The Intel PEBS-via-PT feature introduces a new output mechanism that
directs PEBS records to the PT buffer, and after each PEBS record is
generated, it automatically reloads the counter values from a new set
of "reload values" MSRs (based on MSR_RELOAD_FIXED_CTRx and
MSR_RELOAD_PMCx), instead of the counter reload values stored in
the DS management area.
If perf_capabilities supports this capability, PEBS records will be
directed to the PT buffer when the relevant bit in pebs_enable is set.
Co-developed-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
---
arch/x86/events/perf_event.h | 5 -----
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/include/asm/msr-index.h | 6 ++++++
arch/x86/kvm/pmu.h | 8 ++++++++
arch/x86/kvm/vmx/pmu_intel.c | 18 ++++++++++++++++++
5 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 685a1a4e9438..4171f1328732 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -115,11 +115,6 @@ struct amd_nb {
};
#define PEBS_COUNTER_MASK ((1ULL << MAX_PEBS_EVENTS) - 1)
-#define PEBS_PMI_AFTER_EACH_RECORD BIT_ULL(60)
-#define PEBS_OUTPUT_OFFSET 61
-#define PEBS_OUTPUT_MASK (3ull << PEBS_OUTPUT_OFFSET)
-#define PEBS_OUTPUT_PT (1ull << PEBS_OUTPUT_OFFSET)
-#define PEBS_VIA_PT_MASK (PEBS_OUTPUT_PT | PEBS_PMI_AFTER_EACH_RECORD)
/*
* Flags PEBS can handle without an PMI.
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 15bff609fd57..29d2d8027014 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -443,6 +443,7 @@ struct kvm_pmc {
u8 idx;
u64 counter;
u64 eventsel;
+ u64 reload_counter;
struct perf_event *perf_event;
struct kvm_vcpu *vcpu;
/*
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 1ab3f280f3a9..364c40ecd963 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -187,12 +187,18 @@
#define MSR_IA32_PERF_CAPABILITIES 0x00000345
#define PERF_CAP_METRICS_IDX 15
#define PERF_CAP_PT_IDX 16
+#define PEBS_PMI_AFTER_EACH_RECORD BIT_ULL(60)
+#define PEBS_OUTPUT_OFFSET 61
+#define PEBS_OUTPUT_MASK (3ull << PEBS_OUTPUT_OFFSET)
+#define PEBS_OUTPUT_PT (1ull << PEBS_OUTPUT_OFFSET)
+#define PEBS_VIA_PT_MASK (PEBS_OUTPUT_PT | PEBS_PMI_AFTER_EACH_RECORD)
#define MSR_PEBS_LD_LAT_THRESHOLD 0x000003f6
#define PERF_CAP_PEBS_TRAP BIT_ULL(6)
#define PERF_CAP_ARCH_REG BIT_ULL(7)
#define PERF_CAP_PEBS_FORMAT 0xf00
#define PERF_CAP_PEBS_BASELINE BIT_ULL(14)
+#define PERF_CAP_PEBS_OUTPUT_PT BIT_ULL(16)
#define PERF_CAP_PEBS_MASK (PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \
PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE)
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 6720881b8370..f9895a7a59bc 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -115,6 +115,10 @@ static inline bool kvm_valid_perf_global_ctrl(struct kvm_pmu *pmu,
static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr,
u32 base)
{
+ if ((msr == MSR_RELOAD_PMC0 || msr == MSR_RELOAD_FIXED_CTR0) &&
+ !(pmu_to_vcpu(pmu)->arch.perf_capabilities & PERF_CAP_PEBS_OUTPUT_PT))
+ return NULL;
+
if (msr >= base && msr < base + pmu->nr_arch_gp_counters) {
u32 index = array_index_nospec(msr - base,
pmu->nr_arch_gp_counters);
@@ -129,6 +133,10 @@ static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr,
static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu,
u32 msr, u32 base)
{
+ if ((msr == MSR_RELOAD_PMC0 || msr == MSR_RELOAD_FIXED_CTR0) &&
+ !(pmu_to_vcpu(pmu)->arch.perf_capabilities & PERF_CAP_PEBS_OUTPUT_PT))
+ return NULL;
+
if (msr >= base && msr < base + pmu->nr_arch_fixed_counters) {
u32 index = array_index_nospec(msr - base,
pmu->nr_arch_fixed_counters);
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index c10cb3008bf1..e5c12c958cdb 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -226,6 +226,8 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) ||
get_fixed_pmc(pmu, msr, MSR_CORE_PERF_FIXED_CTR0) ||
get_fw_gp_pmc(pmu, msr) ||
+ get_gp_pmc(pmu, msr, MSR_RELOAD_PMC0) ||
+ get_fixed_pmc(pmu, msr, MSR_RELOAD_FIXED_CTR0) ||
intel_pmu_is_valid_lbr_msr(vcpu, msr);
break;
}
@@ -241,6 +243,8 @@ static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
pmc = get_fixed_pmc(pmu, msr, MSR_CORE_PERF_FIXED_CTR0);
pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0);
pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0);
+ pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_RELOAD_PMC0);
+ pmc = pmc ? pmc : get_fixed_pmc(pmu, msr, MSR_RELOAD_FIXED_CTR0);
return pmc;
}
@@ -394,6 +398,10 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
msr_info->data = pmc->eventsel;
return 0;
+ } else if ((pmc = get_gp_pmc(pmu, msr, MSR_RELOAD_PMC0)) ||
+ (pmc = get_fixed_pmc(pmu, msr, MSR_RELOAD_FIXED_CTR0))) {
+ msr_info->data = pmc->reload_counter;
+ return 0;
} else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true))
return 0;
}
@@ -488,6 +496,12 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
reprogram_gp_counter(pmc, data);
return 0;
}
+ } else if ((pmc = get_gp_pmc(pmu, msr, MSR_RELOAD_PMC0)) ||
+ (pmc = get_fixed_pmc(pmu, msr, MSR_RELOAD_FIXED_CTR0))) {
+ if (!(data & ~pmc_bitmask(pmc))) {
+ pmc->reload_counter = data;
+ return 0;
+ }
} else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false))
return 0;
}
@@ -595,6 +609,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->pebs_enable_mask =
~((1ull << pmu->nr_arch_gp_counters) - 1);
}
+ if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_OUTPUT_PT)
+ pmu->pebs_enable_mask &= ~PEBS_VIA_PT_MASK;
} else {
vcpu->arch.ia32_misc_enable_msr |= MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL;
vcpu->arch.perf_capabilities &= ~PERF_CAP_PEBS_MASK;
@@ -612,6 +628,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
pmu->gp_counters[i].vcpu = vcpu;
pmu->gp_counters[i].idx = i;
pmu->gp_counters[i].current_config = 0;
+ pmu->gp_counters[i].reload_counter = 0;
}
for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) {
@@ -619,6 +636,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
pmu->fixed_counters[i].vcpu = vcpu;
pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
pmu->fixed_counters[i].current_config = 0;
+ pmu->fixed_counters[i].reload_counter = 0;
}
vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
--
2.31.1
