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

Paolo Bonzini
2020-04-21T21:46:47Z

On 21/04/20 20:41, Andra Paraschiv wrote:
> An enclave communicates with the primary VM via a local communication channel,
> using virtio-vsock [2]. An enclave does not have a disk or a network device
> attached.

Is it possible to have a sample of this in the samples/ directory?

I am interested especially in:

- the initial CPU state: CPL0 vs. CPL3, initial program counter, etc.

- the communication channel; does the enclave see the usual local APIC
and IOAPIC interfaces in order to get interrupts from virtio-vsock, and
where is the virtio-vsock device (virtio-mmio I suppose) placed in memory?

- what the enclave is allowed to do: can it change privilege levels,
what happens if the enclave performs an access to nonexistent memory, etc.

- whether there are special hypercall interfaces for the enclave

> The proposed solution is following the KVM model and uses the KVM API to be able
> to create and set resources for enclaves. An additional ioctl command, besides
> the ones provided by KVM, is used to start an enclave and setup the addressing
> for the communication channel and an enclave unique id.

Reusing some KVM ioctls is definitely a good idea, but I wouldn't really
say it's the KVM API since the VCPU file descriptor is basically non
functional (without KVM_RUN and mmap it's not really the KVM API).

Paolo