Re: [PATCH v28 11/22] x86/sgx: Linux Enclave Driver

[Jarkko Sakkinen]

On Thu, Mar 05, 2020 at 09:40:15AM -0800, Sean Christopherson wrote:
> Would it make sense to add reserved fields to the structs so that new
> features can be added in a backwards compatible way?  E.g. if we want to
> allow userspace to control the backing store by passing in a file
> descriptor ENCLAVE_CREATE.

It would not really be a huge win even if you did that since old
software would not be aware of the new fields. Sounds somewhat
messy to me.

Even a new ioctl later on is in my opinion always a better option
than reserved fields when you add ioctl's.

/Jarkko