[PATCH v2 0/5] KVM: x86/pmu: Add support for AMD Host-Only/Guest-Only bits

[Jim Mattson <jmattson@google.com>]

This series adds 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

v1: https://lore.kernel.org/kvm/20260121225438.3908422-1-jmattson@google.com/

v1 -> v2:
  - Fixed various style issues, including indentation, comment
    placement, and comparison to 0 [Sean]
  - Replaced "hg_only" with "host_guest" [Sean]
  - Reversed the polarity of the dormant/active logic [Sean]
  - Removed the pmc_hostonly and pmc_guestonly bitmaps [Sean]
  - Added a refresh helper that iterates over PMCs during transitions [Sean]
  - Introduced svm_enter_guest_mode() and svm_leave_guest_mode() [Sean]
  - Moved transition logic from VMRUN/VMEXIT emulation to the above [Sean]
  - Moved architectural definitions in the selftest to pmu.h [Sean]
  - Added a test for neither Host-Only nor Guest-Only [Sean]
  - Refactored the selftest to program all 4 bit combinations
    simultaneously, reducing code replication [Sean]


Jim Mattson (5):
  KVM: x86/pmu: Introduce amd_pmu_set_eventsel_hw()
  KVM: x86/pmu: Disable Host-Only/Guest-Only events as appropriate for
    vCPU state
  KVM: x86/pmu: Refresh Host-Only/Guest-Only eventsel at nested
    transitions
  KVM: x86/pmu: Allow Host-Only/Guest-Only bits with nSVM and mediated
    PMU
  KVM: selftests: x86: Add svm_pmu_host_guest_test for
    Host-Only/Guest-Only bits

 arch/x86/include/asm/perf_event.h             |   2 +
 arch/x86/kvm/svm/nested.c                     |   6 +-
 arch/x86/kvm/svm/pmu.c                        |  42 +++-
 arch/x86/kvm/svm/svm.c                        |   2 +
 arch/x86/kvm/svm/svm.h                        |  17 ++
 tools/testing/selftests/kvm/Makefile.kvm      |   1 +
 tools/testing/selftests/kvm/include/x86/pmu.h |   6 +
 .../kvm/x86/svm_pmu_host_guest_test.c         | 199 ++++++++++++++++++
 8 files changed, 270 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/x86/svm_pmu_host_guest_test.c


base-commit: 1a424e9e0616db91010f08e5985bcc6edc504205
-- 
2.53.0.rc1.225.gd81095ad13-goog