxxxxxxxx> wrote: > > > > In a past revision of this patch, I had requested a void *misc > > parameter that could be passed through vdso_sgx_enter_enclave_t into > > sgx_enclave_exit_handler_t. This request encountered some push back > > and I dropped the issue. However, I'd like to revisit it or something > > similar. > > Why do you need an exit handler at all? IIRC way back when I > suggested that we simply not support it at all. If you want to > call__vdso_sgx_enter_enclave() in a loop, call it in a loop. If you > want to wrap it intelligently in Rust, you don't want a callback > anyway -- that forces you have an FFI (or non-Rust, anyway) frame on > the stack, which interacts poorly with panic handling and prevents you > from using await in your Rust callback handler. If, on the other > hand, you just call __vdso_sg_enter_enclave() in a loop, all these > problems go away and, if you really want, you can pass in a callback > in Rust and call the callback from Rust. How would Intel SDK be able to do its stack manipulation? > What am I missing? I still don't really understand why we are > supporting this mechanism at all. Just the asm code to invoke the > callback seems to be about half of the entire function. I'm most worried maintaining all of this given all the innovative ways that users can exploit an uapi. /Jarkko
