[PATCH 0/4] KVM: Register cpuhp/syscore callbacks when enabling virt

[Sean Christopherson]

Register KVM's cpuhp and syscore callbacks when enabling virtualization in
hardware, as the sole purpose of said callbacks is to disable and re-enable
virtualization as needed.

The primary motivation for this series is to simplify dealing with enabling
virtualization for Intel's TDX, which needs to temporarily enable virtualization
when kvm-intek.ko is loaded, i.e. long before the first VM is created.

That said, this is a nice cleanup on its own, assuming I haven't broken
something.  By registering the callbacks on-demand, the callbacks themselves
don't need to check kvm_usage_count, because their very existence implies a
non-zero count.

The meat is in patch 3, patches 1 and 2 are tangentially related x86
cleanups, patch 4 renames helpers to further pave the way for TDX.

Moderately well tested on x86, though I haven't (yet) done due dilegence on
the suspend/resume and cphup paths.  I ran selftests on arm64 and nothing
exploded.
 
Sean Christopherson (4):
  x86/reboot: Unconditionally define cpu_emergency_virt_cb typedef
  KVM: x86: Register emergency virt callback in common code, via
    kvm_x86_ops
  KVM: Register cpuhp and syscore callbacks when enabling hardware
  KVM: Rename functions related to enabling virtualization hardware

 arch/x86/include/asm/kvm_host.h |   3 +
 arch/x86/include/asm/reboot.h   |   2 +-
 arch/x86/kvm/svm/svm.c          |   5 +-
 arch/x86/kvm/vmx/main.c         |   2 +
 arch/x86/kvm/vmx/vmx.c          |   6 +-
 arch/x86/kvm/vmx/x86_ops.h      |   1 +
 arch/x86/kvm/x86.c              |   5 +
 virt/kvm/kvm_main.c             | 186 +++++++++++---------------------
 8 files changed, 78 insertions(+), 132 deletions(-)


base-commit: 7b076c6a308ec5bce9fc96e2935443ed228b9148
-- 
2.44.0.769.g3c40516874-goog