If the cpuid10_eax.split.num_counters* from kvm_vcpu_ioctl_set_cpuid2
is larger than the host x86_pmu.num_counters_*, the min_t() is applied.
We need do cpuid synchronisation locally for cpuid10 entry to avoid
functional ambiguity and it's heavyweight to call kvm_update_cpuid for
these simple assignments.
Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx/pmu_intel.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 3e9c059099e9..f83b7506dcff 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -266,6 +266,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
struct kvm_cpuid_entry2 *entry;
union cpuid10_eax eax;
union cpuid10_edx edx;
+ bool cpuid_update_needed = false;
pmu->nr_arch_gp_counters = 0;
pmu->nr_arch_fixed_counters = 0;
@@ -288,6 +289,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
x86_pmu.num_counters_gp);
+ if (pmu->nr_arch_gp_counters != eax.split.num_counters)
+ cpuid_update_needed = true;
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1;
pmu->available_event_types = ~entry->ebx &
((1ull << eax.split.mask_length) - 1);
@@ -298,6 +301,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->nr_arch_fixed_counters =
min_t(int, edx.split.num_counters_fixed,
x86_pmu.num_counters_fixed);
+ if (pmu->nr_arch_fixed_counters != edx.split.num_counters_fixed)
+ cpuid_update_needed = true;
pmu->counter_bitmask[KVM_PMC_FIXED] =
((u64)1 << edx.split.bit_width_fixed) - 1;
}
@@ -317,6 +322,13 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
(boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
(entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM)))
pmu->reserved_bits ^= HSW_IN_TX|HSW_IN_TX_CHECKPOINTED;
+
+ if (cpuid_update_needed) {
+ ((union cpuid10_eax *)&entry->eax)->split.num_counters
+ = pmu->nr_arch_gp_counters;
+ ((union cpuid10_edx *)&entry->edx)->split.num_counters_fixed
+ = pmu->nr_arch_fixed_counters;
+ }
}
static void intel_pmu_init(struct kvm_vcpu *vcpu)
--
2.21.0
