diff options
| author | Dapeng Mi <dapeng1.mi@linux.intel.com> | 2025-12-06 03:17:01 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-01-08 22:52:10 +0300 |
| commit | 3db871fe185baca66e78b56a230e236af40f1027 (patch) | |
| tree | 00ed33319c657a95e5863b469cfb0b7dfe6a4a7b | |
| parent | 02918f0077925994b04be147875b6de8b63ca249 (diff) | |
| download | linux-3db871fe185baca66e78b56a230e236af40f1027.tar.xz | |
KVM: x86/pmu: Reprogram mediated PMU event selectors on event filter updates
Refresh the event selectors that are programmed into hardware when a PMC
is "reprogrammed" for a mediated PMU, i.e. if userspace changes the PMU
event filters
Note, KVM doesn't utilize the reprogramming infrastructure to handle
counter overflow for mediated PMUs, as there's no need to reprogram a
non-existent perf event.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Co-developed-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
[sean: add a helper to document behavior, split patch and rewrite changelog]
Tested-by: Xudong Hao <xudong.hao@intel.com>
Tested-by: Manali Shukla <manali.shukla@amd.com>
Link: https://patch.msgid.link/20251206001720.468579-26-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/pmu.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index a05366e4eef2..24f5c14715ef 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -520,6 +520,25 @@ static bool pmc_is_event_allowed(struct kvm_pmc *pmc) return is_fixed_event_allowed(filter, pmc->idx); } +static void kvm_mediated_pmu_refresh_event_filter(struct kvm_pmc *pmc) +{ + bool allowed = pmc_is_event_allowed(pmc); + struct kvm_pmu *pmu = pmc_to_pmu(pmc); + + if (pmc_is_gp(pmc)) { + pmc->eventsel_hw &= ~ARCH_PERFMON_EVENTSEL_ENABLE; + if (allowed) + pmc->eventsel_hw |= pmc->eventsel & + ARCH_PERFMON_EVENTSEL_ENABLE; + } else { + u64 mask = intel_fixed_bits_by_idx(pmc->idx - KVM_FIXED_PMC_BASE_IDX, 0xf); + + pmu->fixed_ctr_ctrl_hw &= ~mask; + if (allowed) + pmu->fixed_ctr_ctrl_hw |= pmu->fixed_ctr_ctrl & mask; + } +} + static int reprogram_counter(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); @@ -528,6 +547,11 @@ static int reprogram_counter(struct kvm_pmc *pmc) bool emulate_overflow; u8 fixed_ctr_ctrl; + if (kvm_vcpu_has_mediated_pmu(pmu_to_vcpu(pmu))) { + kvm_mediated_pmu_refresh_event_filter(pmc); + return 0; + } + emulate_overflow = pmc_pause_counter(pmc); if (!pmc_is_globally_enabled(pmc) || !pmc_is_locally_enabled(pmc) || |