[PATCH v4 0/3] KVM: arm64: ID register finalisation fixes

[Mark Brown]

While looking at some feature enablement I noticed that there are some
scenarios where we can end up with an inconsistently configured vCPU due
to finalizing configuration based on ID registers before we have blocked
writes to the ID registers. This series aims to clean up these issues.

Signed-off-by: Mark Brown <broonie at kernel.org>
---
Changes in v4:
- Rebase onto v7.3-rc3.
- Add a lockdep assert.
- Update Fuad's LLM tag.
- Link to v3: https://patch.msgid.link/20260901-kvm-arm64-idreg-final-v3-0-a0ffa06fa872@kernel.org

Changes in v3:
- Rebase onto v7.3-rc1.
- Explain why KVM_ARCH_FLAG_ID_REGS_INITIALIZED is not reused.
- Pull in Fuad's test cases.
- Link to v2: https://patch.msgid.link/20260803-kvm-arm64-idreg-final-v2-0-d7d7e4efc640@kernel.org

Changes in v2:
- Also replace the kvm_vm_has_ran_once() usage in kvm_set_vm_id_rg() and
  kvm_vm_finalize_sys_regs() with kvm_id_regs_final().
- Link to v1: https://patch.msgid.link/20260731-kvm-arm64-idreg-final-v1-0-3de2a5616dc6@kernel.org

---
Fuad Tabba (1):
      KVM: arm64: selftests: Check ID regs are immutable after a failed run

Mark Brown (2):
      KVM: arm64: Finalize guest-wide sysregs prior to per-vCPU sysregs
      KVM: arm64: Block ID register changes after we rely on the values

 arch/arm64/include/asm/kvm_host.h               |   8 ++
 arch/arm64/kvm/arm.c                            |   2 +-
 arch/arm64/kvm/sys_regs.c                       |  57 ++++++++-----
 arch/arm64/kvm/sys_regs.h                       |   2 +-
 arch/arm64/kvm/vgic/vgic-init.c                 |   6 +-
 tools/testing/selftests/kvm/arm64/set_id_regs.c | 106 +++++++++++++++++++++++-
 6 files changed, 154 insertions(+), 27 deletions(-)
---
base-commit: fd73f4a6659897191fa0d40695fe370925dd3780
change-id: 20260729-kvm-arm64-idreg-final-77cbc46b558a

Best regards,
--  
Mark Brown <broonie at kernel.org>