On 1/9/2023 3:28 pm, Xiong Zhang wrote:
Arch PMU v4 introduces a new MSR, IA32_PERF_GLOBAL_INUSE. It provides
as "InUse" bit for each GP counter and fixed counter in processor.
Additionally PMI InUse[bit 63] indicates if the PMI mechanism has been
configured.
Each bit's definition references Architectural Performance Monitoring
Version 4 section of SDM.
Signed-off-by: Xiong Zhang <xiong.y.zhang@xxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 4 +++
arch/x86/kvm/vmx/pmu_intel.c | 58 ++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+)
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 7c8cf6b53a76..31bb425899fb 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -1036,6 +1036,7 @@
#define MSR_CORE_PERF_GLOBAL_CTRL 0x0000038f
#define MSR_CORE_PERF_GLOBAL_OVF_CTRL 0x00000390
#define MSR_CORE_PERF_GLOBAL_STATUS_SET 0x00000391
+#define MSR_CORE_PERF_GLOBAL_INUSE 0x00000392
#define MSR_PERF_METRICS 0x00000329
@@ -1048,6 +1049,9 @@
#define MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD_BIT 63
#define MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD (1ULL << MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD_BIT)
+/* PERF_GLOBAL_INUSE bits */
+#define MSR_CORE_PERF_GLOBAL_INUSE_PMI BIT_ULL(63)
+
/* Geode defined MSRs */
#define MSR_GEODE_BUSCONT_CONF0 0x00001900
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index b25df421cd75..46363ac82a79 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -207,6 +207,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
case MSR_CORE_PERF_FIXED_CTR_CTRL:
return kvm_pmu_has_perf_global_ctrl(pmu);
case MSR_CORE_PERF_GLOBAL_STATUS_SET:
+ case MSR_CORE_PERF_GLOBAL_INUSE:
return vcpu_to_pmu(vcpu)->version >= 4;
case MSR_IA32_PEBS_ENABLE:
ret = vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PEBS_FORMAT;
@@ -347,6 +348,58 @@ static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu,
return true;
}
+static u64 intel_pmu_global_inuse_emulation(struct kvm_pmu *pmu)
+{
+ u64 data = 0;
+ int i;
+
+ for (i = 0; i < pmu->nr_arch_gp_counters; i++) {
+ struct kvm_pmc *pmc = &pmu->gp_counters[i];
+
+ /*
+ * IA32_PERF_GLOBAL_INUSE.PERFEVTSELn_InUse[bit n]: This bit
+ * reflects the logical state of (IA32_PERFEVTSELn[7:0]),
+ * n < CPUID.0AH.EAX[15:8].
+ */
+ if (pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT)
+ data |= 1 << i;
+ /*
+ * IA32_PERF_GLOBAL_INUSE.PMI_InUse[bit 63]: This bit is set if
+ * IA32_PERFEVTSELn.INT[bit 20], n < CPUID.0AH.EAX[15:8] is set.
+ */
+ if (pmc->eventsel & ARCH_PERFMON_EVENTSEL_INT)
+ data |= MSR_CORE_PERF_GLOBAL_INUSE_PMI;
If this bit is already set, there is no need to repeat it to avoid wasting cycles.
+ }
+
+ for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
+ /*
+ * IA32_PERF_GLOBAL_INUSE.FCi_InUse[bit (i + 32)]: This bit
+ * reflects the logical state of
+ * IA32_FIXED_CTR_CTRL[i * 4 + 1, i * 4] != 0
+ */
+ if (pmu->fixed_ctr_ctrl &
+ intel_fixed_bits_by_idx(i, INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER))
+ data |= 1ULL << (i + INTEL_PMC_IDX_FIXED);
+ /*
+ * IA32_PERF_GLOBAL_INUSE.PMI_InUse[bit 63]: This bit is set if
+ * IA32_FIXED_CTR_CTRL.ENi_PMI, i = 0, 1, 2 is set.
+ */
+ if (pmu->fixed_ctr_ctrl &
+ intel_fixed_bits_by_idx(i, INTEL_FIXED_0_ENABLE_PMI))
+ data |= MSR_CORE_PERF_GLOBAL_INUSE_PMI;
+ }
+
+ /*
+ * IA32_PERF_GLOBAL_INUSE.PMI_InUse[bit 63]: This bit is set if
+ * any IA32_PEBS_ENABLES bit is set, which enables PEBS for a GP or
+ * fixed counter.
+ */
+ if (pmu->pebs_enable)
+ data |= MSR_CORE_PERF_GLOBAL_INUSE_PMI;
+
+ return data;
+}
+
static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -360,6 +413,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_CORE_PERF_GLOBAL_STATUS_SET:
msr_info->data = 0;
break;
+ case MSR_CORE_PERF_GLOBAL_INUSE:
+ msr_info->data = intel_pmu_global_inuse_emulation(pmu);
+ break;
case MSR_IA32_PEBS_ENABLE:
msr_info->data = pmu->pebs_enable;
break;
@@ -409,6 +465,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (pmu->fixed_ctr_ctrl != data)
reprogram_fixed_counters(pmu, data);
break;
+ case MSR_CORE_PERF_GLOBAL_INUSE:
+ return 1; /* RO MSR */
Is msrs_to_save_pmu[] updated?
case MSR_IA32_PEBS_ENABLE:
if (data & pmu->pebs_enable_mask)
return 1;
