Re: [PATCH v3 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()

From: Paolo Bonzini
Date: Tue Mar 23 2021 - 12:39:42 EST

On 23/03/21 17:06, Borislav Petkov wrote:
Practically speaking, "basic" deployments of SGX VMs will be insulated from
this bug. KVM doesn't support EPC oversubscription, so even if all EPC is
exhausted, new VMs will fail to launch, but existing VMs will continue to chug
along with no ill effects....

Ok, so it sounds to me like*at* *least* there should be some writeup in
Documentation/ explaining to the user what to do when she sees such an
EREMOVE failure, perhaps the gist of this thread and then possibly the
error message should point to that doc.

That's important, but it's even more important *to developers* that the commit message spells out why this would be a kernel bug more often than not. I for one do not understand it, and I suspect I'm not alone.

Maybe (optimistically) once we see that explanation we decide that the documentation is not important. Sean, Kai, can you explain it?