On Mon, May 20, 2019 at 02:41:05PM +0300, Jarkko Sakkinen wrote:

On Thu, May 16, 2019 at 05:26:15PM -0700, Andy Lutomirski wrote:

quoted

Is userspace actually requred to mmap() the enclave prior to EADDing things?

Nope, not since v20. Here is what I wrote about API to the kernel
documentation:

"The enclave life-cycle starts by opening `/dev/sgx/enclave`. After this
there is already a data structure inside kernel tracking the enclave
that is initially uncreated. After this a set of ioctl's can be used to
create, populate and initialize the enclave.

You can close (if you want) the fd after you've mmap()'d. As long as the
file is open the enclave stays alive so you might want to do that after
you don't need it anymore. Even munmap() won't destruct the enclave if
the file is open.  Neither will closing the fd as long as you have
mmap() done over the fd (even if it does not across the range defined in
SECS)."

Enclave can be created and initialized without doing a single mmap()
call.

We could even disallow mmap() before EINIT done. The way enclave
management internally works right now is quite robust and completely
detached from requiring process address space for anything.

/Jarkko