On Tue, Nov 02, 2021 at 01:24:01PM -0500, Brijesh Singh wrote: > To answer your question, GHCB is registered at the time of first #VC > handling by the second exception handler. And this is what I don't like - register at use. Instead of init everything *before* use. > Mike can correct me, the CPUID page check is going to happen on first > #VC handling inside the early exception handler (i.e case 1). What is the "CPUID page check"? And no, you don't want to do any detection when an exception happens - you want to detect *everything* *first* and then do exceptions. > See if my above explanation make sense. Based on it, I don't think it > makes sense to register the GHCB during the CPUID page detection. The > CPUID page detection will occur in early VC handling. See above. If this needs more discussion, we can talk on IRC. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette