On Wed, Oct 20, 2021 at 07:35:35PM -0500, Michael Roth wrote:
> Fortunately, all the code makes use of sev_status to get at the SEV MSR
> bits, so breaking the appropriate bits out of sme_enable() into an earlier
> sev_init() routine that's the exclusive writer of sev_status sounds like a
> promising approach.
Ack.
> It makes sense to do it immediately after the first #VC handler is set
> up, so CPUID is available, and since that's where SNP CPUID table
> initialization would need to happen if it's to be made available in
> #VC handler.
Right, and you can do all your init/CPUID prep there.
> It may even be similar enough between boot/compressed and run-time kernel
> that it could be a shared routine in sev-shared.c.
Uuh, bonus points! :-)
> But then again it also sounds like the appropriate place to move the
> snp_cpuid_init*() calls, and locating the cc_blob, and since there's
> differences there it might make sense to keep the boot/compressed and
> kernel proper sev_init() routines separate to avoid #ifdeffery).
>
> Not to get ahead of myself though. Just seems like a good starting point
> for how to consolidate the various users.
I like how you're thinking. :)
> Got it, and my apologies if I've given you that impression as it's
> certainly not my intent. (though I'm sure you've heard that before.)
Nothing to apologize - all good.
> Agreed, if we need to check SEV MSR early for the purposes of SNP it makes
> sense to move the overall SEV feature detection code earlier as well. I
> should have looked into that aspect more closely before introducing the
> changes.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
