Re: [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address

From: Jarkko Sakkinen
Date: Wed Jun 05 2019 - 11:21:23 EST

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.