Re: SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support)

From: Jarkko Sakkinen
Date: Mon May 20 2019 - 07:43:44 EST

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

"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

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