Re: [PATCH v1 00/15] Add support for Nitro Enclaves

From: Paraschiv, Andra-Irina
Date: Mon May 11 2020 - 06:50:14 EST




On 10/05/2020 14:02, Herrenschmidt, Benjamin wrote:
On Sat, 2020-05-09 at 21:21 +0200, Pavel Machek wrote:
On Fri 2020-05-08 10:00:27, Paraschiv, Andra-Irina wrote:

On 07/05/2020 20:44, Pavel Machek wrote:
Hi!

it uses its own memory and CPUs + its virtio-vsock emulated device for
communication with the primary VM.

The memory and CPUs are carved out of the primary VM, they are dedicated
for the enclave. The Nitro hypervisor running on the host ensures memory
and CPU isolation between the primary VM and the enclave VM.

These two components need to reflect the same state e.g. when the
enclave abstraction process (1) is terminated, the enclave VM (2) is
terminated as well.

With regard to the communication channel, the primary VM has its own
emulated virtio-vsock PCI device. The enclave VM has its own emulated
virtio-vsock device as well. This channel is used, for example, to fetch
data in the enclave and then process it. An application that sets up the
vsock socket and connects or listens, depending on the use case, is then
developed to use this channel; this happens on both ends - primary VM
and enclave VM.

Let me know if further clarifications are needed.
Thanks, this is all useful. However can you please clarify the
low-level details here?
Is the virtual machine manager open-source? If so, I guess pointer for sources
would be useful.
Hi Pavel,

Thanks for reaching out.

The VMM that is used for the primary / parent VM is not open source.
Do we want to merge code that opensource community can not test?
Hehe.. this isn't quite the story Pavel :)

We merge support for proprietary hypervisors, this is no different. You
can test it, well at least you'll be able to ... when AWS deploys the
functionality. You don't need the hypervisor itself to be open source.

In fact, in this case, it's not even low level invasive arch code like
some of the above can be. It's a driver for a PCI device :-) Granted a
virtual one. We merge drivers for PCI devices routinely without the RTL
or firmware of those devices being open source.

So yes, we probably want this if it's going to be a useful features to
users when running on AWS EC2. (Disclaimer: I work for AWS these days).

Indeed, it will available for checking out how it works.

The discussions are ongoing here on the LKML - understanding the context, clarifying items, sharing feedback and coming with codebase updates and basic example flow of the ioctl interface usage. This all helps with the path towards merging.

Thanks, Ben, for the follow-up.

Andra




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