Re: [PATCH v8 5/5] x86/tdx: Add Quote generation support

Dave Hansen
2022-07-22T19:13:46Z

On 7/22/22 12:05, Isaku Yamahata wrote:
>> So, the quote portion of this is basically a bidirectional blob sender.
>> It's to send a blob between guest userspace to host userspace.
>>
>> Do we *REALLY* need specific driver functionality for this? For
>> instance, is there no existing virtio device that can send blobs back
>> and forth?
> It's virtio-vsock. If virtio-vsock is available, the communication works.
> However, some users would like to disable virtio-vsock on their environment for
> some reasons. Even virtio at all. Especially for confidential computing use
> case. It's their choice. It can't be assumed that virtio is available.
>
> The goal is VMM-agnostic (but TDX-specific) interface for that.

You're basically saying that every confidential computing technology
should have its own host user <-> guest kernel <-> guest user ABI.
That's insanity. If we do this, we need *one* interface that says "talk
to the hypervisor" that's common for all hypervisors and hardware
vendors, or at least more than *one*.

We don't need a way to talk to hypervisors for Intel systems and another
for AMD and yet another on whatever.