Re: [PATCH v20 15/28] x86/sgx: Add the Linux SGX Enclave Driver

From: Sean Christopherson
Date: Tue Jun 04 2019 - 16:16:30 EST

On Tue, Apr 23, 2019 at 05:26:53PM -0700, Sean Christopherson wrote:
> On Tue, Apr 23, 2019 at 11:29:24PM +0000, Jethro Beekman wrote:
> > On 2019-04-22 14:58, Sean Christopherson wrote:
> > >Where do we stand on removing the ACPI and platform_driver dependencies?
> > >Can we get rid of them sooner rather than later?
> >
> > You know my position on this...
> > . I don't really have
> > any new arguments.
> >
> > Considering the amount of planned changes for the driver post-merge, I think
> > it's crucial that the driver part can be swapped out with alternative
> > implementations.
> This gets far outside of my area of expertise as I think this is more of
> a policy question as opposed to a technical question, e.g. do we export
> function simply to allow out-of-tree alternatives.
> > >Now that the core SGX code is approaching stability, I'd like to start
> > >sending RFCs for the EPC virtualization and KVM bits to hash out that side
> > >of things. The ACPI crud is the last chunk of code that would require
> > >non-trivial changes to the core SGX code for the proposed virtualization
> > >implementation. I'd strongly prefer to get it out of the way before
> > >sending the KVM RFCs.
> >
> > What kind of changes? Wouldn't KVM just be another consumer of the same API
> > used by the driver?
> Nope, userspace "only" needs to be able to mmap() arbitrary chunks of EPC.
> Except for EPC management, which is already in built into the kernel, the
> EPC virtualization code has effectively zero overlap with the driver. Of
> course this is all technically speculative since none of this is upstream...

Jarkko, can you weigh in with your thoughts on the ACPI stuff?