From: Dapeng Mi dapeng1.mi@linux.intel.com
Mediated vPMU needs to intercept EVENTSELx and FIXED_CNTR_CTRL MSRs to filter out guest malicious perf events. Either writing these MSRs or updating event filters would call reprogram_counter() eventually. Thus check if the guest event should be filtered out in reprogram_counter(). If so, clear corresponding EVENTSELx MSR or FIXED_CNTR_CTRL field to ensure the guest event won't be really enabled at vm-entry.
Besides, mediated vPMU intercepts the MSRs of these guest not owned counters and it just needs simply to read/write from/to pmc->counter.
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 --- arch/x86/kvm/pmu.c | 27 +++++++++++++++++++++++++++ arch/x86/kvm/pmu.h | 3 +++ 2 files changed, 30 insertions(+)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 63143eeb5c44..e9100dc49fdc 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -305,6 +305,11 @@ static void pmc_update_sample_period(struct kvm_pmc *pmc)
void pmc_write_counter(struct kvm_pmc *pmc, u64 val) { + if (kvm_mediated_pmu_enabled(pmc->vcpu)) { + pmc->counter = val & pmc_bitmask(pmc); + return; + } + /* * Drop any unconsumed accumulated counts, the WRMSR is a write, not a * read-modify-write. Adjust the counter value so that its value is @@ -455,6 +460,28 @@ static int reprogram_counter(struct kvm_pmc *pmc) bool emulate_overflow; u8 fixed_ctr_ctrl;
+ if (kvm_mediated_pmu_enabled(pmu_to_vcpu(pmu))) { + bool allowed = check_pmu_event_filter(pmc); + + if (pmc_is_gp(pmc)) { + if (allowed) + pmc->eventsel_hw |= pmc->eventsel & + ARCH_PERFMON_EVENTSEL_ENABLE; + else + pmc->eventsel_hw &= ~ARCH_PERFMON_EVENTSEL_ENABLE; + } else { + int idx = pmc->idx - KVM_FIXED_PMC_BASE_IDX; + + if (allowed) + pmu->fixed_ctr_ctrl_hw = pmu->fixed_ctr_ctrl; + else + pmu->fixed_ctr_ctrl_hw &= + ~intel_fixed_bits_by_idx(idx, 0xf); + } + + return 0; + } + emulate_overflow = pmc_pause_counter(pmc);
if (!pmc_event_is_allowed(pmc)) diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 509c995b7871..6289f523d893 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -113,6 +113,9 @@ static inline u64 pmc_read_counter(struct kvm_pmc *pmc) { u64 counter, enabled, running;
+ if (kvm_mediated_pmu_enabled(pmc->vcpu)) + return pmc->counter & pmc_bitmask(pmc); + counter = pmc->counter + pmc->emulated_counter;
if (pmc->perf_event && !pmc->is_paused)