KVM: x86: use the KVM side max supported fixed counter

KVM vPMU doesn't support to emulate all the fixed counters that the
host PMU driver has supported, e.g. the fixed counter 3 used by
Topdown metrics hasn't been supported by KVM so far.

Rename MAX_FIXED_COUNTERS to KVM_PMC_MAX_FIXED to have a more
straightforward naming convention as INTEL_PMC_MAX_FIXED used by the
host PMU driver, and fix vPMU to use the KVM side KVM_PMC_MAX_FIXED
for the virtual fixed counter emulation, instead of the host side
INTEL_PMC_MAX_FIXED.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1643750603-100733-2-git-send-email-kan.liang@linux.intel.com

Author: wei-w-wang

arch/x86/include/asm/kvm_host.h

@@ -498,6 +498,7 @@ struct kvm_pmc {
 	bool intr;
 };
 
+#define KVM_PMC_MAX_FIXED	3
 struct kvm_pmu {
 	unsigned nr_arch_gp_counters;
 	unsigned nr_arch_fixed_counters;
@@ -511,7 +512,7 @@ struct kvm_pmu {
 	u64 reserved_bits;
 	u8 version;
 	struct kvm_pmc gp_counters[INTEL_PMC_MAX_GENERIC];
-	struct kvm_pmc fixed_counters[INTEL_PMC_MAX_FIXED];
+	struct kvm_pmc fixed_counters[KVM_PMC_MAX_FIXED];
 	struct irq_work irq_work;
 	DECLARE_BITMAP(reprogram_pmi, X86_PMC_IDX_MAX);
 	DECLARE_BITMAP(all_valid_pmc_idx, X86_PMC_IDX_MAX);

arch/x86/kvm/cpuid.c

@@ -875,7 +875,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		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.num_counters_fixed =
+			min(cap.num_counters_fixed, KVM_PMC_MAX_FIXED);
 		edx.split.bit_width_fixed = cap.bit_width_fixed;
 		if (cap.version)
 			edx.split.anythread_deprecated = 1;

arch/x86/kvm/pmu.h

@@ -15,8 +15,6 @@
 #define VMWARE_BACKDOOR_PMC_REAL_TIME		0x10001
 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME	0x10002
 
-#define MAX_FIXED_COUNTERS	3
-
 struct kvm_event_hw_type_mapping {
 	u8 eventsel;
 	u8 unit_mask;

arch/x86/kvm/vmx/pmu_intel.c

@@ -565,7 +565,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
 		pmu->gp_counters[i].current_config = 0;
 	}
 
-	for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) {
+	for (i = 0; i < KVM_PMC_MAX_FIXED; i++) {
 		pmu->fixed_counters[i].type = KVM_PMC_FIXED;
 		pmu->fixed_counters[i].vcpu = vcpu;
 		pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
@@ -591,7 +591,7 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
 		pmc->counter = pmc->eventsel = 0;
 	}
 
-	for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) {
+	for (i = 0; i < KVM_PMC_MAX_FIXED; i++) {
 		pmc = &pmu->fixed_counters[i];
 
 		pmc_stop_counter(pmc);

arch/x86/kvm/x86.c

@@ -6514,7 +6514,7 @@ static void kvm_init_msr_list(void)
 	u32 dummy[2];
 	unsigned i;
 
-	BUILD_BUG_ON_MSG(INTEL_PMC_MAX_FIXED != 4,
+	BUILD_BUG_ON_MSG(KVM_PMC_MAX_FIXED != 3,
 			 "Please update the fixed PMCs in msrs_to_saved_all[]");
 
 	perf_get_x86_pmu_capability(&x86_pmu);