[PATCH 1/2] KVM: x86/pmu: Define KVM_PMC_MAX_GENERIC for platform independence

Dapeng Mi
2024-06-19T02:20:23Z

The existing macro, KVM_INTEL_PMC_MAX_GENERIC, ambiguously represents the
maximum supported General Purpose (GP) counter number for both Intel and
AMD platforms. This could lead to issues if AMD begins to support more GP
counters than Intel.

To resolve this, a new platform-independent macro, KVM_PMC_MAX_GENERIC,
is introduced to represent the maximum GP counter number across all x86
platforms.

No logic changes are introduced in this patch.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/include/asm/kvm_host.h | 9 +++++----
arch/x86/kvm/svm/pmu.c | 2 +-
arch/x86/kvm/vmx/pmu_intel.c | 2 ++
3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 57440bda4dc4..18137be6504a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -534,11 +534,12 @@ struct kvm_pmc {

/* More counters may conflict with other existing Architectural MSRs */
#define KVM_INTEL_PMC_MAX_GENERIC 8
-#define MSR_ARCH_PERFMON_PERFCTR_MAX (MSR_ARCH_PERFMON_PERFCTR0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
-#define MSR_ARCH_PERFMON_EVENTSEL_MAX (MSR_ARCH_PERFMON_EVENTSEL0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
+#define KVM_AMD_PMC_MAX_GENERIC 6
+#define KVM_PMC_MAX_GENERIC KVM_INTEL_PMC_MAX_GENERIC
+#define MSR_ARCH_PERFMON_PERFCTR_MAX (MSR_ARCH_PERFMON_PERFCTR0 + KVM_PMC_MAX_GENERIC - 1)
+#define MSR_ARCH_PERFMON_EVENTSEL_MAX (MSR_ARCH_PERFMON_EVENTSEL0 + KVM_PMC_MAX_GENERIC - 1)
#define KVM_PMC_MAX_FIXED 3
#define MSR_ARCH_PERFMON_FIXED_CTR_MAX (MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_PMC_MAX_FIXED - 1)
-#define KVM_AMD_PMC_MAX_GENERIC 6

struct kvm_pmu {
u8 version;
@@ -554,7 +555,7 @@ struct kvm_pmu {
u64 global_status_rsvd;
u64 reserved_bits;
u64 raw_event_mask;
- struct kvm_pmc gp_counters[KVM_INTEL_PMC_MAX_GENERIC];
+ struct kvm_pmc gp_counters[KVM_PMC_MAX_GENERIC];
struct kvm_pmc fixed_counters[KVM_PMC_MAX_FIXED];

/*
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 6e908bdc3310..2fca247798eb 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -218,7 +218,7 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu)
int i;

BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > AMD64_NUM_COUNTERS_CORE);
- BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > INTEL_PMC_MAX_GENERIC);
+ BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > KVM_PMC_MAX_GENERIC);

for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC ; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index fb5cbd6cbeff..a4b0bee04596 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -570,6 +570,8 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);

+ BUILD_BUG_ON(KVM_INTEL_PMC_MAX_GENERIC > KVM_PMC_MAX_GENERIC);
+
for (i = 0; i < KVM_INTEL_PMC_MAX_GENERIC; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
pmu->gp_counters[i].vcpu = vcpu;
--
2.34.1