[PATCH v1 5/8] KVM/x86/vPMU: intel_pmu_read_pmc

[Wei Wang]

This patch adds the handling of guest rdpmc. If the physical counter has
been assigned, directly reads the value from the hardware. Otherwise,
return to the guest the virtual counter value.

Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
 arch/x86/kvm/pmu.c       |  3 +++
 arch/x86/kvm/pmu.h       |  1 +
 arch/x86/kvm/pmu_intel.c | 27 +++++++++++++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 58ead7d..7f2f63e 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -284,6 +284,9 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 	struct kvm_pmc *pmc;
 	u64 ctr_val;
 
+	if (kvm_x86_ops->pmu_ops->read_pmc)
+		return kvm_x86_ops->pmu_ops->read_pmc(vcpu, idx, data);
+
 	if (is_vmware_backdoor_pmc(idx))
 		return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
 
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index b3b0238..7ab85bf 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -30,6 +30,7 @@ struct kvm_pmu_ops {
 	bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr);
 	int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
 	int (*set_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
+	int (*read_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *data);
 	void (*refresh)(struct kvm_vcpu *vcpu);
 	void (*init)(struct kvm_vcpu *vcpu);
 	void (*reset)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/pmu_intel.c b/arch/x86/kvm/pmu_intel.c
index 2be31ad..4c6183b 100644
--- a/arch/x86/kvm/pmu_intel.c
+++ b/arch/x86/kvm/pmu_intel.c
@@ -20,6 +20,9 @@
 #include "lapic.h"
 #include "pmu.h"
 
+#define INTEL_PMU_RDPMC_FIXED_PMC (1ULL << 30)
+#define INTEL_PMU_RDPMC_COUNTER_MASK (INTEL_PMU_RDPMC_FIXED_PMC - 1)
+
 static struct kvm_event_hw_type_mapping intel_arch_events[] = {
 	/* Index must match CPUID 0x0A.EBX bit vector */
 	[0] = { 0x3c, 0x00, PERF_COUNT_HW_CPU_CYCLES },
@@ -409,6 +412,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	return 1;
 }
 
+static int intel_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned int idx,
+			      u64 *data)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	unsigned int pmc_idx;
+
+	if (idx & INTEL_PMU_RDPMC_FIXED_PMC)
+		pmc_idx = INTEL_PMC_IDX_FIXED +
+			  (idx & INTEL_PMU_RDPMC_COUNTER_MASK);
+	else
+		pmc_idx = idx & INTEL_PMU_RDPMC_COUNTER_MASK;
+
+	if (test_bit(pmc_idx,
+		(unsigned long *)&pmu->assigned_pmc_bitmap))
+		rdpmcl(idx, *data);
+	else {
+		struct kvm_pmc *pmc = intel_pmc_idx_to_pmc(pmu, pmc_idx);
+		*data = pmc->counter;
+	}
+
+	return 0;
+}
+
 static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -530,6 +556,7 @@ struct kvm_pmu_ops intel_pmu_ops = {
 	.is_valid_msr = intel_is_valid_msr,
 	.get_msr = intel_pmu_get_msr,
 	.set_msr = intel_pmu_set_msr,
+	.read_pmc = intel_pmu_read_pmc,
 	.refresh = intel_pmu_refresh,
 	.init = intel_pmu_init,
 	.reset = intel_pmu_reset,
-- 
2.7.4