KVM: x86/vPMU: introduce kvm_pmu_msr_idx_to_pmc

This function will be part of the kvm_pmu_ops interface.  Introduce
it already.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index f38ad84..bd5dbd9 100644 (file)
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -348,22 +348,34 @@ int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
                (fixed && idx >= pmu->nr_arch_fixed_counters);
 }
 
-int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
+static struct kvm_pmc *kvm_pmu_msr_idx_to_pmc(struct kvm_vcpu *vcpu,
+                                            unsigned idx)
 {
        struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
-       bool fast_mode = idx & (1u << 31);
        bool fixed = idx & (1u << 30);
        struct kvm_pmc *counters;
-       u64 ctr_val;
 
        idx &= ~(3u << 30);
        if (!fixed && idx >= pmu->nr_arch_gp_counters)
-               return 1;
+               return NULL;
        if (fixed && idx >= pmu->nr_arch_fixed_counters)
-               return 1;
+               return NULL;
        counters = fixed ? pmu->fixed_counters : pmu->gp_counters;
 
-       ctr_val = pmc_read_counter(&counters[idx]);
+       return &counters[idx];
+}
+
+int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
+{
+       bool fast_mode = idx & (1u << 31);
+       struct kvm_pmc *pmc;
+       u64 ctr_val;
+
+       pmc = kvm_pmu_msr_idx_to_pmc(vcpu, idx);
+       if (!pmc)
+               return 1;
+
+       ctr_val = pmc_read_counter(pmc);
        if (fast_mode)
                ctr_val = (u32)ctr_val;