Re: [PATCH] [v2] x86/sgx: Allow enclaves to use Asynchrounous Exit Notification

From: Sean Christopherson
Date: Fri Jul 22 2022 - 14:44:30 EST


On Fri, Jul 22, 2022, Dave Hansen wrote:
> On 7/22/22 06:26, Kai Huang wrote:
> > Did a quick look at the spec. It appears ENCLU[EDECCSSA] should be used
> > together with AEX-notify. So besides advertising the new
> > SGX_ATTR_ASYNC_EXIT_NOTIFY bit to the KVM guest, I think we should also
> > advertise the ENCLU[EDECCSSA] support in guest's CPUID, like below (untested)?
>
> Sounds like a great follow-on patch! It doesn't seem truly functionally
> required from the spec:
>
> > EDECCSSA is a new Intel SGX user leaf function
> > (ENCLU[EDECCSSA]) that can facilitate AEX notification handling...

Yeah, it's enumerated separately.

> If that's wrong or imprecise, I'd love to hear more about it and also
> about how the spec will be updated.
>
> Oh, and the one-liner patch that I was promised for enabling this is
> getting a _wee_ bit longer than one line.

Heh, fool me once...