[PATCH V7 16/18] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability

Zhu Lingshan
2021-06-22T09:44:52Z

From: Like Xu <like.xu@linux.intel.com>

The information obtained from the interface perf_get_x86_pmu_capability()
doesn't change, so an exported "struct x86_pmu_capability" is introduced
for all guests in the KVM, and it's initialized before hardware_setup().

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
arch/x86/kvm/cpuid.c | 24 +++++++-----------------
arch/x86/kvm/pmu.c | 3 +++
arch/x86/kvm/pmu.h | 20 ++++++++++++++++++++
arch/x86/kvm/vmx/pmu_intel.c | 17 ++++++++---------
arch/x86/kvm/x86.c | 9 ++++-----
5 files changed, 42 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 9a48f138832d..a654fac41c22 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -744,32 +744,22 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
case 9:
break;
case 0xa: { /* Architectural Performance Monitoring */
- struct x86_pmu_capability cap;
union cpuid10_eax eax;
union cpuid10_edx edx;

- perf_get_x86_pmu_capability(&cap);
+ eax.split.version_id = kvm_pmu_cap.version;
+ eax.split.num_counters = kvm_pmu_cap.num_counters_gp;
+ eax.split.bit_width = kvm_pmu_cap.bit_width_gp;
+ eax.split.mask_length = kvm_pmu_cap.events_mask_len;

- /*
- * Only support guest architectural pmu on a host
- * with architectural pmu.
- */
- if (!cap.version)
- memset(&cap, 0, sizeof(cap));
-
- eax.split.version_id = min(cap.version, 2);
- eax.split.num_counters = cap.num_counters_gp;
- eax.split.bit_width = cap.bit_width_gp;
- eax.split.mask_length = cap.events_mask_len;
-
- edx.split.num_counters_fixed = min(cap.num_counters_fixed, MAX_FIXED_COUNTERS);
- edx.split.bit_width_fixed = cap.bit_width_fixed;
+ edx.split.num_counters_fixed = kvm_pmu_cap.num_counters_fixed;
+ edx.split.bit_width_fixed = kvm_pmu_cap.bit_width_fixed;
edx.split.anythread_deprecated = 1;
edx.split.reserved1 = 0;
edx.split.reserved2 = 0;

entry->eax = eax.full;
- entry->ebx = cap.events_mask;
+ entry->ebx = kvm_pmu_cap.events_mask;
entry->ecx = 0;
entry->edx = edx.full;
break;
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index d957c1e83ec9..ec10a635b057 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -19,6 +19,9 @@
#include "lapic.h"
#include "pmu.h"

+struct x86_pmu_capability __read_mostly kvm_pmu_cap;
+EXPORT_SYMBOL_GPL(kvm_pmu_cap);
+
/* This is enough to filter the vast majority of currently defined events. */
#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300

diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 5795bb113e76..1903c0fe01ca 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -160,6 +160,24 @@ static inline bool pmc_speculative_in_use(struct kvm_pmc *pmc)
return pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE;
}

+extern struct x86_pmu_capability kvm_pmu_cap;
+
+static inline void kvm_init_pmu_capability(void)
+{
+ perf_get_x86_pmu_capability(&kvm_pmu_cap);
+
+ /*
+ * Only support guest architectural pmu on
+ * a host with architectural pmu.
+ */
+ if (!kvm_pmu_cap.version)
+ memset(&kvm_pmu_cap, 0, sizeof(kvm_pmu_cap));
+
+ kvm_pmu_cap.version = min(kvm_pmu_cap.version, 2);
+ kvm_pmu_cap.num_counters_fixed = min(kvm_pmu_cap.num_counters_fixed,
+ MAX_FIXED_COUNTERS);
+}
+
void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel);
void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int fixed_idx);
void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx);
@@ -177,9 +195,11 @@ void kvm_pmu_init(struct kvm_vcpu *vcpu);
void kvm_pmu_cleanup(struct kvm_vcpu *vcpu);
void kvm_pmu_destroy(struct kvm_vcpu *vcpu);
int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp);
+void kvm_init_pmu_capability(void);

bool is_vmware_backdoor_pmc(u32 pmc_idx);

extern struct kvm_pmu_ops intel_pmu_ops;
extern struct kvm_pmu_ops amd_pmu_ops;
+
#endif /* __KVM_X86_PMU_H */
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 28152d7fd12d..d0610716675b 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -504,8 +504,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
-
- struct x86_pmu_capability x86_pmu;
struct kvm_cpuid_entry2 *entry;
union cpuid10_eax eax;
union cpuid10_edx edx;
@@ -532,13 +530,14 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
return;

vcpu->arch.ia32_misc_enable_msr |= MSR_IA32_MISC_ENABLE_EMON;
- perf_get_x86_pmu_capability(&x86_pmu);

pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
- x86_pmu.num_counters_gp);
- eax.split.bit_width = min_t(int, eax.split.bit_width, x86_pmu.bit_width_gp);
+ kvm_pmu_cap.num_counters_gp);
+ eax.split.bit_width = min_t(int, eax.split.bit_width,
+ kvm_pmu_cap.bit_width_gp);
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1;
- eax.split.mask_length = min_t(int, eax.split.mask_length, x86_pmu.events_mask_len);
+ eax.split.mask_length = min_t(int, eax.split.mask_length,
+ kvm_pmu_cap.events_mask_len);
pmu->available_event_types = ~entry->ebx &
((1ull << eax.split.mask_length) - 1);

@@ -547,9 +546,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
} else {
pmu->nr_arch_fixed_counters =
min_t(int, edx.split.num_counters_fixed,
- x86_pmu.num_counters_fixed);
- edx.split.bit_width_fixed = min_t(int,
- edx.split.bit_width_fixed, x86_pmu.bit_width_fixed);
+ kvm_pmu_cap.num_counters_fixed);
+ edx.split.bit_width_fixed = min_t(int, edx.split.bit_width_fixed,
+ kvm_pmu_cap.bit_width_fixed);
pmu->counter_bitmask[KVM_PMC_FIXED] =
((u64)1 << edx.split.bit_width_fixed) - 1;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8a905c098787..096593956e1a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5971,15 +5971,12 @@ long kvm_arch_vm_ioctl(struct file *filp,

static void kvm_init_msr_list(void)
{
- struct x86_pmu_capability x86_pmu;
u32 dummy[2];
unsigned i;

BUILD_BUG_ON_MSG(INTEL_PMC_MAX_FIXED != 4,
"Please update the fixed PMCs in msrs_to_saved_all[]");

- perf_get_x86_pmu_capability(&x86_pmu);
-
num_msrs_to_save = 0;
num_emulated_msrs = 0;
num_msr_based_features = 0;
@@ -6031,12 +6028,12 @@ static void kvm_init_msr_list(void)
break;
case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + 17:
if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_PERFCTR0 >=
- min(INTEL_PMC_MAX_GENERIC, x86_pmu.num_counters_gp))
+ min(INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
continue;
break;
case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 17:
if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >=
- min(INTEL_PMC_MAX_GENERIC, x86_pmu.num_counters_gp))
+ min(INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
continue;
break;
default:
@@ -10632,6 +10629,8 @@ int kvm_arch_hardware_setup(void *opaque)
if (boot_cpu_has(X86_FEATURE_XSAVES))
rdmsrl(MSR_IA32_XSS, host_xss);

+ kvm_init_pmu_capability();
+
r = ops->hardware_setup();
if (r != 0)
return r;
--
2.27.0