[PATCH v3 2/3] x86/kvm: Add support for AMD Core Perf Extension in guest

From: Janakarajan Natarajan
Date: Fri Dec 08 2017 - 17:40:18 EST

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Add support for AMD Core Performance counters in the guest. The base
event select and counter MSRs are changed. In addition, with the core
extension, there are 2 extra counters available for performance
measurements for a total of 6.

With the new MSRs, the logic to map them to the gp_counters[] is changed.
New functions are added to check the validity of the get/set MSRs.

If the guest has the X86_FEATURE_PERFCTR_CORE cpuid flag set, the number
of counters available to the vcpu is set to 6. It the flag is not set
then it is 4.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@xxxxxxx>
---
arch/x86/kvm/pmu_amd.c | 140 ++++++++++++++++++++++++++++++++++++++++++++-----
arch/x86/kvm/x86.c | 1 +
2 files changed, 127 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/pmu_amd.c b/arch/x86/kvm/pmu_amd.c
index cd94443..233354a 100644
--- a/arch/x86/kvm/pmu_amd.c
+++ b/arch/x86/kvm/pmu_amd.c
@@ -19,6 +19,21 @@
#include "lapic.h"
#include "pmu.h"

+enum pmu_type {
+ PMU_TYPE_COUNTER = 0,
+ PMU_TYPE_EVNTSEL,
+};
+
+enum index {
+ INDEX_ZERO = 0,
+ INDEX_ONE,
+ INDEX_TWO,
+ INDEX_THREE,
+ INDEX_FOUR,
+ INDEX_FIVE,
+ INDEX_ERROR,
+};
+
/* 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 },
@@ -31,6 +46,88 @@ static struct kvm_event_hw_type_mapping amd_event_mapping[] = {
[7] = { 0xd1, 0x00, PERF_COUNT_HW_STALLED_CYCLES_BACKEND },
};

+static unsigned int get_msr_base(struct kvm_pmu *pmu, enum pmu_type type)
+{
+ struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
+
+ if (guest_cpuid_has(vcpu, X86_FEATURE_PERFCTR_CORE)) {
+ if (type == PMU_TYPE_COUNTER)
+ return MSR_F15H_PERF_CTR;
+ else
+ return MSR_F15H_PERF_CTL;
+ } else {
+ if (type == PMU_TYPE_COUNTER)
+ return MSR_K7_PERFCTR0;
+ else
+ return MSR_K7_EVNTSEL0;
+ }
+}
+
+static enum index msr_to_index(u32 msr)
+{
+ switch (msr) {
+ case MSR_F15H_PERF_CTL0:
+ case MSR_F15H_PERF_CTR0:
+ case MSR_K7_EVNTSEL0:
+ case MSR_K7_PERFCTR0:
+ return INDEX_ZERO;
+ case MSR_F15H_PERF_CTL1:
+ case MSR_F15H_PERF_CTR1:
+ case MSR_K7_EVNTSEL1:
+ case MSR_K7_PERFCTR1:
+ return INDEX_ONE;
+ case MSR_F15H_PERF_CTL2:
+ case MSR_F15H_PERF_CTR2:
+ case MSR_K7_EVNTSEL2:
+ case MSR_K7_PERFCTR2:
+ return INDEX_TWO;
+ case MSR_F15H_PERF_CTL3:
+ case MSR_F15H_PERF_CTR3:
+ case MSR_K7_EVNTSEL3:
+ case MSR_K7_PERFCTR3:
+ return INDEX_THREE;
+ case MSR_F15H_PERF_CTL4:
+ case MSR_F15H_PERF_CTR4:
+ return INDEX_FOUR;
+ case MSR_F15H_PERF_CTL5:
+ case MSR_F15H_PERF_CTR5:
+ return INDEX_FIVE;
+ default:
+ return INDEX_ERROR;
+ }
+}
+
+static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
+ enum pmu_type type)
+{
+ switch (msr) {
+ case MSR_F15H_PERF_CTL0:
+ case MSR_F15H_PERF_CTL1:
+ case MSR_F15H_PERF_CTL2:
+ case MSR_F15H_PERF_CTL3:
+ case MSR_F15H_PERF_CTL4:
+ case MSR_F15H_PERF_CTL5:
+ case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3:
+ if (type != PMU_TYPE_EVNTSEL)
+ return NULL;
+ break;
+ case MSR_F15H_PERF_CTR0:
+ case MSR_F15H_PERF_CTR1:
+ case MSR_F15H_PERF_CTR2:
+ case MSR_F15H_PERF_CTR3:
+ case MSR_F15H_PERF_CTR4:
+ case MSR_F15H_PERF_CTR5:
+ case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
+ if (type != PMU_TYPE_COUNTER)
+ return NULL;
+ break;
+ default:
+ return NULL;
+ }
+
+ return &pmu->gp_counters[msr_to_index(msr)];
+}
+
static unsigned amd_find_arch_event(struct kvm_pmu *pmu,
u8 event_select,
u8 unit_mask)
@@ -64,7 +161,18 @@ static bool amd_pmc_is_enabled(struct kvm_pmc *pmc)

static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
{
- return get_gp_pmc(pmu, MSR_K7_EVNTSEL0 + pmc_idx, MSR_K7_EVNTSEL0);
+ unsigned int base = get_msr_base(pmu, PMU_TYPE_COUNTER);
+ struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
+
+ if (guest_cpuid_has(vcpu, X86_FEATURE_PERFCTR_CORE)) {
+ /*
+ * The idx is contiguous. The MSRs are not. The counter MSRs
+ * are interleaved with the event select MSRs.
+ */
+ pmc_idx *= 2;
+ }
+
+ return get_gp_pmc_amd(pmu, base + pmc_idx, PMU_TYPE_COUNTER);
}

/* returns 0 if idx's corresponding MSR exists; otherwise returns 1. */
@@ -96,8 +204,8 @@ static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
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);
+ ret = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER) ||
+ get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);

return ret;
}
@@ -107,14 +215,14 @@ 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);
+ /* MSR_PERFCTRn */
+ pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER);
if (pmc) {
*data = pmc_read_counter(pmc);
return 0;
}
- /* MSR_K7_EVNTSELn */
- pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
+ /* MSR_EVNTSELn */
+ pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);
if (pmc) {
*data = pmc->eventsel;
return 0;
@@ -130,14 +238,14 @@ static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
u32 msr = msr_info->index;
u64 data = msr_info->data;

- /* MSR_K7_PERFCTRn */
- pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
+ /* MSR_PERFCTRn */
+ pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER);
if (pmc) {
pmc->counter += data - pmc_read_counter(pmc);
return 0;
}
- /* MSR_K7_EVNTSELn */
- pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
+ /* MSR_EVNTSELn */
+ pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);
if (pmc) {
if (data == pmc->eventsel)
return 0;
@@ -154,7 +262,11 @@ 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;
+ if (guest_cpuid_has(vcpu, X86_FEATURE_PERFCTR_CORE))
+ pmu->nr_arch_gp_counters = AMD64_NUM_COUNTERS_CORE;
+ else
+ 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 */
@@ -169,7 +281,7 @@ 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++) {
+ for (i = 0; i < AMD64_NUM_COUNTERS_CORE ; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
pmu->gp_counters[i].vcpu = vcpu;
pmu->gp_counters[i].idx = i;
@@ -181,7 +293,7 @@ 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++) {
+ for (i = 0; i < AMD64_NUM_COUNTERS_CORE; i++) {
struct kvm_pmc *pmc = &pmu->gp_counters[i];

pmc_stop_counter(pmc);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6ca747a..5a32e17 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2451,6 +2451,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_AMD64_DC_CFG:
msr_info->data = 0;
break;
+ case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3:
case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1:
--
2.7.4

Next message: Dave Chinner: "Re: Lockdep is less useful than it was"
Previous message: Janakarajan Natarajan: "[PATCH v3 0/3] Support Perf Extension on AMD KVM guests"
In reply to: Janakarajan Natarajan: "[PATCH v3 3/3] x86/kvm: Expose AMD Core Perf Extension flag to guests"
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