Re: [RFC PATCH v3 26/59] KVM: x86: Introduce vm_teardown() hook in kvm_arch_vm_destroy()

[Thomas Gleixner]

On Wed, Nov 24 2021 at 16:20, isaku yamahata wrote:
> Add a second kvm_x86_ops hook in kvm_arch_vm_destroy() to support TDX's
> destruction path, which needs to first put the VM into a teardown state,
> then free per-vCPU resource, and finally free per-VM resources.
>
> Note, this knowingly creates a discrepancy in nomenclature for SVM as
> svm_vm_teardown() invokes avic_vm_destroy() and sev_vm_destroy().
> Moving the now-misnamed functions or renaming them is left to a future
> patch so as not to introduce a functional change for SVM.

That's just the wrong way around. Fixup SVM first and then add the TDX
muck on top. Stop this 'left to a future patch' nonsense. I know for
sure that those future patches never materialize.

The way it works is:

    1) Refactor the code to make room for your new functionality in a
       way that the existing code still works.

    2) Add your new muck on top.

Anything else is not acceptable at all.

Thanks,

        tglx