[PATCH v4 0/6] KVM: x86/pmu: Add support for AMD Host-Only/Guest-Only bits

[Yosry Ahmed <yosry@kernel.org>]

v4 of Jim's series adding support for AMD's Host-Only and Guest-Only
performance counter eventsel bits in KVM's mediated PMU passthrough
implementation.

These bits allow an nSVM-enabled guest to configure performance counters
that count only during L1 execution (Host-Only) or only during L2 execution
(Guest-Only).

KVM updates the hardware event selector ENABLE bit at the following state
transitions to ensure counters only count in the appropriate mode:

  - EFER.SVME changes: Enable/disable Guest-Only counters
  - Nested VMRUN: Disable Host-Only, enable Guest-Only counters
  - Nested VMEXIT: Enable Host-Only, disable Guest-Only counters

v3 -> v4:
- Dropped amd_pmu_set_eventsel_hw(), moved handling of
  Host-Only/Guest-Only bits to PMU counter reprogramming and funnelled
  all processing through KVM_REQ_PMU [Sean].
  - For this to work, added a per-vendor callback for reprogramming PMU
    counters.
- Sorta restored the bitmask from v1, except now it's a single bitmask
  tracking all counters that need to be reprogrammed on nested
  transitions. The bitmask is used to avoid unnecessary KVM_REQ_PMU
  requests and only reprogram counters as needed  [Jim].
  - This is also needed to avoid directling calling vendor code from
    {enter/leave}_guest_mode() as requested by Sean.
- Added prep patches moving enable_pmu/enable_mediated_pmu and
  guest_mode helpers to facilitate following changes without circular
  dependencies and to avoid including new headers from leaf headers.

v3: https://lore.kernel.org/kvm/20260207012339.2646196-1-jmattson@google.com/

Jim Mattson (2):
  KVM: x86/pmu: Allow Host-Only/Guest-Only bits with nSVM and mediated
    PMU
  KVM: selftests: Add svm_pmu_host_guest_test for Host-Only/Guest-Only
    bits

Yosry Ahmed (4):
  KVM: x86: Move enable_pmu/enable_mediated_pmu to pmu.h and pmu.c
  KVM: x86: Move guest_mode helpers to x86.h
  KVM: x86/pmu: Disable counters based on Host-Only/Guest-Only bits in
    SVM
  KVM: x86/pmu: Re-evaluate Host-Only/Guest-Only on nested SVM
    transitions

 arch/x86/include/asm/kvm-x86-pmu-ops.h        |   1 +
 arch/x86/include/asm/kvm_host.h               |   6 +
 arch/x86/include/asm/perf_event.h             |   2 +
 arch/x86/kvm/kvm_cache_regs.h                 |  23 --
 arch/x86/kvm/pmu.c                            |  12 ++
 arch/x86/kvm/pmu.h                            |  17 ++
 arch/x86/kvm/svm/pmu.c                        |  44 ++++
 arch/x86/kvm/svm/svm.c                        |   1 +
 arch/x86/kvm/x86.c                            |   9 -
 arch/x86/kvm/x86.h                            |  31 ++-
 tools/testing/selftests/kvm/Makefile.kvm      |   1 +
 tools/testing/selftests/kvm/include/x86/pmu.h |   6 +
 .../selftests/kvm/include/x86/processor.h     |   2 +
 .../kvm/x86/svm_pmu_host_guest_test.c         | 199 ++++++++++++++++++
 14 files changed, 319 insertions(+), 35 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/x86/svm_pmu_host_guest_test.c


base-commit: 3d6cdcc8883b5726513d245eef0e91cabfc397f7
-- 
2.53.0.1018.g2bb0e51243-goog