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Subject[RFC] [PATCH v2 2/5] KVM/x86/vPMU: add pmc operations for vmx and count to track release
Date
The introduced hw_life_count is initialized with HW_LIFE_COUNT_MAX
when the vPMC holds a hw-assigned perf_event and the kvm_pmu_sched ctx
would start counting down (0 means to be released) if not be charged.

If vPMC is assigned, the intel_pmc_read_counter() would use rdpmcl
directly not perf_event_read_value() and charge hw_life_count to max.

To clear out responsibility for potential operating space in kvm,
this patch is not going to invoke similar functions from host perf.

Signed-off-by: Wang Wei <wei.w.wang@intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/vmx/pmu_intel.c | 98 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 100 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a5db447..2a2c78f2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -449,6 +449,7 @@ enum pmc_type {
KVM_PMC_FIXED,
};

+#define HW_LIFE_COUNT_MAX 2
struct kvm_pmc {
enum pmc_type type;
u8 idx;
@@ -456,6 +457,7 @@ struct kvm_pmc {
u64 eventsel;
struct perf_event *perf_event;
struct kvm_vcpu *vcpu;
+ int hw_life_count;
};

struct kvm_pmu {
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 5ab4a36..bb16031 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -35,6 +35,104 @@
/* mapping between fixed pmc index and intel_arch_events array */
static int fixed_pmc_events[] = {1, 0, 7};

+static bool intel_pmc_is_assigned(struct kvm_pmc *pmc)
+{
+ return pmc->perf_event != NULL &&
+ pmc->perf_event->hw.idx != -1 &&
+ pmc->perf_event->oncpu != -1;
+}
+
+static int intel_pmc_read_counter(struct kvm_vcpu *vcpu,
+ unsigned int idx, u64 *data)
+{
+ struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx);
+
+ if (intel_pmc_is_assigned(pmc)) {
+ rdpmcl(pmc->perf_event->hw.event_base_rdpmc, *data);
+ pmc->counter = *data;
+ pmc->hw_life_count = HW_LIFE_COUNT_MAX;
+ } else {
+ *data = pmc->counter;
+ }
+ return 0;
+}
+
+static void intel_pmu_enable_host_gp_counter(struct kvm_pmc *pmc)
+{
+ u64 config;
+
+ if (!intel_pmc_is_assigned(pmc))
+ return;
+
+ config = (pmc->type == KVM_PMC_GP) ? pmc->eventsel :
+ pmc->perf_event->hw.config | ARCH_PERFMON_EVENTSEL_ENABLE;
+ wrmsrl(pmc->perf_event->hw.config_base, config);
+}
+
+static void intel_pmu_disable_host_gp_counter(struct kvm_pmc *pmc)
+{
+ if (!intel_pmc_is_assigned(pmc))
+ return;
+
+ wrmsrl(pmc->perf_event->hw.config_base, 0);
+}
+
+static void intel_pmu_enable_host_fixed_counter(struct kvm_pmc *pmc)
+{
+ struct kvm_pmu *pmu = vcpu_to_pmu(pmc->vcpu);
+ int host_idx = pmc->perf_event->hw.idx - INTEL_PMC_IDX_FIXED;
+ u64 ctrl_val, mask, bits = 0;
+
+ if (!intel_pmc_is_assigned(pmc))
+ return;
+
+ if (!pmc->perf_event->attr.precise_ip)
+ bits |= 0x8;
+ if (pmc->perf_event->hw.config & ARCH_PERFMON_EVENTSEL_USR)
+ bits |= 0x2;
+ if (pmc->perf_event->hw.config & ARCH_PERFMON_EVENTSEL_OS)
+ bits |= 0x1;
+
+ if (pmu->version > 2
+ && (pmc->perf_event->hw.config & ARCH_PERFMON_EVENTSEL_ANY))
+ bits |= 0x4;
+
+ bits <<= (host_idx * 4);
+ mask = 0xfULL << (host_idx * 4);
+
+ rdmsrl(pmc->perf_event->hw.config_base, ctrl_val);
+ ctrl_val &= ~mask;
+ ctrl_val |= bits;
+ wrmsrl(pmc->perf_event->hw.config_base, ctrl_val);
+}
+
+static void intel_pmu_disable_host_fixed_counter(struct kvm_pmc *pmc)
+{
+ u64 ctrl_val, mask = 0;
+ u8 host_idx;
+
+ if (!intel_pmc_is_assigned(pmc))
+ return;
+
+ host_idx = pmc->perf_event->hw.idx - INTEL_PMC_IDX_FIXED;
+ mask = 0xfULL << (host_idx * 4);
+ rdmsrl(pmc->perf_event->hw.config_base, ctrl_val);
+ ctrl_val &= ~mask;
+ wrmsrl(pmc->perf_event->hw.config_base, ctrl_val);
+}
+
+static void intel_pmu_update_host_fixed_ctrl(u64 new_ctrl, u8 host_idx)
+{
+ u64 host_ctrl, mask;
+
+ rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, host_ctrl);
+ mask = 0xfULL << (host_idx * 4);
+ host_ctrl &= ~mask;
+ new_ctrl <<= (host_idx * 4);
+ host_ctrl |= new_ctrl;
+ wrmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, host_ctrl);
+}
+
static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
{
int i;
--
1.8.3.1
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