[PATCH v2 0/6] Support writable CPU ID registers from userspace

[Jing Zhang]

This patchset refactors/adds code to support writable per guest CPU ID feature
registers. Part of the code/ideas are from
https://lore.kernel.org/all/20220419065544.3616948-1-reijiw@google.com .
No functional change is intended in this patchset. With the new CPU ID feature
registers infrastructure, only writtings of ID_AA64PFR0_EL1.[CSV2|CSV3],
ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon are allowed as KVM does before.

Writable (Configurable) per guest CPU ID feature registers are useful for
creating/migrating guest on ARM CPUs with different kinds of features.

---

* v1 -> v2
  - Rebase to 7121a2e1d107 (kvmarm/next) Merge branch kvm-arm64/nv-prefix into kvmarm/next
  - Address writing issue for PMUVer

[1] https://lore.kernel.org/all/20230201025048.205820-1-jingzhangos@google.com

---

Jing Zhang (5):
  KVM: arm64: Move CPU ID feature registers emulation into a separate
    file
  KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3]
  KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer
  KVM: arm64: Introduce ID register specific descriptor
  KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3

Reiji Watanabe (1):
  KVM: arm64: Save ID registers' sanitized value per guest

 arch/arm64/include/asm/cpufeature.h |  25 +
 arch/arm64/include/asm/kvm_host.h   |  26 +-
 arch/arm64/kernel/cpufeature.c      |  26 +-
 arch/arm64/kvm/Makefile             |   2 +-
 arch/arm64/kvm/arm.c                |  24 +-
 arch/arm64/kvm/hyp/nvhe/sys_regs.c  |   7 +-
 arch/arm64/kvm/id_regs.c            | 773 ++++++++++++++++++++++++++++
 arch/arm64/kvm/sys_regs.c           | 468 +----------------
 arch/arm64/kvm/sys_regs.h           |  30 ++
 include/kvm/arm_pmu.h               |   6 +-
 10 files changed, 885 insertions(+), 502 deletions(-)
 create mode 100644 arch/arm64/kvm/id_regs.c


base-commit: 7121a2e1d1070913f692d32806a36b8b3b3f0008
-- 
2.39.1.581.gbfd45094c4-goog