diff options
| author | Like Xu <likexu@tencent.com> | 2022-09-23 00:13:54 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-11-09 12:31:36 -0500 |
| commit | 68fb4757e8678894530ee0b15c29a3567207b970 (patch) | |
| tree | 711ba4357bd7d0f1fa7266f7ca36ca1820a3205e /arch/x86/kvm/vmx/pmu_intel.c | |
| parent | dcbb816a2842e41d3ec22605c6760837d800b20a (diff) | |
| download | lwn-68fb4757e8678894530ee0b15c29a3567207b970.tar.gz lwn-68fb4757e8678894530ee0b15c29a3567207b970.zip | |
KVM: x86/pmu: Defer reprogram_counter() to kvm_pmu_handle_event()
Batch reprogramming PMU counters by setting KVM_REQ_PMU and thus
deferring reprogramming kvm_pmu_handle_event() to avoid reprogramming
a counter multiple times during a single VM-Exit.
Deferring programming will also allow KVM to fix a bug where immediately
reprogramming a counter can result in sleeping (taking a mutex) while
interrupts are disabled in the VM-Exit fastpath.
Introduce kvm_pmu_request_counter_reprogam() to make it obvious that
KVM is _requesting_ a reprogram and not actually doing the reprogram.
Opportunistically refine related comments to avoid misunderstandings.
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-5-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220923001355.3741194-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/pmu_intel.c')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index b7c3a9874a93..6c80dff37b77 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -52,7 +52,7 @@ static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) pmc = get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + i); __set_bit(INTEL_PMC_IDX_FIXED + i, pmu->pmc_in_use); - reprogram_counter(pmc); + kvm_pmu_request_counter_reprogam(pmc); } } @@ -76,7 +76,7 @@ static void reprogram_counters(struct kvm_pmu *pmu, u64 diff) for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX) { pmc = intel_pmc_idx_to_pmc(pmu, bit); if (pmc) - reprogram_counter(pmc); + kvm_pmu_request_counter_reprogam(pmc); } } @@ -477,7 +477,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) reserved_bits ^= HSW_IN_TX_CHECKPOINTED; if (!(data & reserved_bits)) { pmc->eventsel = data; - reprogram_counter(pmc); + kvm_pmu_request_counter_reprogam(pmc); return 0; } } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) |