[PATCH V3 3/4] KVM: x86/vPMU: Implement AMD vPMU code for KVM

[Wei Huang <wei@redhat.com>]

This patch replaces the empty AMD vPMU functions (in pmu_amd.c) with real
implementation.

Signed-off-by: Wei Huang <wei@redhat.com>
---
 arch/x86/kvm/pmu_amd.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 116 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/pmu_amd.c b/arch/x86/kvm/pmu_amd.c
index 95fbb8f..15e8d4a 100644
--- a/arch/x86/kvm/pmu_amd.c
+++ b/arch/x86/kvm/pmu_amd.c
@@ -19,11 +19,33 @@
 #include "lapic.h"
 #include "pmu.h"
 
+/* duplicated from amd_perfmon_event_map, K7 and above should work. */
+static struct kvm_event_hw_type_mapping amd_event_mapping[] = {
+	[0] = { 0x76, 0x00, PERF_COUNT_HW_CPU_CYCLES },
+	[1] = { 0xc0, 0x00, PERF_COUNT_HW_INSTRUCTIONS },
+	[2] = { 0x80, 0x00, PERF_COUNT_HW_CACHE_REFERENCES },
+	[3] = { 0x81, 0x00, PERF_COUNT_HW_CACHE_MISSES },
+	[4] = { 0xc2, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
+	[5] = { 0xc3, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
+	[6] = { 0xd0, 0x00, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND },
+	[7] = { 0xd1, 0x00, PERF_COUNT_HW_STALLED_CYCLES_BACKEND },
+};
+
 static unsigned amd_find_arch_event(struct kvm_pmu *pmu,
 				    u8 event_select,
 				    u8 unit_mask)
 {
-	return PERF_COUNT_HW_MAX;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
+		if (amd_event_mapping[i].eventsel == event_select
+		    && amd_event_mapping[i].unit_mask == unit_mask)
+			break;
+
+	if (i == ARRAY_SIZE(amd_event_mapping))
+		return PERF_COUNT_HW_MAX;
+
+	return amd_event_mapping[i].event_type;
 }
 
 /* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
@@ -32,53 +54,141 @@ static unsigned amd_find_fixed_event(int idx)
 	return PERF_COUNT_HW_MAX;
 }
 
+/* check if a PMC is enabled by comparing it against global_ctrl bits. Because
+ * AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
+ */
 static bool amd_pmc_enabled(struct kvm_pmc *pmc)
 {
-	return false;
+	return true;
 }
 
 static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
 {
-	return NULL;
+	return get_gp_pmc(pmu, MSR_K7_EVNTSEL0 + pmc_idx, MSR_K7_EVNTSEL0);
 }
 
 /* returns 0 if idx's corresponding MSR exists; otherwise returns 1. */
 static int amd_check_msr(struct kvm_vcpu *vcpu, unsigned idx)
 {
-	return 1;
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+
+	idx &= ~(3u << 30);
+
+	return (idx >= pmu->nr_arch_gp_counters);
 }
 
 /* idx is the ECX register of RDPMC instruction */
 static struct kvm_pmc *amd_msr_to_pmc(struct kvm_vcpu *vcpu, unsigned idx)
 {
-	return NULL;
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *counters;
+
+	idx &= ~(3u << 30);
+	if (idx >= pmu->nr_arch_gp_counters)
+		return NULL;
+	counters = pmu->gp_counters;
+
+	return &counters[idx];
 }
 
 static bool amd_is_pmu_msr(struct kvm_vcpu *vcpu, u32 msr)
 {
-	return false;
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	int ret = false;
+
+	ret = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0) ||
+		get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
+
+	return ret;
 }
 
 static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *pmc;
+
+	/* MSR_K7_PERFCTRn */
+	pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
+	if (pmc) {
+		*data = pmc_read_counter(pmc);
+		return 0;
+	}
+	/* MSR_K7_EVNTSELn */
+	pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
+	if (pmc) {
+		*data = pmc->eventsel;
+		return 0;
+	}
+
 	return 1;
 }
 
 static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *pmc;
+	u32 msr = msr_info->index;
+	u64 data = msr_info->data;
+
+	/* MSR_K7_PERFCTRn */
+	pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
+	if (pmc) {
+		if (!msr_info->host_initiated)
+			data = (s64)data;
+		pmc->counter += data - pmc_read_counter(pmc);
+		return 0;
+	}
+	/* MSR_K7_EVNTSELn */
+	pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
+	if (pmc) {
+		if (data == pmc->eventsel)
+			return 0;
+		if (!(data & pmu->reserved_bits)) {
+			reprogram_gp_counter(pmc, data);
+			return 0;
+		}
+	}
+
 	return 1;
 }
 
 static void amd_pmu_refresh(struct kvm_vcpu *vcpu)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+
+	pmu->nr_arch_gp_counters = AMD64_NUM_COUNTERS;
+	pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1;
+	pmu->reserved_bits = 0xffffffff00200000ull;
+	/* not applicable to AMD; but clean them to prevent any fall out */
+	pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
+	pmu->nr_arch_fixed_counters = 0;
+	pmu->version = 0;
+	pmu->global_status = 0;
 }
 
 static void amd_pmu_init(struct kvm_vcpu *vcpu)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	int i;
+
+	for (i = 0; i < AMD64_NUM_COUNTERS ; i++) {
+		pmu->gp_counters[i].type = KVM_PMC_GP;
+		pmu->gp_counters[i].vcpu = vcpu;
+		pmu->gp_counters[i].idx = i;
+	}
 }
 
 static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 {
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	int i;
+
+	for (i = 0; i < AMD64_NUM_COUNTERS; i++) {
+		struct kvm_pmc *pmc = &pmu->gp_counters[i];
+
+		pmc_stop_counter(pmc);
+		pmc->counter = pmc->eventsel = 0;
+	}
 }
 
 struct kvm_pmu_ops amd_pmu_ops = {
-- 
1.8.3.1