On Jun 5, 2019, at 8:17 AM, Jarkko Sakkinen [off-list ref] wrote:

quoted

On Tue, Jun 04, 2019 at 10:10:22PM +0000, Xing, Cedric wrote:
A bit off topic here. This mmap()/mprotect() discussion reminds me a
question (guess for Jarkko): Now that vma->vm_file->private_data keeps
a pointer to the enclave, why do we store it again in vma->vm_private?
It isn't a big deal but non-NULL vm_private does prevent mprotect()
from merging adjacent VMAs. 

Same semantics as with a regular mmap i.e. you can close the file and
still use the mapping.

The file should be properly refcounted — vm_file should not go away while it’s mapped.