Messages in this thread | | | Date | Wed, 9 Feb 2022 20:11:57 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCHv2 00/29] TDX Guest: TDX core support |
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On Wed, Feb 09, 2022 at 04:50:08PM +0000, Sean Christopherson wrote: > On Wed, Feb 09, 2022, Borislav Petkov wrote: > > On Thu, Feb 10, 2022 at 12:48:31AM +1300, Kai Huang wrote: > > > Are you suggesting even for now we can start to put TDX host support to > > > arch/x86/coco/tdx/ ? > > > > That's exactly what I'm suggesting. The TDX stuff is not upstream so > > nothing's cast in stone yet. This way there won't be any unpleasant code > > movements later. > > I strongly prefer we put the guest and host code in separate directories. Both > TDX and SEV are big enough that they'll benefit from splitting up files, having > to fight over file names or tag all files with guest/host will get annoying. > > I do like the idea of arch/x86/coco though. The most straightforward approach > would be: > > arch/x86/coco/guest/ > arch/x86/coco/host/ > > but that doesn't provide any extensibility on the host virtualization side, e.g. > to land non-coco, non-KVM-specific host virtualization code (we have a potential > use case for this). If that happens, we'd end up with x86 KVM having code and > dependencies split across: > > arch/x86/coco/host > arch/x86/kvm/ > arch/x86/???/ > > An alternative idea would be to mirror what generic KVM does (virt/kvm/), and do: > > arch/x86/coco/<guest stuff> > arch/x86/virt/<"generic" x86 host virtualization stuff> > arch/x86/virt/coco/<host coco stuff> > arch/x86/virt/kvm/ > > Though I can already hear the stable trees and downstream kernels crying out in > horror at moving arch/x86/kvm :-)
Hmmm, so I am still thinking about guest-only when we're talking about arch/x86/coco/.
Lemme look at the other virt things:
the kvm host virt stuff is in:
arch/x86/kvm/
(btw, this is where the SEV host stuff is: arch/x86/kvm/svm/sev.c)
arch/x86/hyperv/ - looks like hyperv guest stuff
arch/x86/xen/ - xen guest stuff
arch/x86/kernel/cpu/vmware.c - vmware guest stuff
arch/x86/kernel/cpu/acrn.c - Acorn guest stuff
So we have a real mess. :-(
Not surprised though. So that last thing you're suggesting kinda makes sense but lemme tweak it a bit:
arch/x86/coco/<guest stuff> arch/x86/virt/<"generic" x86 host virtualization stuff> arch/x86/virt/tdx/ - no need for the "coco" thing - TDX is nothing but coco. TDX host stuff
arch/x86/virt/sev/ - ditto
and we'll keep arch/x86/kvm because of previous precedents with other things I've enumerated above.
Hmmm?
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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