EXPORT_SYMBOL_FOR_KVM() exists to export symbols to KVM modules. Static
calls need the same treatment when the core kernel defines a static_call
that KVM needs access to (e.g. from a VM-exit path).

Define EXPORT_STATIC_CALL_FOR_KVM() as the static_call analogue of
EXPORT_SYMBOL_FOR_KVM(). The same three-way logic applies:

  - KVM_SUB_MODULES defined: export to "kvm," plus all sub-modules
  - KVM=m, no sub-modules: export to "kvm" only
  - KVM built-in: no export needed (noop)

  As with EXPORT_SYMBOL_FOR_KVM(), allow architectures to override both
  macros (e.g. to suppress the export when kvm.ko itself will not be
  built despite CONFIG_KVM=m). Add the x86 no-op overrides in
  arch/x86/include/asm/kvm_types.h for that case. To keep the pair in
  sync, EXPORT_STATIC_CALL_FOR_KVM() is defined inside the
  EXPORT_SYMBOL_FOR_KVM #ifndef block; an arch that defines
  EXPORT_SYMBOL_FOR_KVM must also define EXPORT_STATIC_CALL_FOR_KVM or the
  build will fail with a compile-time error.

As with EXPORT_SYMBOL_FOR_KVM(), allow architectures to override
EXPORT_STATIC_CALL_FOR_KVM definition (e.g. to suppress the export when
kvm.ko itself will not be built despite CONFIG_KVM=m). Add the x86 no-op
override in arch/x86/include/asm/kvm_types.h for that case.

Architectures must also define EXPORT_STATIC_CALL_FOR_KVM when they define
EXPORT_SYMBOL_FOR_KVM.

This isn't a bug, but the arch-override rationale appears twice in nearly
identical form.  The third paragraph (starting "As with
EXPORT_SYMBOL_FOR_KVM(), allow architectures to override both macros") and
the fourth paragraph (starting "As with EXPORT_SYMBOL_FOR_KVM(), allow
architectures to override EXPORT_STATIC_CALL_FOR_KVM definition") both
explain suppressing the export when kvm.ko will not be built and both
mention adding the x86 no-op override.

The requirement that an arch defining EXPORT_SYMBOL_FOR_KVM must also
define EXPORT_STATIC_CALL_FOR_KVM also shows up twice: once inside the
third paragraph ("an arch that defines EXPORT_SYMBOL_FOR_KVM must also
define EXPORT_STATIC_CALL_FOR_KVM or the build will fail") and again as the
standalone final sentence ("Architectures must also define
EXPORT_STATIC_CALL_FOR_KVM when they define EXPORT_SYMBOL_FOR_KVM").

Could the duplicate paragraphs be folded into a single statement?


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/28046221590