On Fri, 2022-07-22 at 08:21 -0700, 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... > > If that's wrong or imprecise, I'd love to hear more about it and also > about how the spec will be updated. > They are enumerated separately, but looks in practice the notify handler will use it to switch back to the correct/targeted CSSA to continue to run normally after handling the exit notify. This is my understanding of the "facilitate" mean in the spec. Btw, in real hardware I think the two should come together, meaning no real hardware will only support one. Haitao, could you give us more information? -- Thanks, -Kai
